Exploring entomological factors associated with high dengue incidence in Thai schools
2015 (English)In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 20, no Suppl. 1, 411-411 p.Article in journal, Meeting abstract (Other academic) Published
Introduction: Dengue infection is a leading cause of child hospitalization in Thailand and schools may represent an important site of infection. Because high variations in the number of dengue cases were observed among schools, the aim of this study was to explore what entomological factors were associated with high dengue incidence in selected schools located in Chacheongsao Province, Thailand.
Methods: Students from ten schools were enrolled; blood was taken at baseline (June 2012) and at the end of the school term (Nov. 2012). New dengue infections during this period were determined by dengue IgG conversion or a > 4-fold higher dengue IgG compared to baseline. Location of the homes and schools of infected students were mapped using GIS. Through monthly surveys from May 2013 to June 2014, potential breeding sites were identiﬁed, infestation with Aedes larvae and pupae recorded, and adult mosquitoes collected using portable aspirators. Logistic regression was used for statistical analysis.
Results: A total of 1825 students were included in the study. They were distributed among 88 classrooms within the 10 schools. 55 conﬁrmed dengue cases were detected in seven of the 10 schools. 67% of the cases occurred in 13 (15%) of the 88 classrooms, with at least 2 (and as many as 6) cases occurring per classroom. The remaining 18 cases were detected as single cases per classroom. No two cases occurred in the same households and eight cases occurred in households distant 100 meters or less from each other. There was no direct association between high and low incidence schools in relation to the number of breeding sites, mosquitoes, or mosquito control methods used. Of the 2399 potential breeding sites recorded, 484 (20%) were positive for Aedes larvae or pupae. Among the productive sites, the most common were water and cement tanks (30%) and car tires (9%). Mosquito control was used for 11% of breeding sites, with temephos (32%), ﬁsh (24%) and covers (30%) being the most common measures taken.
Conclusion: The study provides information on the main breeding sites for larvae and pupae and the commonly used mosquito control methods around schools. Although there was no signiﬁcant association found between entomological factors and dengue cases at school levels, the study suggests that transmission may be clustered at classroom level rather than at household level.
Disclosure: This research was funded by the European Union 7th Framework Programme through 'DengueTools'.
Place, publisher, year, edition, pages
Wiley-Blackwell, 2015. Vol. 20, no Suppl. 1, 411-411 p.
Public Health, Global Health, Social Medicine and Epidemiology
IdentifiersURN: urn:nbn:se:umu:diva-109937ISI: 000360758802267OAI: oai:DiVA.org:umu-109937DiVA: diva2:861339
The 9th European Congress on Tropical Medicine and International Health (ECTMIH), Basel, Switzerland, September 6-10, 2015