DOUBLE INFECTION OF HETEROSEROTYPES OF DENGUE VIRUSES IN FIELD POPULATIONS OF AEDES AEGYPTI  AND AEDES ALBOPICTUS (DIPTERA: CULICIDAE) AND SEROLOGICAL FEATURES OF DENGUE VIRUSES FOUND IN PATIENTS IN SOUTHERN THAILAND


Usavadee Thavara 1
Padet Siriyasatien 2
Apiwat Tawatsin 1
Preecha Asavadachanukorn 3
Surapee Anantapreecha 1
Ratree Wongwanich 4
Mir S Mulla 5

Affiliations :
1 National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Nonthaburi
2 Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok
3 Department of Statistics, Faculty of Commerce and Accountancy, Chulalongkorn University, Bangkok
4 Krabi Provincial Health Office, Krabi, Thailand
5 Department of Entomology, University of California, Riverside, California, USA

Source :
       Southeast Asian J Trop Med Public Health Vol 37 No3 May 2006 : 468-476

Language :
       English

Abstract :
      In order to understand more about the epidemiology of DHF, a study of the type of dengue viruses and vectors under natural conditions was carried out. Mosquito vectors in the field and the serum of DHF patients in southern Thailand were examined. The two mosquito species are abundant and DHF incidence remains high in this region. Dengue viruses were examined in field-caught mosquitoes by RT-PCR technique. The mosquitoes were caught in 4 provinces: Krabi, Phuket, Phang-Nga and Surat Thani during the late dry season until the early rainy season in 2005. Three dengue serotypes (DEN-2, DEN-3, DEN-4) were detected in Ae. aegypti  males and females, and 2 (DEN-2, DEN-3) were detected in Ae. aibopictus  females. Double infection with 2 serotypes of dengue viruses (DEN-2 and DEN-3) were detected in Ae. aegypti  males and females and Ae. aibopictus  females. DEN-2 and DEN-1 were the most prevalent serotypes found in the serum of the patients in this area, followed by DEN-4 and DEN-3, The prevalence of the predominant dengue serotype varied from province to province. Detection of viruses in adult male mosquitoes reveals the role of transovarial transmission of dengue viruses in field populations of DHF vectors and elucidates circulation of dengue viruses in vectors in the natural environment of endemic areas. The incidence of multiple serotypes of dengue virus in Ae. aegypti  and Ae. aibopictus  in the same area points toward a high risk for an epidemic of DHF. These findings provide greater understanding of the relationship among mosquito vectors, virus transmission and DHF epidemiology in endemic areas.

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