Change search
ReferencesLink to record
Permanent link

Direct link
The 2012 dengue outbreak in Madeira: exploring the origins
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.ORCID iD: 0000-0003-0362-5375
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, Epidemiology and Global Health.ORCID iD: 0000-0003-4030-0449
Show others and affiliations
2014 (English)In: Eurosurveillance, ISSN 1025-496X, E-ISSN 1560-7917, Vol. 19, no 8, 20718- p.Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
2014. Vol. 19, no 8, 20718- p.
National Category
Infectious Medicine
URN: urn:nbn:se:umu:diva-87645ISI: 000332376900002OAI: diva2:711234
Available from: 2014-04-09 Created: 2014-04-07 Last updated: 2016-03-30Bibliographically approved
In thesis
1. Imported infections’ importance: global change driving Dengue dynamics
Open this publication in new window or tab >>Imported infections’ importance: global change driving Dengue dynamics
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Vikten av importerade infektioner : kan globala förändringar förklara Dengue utbrott?
Abstract [en]

Background Dengue is a significant problem of international health concern. According to the World Health Organization in 2012, globally, dengue is “the most important mosquito borne viral disease” with incidence 30 higher than it had been 50 years ago. While most of the burden of disease associated with dengue is located in areas with a tropical and sub-tropical climate, increasing evidence suggests temperate areas are also at risk. Considering the recent introduction of relevant mosquito vectors into Southern Europe, and increasing numbers of imported dengue via travelers, Europe and other temperate areas may be increasingly at risk for dengue emergence, establishment and local transmission in the foreseeable future.

Methods Recent dengue emergence in Madeira and reemergence in Tokyo underline the hypothesis that passenger air-travel can be an important conduit for the importation of vector-borne disease leading to emergence in naïve areas climatically suitable for dengue transmission, including parts of Europe. Combining information on travel with virus genetic similarity was useful in discerning likely pathways of for the importation of infections. Generalizing information learned from outbreaks in Tokyo and Madeira with global epidemic intelligence, global travel networks, and climate change projections, leads to more refined understanding of the magnitude of dengue infectious imported into temperate areas and these virus introduction events’ potential implications for seeding epidemics in the 21st century.

Results While compared to total travel, imported dengue events and epidemics of dengue outside the tropics are rare, our combined evidence and modeled estimations suggest strongly that epidemic dengue emergence in temperate areas is possible and will continue to increase. We found that global change dynamics including warming temperatures in the much of the northern hemisphere and increasing passenger interconnectivity between areas endemic for dengue and dengue free areas are key mechanisms partly explaining these unprecedented epidemiological transitions.

Conclusion While we calibrated our models on information known about dengue, many elements of the methods and conclusions may increase understanding of the potentially global implications for imported infections of other climate-sensitive infectious diseases’ that may have similar parameters. During 2016 and the years to come, techniques developed in this doctoral research will contribute to models used in risk analysis for vector-borne diseases of interest, including the increasing important potential for imported Chikungunya and Zika viruses into a variety of unexposed areas. 

Place, publisher, year, edition, pages
Umeå: Umeå University, 2016. 99 p.
Umeå University medical dissertations, ISSN 0346-6612 ; 1793
Dengue, Zika, Vector-borne Disease, Aedes, Global Change, Climate Change, Viral Evolution, Phylogenetics, Travel, Interconnectivity, Disease Modeling, Madeira, Italy, Japan, Europe
National Category
Public Health, Global Health, Social Medicine and Epidemiology
urn:nbn:se:umu:diva-118645 (URN)978-91-7601-443-1 (ISBN)
Public defence
2016-04-22, Room 135, Building 9A, Northlands University Hospital (sal 135, byggnad 9A, Norrlands Universitetssjukhus), Umeå, Sweden, 13:00 (English)
EU, FP7, Seventh Framework Programme, 282589
Available from: 2016-03-31 Created: 2016-03-28 Last updated: 2016-04-20Bibliographically approved

Open Access in DiVA

No full text

Other links

Search in DiVA

By author/editor
Wilder-Smith, AnneliesQuam, MikkelRocklöv, JoacimLiu-Helmersson, Jing
By organisation
Epidemiology and Global Health
In the same journal
Infectious Medicine

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 117 hits
ReferencesLink to record
Permanent link

Direct link