Transmission of endemic St Louis encephalitis virus strains by local Culex quinquefasciatus populations in Córdoba, Argentina

Received 20 September 2012; revised 21 January 2013; accepted 23 January 2013Background: St Louis encephalitis virus (SLEV) is a re-emerging human pathogen widely distributed in theAmerican continent. Although it is not fully understood, the SLEV transmission network may involve Culexquinquefasciatus mosquitoes as vectors and Columbidae species as hosts.Methods: To calculate infection rates, we inoculated Cx. quinquefasciatus mosquitoes from Co´rdoba, Argentinaby feeding them on viremic chicks.Results: We observed differences in infection rate among the viral strains, the highest rate (78/87 mosquitoes,90.8%) being seen in strain 78V-6507. After re-feeding on susceptible chicks, mosquitoes were able to transmitthe virus.Conclusion: Our findings suggest that Cx. quinquefasciatus populations are susceptible to and able to transmitdifferent SLEV strains.Keywords: St Louis encephalitis virus, Culex quinquefasciatus, Mosquitoes, Viral strains, Vector competence, Co´rdoba, Argentina