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  • 1. Banks, S. D.
    et al.
    Murray, N.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Logan, J. G.
    Insecticide-treated clothes for the control of vector-borne diseases: a review on effectiveness and safety2014In: Medical and Veterinary Entomology, ISSN 0269-283X, E-ISSN 1365-2915, Vol. 28, no S1, p. 14-25Article, review/survey (Refereed)
    Abstract [en]

    Insecticide-treated clothing has been used for many years by the military and in recreational activities as personal protection against bites from a variety of arthropods including ticks, chigger mites, sandflies and mosquitoes. Permethrin is the most commonly used active ingredient, but others, including bifenthrin, deltamethrin, cyfluthrin, DEET (N,N-diethyl-3-methylbenz-amide) and KBR3023, have also been trialled. Treatment is usually carried out by home or factory dipping. However, new microencapsulation technologies which may prolong the activity of insecticides on clothing are now available and may help to overcome the inevitable reduction in efficacy over time that occurs as a result of washing, ultraviolet light exposure, and the normal wear and tear of the fabric. The aim of this article is to review the evidence base for the use of insecticide-treated clothing for protection against bites from arthropods and its effect on arthropod-borne pathogen transmission. Although some studies do demonstrate protection against pathogen transmission, there are surprisingly few, and the level of protection provided varies according to the disease and the type of study conducted. For example, insecticide-treated clothing has been reported to give between 0% and 75% protection against malaria and between 0% and 79% protection against leishmaniasis. Studies vary in the type of treatment used, the age group of participants, the geographical location of the study, and the pathogen transmission potential. This makes it difficult to compare and assess intervention trials. Overall, there is substantial evidence that insecticide-treated clothing can provide protection against arthropod bites. Bite protection evidence suggests that insecticide-treated clothing may be useful in the prevention of pathogen transmission, but further investigations are required to accurately demonstrate transmission reduction.

  • 2. Banks, S De Raedt
    et al.
    Orsborne, J
    Gezan, S A
    Kaur, H
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore City, Singapore.
    Lindsey, S W
    Logan, J G
    Permethrin-treated clothing as protection against the dengue vector, Aedes aegypti: extent and duration of protection2015In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 20, no Suppl. 1, p. 399-400Article in journal (Other academic)
    Abstract [en]

    Background: 3900 million people globally are at risk of dengue fever infection, with its distribution increasing rapidly over the past 50 years. Since the primary vector, Aedes aegypti, is exophilic and most active during the day, personal protection technologies, such as insecticide treated clothing, could provide significant protection from mosquito bites.

    Methods: World Health Organisation Pesticide Evaluation Scheme (WHOPES) cone and arm-in-cage assays were used to assess protection, knockdown and mortality against factory, home-dipped and microencapsulated permethrin-treated fabrics using Ae. aegypti mosquitoes. Factory-treated clothing was then analysed further to investigate the effects of insecticide resistance, clothing coverage, washing, Ultra-violet light and ironing.

    Results: Factory-treated clothing showed the greatest protective effect (1 h KD 96.5% and 24 h mortality 97.1%), landing protection (59% (95% CI = 49.2–66.9) and bite protection (100%). Landing and biting protection reduced significantly from 58.9% to 18.5% and 28.6% to 11.1% after 10 washes for simulated hand washing. Resistance to permethrin had no effect on the efficacy of the clothing, with coverage playing an important role. Full coverage provided the highest protection (79.4% landing protection, 100% biting protection). Free flight room assays showed no difference in landing protection between the two coverage types but bite protection was significantly greater (>90%) with full coverage. HPLC confirmed ironing reduced permethrin content after 1 week simulated use, with a 96.7% decrease after 3 months. UV exposure was shown to have no effect.

    Conclusion: Insecticide treated clothing can provide significant biting and landing protection, even in a resistant strain. However, our findings also suggest that clothing may provide only short-term protection due to the effect of washing and ironing, highlighting the need for improved clothing treatment techniques.

    Disclosure: Nothing to disclose.

  • 3. Boggild, Andrea K
    et al.
    Castelli, Francesco
    Gautret, Philippe
    Torresi, Joseph
    von Sonnenburg, Frank
    Barnett, Elizabeth D
    Greenaway, Christina A
    Lim, Poh-Lian
    Schwartz, Eli
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    Wilson, Mary E
    Latitudinal patterns of travel among returned travelers with influenza: results from the GeoSentinel Surveillance Network, 1997-2007.2012In: Journal of Travel Medicine, ISSN 1195-1982, E-ISSN 1708-8305, Vol. 19, no 1, p. 4-8Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Influenza is a common vaccine-preventable disease among international travelers, but few data exist to guide use of reciprocal hemisphere or out-of-season vaccines.

    METHODS: We analyzed records of ill-returned travelers in the GeoSentinel Surveillance Network to determine latitudinal travel patterns in those who acquired influenza abroad.

    RESULTS: Among 37,542 ill-returned travelers analyzed, 59 were diagnosed with influenza A and 11 with influenza B. Half of travelers from temperate regions to the tropics departed outside influenza season. Twelve travelers crossed hemispheres from one temperate region to another, five during influenza season. Ten of 12 travelers (83%) with influenza who crossed hemispheres were managed as inpatients. Proportionate morbidity estimates for influenza A acquisition were highest for travel to the East-Southeast Asian influenza circulation network with 6.13 (95% CI 4.5-8.2) cases per 1000 ill-returned travelers, a sevenfold increased proportionate morbidity compared to travel outside the network.

    CONCLUSIONS: Alternate hemisphere and out-of-season influenza vaccine availability may benefit a small proportion of travelers. Proportionate morbidity estimates by region of travel can inform pre-travel consultation and emphasize the ease of acquisition of infections such as influenza during travel.

  • 4. Chen, Lin H
    et al.
    Hill, David R
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    Vaccination of travelers: how far have we come and where are we going?2011In: Expert review of vaccines, ISSN 1744-8395, Vol. 10, no 11, p. 1609-20Article in journal (Refereed)
    Abstract [en]

    Vaccine recommendations are a prominent part of health preparations before international travel. We review progress made in the past decade regarding vaccines used primarily by persons traveling from high-income countries to low- and middle-income countries. The combined hepatitis A-B vaccine, the recently licensed Vero cell-derived Japanese encephalitis vaccine and conjugated quadrivalent meningococcal vaccines are discussed. This article provides updates on yellow fever vaccine-associated visceral and neurologic adverse events, indications for influenza vaccine in travelers, the rapid immunization schedule for tick-borne encephalitis vaccine, schedules for postexposure rabies prophylaxis, and new insights about oral cholera vaccines following the outbreak in Haiti. The future should bring vaccines for serogroup B Neiserria meningitidis, dengue and malaria, as well as an inactivated yellow fever vaccine.

  • 5. DeRaedt Banks, Sarah
    et al.
    Orsborne, James
    Gezan, Salvador A
    Kaur, Harparkash
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Lindsey, Steve W
    Logan, James G
    Permethrin-Treated Clothing as Protection against the Dengue Vector, Aedes aegypti: Extent and Duration of Protection2015In: PLoS Neglected Tropical Diseases, ISSN 1935-2727, E-ISSN 1935-2735, Vol. 9, no 10, article id e0004109Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: Dengue transmission by the mosquito vector, Aedes aegypti, occurs indoors and outdoors during the day. Personal protection of individuals, particularly when outside, is challenging. Here we assess the efficacy and durability of different types of insecticide-treated clothing on laboratory-reared Ae. aegypti.

    METHODS: Standardised World Health Organisation Pesticide Evaluation Scheme (WHOPES) cone tests and arm-in-cage assays were used to assess knockdown (KD) and mortality of Ae. aegypti tested against factory-treated fabric, home-dipped fabric and microencapsulated fabric. Based on the testing of these three different treatment types, the most protective was selected for further analysis using arm-in cage assays with the effect of washing, ultra-violet light, and ironing investigated using high pressure liquid chromatography.

    RESULTS: Efficacy varied between the microencapsulated and factory dipped fabrics in cone testing. Factory-dipped clothing showed the greatest effect on KD (3 min 38.1%; 1 hour 96.5%) and mortality (97.1%) with no significant difference between this and the factory dipped school uniforms. Factory-dipped clothing was therefore selected for further testing. Factory dipped clothing provided 59% (95% CI = 49.2%- 66.9%) reduction in landing and a 100% reduction in biting in arm-in-cage tests. Washing duration and technique had a significant effect, with insecticidal longevity shown to be greater with machine washing (LW50 = 33.4) compared to simulated hand washing (LW50 = 17.6). Ironing significantly reduced permethrin content after 1 week of simulated use, with a 96.7% decrease after 3 months although UV exposure did not reduce permethrin content within clothing significantly after 3 months simulated use.

    CONCLUSION: Permethrin-treated clothing may be a promising intervention in reducing dengue transmission. However, our findings also suggest that clothing may provide only short-term protection due to the effect of washing and ironing, highlighting the need for improved fabric treatment techniques.

  • 6. Earnest, A
    et al.
    Tan, S B
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    Meteorological factors and El Niño Southern Oscillation are independently associated with dengue infections2012In: Epidemiology and Infection, ISSN 0950-2688, E-ISSN 1469-4409, Vol. 140, no 07, p. 1244-1251Article in journal (Refereed)
    Abstract [en]

    Our objective was to determine the association between temperature, humidity, rainfall and dengue activity in Singapore, after taking into account lag periods as well as long-term climate variability such as the El Niño Southern Oscillation Index (SOI). We used a Poisson model which allowed for autocorrelation and overdispersion in the data. We found weekly mean temperature and mean relative humidity as well as SOI to be significantly and independently associated with dengue notifications. There was an interaction effect by periods of dengue outbreaks, but periods where El Niño was present did not moderate the relationship between humidity and temperature with dengue notifications. Our results help to understand the temporal trends of dengue in Singapore, and further reinforce the findings that meteorological factors are important in the epidemiology of dengue.

  • 7. Flores-Figueroa, Jose
    et al.
    Okhuysen, Pablo C
    von Sonnenburg, Frank
    DuPont, Herbert L
    Libman, Michael D
    Keystone, Jay S
    Hale, Devon C
    Burchard, Gerd
    Han, Pauline V
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    Freedman, David O
    Patterns of illness in travelers visiting Mexico and Central America: the GeoSentinel experience.2011In: Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, ISSN 1537-6591, Vol. 53, no 6, p. 523-531Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Mexico and Central America are important travel destinations for North American and European travelers. There is limited information on regional differences in travel related morbidity.

    METHODS: We describe the morbidity among 4779 ill travelers returned from Mexico and Central America who were evaluated at GeoSentinel network clinics during December 1996 to February 2010.

    RESULTS: The most frequent presenting syndromes included acute and chronic diarrhea, dermatologic diseases, febrile systemic illness, and respiratory disease. A higher proportion of ill travelers from the United States had acute diarrhea, compared with their Canadian and European counterparts (odds ratio, 1.9; P < .0001). During the 2009 H1N1 influenza outbreak from March 2009 through February 2010, the proportionate morbidity (PM) associated with respiratory illnesses in ill travelers increased among those returned from Mexico, compared with prior years (196.0 cases per 1000 ill returned travelers vs 53.7 cases per 1000 ill returned travelers; P < .0001); the PM remained constant in the rest of Central America (57.3 cases per 1000 ill returned travelers). We identified 50 travelers returned from Mexico and Central America who developed influenza, including infection due to 2009 H1N1 strains and influenza-like illness. The overall risk of malaria was low; only 4 cases of malaria were acquired in Mexico (PM, 2.2 cases per 1000 ill returned travelers) in 13 years, compared with 18 from Honduras (PM, 79.6 cases per 1000 ill returned travelers) and 14 from Guatemala (PM, 34.4 cases per 1000 ill returned travelers) during the same period. Plasmodium vivax malaria was the most frequent malaria diagnosis.

    CONCLUSIONS: Travel medicine practitioners advising and treating travelers visiting these regions should dedicate special attention to vaccine-preventable illnesses and should consider the uncommon occurrence of acute hepatitis A, leptospirosis, neurocysticercosis, acute Chagas disease, onchocerciasis, mucocutaneous leishmaniasis, neurocysticercosis, HIV, malaria, and brucellosis.

  • 8. Franco, L.
    et al.
    Serre, N.
    Poluda, D.
    Kurolt, I.
    Molero, F.
    Zarzuela, F.
    Neumayr, A.
    Hatz, C.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Tenorio, A.
    Deciphering the origin of dengue virus introduced in Madeira, Portugal2013Conference paper (Other academic)
  • 9. Harrison, Lee H
    et al.
    Pelton, Stephen I
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    Holst, Johan
    Safadi, Marco A P
    Vazquez, Julio A
    Taha, Muhamed-Kheir
    LaForce, F Marc
    von Gottberg, Anne
    Borrow, Ray
    Plotkin, Stanley A
    The global Meningococcal initiative: recommendations for reducing the global burden of meningococcal disease2011In: Vaccine, ISSN 0264-410X, E-ISSN 1873-2518, Vol. 29, no 18, p. 3363-3371Article in journal (Refereed)
    Abstract [en]

    The Global Meningococcal Initiative (GMI) is composed of an international group of scientists, clinicians and public health officials with expertise in meningococcal immunology, epidemiology and prevention. The primary goal of the GMI is the promotion of the global prevention of invasive meningococcal disease through education and research. The GMI members reviewed global meningococcal disease epidemiology, immunization strategies, and research needs. Over the past decade, substantial advances in meningococcal vaccine development have occurred and much has been learned about prevention from countries that have incorporated meningococcal vaccines into their immunization programs. The burden of meningococcal disease is unknown for many parts of the world because of inadequate surveillance, which severely hampers evidence-based immunization policy. As the field of meningococcal vaccine development advances, global surveillance for meningococcal disease needs to be strengthened in many regions of the world. For countries with meningococcal vaccination policies, research on vaccine effectiveness and impact, including indirect effects, is crucial for informing policy decisions. Each country needs to tailor meningococcal vaccination policy according to individual country needs and knowledge of disease burden. Innovative approaches are needed to introduce and sustain meningococcal vaccination programs in resource-poor settings with a high incidence of meningococcal disease.

  • 10. Jaenisch, Thomas
    et al.
    Sakuntabhai, Anavaj
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Dengue research funded by the European commission: scientific strategies of three European dengue research consortia2013In: PLoS Neglected Tropical Diseases, ISSN 1935-2727, E-ISSN 1935-2735, Vol. 7, no 12, article id e2320Article in journal (Refereed)
  • 11. Jentes, Emily S
    et al.
    Poumerol, Gilles
    Gershman, Mark D
    Hill, David R
    Lemarchand, Johan
    Lewis, Rosamund F
    Staples, J Erin
    Tomori, Oyewale
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    Monath, Thomas P
    The revised global yellow fever risk map and recommendations for vaccination, 2010: consensus of the Informal WHO Working Group on geographic risk for Yellow Fever.2011In: Lancet. Infectious diseases (Print), ISSN 1473-3099, E-ISSN 1474-4457, Vol. 11, no 8, p. 622-632Article in journal (Refereed)
    Abstract [en]

    The changing epidemiology of yellow fever and continued reports of rare but serious adverse events associated with yellow fever vaccine have drawn attention to the need to revisit criteria for the designation of areas with risk for yellow fever virus activity, and to revise the vaccine recommendations for international travel. WHO convened a working group of international experts to review factors important for the transmission of yellow fever virus and country-specific yellow fever information, to establish criteria for additions to or removal from the list of countries with risk for yellow fever virus transmission, to update yellow fever risk maps, and to revise the recommendations for vaccination for international travel. This report details the recommendations made by the working group about criteria for the designation of risk and specific changes to the classification of areas with risk for transmission of yellow fever virus.

  • 12. Kittayapong, P.
    et al.
    Olanratmanee, P.
    Maskhao, P.
    Byass, Peter
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Louis, V.
    Gubler, D.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Innovative dengue prevention and control using permethrin-impregnated school uniforms: experiences from a 1-year field trial in Thailand2013Conference paper (Other academic)
  • 13.
    Liu-Helmersson, Jing
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Stenlund, Hans
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Vectorial capacity of Aedes aegypti: Effects of temperature and implications for global dengue epidemic potential2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 3, article id e89783Article in journal (Refereed)
    Abstract [en]

    Dengue is a mosquito-borne viral disease that occurs mainly in the tropics and subtropics but has a high potential to spread to new areas. Dengue infections are climate sensitive, so it is important to better understand how changing climate factors affect the potential for geographic spread and future dengue epidemics. Vectorial capacity (VC) describes a vector's propensity to transmit dengue taking into account human, virus, and vector interactions. VC is highly temperature dependent, but most dengue models only take mean temperature values into account. Recent evidence shows that diurnal temperature range (DTR) plays an important role in influencing the behavior of the primary dengue vector Aedes aegypti. In this study, we used relative VC to estimate dengue epidemic potential (DEP) based on the temperature and DTR dependence of the parameters of A. aegypti. We found a strong temperature dependence of DEP; it peaked at a mean temperature of 29.3°C when DTR was 0°C and at 20°C when DTR was 20°C. Increasing average temperatures up to 29°C led to an increased DEP, but temperatures above 29°C reduced DEP. In tropical areas where the mean temperatures are close to 29°C, a small DTR increased DEP while a large DTR reduced it. In cold to temperate or extremely hot climates where the mean temperatures are far from 29°C, increasing DTR was associated with increasing DEP. Incorporating these findings using historical and predicted temperature and DTR over a two hundred year period (1901–2099), we found an increasing trend of global DEP in temperate regions. Small increases in DEP were observed over the last 100 years and large increases are expected by the end of this century in temperate Northern Hemisphere regions using climate change projections. These findings illustrate the importance of including DTR when mapping DEP based on VC.

  • 14. Louis, Valérie R
    et al.
    Montenegro Quiñonez, Carlos Alberto
    Kusumawathie, Pad
    Palihawadana, Paba
    Janaki, Sakoo
    Tozan, Yesim
    Wijemuni, Ruwan
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. nstitute of Public Health, Heidelberg University, Heidelberg, Germany; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Tissera, Hasitha A
    Characteristics of and factors associated with dengue vector breeding sites in the City of Colombo, Sri Lanka.2016In: Pathogens and Global Health, ISSN 2047-7724, E-ISSN 2047-7732, Vol. 110, no 2, p. 79-86Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: Dengue has emerged as a major public health problem in Sri Lanka. Vector control at community level is a frequent and widespread strategy for dengue control. The aim of the study was to assess Aedes mosquito breeding sites and the prevention practices of community members in a heavily urbanized part of Colombo.

    METHODS: A cross-sectional entomological survey was conducted from April to June 2013 in 1469 premises located in a subdistrict of the City of Colombo. Types of breeding sites and, where found, their infestation with larvae or pupae were recorded. Furthermore, a questionnaire was administered to the occupants of these premises to record current practices of dengue vector control.

    RESULTS: The surveyed premises consisted of 1341 residential premises and 110 non-residential premises (11 schools, 99 work or public sites), 5 open lands, and 13 non-specified. In these 1469 premises, 15447 potential breeding sites suitable to host larvae of pupae were found; of these sites18.0% contained water. Among the 2775 potential breeding sites that contained water, 452 (16.3%) were positive for larvae and/or pupae. Schools were associated with the proportionally highest number of breeding sites; 85 out of 133 (63.9%) breeding sites were positive for larvae and/or pupae in schools compared with 338 out of 2288 (14.8%) in residential premises. The odds ratio (OR) for schools and work or public sites for being infested with larvae and/or pupae was 2.77 (95% CI 1.58, 4.86), when compared to residential premises. Occupants of 80.8% of the residential premises, 54.5% of the schools and 67.7% of the work or public sites reported using preventive measures. The main prevention practices were coverage of containers and elimination of mosquito breeding places. Occupants of residential premises were much more likely to practice preventive measures than were those of non-residential premises (OR 2.23; 1.49, 3.36).

    CONCLUSION: Schools and working sites were associated with the highest numbers of breeding sites and lacked preventive measures for vector control. In addition to pursuing vector control measures at residential level, public health strategies should be expanded in schools and work places.

  • 15. Louis, Valérie R
    et al.
    Phalkey, Revati
    Horstick, Olaf
    Ratanawong, Pitcha
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Institute of Public Health, Heidelberg University Medical School, Heidelberg, Germany.
    Tozan, Yesim
    Dambach, Peter
    Modeling tools for dengue risk mapping - a systematic review2014In: International Journal of Health Geographics, ISSN 1476-072X, E-ISSN 1476-072X, Vol. 13, article id 50Article, review/survey (Refereed)
    Abstract [en]

    INTRODUCTION: The global spread and the increased frequency and magnitude of epidemic dengue in the last 50 years underscore the urgent need for effective tools for surveillance, prevention, and control. This review aims at providing a systematic overview of what predictors are critical and which spatial and spatio-temporal modeling approaches are useful in generating risk maps for dengue.

    METHODS: A systematic search was undertaken, using the PubMed, Web of Science, WHOLIS, Center for Disease Control (CDC) and OvidSP databases for published citations, without language or time restrictions. A manual search of the titles and abstracts was carried out using predefined criteria, notably the inclusion of dengue cases. Data were extracted for pre-identified variables, including the type of predictors and the type of modeling approach used for risk mapping.

    RESULTS: A wide variety of both predictors and modeling approaches was used to create dengue risk maps. No specific patterns could be identified in the combination of predictors or models across studies. The most important and commonly used predictors for the category of demographic and socio-economic variables were age, gender, education, housing conditions and level of income. Among environmental variables, precipitation and air temperature were often significant predictors. Remote sensing provided a source of varied land cover data that could act as a proxy for other predictor categories. Descriptive maps showing dengue case hotspots were useful for identifying high-risk areas. Predictive maps based on more complex methodology facilitated advanced data analysis and visualization, but their applicability in public health contexts remains to be established.

    CONCLUSIONS: The majority of available dengue risk maps was descriptive and based on retrospective data. Availability of resources, feasibility of acquisition, quality of data, alongside available technical expertise, determines the accuracy of dengue risk maps and their applicability to the field of public health. A large number of unknowns, including effective entomological predictors, genetic diversity of circulating viruses, population serological profile, and human mobility, continue to pose challenges and to limit the ability to produce accurate and effective risk maps, and fail to support the development of early warning systems.

  • 16. Lover, Andrew A
    et al.
    Sutton, Brett A
    Asy, Angelina J
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    An exploratory study of treated-bed nets in Timor-Leste: patterns of intended and alternative usage.2011In: Malaria Journal, ISSN 1475-2875, E-ISSN 1475-2875, Vol. 10, p. 199-Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The Timor-Leste Ministry of Health has recently finalized the National Malaria Control Strategy for 2010-2020. A key component of this roadmap is to provide universal national coverage with long-lasting insecticide-treated nets (LLINs) in support of achieving the primary goal of reducing both morbidity and mortality from malaria by 30% in the first three years, followed by a further reduction of 20% by end of the programme cycle in 2020 1. The strategic plan calls for this target to be supported by a comprehensive information, education and communication (IEC) programme; however, there is limited prior research into household and personal usage patterns to assist in the creation of targeted, effective, and socio-culturally specific behaviour change materials.

    METHODS: Nine separate focus group discussions (FGDs) were carried out in Dili, Manatuto, and Covalima districts, Democratic Republic of Timor-Leste, in July 2010.These focus groups primarily explored themes of perceived malaria risk, causes of malaria, net usage patterns within families, barriers to correct and consistent usage, and the daily experience of users (both male and female) in households with at least one net. Comprehensive qualitative analysis utilized open source analysis software.

    RESULTS: The primary determinants of net usage were a widespread perception that nets could or should only be used by pregnant women and young children, and the availability of sufficient sleeping space under a limited number of nets within households. Both nuisance biting and disease prevention were commonly cited as primary motivations for usage, while seasonality was not a significant factor. Long-term net durability and ease of hanging were seen as key attributes in net design preference. Very frequent washing cycles were common, potentially degrading net effectiveness. Finally, extensive re-purposing of nets (fishing, protecting crops) was both reported and observed, and may significantly decrease availability of nighttime sleeping space for all family members if distributed nets do not remain within the household.

    CONCLUSIONS: Emphasizing that net usage is acceptable and important for all family members regardless of age or gender, and addressing the complex behavioural economics of alternative net usages could have significant impacts on malaria control efforts in Timor-Leste, as the country's programmes make progress towards universal net coverage.

  • 17. Massad, E.
    et al.
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Coutinho, F.
    Struchiner, C.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Determining the main driver for the increase of epidemic dengue in Singapore2013Conference paper (Other academic)
  • 18. Massad, E
    et al.
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Dengue infections in non-immune travellers to Thailand2013In: Epidemiology and Infection, ISSN 0950-2688, E-ISSN 1469-4409, Vol. 141, no 2, p. 412-417Article in journal (Refereed)
    Abstract [en]

    Dengue is the most frequent arboviral disease and is expanding geographically. Dengue is also increasingly being reported in travellers, in particular in travellers to Thailand. However, data to quantify the risk of travellers acquiring dengue when travelling to Thailand are lacking. Using mathematical modelling, we set out to estimate the risk of non-immune persons acquiring dengue when travelling to Thailand. The model is deterministic with stochastic parameters and assumes a Poisson distribution for the mosquitoes' biting rate and a Gamma distribution for the probability of acquiring dengue from an infected mosquito. From the force of infection we calculated the risk of dengue acquisition for travellers to Thailand arriving in a typical year (averaged over a 17-year period) in the high season of transmission. A traveller arriving in the high season of transmission and remaining for 7 days has a risk of acquiring dengue of 0.2% (95% CI 0.16-0.23), whereas the risk for travel of 15 and 30 days' duration is 0.46% (95% CI 0.41-0.50) and 0.81% (95% CI 0.76-0.87), respectively. Our data highlight that the risk of non-immune travellers acquiring dengue in Thailand is substantial. The incidence of 0.81% after a 1-month stay is similar to that reported in prospective seroconversion studies in Israeli travellers to Thailand, highlighting that our models are consistent with actual data. Risk estimates based on mathematical modelling offer more detailed information depending on various travel scenarios, and will help the travel medicine provider give better evidence-based advice for travellers to dengue-endemic countries.

  • 19. Massad, Eduardo
    et al.
    Amaku, Marcos
    Bezerra Coutinho, Francisco Antonio
    Kittayapong, Pattamaporn
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Theoretical impact of insecticide-impregnated school uniforms on dengue incidence in Thai children2013In: Global Health Action, ISSN 1654-9716, E-ISSN 1654-9880, Vol. 6, p. 1-6Article in journal (Refereed)
    Abstract [en]

    Background: Children carry the main burden of morbidity and mortality caused by dengue. Children spend a considerable amount of their day at school; hence strategies that reduce human-mosquito contact to protect against the day-biting habits of Aedes mosquitoes at schools, such as insecticide-impregnated uniforms, could be an effective prevention strategy.

    Methodology: We used mathematical models to calculate the risk of dengue infection based on force of infection taking into account the estimated proportion of mosquito bites that occur in school and the proportion of school time that children wear the impregnated uniforms. Principal findings: The use of insecticide-impregnated uniforms has efficacy varying from around 6% in the most pessimistic estimations, to 55% in the most optimistic scenarios simulated.

    Conclusions: Reducing contact between mosquito bites and human hosts via insecticide-treated uniforms during school time is theoretically effective in reducing dengue incidence and may be a valuable additional tool for dengue control in school-aged children. The efficacy of this strategy, however, is dependent on the compliance of the target population in terms of proper and consistent wearing of uniforms and, perhaps more importantly, the proportion of bites inflicted by the Aedes population during school time.

  • 20. Massad, Eduardo
    et al.
    Amaku, Marcos
    Coutinho, Francisco Antonio Bezerra
    Struchiner, Claudio José
    Burattini, Marcelo Nascimento
    Khan, Kamran
    Liu-Helmersson, Jing
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Kraemer, Moritz U. G.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Institute of Public Health, University of Heidelberg, Germany; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Estimating the probability of dengue virus introduction and secondary autochthonous cases in Europe2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, no 1, article id 4629Article in journal (Refereed)
    Abstract [en]

    Given the speed of air travel, diseases even with a short viremia such as dengue can be easily exported to dengue naïve areas within 24 hours. We set out to estimate the risk of dengue virus introductions via travelers into Europe and number of secondary autochthonous cases as a result of the introduction. We applied mathematical modeling to estimate the number of dengue-viremic air passengers from 16 dengue-endemic countries to 27 European countries, taking into account the incidence of dengue in the exporting countries, travel volume and the probability of being viremic at the time of travel. Our models estimate a range from zero to 167 air passengers who are dengue-viremic at the time of travel from dengue endemic countries to each of the 27 receiving countries in one year. Germany receives the highest number of imported dengue-viremic air passengers followed by France and the United Kingdom. Our findings estimate 10 autochthonous secondary asymptomatic and symptomatic dengue infections, caused by the expected 124 infected travelers who arrived in Italy in 2012. The risk of onward transmission in Europe is reassuringly low, except where Aedes aegypti is present.

  • 21. Massad, Eduardo
    et al.
    Burattini, Marcelo N.
    Ximenes, Raphael
    Amaku, Marcos
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Dengue outlook for the World Cup in Brazil2014In: Lancet. Infectious diseases (Print), ISSN 1473-3099, E-ISSN 1474-4457, Vol. 14, no 7, p. 552-553Article in journal (Refereed)
  • 22. Massad, Eduardo
    et al.
    Tan, Ser-Han
    Khan, Kamran
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Institute of Public Health, University of Heidelberg, Germany ; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Estimated Zika virus importations to Europe by travellers from Brazil2016In: Global Health Action, ISSN 1654-9716, E-ISSN 1654-9880, Vol. 9, p. 1-7, article id 31669Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Given the interconnectivity of Brazil with the rest of the world, Zika virus (ZIKV) infections have the potential to spread rapidly around the world via viremic travellers. The extent of spread depends on the travel volume and the endemicity in the exporting country. In the absence of reliable surveillance data, we did mathematical modelling to estimate the number of importations of ZIKV from Brazil into Europe.

    DESIGN: We applied a previously developed mathematical model on importations of dengue to estimate the number of ZIKV importations into Europe, based on the travel volume, the probability of being infected at the time of travel, the population size of Brazil, and the estimated incidence of ZIKV infections.

    RESULTS: Our model estimated between 508 and 1,778 imported infections into Europe in 2016, of which we would expect between 116 and 355 symptomatic Zika infections; with the highest number of importations being into France, Portugal and Italy.

    CONCLUSIONS: Our model identified high-risk countries in Europe. Such data can assist policymakers and public health professionals in estimating the extent of importations in order to prepare for the scale up of laboratory diagnostic assays and estimate the occurrence of Guillain-Barré Syndrome, potential sexual transmission, and infants with congenital ZIKV syndrome.

  • 23. Massad, Eduardo
    et al.
    Wilder-Smith, Annelies
    Lee Kong Chian School of Medicine, Nanyang University, Singapore.
    Ximenes, Raphael
    Amaku, Marcos
    Lopez, Luis Fernandez
    Coutinho, Francisco Antonio Bezerra
    Coelho, Giovanini Evelim
    Silva, Jarbas Barbosa da
    Struchiner, Claudio José
    Burattini, Marcelo Nascimento
    Risk of symptomatic dengue for foreign visitors to the 2014 FIFA World Cup in Brazil2014In: Memórias do instituto Oswaldo Cruz, ISSN 0074-0276, E-ISSN 1678-8060, Vol. 109, no 3, p. 394-397Article in journal (Refereed)
    Abstract [en]

    Brazil will host the FIFA World Cup™, the biggest single-event competition in the world, from June 12-July 13 2014 in 12 cities. This event will draw an estimated 600,000 international visitors. Brazil is endemic for dengue. Hence, attendees of the 2014 event are theoretically at risk for dengue. We calculated the risk of dengue acquisition to non-immune international travellers to Brazil, depending on the football match schedules, considering locations and dates of such matches for June and July 2014. We estimated the average per-capita risk and expected number of dengue cases for each host-city and each game schedule chosen based on reported dengue cases to the Brazilian Ministry of Health for the period between 2010-2013. On the average, the expected number of cases among the 600,000 foreigner tourists during the World Cup is 33, varying from 3-59. Such risk estimates will not only benefit individual travellers for adequate pre-travel preparations, but also provide valuable information for public health professionals and policy makers worldwide. Furthermore, estimates of dengue cases in international travellers during the World Cup can help to anticipate the theoretical risk for exportation of dengue into currently non-infected areas.

  • 24. Montenegro, C A
    et al.
    Louis, V R
    Kusumawathie, P
    Palihawadana, P
    Tozan, Y
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Institute of Public Health, Heidelberg University, Heidelberg, Germany; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore City, Singapore.
    Tissera, H
    Entomological survey of dengue vector breeding sites in Colombo, Sri Lanka2015In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 20, no Suppl. 1, p. 409-410Article in journal (Other academic)
    Abstract [en]

    Introduction: In Sri Lanka, the number of dengue cases has steadily increased in recent years. Prevention through disease and vector surveillance is an important strategy in dengue control. The aim of the study was to assess Aedes mosquito breeding sites and the prevention practices of community members in one heavily urbanized area of Colombo.

    Methods: A cross-sectional entomological survey was conducted from April to June 2013 in 1469 premises located in a sub-district of Colombo Municipality. Types of breeding sites and infestation with larvae or pupae were recorded and a questionnaire was administered to occupants to assess knowledge and practises concerning dengue vector control.

    Results: The surveyed premises included 1341 households (91%), 99 work or public sites and 11 schools. 126 premises were positive for Aedes larvae or pupae. 12 672 potential breeding sites susceptible to host larvae or pupae were recorded, of which 21% contained water. Among these, 6% were positive for larvae and 13% for pupae. For schools the percentage rose to 40% and 67%, respectively. The main productive breeding sites were: discarded items, water tanks, ornamental plants, ponds and flowerpots, and non-specified containers. The majority was located on outdoor ground areas. Compared to households, the odds ratio for non-household premises of being infested with larvae was 2.29 (P = 0.005, 95% CI: 1.278–4.129) and with pupae 5.76 (P < 0.001, 95% CI: 2.660–12.497). Occupants of 82% of the premises reported using preventive measures. The main practices were coverage of containers and elimination of mosquito-breeding places. 45% of schools and 19% of households took no preventive measures. There was a significant correlation between the occurrence of preventative measures taken and the type of premise involved (P = 0.002).

    Conclusion: Residential buildings had the lowest relative number of potential breeding sites, and household members reported a high use of vector control measures. Schools and working sites, however, were identified as being at highest risk for productive breeding sites combined with shortcomings in preventive measures. Hence, this study suggests that while it is important to maintain vector control and prevention practices at the household level, schools and working sites should actively be targeted to better combat dengue.

    Acknowledgements: This research was funded by 'DengueTools' of the 7th Framework Programme of the European Community.

    Disclosure: Nothing to disclose.

  • 25. Murray, N.
    et al.
    Louis, V.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Jansarikij, S.
    Olanratmanee, P.
    Maskhao, P.
    Kittayapong, P.
    Innovative dengue prevention and control using permethrin-impregnated school uniforms: a mixed methods study on acceptability2013In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 18, no Special Issue, p. 52-53Article in journal (Other academic)
  • 26. Murray, Natasha
    et al.
    Jansarikij, Suphachai
    Olanratmanee, Phanthip
    Maskhao, Pongsri
    Souares, Aurélia
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Institute of Public Health, University of Heidelberg, Heidelberg, Germany ; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Kittayapong, Pattamaporn
    Louis, Valérie R
    Acceptability of impregnated school uniforms for dengue control in Thailand: a mixed methods approach2014In: Global Health Action, ISSN 1654-9716, E-ISSN 1654-9880, Vol. 7, p. 24887-Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: As current dengue control strategies have been shown to be largely ineffective in reducing dengue in school-aged children, novel approaches towards dengue control need to be studied. Insecticide-impregnated school uniforms represent an innovative approach with the theoretical potential to reduce dengue infections in school children.

    OBJECTIVES: This study took place in the context of a randomised control trial (RCT) to test the effectiveness of permethrin-impregnated school uniforms (ISUs) for dengue prevention in Chachoengsao Province, Thailand. The objective was to assess the acceptability of ISUs among parents, teachers, and principals of school children involved in the trial.

    METHODOLOGY: Quantitative and qualitative tools were used in a mixed methods approach. Class-clustered randomised samples of school children enrolled in the RCT were selected and their parents completed 321 self-administered questionnaires. Descriptive statistics and logistic regression were used to analyse the quantitative data. Focus group discussions and individual semi-structured interviews were conducted with parents, teachers, and principals. Qualitative data analysis involved content analysis with coding and thematic development.

    RESULTS: The knowledge and experience of dengue was substantial. The acceptability of ISUs was high. Parents (87.3%; 95% CI 82.9-90.8) would allow their child to wear an ISU and 59.9% (95% CI 53.7-65.9) of parents would incur additional costs for an ISU over a normal uniform. This was significantly associated with the total monthly income of a household and the educational level of the respondent. Parents (62.5%; 95% CI 56.6-68.1) indicated they would be willing to recommend ISUs to other parents.

    CONCLUSIONS: Acceptability of the novel tool of ISUs was high as defined by the lack of concern along with the willingness to pay and recommend. Considering issues of effectiveness and scalability, assessing acceptability of ISUs over time is recommended.

  • 27. Olanratmanee, P.
    et al.
    Jansarikij, S.
    Kittayapong, P.
    Maskhao, P.
    Louis, V. R.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Innovative dengue prevention and control using permethrin-impregnated school uniforms: purchasing decision based on background knowledge and experience2013In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 18, no Special Issue, p. 121-122Article in journal (Other academic)
  • 28. Orsborne, James
    et al.
    DeRaedt Banks, Sarah
    Hendy, Adam
    Gezan, Salvador A.
    Kaur, Harparkash
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Lindsay, Steve W.
    Logan, James G.
    Personal Protection of Permethrin-Treated Clothing against Aedes aegypti, the Vector of Dengue and Zika Virus, in the Laboratory2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 5, article id e0152805Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The dengue and Zika viruses are primarily transmitted by Aedes aegypti mosquitoes, which are most active during day light hours and feed both in and outside of the household. Personal protection technologies such as insecticide-treated clothing could provide individual protection. Here we assessed the efficacy of permethrin-treated clothing on personal protection in the laboratory.

    METHODS: The effect of washing on treated clothing, skin coverage and protection against resistant and susceptible Ae. aegypti was assessed using modified WHO arm-in-cage assays. Coverage was further assessed using free-flight room tests to investigate the protective efficacy of unwashed factory-dipped permethrin-treated clothing. Clothing was worn as full coverage (long sleeves and trousers) and partial coverage (short sleeves and shorts). Residual permethrin on the skin and its effect on mosquitoes was measured using modified WHO cone assays and quantified using high-pressure liquid chromatography (HPLC) analysis.

    RESULTS: In the arm-in-cage assays, unwashed clothing reduced landing by 58.9% (95% CI 49.2-66.9) and biting by 28.5% (95% CI 22.5-34.0), but reduced to 18.5% (95% CI 14.7-22.3) and 11.1% (95% CI 8.5-13.8) respectively after 10 washes. Landing and biting for resistant and susceptible strains was not significantly different (p<0.05). In free-flight room tests, full coverage treated clothing reduced landing by 24.3% (95% CI 17.4-31.7) and biting by 91% (95% CI 82.2-95.9) with partial coverage reducing landing and biting by 26.4% (95% CI 20.3-31.2) and 49.3% (95% CI 42.1-59.1) respectively with coverage type having no significant difference on landing (p<0.05). Residual permethrin was present on the skin in low amounts (0.0041mg/cm2), but still produced a KD of >80% one hour after wearing treated clothing.

    CONCLUSION: Whilst partially covering the body with permethrin-treated clothing provided some protection against biting, wearing treated clothing with long sleeves and trousers provided the highest form of protection. Washing treated clothing dramatically reduced protection provided. Permethrin-treated clothing could provide protection to individuals from Ae. aegypti that show permethrin resistance. Additionally, it could continue to provide protection even after the clothing has been worn. Field trials are urgently needed to determine whether clothing can protect against dengue and Zika.

  • 29. Paton, Nicholas I
    et al.
    Lee, Lawrence
    Xu, Ying
    Ooi, Eng Eong
    Cheung, Yin Bun
    Archuleta, Sophia
    Wong, Gerard
    Wilder-Smith, Annelies
    Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
    Chloroquine for influenza prevention: a randomised, double-blind, placebo controlled trial2011In: Lancet. Infectious diseases (Print), ISSN 1473-3099, E-ISSN 1474-4457, Vol. 11, no 9, p. 677-683Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Chloroquine has in-vitro activity against influenza and could be an ideal candidate for worldwide prevention of influenza in the period between onset of a pandemic with a virulent influenza strain and the development and widespread dissemination of an effective vaccine. We aimed to assess the efficacy of such an intervention.

    METHODS: In this randomised, double-blind, placebo-controlled trial done at a single centre in Singapore, we randomly assigned (1:1) healthy adults to receive chloroquine phosphate (500 mg/day for 1 week, then once a week to complete 12 weeks) or matching placebo by use of a computer-generated randomisation list. Participants filled an online symptom diary every week, supplemented by daily diaries and self-administered nasal swabs when unwell. Haemagglutination-inhibition assays for influenza A (H1N1, H3N2) and B were done on blood samples taken at baseline and after 12 weeks. The primary outcome was laboratory-confirmed clinical influenza defined by specific symptoms accompanied by influenza RNA on nasal swabs or a four-fold increase in haemagglutination-inhibition titres over the 12-week study period. Analysis was by intention to treat. This trial was registered with ClinicalTrials.gov, number NCT01078779.

    FINDINGS: From November, 2009, to February, 2010, we recruited 1516 eligible participants. 1496 (96%) returned at week 12 and were included in the efficacy analysis. Adherence to study intervention was 97%, and 94% of the scheduled weekly diaries were completed. Eight (1%) of 738 participants had laboratory-confirmed clinical influenza in the placebo group and 12 (2%) of 724 in the chloroquine group (relative risk 1·53, 95% CI 0·63-3·72; p=0·376). 29 (4%) of 738 had laboratory-confirmed influenza infection (symptomatic or asymptomatic) in the placebo group and 38 (5%) of 724 in the chloroquine group (1·34, 0·83-2·14; p=0·261). 249 (33%) of 759 participants reported adverse events (mostly mild) in the placebo group and 341 (45%) of 757 in chloroquine group (p<0·0001). Headache, dizziness, nausea, diarrhoea, and blurred vision were more common in the chloroquine group, but rarely resulted in treatment discontinuation. One serious adverse event (hepatitis) was possibly related to chloroquine.

    INTERPRETATION: Although generally well tolerated by a healthy community population, chloroquine does not prevent infection with influenza. Alternative drugs are needed for large-scale prevention of influenza.

    FUNDING: National Medical Research Council, Singapore.

  • 30.
    Quam, Mikkel B
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Wilder-Smith, Annelies
    Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Importation index of dengue to determine the most probable origin of importation2015In: Journal of Travel Medicine, ISSN 1195-1982, E-ISSN 1708-8305, Vol. 22, no 1, p. 72-Article in journal (Refereed)
  • 31.
    Quam, Mikkel
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Khan, K.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Flight travel related risk of dengue introduction in Mediterranean cities2013Conference paper (Other academic)
  • 32.
    Quam, Mikkel
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Sessions, O
    Liu-Helmersson, Jing
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Dissecting the origin of the 2014 dengue outbreak in Japan2015In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 20, no Suppl. 1, p. 408-408Article in journal (Other academic)
    Abstract [en]

    Introduction: Endemic in at least 100 countries, dengue is currently regarded as world's most important mosquito borne viral disease. While most of the disease burden is limited to areas with tropical and sub-tropical climates, evidence suggests that temperate areas may be increasingly at risk as the geographic distribution of relevant vectors expands. Japan, a country with a temperate climate, reported the first major dengue outbreak in 2014. We examined the factors that may have facilitated the dengue outbreak in Tokyo during 2014.

    Methods: Multiple sequence alignment of the dengue virus 1 (DENV1) sequence from the 2014 dengue outbreak in Tokyo was carried out using a fast Fourier transformation method in MAFFT v6.940b. We collected the Japan National Tourism Organization’s data on inbound travelers between January and September 2014 from dengue endemic countries in Asia to Japan. Daily observations of temperature (minimum, maximum, and mean) and precipitation were obtained from the MIDAS dataset for Tokyo. We calculated the relative vectorial capacity (rVc) for Aedes vectors to quantify the dengue epidemic potential based on temperature dependent parameters, by applying a modified Ross-McDonald model.

    Findings: Tourist arrivals into Japan in 2014 coincided by 70% with its warm summer months suitable for dengue transmission, The phylogenetic similarity of DENV-1 isolated from the 2014 outbreak in Japan with viruses from China, Indonesia, Singapore, and Vietnam renders any of these four countries a likely source of importation. Several conducive climate factors converged preceding and during the time of the dengue outbreak in Tokyo, August until October 2014. Climate conditions, in particular mean temperature and precipitation, were favorable for the amplification of Aedes vectors. Furthermore, the ability for the vector to transmit dengue, as measured by the relative vectorial capacity, was highest at the time of the 2014 outbreak.

    Conclusions: Taking into account the travel volume into Japan, China appears the most probable source of dengue virus introduction that triggered Tokyo's outbreak. Despite Japan's temperate climate, dengue epidemic potential already exists. Under scenarios of changing climate and increasing regional travel, Japan will likely face more dengue outbreaks in the future.

    Acknowledgements: The study was financially supported by the European Union's Seventh Framework Programme- DengueTools (www.denguetools.net).

    Disclosure: Nothing to disclose.

  • 33. Ratanawong, Pitcha
    et al.
    Kittayapong, Pattamaporn
    Olanratmanee, Phanthip
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
    Byass, Peter
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Medical Research Council/Wits University Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
    Tozan, Yesim
    Dambach, Peter
    Quiñonez, Carlos Alberto Montenegro
    Louis, Valérie R
    Spatial Variations in Dengue Transmission in Schools in Thailand2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 9, article id e0161895Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Dengue is an important neglected tropical disease, with more than half of the world's population living in dengue endemic areas. Good understanding of dengue transmission sites is a critical factor to implement effective vector control measures.

    METHODS: A cohort of 1,811 students from 10 schools in rural, semi-rural and semi-urban Thailand participated in this study. Seroconversion data and location of participants' residences and schools were recorded to determine spatial patterns of dengue infections. Blood samples were taken to confirm dengue infections in participants at the beginning and the end of school term. Entomological factors included a survey of adult mosquito density using a portable vacuum aspirator during the school term and a follow up survey of breeding sites of Aedes vectors in schools after the school term. Clustering analyses were performed to detect spatial aggregation of dengue infections among participants.

    RESULTS: A total of 57 dengue seroconversions were detected among the 1,655 participants who provided paired blood samples. Of the 57 confirmed dengue infections, 23 (40.0%) occurred in students from 6 (6.8%) of the 88 classrooms in 10 schools. Dengue infections did not show significant clustering by residential location in the study area. During the school term, a total of 66 Aedes aegypti mosquitoes were identified from the 278 mosquitoes caught in 50 classrooms of the 10 schools. In a follow-up survey of breeding sites, 484 out of 2,399 water containers surveyed (20.2%) were identified as active mosquito breeding sites.

    DISCUSSION AND CONCLUSION: Our findings suggest that dengue infections were clustered among schools and among classrooms within schools. The schools studied were found to contain a large number of different types of breeding sites. Aedes vector densities in schools were correlated with dengue infections and breeding sites in those schools. Given that only a small proportion of breeding sites in the schools were subjected to vector control measures (11%), this study emphasizes the urgent need to implement vector control strategies at schools, while maintaining efforts at the household level.

  • 34.
    Rocklöv, Joacim
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Lohr, Wolfgang
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Hjertqvist, Marika
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Attack rates of dengue fever in Swedish travellers2014In: Scandinavian Journal of Infectious Diseases, ISSN 0036-5548, E-ISSN 1651-1980, Vol. 46, no 6, p. 412-417Article in journal (Refereed)
    Abstract [en]

    Background: Dengue is endemic in many countries visited by Swedish travellers. We aimed to determine the attack rate of dengue in Swedish travellers and analyse the trends over time and the geographical variation. Methods: We obtained the following data from the Swedish Institute for Communicable Disease Control for the y 1995-2010: number of Swedish residents with confirmed dengue, the country and year of infection. We also obtained registers on the Swedish annual air traveller arrivals to dengue endemic areas from the United Nations World Tourist Organization for the time period. We estimated attack rates with 95% confidence intervals (CI). Results: In total, 925 Swedish travellers with confirmed dengue were reported. We found an increasing trend over time for most destinations. The majority of the dengue cases were acquired in Thailand (492 out of 925 travellers; 53%), with an attack rate of 13.6 (95% CI 12.7, 14.4) per 100,000 travellers. However, the 2 highest attack rates per 100,000 travellers were found for Sri Lanka (45.3, 95% CI 34.3, 56.4) and Bangladesh (42.6, 95% CI 23.8, 61.5). Conclusions: Information on attack rates in travellers is more helpful in guiding travel medicine practitioners than reports of absolute numbers, as the latter reflect travel preferences rather than the true risk. Although the majority of dengue infections in Swedish travellers were acquired in Thailand, the attack rates for dengue in travellers to Sri Lanka and Bangladesh were much higher. These data aid in refining information on the risk of dengue in travellers.

  • 35.
    Rocklöv, Joacim
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    Climate change and vector-borne infections: Comment on "Modeling the impact of global warming on vector-borne infections" by Eduardo Massad, Francisco Antonio Bezerra Coutinho, Luiz Fernandes Lopez and Daniel Rodrigues da Silva.2011In: Physics of life reviews, ISSN 1873-1457, Vol. 8, no 2, p. 204-205Article in journal (Refereed)
  • 36. Schwartz, E
    et al.
    Meltzer, E
    Mendelson, M
    Tooke, A
    Steiner, F
    Gautret, P
    Friedrich-Jaenicke, B
    Libman, M
    Bin, H
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    Gubler, Dj
    Freedman, D O
    Parola, P
    Detection on four continents of dengue fever cases related to an ongoing outbreak in Luanda, Angola, March to May 20132013In: Eurosurveillance, ISSN 1025-496X, E-ISSN 1560-7917, Vol. 18, no 21Article in journal (Refereed)
  • 37. Sessions, October M
    et al.
    Khan, Kamran
    Hou, Yan'an
    Meltzer, Eyal
    Quam, Mikkel
    Institute of Public Health, University of Heidelberg, Heidelberg, Germany.
    Schwartz, Eli
    Gubler, Duane J
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Exploring the origin and potential for spread of the 2013 dengue outbreak in Luanda, Angola2013In: Global Health Action, ISSN 1654-9716, E-ISSN 1654-9880, Vol. 6, article id 21822Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: Dengue in Africa is underreported. Simultaneous reports of travellers with dengue returning from Luanda, Angola, to six countries on four continents suggest that a major dengue outbreak is currently occurring in Angola, South West Africa.

    METHODS: To identify the origin of the imported dengue virus, we sequenced the virus from Angola and investigated the interconnectivity via air travel between dengue-endemic countries and Angola.

    RESULTS AND CONCLUSION: Our analyses show that the Angola outbreak was most likely caused by an endemic virus strain that had been circulating in West Africa for many years. We also show that Portugal and South Africa are most likely at the highest risk of importation of dengue from Angola due to the large number of air passengers between Angola and these countries.

  • 38.
    Struchiner, Claudio Jose
    et al.
    Rio de Janeiro, Brazil.
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Wilder-Smith, Annelies
    Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
    Massad, Eduardo
    Sao Paulo, Brazil; London, United Kingdom.
    Increasing Dengue Incidence in Singapore over the Past 40 Years: Population Growth, Climate and Mobility2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 8, article id e0136286Article in journal (Refereed)
    Abstract [en]

    In Singapore, the frequency and magnitude of dengue epidemics have increased significantly over the past 40 years. It is important to understand the main drivers for the rapid increase in dengue incidence. We studied the relative contributions of putative drivers for the rise of dengue in Singapore: population growth, climate parameters and international air passenger arrivals from dengue endemic countries, for the time period of 1974 until 2011. We used multivariable Poisson regression models with the following predictors: Annual Population Size; Aedes Premises Index; Mean Annual Temperature; Minimum and Maximum Temperature Recorded in each year; Annual Precipitation and Annual Number of Air Passengers arriving from dengue-endemic South-East Asia to Singapore. The relative risk (RR) of the increase in dengue incidence due to population growth over the study period was 42.7, while the climate variables (mean and minimum temperature) together explained an RR of 7.1 (RR defined as risk at the end of the time period relative to the beginning and goodness of fit associated with the model leading to these estimates assessed by pseudo-R2 equal to 0.83). Estimating the extent of the contribution of these individual factors on the increasing dengue incidence, we found that population growth contributed to 86% while the residual 14% was explained by increase in temperature. We found no correlation with incoming air passenger arrivals into Singapore from dengue endemic countries. Our findings have significant implications for predicting future trends of the dengue epidemics given the rapid urbanization with population growth in many dengue endemic countries. It is time for policy-makers and the scientific community alike to pay more attention to the negative impact of urbanization and urban climate on diseases such as dengue.

  • 39. Tambyah, Paul A
    et al.
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    Pavlova, Borislava G
    Barrett, P Noel
    Oh, Helen M L
    Hui, David S
    Yuen, Kwok-yung
    Fritsch, Sandor
    Aichinger, Gerald
    Loew-Baselli, Alexandra
    van der Velden, Maikel
    Maritsch, Friedrich
    Kistner, Otfried
    Ehrlich, Hartmut J
    Safety and immunogenicity of two different doses of a Vero cell-derived, whole virus clade 2 H5N1 (A/Indonesia/05/2005) influenza vaccine.2012In: Vaccine, ISSN 0264-410X, E-ISSN 1873-2518, Vol. 30, no 2, p. 329-35Article in journal (Refereed)
    Abstract [en]

    A successful vaccine development strategy for areas with clustered H5N1 events requires conduct of vaccine trials in potentially non-naïve subjects and evaluation of post-vaccination responsiveness. An open-label, randomized, phase I/II study therefore assessed the immunogenicity and safety of two different dose levels of an inactivated, non-adjuvanted, whole virus clade 2.1 (A/Indonesia/05/2005) H5N1 Vero cell-derived influenza vaccine in healthy adults (21-45 years) from a region where the virus has been circulating (Hong Kong) as well as Singapore. Subjects (N=110) were randomized 1:1 to receive two vaccinations with either 3.75 μg or 7.5 μg H5N1 haemagglutinin antigen 21 days apart. Safety, immunogenicity (microneutralization [MN] and single radial haemolysis [SRH] at baseline and post-vaccination) and cross-reactivity against a heterologous clade 1 strain (A/Vietnam/1203/2004) of the vaccine were assessed. Pre-existing immunity to the vaccine strain was 14% which is higher than previously reported for these regions. Two vaccinations with either vaccine formulation induced high seroprotection rates (MN titre ≥ 1:20) against the vaccine strain A/Indonesia/05/2005: 82.7% and 86.5% in the 3.75 μg and 7.5 μg dose groups. Seroconversion rates and fold increase exceeded the CPMP criterion of >40% and >2.5 for MN and SRH in both dose groups after the second vaccination, while the seroprotection rate in the 7.5 μg dose group determined by SRH was only marginally lower (69.2%) than the CPMP criterion of >70%. Thus, 11 of 12 CHMP criteria were fulfilled. A cross-reactive antibody response against the heterologous A/Vietnam/1203/2004 strain was demonstrated after the second vaccination (>21% by MN and ≥ 25% by SRH). Persistence of antibodies against the vaccine strain was also demonstrated 6 months after the first vaccination, indicating that a booster vaccination would be effective in those who have received two priming doses. No serious adverse events were reported. The H5N1 influenza vaccine against clade 2.1 strain A/Indonesia/05/2005 was well tolerated and immunogenic after two vaccinations, and induced a cross-neutralizing antibody response, with no dose effect.

  • 40.
    Teoh, Boon-Teong
    et al.
    Malaysia.
    Sam, Sing-Sin
    Malaysia.
    Tan, Kim-Kee
    Malaysia.
    Danlami, Mohammed Bashar
    Malaysia.
    Shu, Meng-Hooi
    Malaysia.
    Johari, Jefree
    Malaysia.
    Hooi, Poh-Sim
    Malaysia.
    Brooks, David
    United Kingdom.
    Piepenburg, Olaf
    United Kingdom.
    Nentwich, Oliver
    United Kingdom.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Franco, Leticia
    Spain.
    Tenorio, Antonio
    Spain.
    AbuBakar, Sazaly
    Malaysia.
    Early detection of the dengue virus using reverse transcription-recombinase polymerase amplification2015In: Journal of Clinical Microbiology, ISSN 0095-1137, E-ISSN 1098-660X, Vol. 53, no 3, p. 830-837Article in journal (Refereed)
    Abstract [en]

    A method for the rapid diagnosis of early dengue virus (DENV) infection is highly needed. Here, a prototype reverse transcription-recombinase polymerase amplification (RT-RPA) assay was developed. The assay detected DENV RNA in <20 minutes without the need for thermocycling amplification. The assay enabled the detection of as few as 10 copies of DENV RNA. The designed RT-RPA primers and exo-probe detected the DENV genome of at least 12 genotypes of DENV circulating globally without cross-reacting with other arboviruses. We assessed the diagnostic performance of the RT-RPA assay for the detection of DENV RNA in 203 sera of clinically suspected dengue patients. The sera were simultaneously tested for DENV using RT-loop-mediated isothermal amplification (RT-LAMP), quantitative RT-polymerase chain reaction (qRT-PCR), and IgM- and IgG-capture enzyme-linked immunosorbent assays (ELISA). Acute DENV infection was confirmed in 130 samples and 61 of the samples (46.9%) were classified as viremic with qRT-PCR. The RT-RPA assay showed good concordance (κ ≥ 0.723) with the RT-LAMP and qRT-PCR assays in detecting the dengue viremic samples. When used in combination with ELISA, both the RT-RPA and RT-LAMP assays increased the detection of acute DENV infection to ≥95.7% (≥45/47) in samples obtained within 5 days of illness. The results from the study suggest that the RT-RPA assay is the most rapid molecular diagnostic tool available for the detection of DENV. Hence, it is possible to use the RT-RPA assay in a laboratory to complement routine serology testing for dengue.

    IMPORTANCE: Nucleic acid detection methods are gradually being accepted as diagnostic platforms for the detection of DENV, especially in well-equipped diagnostic facilities. Their application in low-resource settings, however, is limited mostly due to the high cost and skill required. In this study, a novel RT-RPA assay was developed for the detection of DENV. The sensitivity and specificity of the RT-RPA assay were comparable to those of the RT-LAMP and qRT-PCR methods. The RT-RPA assay is rapid and simple to perform without the need for costly equipment or a high level of skill. Hence, it has the potential to be implemented as a routine diagnostic tool at health care centers and clinics in endemic regions where early detection of viremic dengue patients is needed for better treatment and outbreak control measures.

  • 41.
    Thalagala, Neil
    et al.
    Colombo, Sri Lanka.
    Tissera, Hasitha
    Colombo, Sri Lanka.
    Palihawadana, Paba
    Colombo, Sri Lanka.
    Amarasinghe, Ananda
    Colombo, Sri Lanka.
    Ambagahawita, Anuradha
    Colombo, Sri Lanka.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
    Shepard, Donald S
    Waltham, Massachusetts, United States of America.
    Tozan, Yeşim
    Heidelberg, Germany; New York, United States of America.
    Costs of Dengue Control Activities and Hospitalizations in the Public Health Sector during an Epidemic Year in Urban Sri Lanka2016In: PLoS Neglected Tropical Diseases, ISSN 1935-2727, E-ISSN 1935-2735, Vol. 10, no 2, article id e0004466Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Reported as a public health problem since the 1960s in Sri Lanka, dengue has become a high priority disease for public health authorities. The Ministry of Health is responsible for controlling dengue and other disease outbreaks and associated health care. The involvement of large numbers of public health staff in dengue control activities year-round and the provision of free medical care to dengue patients at secondary care hospitals place a formidable financial burden on the public health sector.

    METHODS: We estimated the public sector costs of dengue control activities and the direct costs of hospitalizations in Colombo, the most heavily urbanized district in Sri Lanka, during the epidemic year of 2012 from the Ministry of Health's perspective. The financial costs borne by public health agencies and hospitals are collected using cost extraction tools designed specifically for the study and analysed retrospectively using a combination of activity-based and gross costing approaches.

    RESULTS: The total cost of dengue control and reported hospitalizations was estimated at US$3.45 million (US$1.50 per capita) in Colombo district in 2012. Personnel costs accounted for the largest shares of the total costs of dengue control activities (79%) and hospitalizations (46%). The results indicated a per capita cost of US$0.42 for dengue control activities. The average costs per hospitalization ranged between US$216-609 for pediatric cases and between US$196-866 for adult cases according to disease severity and treatment setting.

    CONCLUSIONS: This analysis is a first attempt to assess the economic burden of dengue response in the public health sector in Sri Lanka. Country-specific evidence is needed for setting public health priorities and deciding about the deployment of existing or new technologies. Our results suggest that dengue poses a major economic burden on the public health sector in Sri Lanka.

  • 42.
    Tissera, Hasitha
    et al.
    Colombo, Sri Lanka.
    Amarasinghe, Ananda
    Colombo, Sri Lanka.
    Gunasena, Sunethra
    Colombo, Sri Lanka.
    DeSilva, Aruna Dharshan
    Colombo, Sri Lanka.
    Yee, Leong Wei
    Singapore, Singapore.
    Sessions, October
    Singapore, Singapore.
    Muthukuda, Chanaka
    Colombo, Sri Lanka.
    Palihawadana, Paba
    Colombo, Sri Lanka.
    Lohr, Wolfgang
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Byass, Peter
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Gubler, Duane J
    Singapore, Singapore.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
    Laboratory-Enhanced Dengue Sentinel Surveillance in Colombo District, Sri Lanka: 2012-20142016In: PLoS Neglected Tropical Diseases, ISSN 1935-2727, E-ISSN 1935-2735, Vol. 10, no 2, article id e0004477Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: Dengue has emerged as a significant public health problem in Sri Lanka. Historically surveillance was passive, with mandatory dengue notifications based on clinical diagnosis with only limited laboratory confirmation. To obtain more accurate data on the disease burden of dengue, we set up a laboratory-based enhanced sentinel surveillance system in Colombo District. Here we describe the study design and report our findings of enhanced surveillance in the years 2012-2014.

    METHODS: Three outpatient clinics and three government hospitals in Colombo District that covered most of the Colombo metropolitan area were selected for the sentinel surveillance system. Up to 60 patients per week presenting with an undifferentiated fever were enrolled. Acute blood samples from each patient were tested by dengue specific PCR, NS1 ELISA and IgM ELISA. A sub-set of samples was sent to Duke-NUS Singapore for quality assurance, virus isolation and serotyping. Trained medical research assistants used a standardized case report form to record clinical and epidemiological data. Clinical diagnoses by the clinicians-in-charge were recorded for hospitalized cases.

    RESULTS: Of 3,127 febrile cases, 43.6% were PCR and/or NS1 positive for dengue. A high proportion of lab confirmed dengue was observed from inpatients (IPD) (53.9%) compared to outpatient (clinics in hospitals and general practice) (7.6%). Dengue hemorrhagic fever (DHF) was diagnosed in 11% of patients at the time of first contact, and the median day of illness at time of presentation to the sentinel sites was 4. Dengue serotype 1 was responsible for 85% of the cases and serotype 4 for 15%. The sensitivity and specificity of the clinicians' presumptive diagnosis of dengue was 84% and 34%, respectively.

    CONCLUSION: DENV-1, and to a lesser degree DENV-4, infection were responsible for a high proportion of febrile illnesses in Colombo in the years 2012 to 2014. Clinicians' diagnoses were associated with high sensitivity, but laboratory confirmation is required to enhance specificity.

  • 43. Tozan, Yesim
    et al.
    Ratanawong, Pitcha
    Louis, Valérie R
    Kittayapong, Pattamaporn
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Use of insecticide-treated school uniforms for prevention of dengue in schoolchildren: a cost-effectiveness analysis2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 9, article id e108017Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Dengue-related illness is a leading cause of hospitalization and death, particularly among children. Practical, acceptable and affordable measures are urgently needed to protect this age group. Schools where children spend most of their day is proposed as an ideal setting to implement preventive strategies against day-biting Aedes mosquitoes. The use of insecticide-treated school uniforms is a promising strategy currently under investigation.

    METHODS: Using a decision-analytic model, we evaluated the cost-effectiveness of the use of insecticide-treated school uniforms for prevention of dengue, compared with a "do-nothing" alternative, in schoolchildren from the societal perspective. We explored how the potential economic value of the intervention varied under various scenarios of intervention effectiveness and cost, as well as dengue infection risk in school-aged children, using data specific to Thailand.

    RESULTS: At an average dengue incidence rate of 5.8% per year in school-aged children, the intervention was cost-effective (ICER≤$16,440) in a variety of scenarios when the intervention cost per child was $5.3 or less and the intervention effectiveness was 50% or higher. In fact, the intervention was cost saving (ICER<0) in all scenarios in which the intervention cost per child was $2.9 or less per year and the intervention effectiveness was 50% or higher. The results suggested that this intervention would be of no interest to Thai policy makers when the intervention cost per child was $10.6 or higher per year regardless of intervention effectiveness (ICER>$16,440).

    CONCLUSIONS: Our results present the potential economic value of the use of insecticide-treated uniforms for prevention of dengue in schoolchildren in a typical dengue endemic setting and highlight the urgent need for additional research on this intervention.

  • 44.
    Wilder-Smith, Annelies
    Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore and Institute of Public Health, University of Heidelberg, Heidelberg, Germany.
    Dengue in international travelers: quo vadis?2013In: Journal of Travel Medicine, ISSN 1195-1982, E-ISSN 1708-8305, Vol. 20, no 6, p. 341-343Article in journal (Refereed)
  • 45.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Nanyang Technol Univ, Lee Kong Chian Sch Med, Singapore 308232, Singapore. Heidelberg Univ, Inst Publ Hlth, Heidelberg, Germany .
    Dengue vaccines: dawning at last?2014In: The Lancet, ISSN 0140-6736, E-ISSN 1474-547X, Vol. 384, no 9951, p. 1327-1329Article in journal (Refereed)
  • 46.
    Wilder-Smith, Annelies
    et al.
    National University of Singapore, Department of Medicine, Singapore.
    Lover, A
    Kittayapong, P
    Burnham, G
    Hypothesis: Impregnated school uniforms reduce the incidence of dengue infections in school children2011In: Medical Hypotheses, ISSN 0306-9877, E-ISSN 1532-2777, Vol. 76, no 6, p. 861-862Article in journal (Refereed)
    Abstract [en]

    Dengue infection causes a significant economic, social and medical burden in affected populations in over 100 countries in the tropics and sub-tropics. Current dengue control efforts have generally focused on vector control but have not shown major impact. School-aged children are especially vulnerable to infection, due to sustained human-vector-human transmission in the close proximity environments of schools. Infection in children has a higher rate of complications, including dengue hemorrhagic fever and shock syndromes, than infections in adults. There is an urgent need for integrated and complementary population-based strategies to protect vulnerable children. We hypothesize that insecticide-treated school uniforms will reduce the incidence of dengue in school-aged children. The hypothesis would need to be tested in a community based randomized trial. If proven to be true, insecticide-treated school uniforms would be a cost-effective and scalable community based strategy to reduce the burden of dengue in children.

  • 47.
    Wilder-Smith, Annelies
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Quam, Mikkel
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Sessions, O.
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Liu-Helmersson, Jing
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Franco, L.
    Khan, K.
    The 2012 dengue outbreak in Madeira: exploring the origins2014In: Eurosurveillance, ISSN 1025-496X, E-ISSN 1560-7917, Vol. 19, no 8, p. 20718-Article in journal (Refereed)
    Abstract [en]

    In 2012, Madeira reported its first major outbreak of dengue. To identify the origin of the imported dengue virus, we investigated the interconnectivity via air travel between dengue-endemic countries and Madeira, and compared available sequences against GenBank. There were 22,948 air travellers to Madeira in 2012, originating from twenty-nine dengue-endemic countries; 89.6% of these international travellers originated from Venezuela and Brazil. We developed an importation index that takes into account both travel volume and the extent of dengue incidence in the country of origin. Venezuela and Brazil had by far the highest importation indices compared with all other dengue-endemic countries. The importation index for Venezuela was twice as high as that for Brazil. When taking into account seasonality in the months preceding the onset of the Madeira outbreak, this index was even seven times higher for Venezuela than for Brazil during this time. Dengue sequencing shows that the virus responsible for the Madeira outbreak was most closely related to viruses circulating in Venezuela, Brazil and Columbia. Applying the importation index, Venezuela was identified as the most likely origin of importation of dengue virus via travellers to Madeira. We propose that the importation index is a new additional tool that can help to identify and anticipate the most probable country of origin for importation of dengue into currently non-endemic countries.

  • 48.
    Wilder-Smith, Annelies
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Renhorn, Karl-Erik
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Tissera, Hasitha
    Abu Bakar, Sazaly
    Alphey, Luke
    Kittayapong, Pattamaporn
    Lindsay, Steve
    Logan, James
    Hatz, Christoph
    Reiter, Paul
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Byass, Peter
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Louis, Valerie R.
    Tozan, Yesim
    Massad, Eduardo
    Tenorio, Antonio
    Lagneau, Christophe
    L'Ambert, Gregory
    Brooks, David
    Wegerdt, Johannah
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Gubler, Duane
    DengueTools: innovative tools and strategies for the surveillance and control of dengue2012In: Global Health Action, ISSN 1654-9716, E-ISSN 1654-9880, Vol. 5, p. 17273-Article in journal (Refereed)
    Abstract [en]

    Dengue fever is a mosquito-borne viral disease estimated to cause about 230 million infections worldwide every year, of which 25,000 are fatal. Global incidence has risen rapidly in recent decades with some 3.6 billion people, over half of the world's population, now at risk, mainly in urban centres of the tropics and subtropics. Demographic and societal changes, in particular urbanization, globalization, and increased international travel, are major contributors to the rise in incidence and geographic expansion of dengue infections. Major research gaps continue to hamper the control of dengue. The European Commission launched a call under the 7th Framework Programme with the title of 'Comprehensive control of Dengue fever under changing climatic conditions'. Fourteen partners from several countries in Europe, Asia, and South America formed a consortium named 'DengueTools' to respond to the call to achieve better diagnosis, surveillance, prevention, and predictive models and improve our understanding of the spread of dengue to previously uninfected regions (including Europe) in the context of globalization and climate change. The consortium comprises 12 work packages to address a set of research questions in three areas: Research area 1: Develop a comprehensive early warning and surveillance system that has predictive capability for epidemic dengue and benefits from novel tools for laboratory diagnosis and vector monitoring. Research area 2: Develop novel strategies to prevent dengue in children. Research area 3: Understand and predict the risk of global spread of dengue, in particular the risk of introduction and establishment in Europe, within the context of parameters of vectorial capacity, global mobility, and climate change. In this paper, we report on the rationale and specific study objectives of 'DengueTools'. DengueTools is funded under the Health theme of the Seventh Framework Programme of the European Community, Grant Agreement Number: 282589 Dengue Tools.

  • 49.
    Wilder-Smith, Annelies
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Sessions, O.
    Massad, E.
    Khan, K.
    The dengue outbreak in Madeira 2012: exploring the origins2013Conference paper (Other academic)
  • 50.
    Wilder-Smith, Annelis
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Preet, Raman
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Renhorn, Karl-Erik
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Ximenes, R. A.
    Rodrigues, L. C.
    Solomon, T.
    Neyts, J.
    Lambrechts, L.
    Willison, H.
    Peeling, R.
    Falconar, A. K.
    Precioso, A. R.
    Logan, J.
    Lang, T.
    Endtz, H. P.
    Erasmus, M. C.
    Massad, E.
    ZikaPLAN: Zika Preparedness Latin American Network2017In: Global Health Action, ISSN 1654-9716, E-ISSN 1654-9880, Vol. 10, no 1, article id 1398485Article in journal (Refereed)
    Abstract [en]

    The ongoing Zika virus (ZIKV) outbreak in Latin America, the Caribbean, and the Pacific Islands has underlined the need for a coordinated research network across the whole region that can respond rapidly to address the current knowledge gaps in Zika and enhance research preparedness beyond Zika. The European Union under its Horizon 2020 Research and Innovation Programme awarded three research consortia to respond to this need. Here we present the ZikaPLAN (Zika Preparedness Latin American Network) consortium. ZikaPLAN combines the strengths of 25 partners in Latin America, North America, Africa, Asia, and various centers in Europe. We will conduct clinical studies to estimate the risk and further define the full spectrum and risk factors of congenital Zika virus syndrome (including neurodevelopmental milestones in the first 3 years of life), delineate neurological complications associated with ZIKV due to direct neuroinvasion and immune-mediated responses in older children and adults, and strengthen surveillance for birth defects and Guillain-Barré Syndrome. Laboratory-based research to unravel neurotropism and investigate the role of sexual transmission, determinants of severe disease, and viral fitness will underpin the clinical studies. Social messaging and engagement with affected communities, as well as development of wearable repellent technologies against Aedes mosquitoes will enhance the impact. Burden of disease studies, data-driven vector control, and vaccine modeling as well as risk assessments on geographic spread of ZIKV will form the foundation for evidence-informed policies. While addressing the research gaps around ZIKV, we will engage in capacity building in laboratory and clinical research, collaborate with existing and new networks to share knowledge, and work with international organizations to tackle regulatory and other bottlenecks and refine research priorities. In this way, we can leverage the ZIKV response toward building a long-term emerging infectious diseases response capacity in the region to address future challenges.

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