Investigation on arboviruses at Sino-Vietnam border areas in Wenshan of Yunnan province

OBJECTIVE: To investigate arboviruses in Wenshan and Hekou county which are the Sino-Vietnam frontier regions of Wenshan, Yunnan province, China. METHODS: In September 2007, 6091 Culicines, 1334 Anophelines, 848 Aedes vexans and 53 Armigeres obturbans were collected from 5 field sites. Mosquitoes were collected and stored in liquid nitrogen after classification. The mosquito pools were homogenized, and centrifuged, then the supematant was inoculated onto C6/36 and BHK-21 cells, and the viral isolates were identified by serological and molecular biological methods.Sequence alignment and phylogenetic analysis on the viral isolates were carried out using Clustal X 1.85, GENEDOC and MEGA4 software. RESULTS: A total of 4 pairs of virus isolated with C6/36 cells cytopathic effect were observed, and other mosquito species have not cytopathic effect.Strain WS0704-2 was Banna virus which identified by antibody response and PCR. Strain WS0704-1, WS0708-1, WS0708-2 were Culex pipens pallens densovirus (CppDNV) which identified by PCR. The phylogenetic analysis the 12th segment showed significant difference between the new Banna virus and other strains isolated in China. CONCLUSION: There are many mosquito vectors in frontier regions (China and Vietnam) of Wenshan in Yunnan province of China, and mosquito-borne arbovirus, such as BAV were isolated here.