West Nile Virus Viremia in Eastern Chipmunks (Tamias striatus) Sufficient for Infecting Different Mosquitoes

Abstract

<p>In eastern chipmunks (<em>Tamias striatus</em>) inoculated intramuscularly with 101.5 to 105.7 PFU of West Nile virus (WNV), serum titers developed sufficient to infect <em>Aedes triseriatus</em> (Say), <em>Ae. vexans</em> (Meigen), and<em>Culex pipiens</em> (L.). Mean titers (95% confidence interval) of 8 chipmunks were 103.9(3.3–4.5), 106.7(6.4–7.0), and 105.8(4.1–7.5) PFU/mL on days 1–3 postinoculation (p.i.) and 105.8 PFU/mL in 1 chipmunk on day 4 p.i. Mean estimated days that WNV titers were >104.8 and >105.6 were 1.7 (1.1–2.3) and 1.4 (1.0–1.6). The longest period of viremia >104.8 PFU/mL was 3–4 days. WNV antigen was detected in the small intestine of 2 chipmunks and the kidneys of 4 chipmunks by immunohistochemistry. WNV also was detected in urine, saliva, and feces of some chipmunks. These data suggest chipmunks might play a role in enzootic WNV cycles and be an amplifying host for mosquitoes that could infect humans.</p>