Detection of host virus-reactive antibodies in blood meals of naturally engorged mosquitoes.
Although serosurvey in human or animals is a useful and straightforward strategy routinely used for public health, it often faces different types of impediments: ethics, beliefs, limitation by animal owners, hazard of access to wild animals. To survey virus circulation, we applied the enzyme-linked immunosorbent assay (ELISA) technique to detect Dengue and Japanese encephalitis (JE) virus-reactive antibodies in blood meals collected from mosquitoes without regard to the potential of mosquito species to be a virus vector. ELISA was performed on mosquito colonies and wild specimens collected from farms and urban areas. Blood meals from Aedes aegypti freshly fed on naturally infected volunteers showed the same levels of dengue immunoglobulin (Ig)G and IgM as the sera directly collected from volunteers. A significant clearance of antibodies during the digestion process started from 13 hours after blood meal, and a negative baseline was reached after 30 hours. The ELISA test performed on wild mosquitoes showed that 37% of Culex quinquefasciatus mosquitoes that engorged on humans in a dengue urban endemic area tested positive for dengue IgG, and in a JE virus-endemic area, 88% of Culex tritaeniorhynchus mosquitoes that engorged on pigs from a large pig farm tested positive for JE virus antibodies versus 11% in a small farm. The main limitation of the ELISA method is the antibody cross-reactivity among flaviviruses; also, sampling strategy should be adjusted to take into account that the actual host from which the blood meal was taken may not be determined. Nevertheless, ELISA performed on recently (1-2 days) engorged mosquito, or any other hematophagous arthropod species, could potentially be used as a "wild phlebotomist" to monitor the prevalence or emergence of a variety of pathogens, with less of the practical, ethical, or risk limitations due to direct blood collection from humans and wild or domestic animals.
Barbazan
Philippe
P
Department of Center for Vectors and Vector-Borne Diseases, Mahidol University, Bangkok, Thailand.
Palabodeewat
Somnuek
S
Nitatpattana
Narong
N
Gonzalez
Jean-Paul
JP
D000330:Aedes / Q000821:virology*; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D003429:Cross Reactions; D003465:Culex / Q000821:virology*; D003715:Dengue / Q000635:transmission; D003716:Dengue Virus / Q000276:immunology / Q000302:isolation & purification*; D004664:Encephalitis Virus, Japanese / Q000276:immunology / Q000302:isolation & purification*; D004672:Encephalitis, Japanese / Q000635:transmission; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007303:Insect Vectors / Q000821:virology*; D011634:Public Health; D013552:Swine; D013997:Time Factors
D000914:Antibodies, Viral