Experimental studies to determine the susceptibility to infection with St. Louis encephalitis virus of five species of Panamanian mosquitoes
Hayes, C.G.; Dutary, B.E.; Reeves, W.C.; Adames, A.J.; Galindo, P.
Journal of the American Mosquito Control Association 7(4): 584-587
1991
ISSN/ISBN: 8756-971X PMID: 1686273 Document Number: 376409
The susceptibility to infection with a Panamanian isolate of St. Louis encephalitis (SLE) virus was evaluated in Culex quinquefasciatus, Haemagogus equinus, Mansonia dyari, Sabethes cyaneus and Deinocerites pseudes. When fed on blood-virus suspensions using the hanging drop or pledget technique, the median infective dose (ID50) of SLE virus for colonized strains of C. quinquefasciatus and H. equinus was 102.8 plaque forming units (PFU)/2 micro l and 103.5 PFU/2 micro l, respectively. The susceptibility of F1 and F2 C. quinquefasciatus females was similar to the colonized strain by the same technique. When fed on viraemic chicks, the ID50 for both C. quinquefasciatus and H. equinus was 100.5 PFU/2 micro l. These results and successful transmission trials indicated that both of these species have the potential to serve as vectors of SLE virus in Panama. Because of their poor feeding response, complete susceptibility profiles were not obtained for the other 3 species tested. They appear to be less susceptible than C. quinquefasciatus and H. equinus, although M. dyari was readily infected after engorging on a blood-virus suspension with a titre of 103.0 PFU/2 micro l. Laboratory results indicated that both Culex quinquefasciatus and Haemagogus equinus could be vectors of St Louis encephalitis virus (although the virus has not been isolated from either species in Panama). Data for 3 other Panamanian mosquito species-Mansonia dyari, Sabethes cyaneus and Deinocerites pseudes-were incomplete but indicated that they were less susceptible to infection with this virus.Carolyn A. Brown.