Eared Dove ( Zenaida Auriculata , Columbidae) as Host for St. Louis Encephalitis Virus (Flaviviridae, Flavivirus)

Abstract

The St. Louis encephalitis virus (SLEV) is an emerging Flavivirus in South America countries. Its ecology and biological transmission cycles are scarcely known. Eared doves (Zenaida auriculata) were frequently found infected by the SLEV, therefore, it could be suspected as SLEV avian host. Thirty eared doves were inoculated subcutaneously with SLEV 78-6507 viral strain and bled daily. Mosquitoes collections were carried out using can traps baited with chicken and eared doves for comparison. No death or clinical signs of illness were observed in the inoculated doves. The viremia titers ranged between 2 and 5.52 log10 pfu/mL during 1 to 7 days post inoculation, the highest being observed on the 4th dpi. Four types of viremia profiles were observed: Class Ia (viremia titers ¡Ý 4 log10/mL, duration 1-3 days), Class Ib (viremia titers ¡Ý 4 log10/mL, duration 4-6 days), Class II (viremia titers ranging 2¨C3 log10/mL, duration 1-3 days), and Class III (no viremia developed). A total of 2,792 mosquitoes belonging to 5 species were collected. The 90% of mosquitoes collected in eared dove baited can traps were Culex quinquefasciatus. Statistical differences were observed between engorged and not engorged mosquitoes in both chicken and eared dove baited can traps (F = 59.71; df = 1; P < 0.0001). Considering eared doves were frequently found naturally infected by the SLEV, developed viremia titers higher than minimal infection threshold and long enough to infect to Cx. quinquefasciatus, and these mosquitoes also fed on eared doves, it could be considered as a competent avian host for the SLE virus.