Bionomic studies of sylvatic mosquito species as putative vectors of arboviral disease in primary forest in Lao PDR.

Project leader: Dr. Khamsing Vongphayloth

Funding of the project:  PTR 409 Institut Pasteur Paris

Partners: None

Description of the project and objectives :

To study the bionomics of the sylvatic Aedes species and to analyze mosquito specimens for arboviral infections using RT-PCR

In depth entomological survey was carried out from 2011 to 2013 on the Nam Noy river basin and 53 species of mosquitoes were identified. These species belong mainly to the genera: Aedes, Anopheles and Culex. Of the 7605 specimens collected (field collected larvae reared to adults in the IP Laos field lab), 3300 have been screened by RT-PCR using pan-alphavirus and pan-flavivirus primers. Among the 31 positives, 14 were pan-alpha positive, and 17 pan-flavi positive. These positives were isolated from 15 different mosquito species. The positive specimens were obtained from laboratory-emerged adults (none of these mosquitoes were blood fed) indicating that the detected viral sequences were derived from vertical transmission. Vertical transmission is well documented in arboviral infections in mosquitoes and could play an important role in the maintenance of the viruses if amplifying hosts such as, monkeys, man, or other forest mammals are not available or immune. The next step is to try to culture these viruses on C636 and vero cells and to sequence the resultant viral isolates.