Usavadee Thavara*
Padet Siriyasatien**
Apiwat Tawatsin*
Jakkrawarn Chompoosri*
Surapee Anantapreecha*
Ratree Wongwanich***
Mir S. Mulla****
Affiliations:
* National Institute of Health, Department of Medical Sciences, Ministry of
Public Health, 88/7 Tiwanon Road, Nonthaburi 11000, Thailand
** Department of Parasitology, Faculty of Medicine, Chulalongkorn University,
Bangkok 10330, Thailand
*** Krabi Provincial Health Office, Krabi 81000, Thailand
**** Department of Entomology, University of California, Riverside, CA 92521,
U.S.A.
Source :
Presented in the 4th International
Congress of Vector Ecology (SOVE),
Reno, Nevada, U.S.A., 2 – 7 October 2005.
Language :
English
Abstract:
Dengue haemorrhagic fever
(DHF) remains one of the major mosquito-borne diseases in Thailand as well as
other countries in tropical regions. The disease is caused by 4 serotypes of
dengue viruses (Den-1, Den-2, Den-3 and Den-4) and transmitted to humans by
two mosquito species: Aedes aegypti (L.) and Aedes albopictus
(Skuse). To understand more about the epidemiology of the disease, study of
the association of viruses and vectors under natural conditions was carried
out employing determination of viruses in field populations of mosquito vectors
in southern provinces of Thailand, where the two mosquito species are abundant
and DHF incidence remains high. Attempts were made to detect dengue viruses
in field-caught mosquitoes individually by Semi-Nested RT-PCR technique. The
vectors were captured from 4 provinces: Krabi, Phang Nga, Phuket and Surat Thani
during the period between late dry season and early rainy season in 2005. The
3 serotypes of dengue viruses: Den-2, Den-3 and Den-4 were detected in both
Ae. aegypti and Ae. albopictus individual females
and males. It is interesting to note that Ae. aegypti larvae
were positive for each the 2 serotypes: Den-2 and Den-3. Double infections of
2 serotypes of the viruses (Den-2 and Den-3) were detected in individual Ae.
aegypti and Ae. albopictus females and males. This study thus
reveals an important role of transovarial trasmission of dengue viruses in field
populations of DHF vectors. The study elucidates circulation of dengue viruses
in vectors in natural environment in endemic areas.