Dose dependence of susceptibility and transmission for an Argentinean West Nile virus strain in local Culex pipiens quinquefasciatus (Diptera: Culicidae)

Abstract

Abstract Background West Nile virus (WNV) activity has been documented in the central region of Argentina since 2005, but its maintenance network has not been elucidated yet. Methods We evaluated the susceptibility to WNV oral infection and transmission in a Culex pipiens quinquefasciatus mosquito population by means of a dose-dependent vector competence assay. Mosquitoes were orally infected with five different viral loads and evaluated for viral infection, dissemination and transmission. Results The evaluated population was susceptible to WNV oral infection. Disseminated infections were detected in all the viral doses but transmission was only detected in the higher doses (6 and 7 log10 plaque-forming units/ml). A linear relationship between doses and transmission rates could be established. Conclusions A minimum transmission threshold suggests that the Cu. p. quinquefasciatus from Argentina could acquire WNV infection from local urban birds and transmit the virus.