Experimental Infection of Fox Squirrels (Sciurus Niger) With West Nile Virus

Authors

J. Jeffrey Root, Colorado State University - Fort CollinsFollow
Paul T. Oesterle, Colorado State University - Fort Collins
Nicole M. Nemeth, Colorado State University - Fort Collins
Kaci Klenk, Colorado State University - Fort Collins
Daniel H. Gould, Colorado State University - Fort Collins
Robert G. Mclean, Colorado State University - Fort CollinsFollow
Larry Clark, Colorado State University - Fort CollinsFollow
Jeffrey S. Hall, Colorado State University - Fort CollinsFollow

Document Type

Article

Date of this Version

2006

Citation

American Journal of Tropical Medicine and Hygiene, 75(4), 2006, pp. 697–701

Comments

Copyright 2006 by The American Society of Tropical Medicine and Hygiene

Abstract

Tree squirrels (Sciurus spp.) have exhibited high seroprevalence rates, suggesting that they are commonly exposed to West Nile virus (WNV). Many characteristics of WNV infections in tree squirrels, such as the durations and levels of viremia, remain unknown. To better understand WNV infections in fox squirrels (S. niger), we subcutaneously inoculated fourteen fox squirrels with WNV. Peak viremias ranged from 10^4.00 plaque-forming units (PFU)/mL of serum on day 2 post-infection (DPI) to 10^4.98 PFU/mL on 3 DPI, although viremias varied between individuals. Oral secretions of some fox squirrels were positive for WNV viral RNA, occasionally to moderate levels (10^3.2 PFU equivalent/swab). WNV PFU equivalents in organs were low or undetectable on 12 DPI; gross and histologic lesions were rare. The viremia profiles of fox squirrels indicate that they could serve as amplifying hosts in nature. In addition, viral RNA in the oral cavity and feces indicate that this species could contribute to alternative WNV transmission in suburban communities.