Experimental Infection of Cliff Swallows (Petrochelidon pyrrhonota) with Varying Doses of West Nile Virus

Authors

Paul T. Oesterle
Nicole M. Nemeth
Kaci K. VanDalen, USDA/APHIS/WS National Wildlife Research CenterFollow
Heather Sullivan, USDA/APHIS/WS National Wildlife Research CenterFollow
Kevin T. BentlerFollow
Ginger R. Young, USDA/APHIS/WS National Wildlife Research Center
Robert G. McLeanFollow
Larry Clark, USDA/APHIS/WS National Wildlife Research CenterFollow
Cynthia Smeraski
Jeffrey S. HallFollow

Document Type

Article

Date of this Version

2009

Comments

Published in Am. J. Trop. Med. Hyg., 81(6), 2009, pp. 1159–1164.

Abstract

Cliff swallows (Petrochelidon pyrrhonota) were inoculated with differing doses of West Nile virus (WNV) to evaluate their potential role as reservoir hosts in nature. Swallows often nest in large colonies in habitats and months associated with high mosquito abundance and early WNV transmission in North America. Additionally, cliff swallow diet consists of insects, including mosquitoes, leading to an additional potential route of WNV infection. The average peak viremia titer among infected cliff swallows was 10^6.3 plaque-forming units (PFU)/mL serum and the reservoir competence index was 0.34. There was no correlation between dose and probability of becoming infected or viremia peak and duration. Oral shedding was detected from 2 to 14 days post-inoculation with an average peak titer of 10^4.4 PFU/swab. These results suggest that cliff swallows are competent reservoir hosts of WNV and therefore, they may play a role in early seasonal amplification and maintenance of WNV.