House sparrows, Passer domesticus (L.), as hosts of arboviruses in Hale County, Texas: I. Field studies, 1965-1969 *

Pathology and Virus Detection in Tissues of Nestling House Sparrows Naturally Infected With Buggy Creek Virus (Togaviridae)

“…Of those, 14 were from nestlings, and virus was isolated from brain, lung, heart, liver, and blood. Holden et al (1973b) also recovered WEEV from brain samples of dead nestlings. Our findings of BCRV in the brains of ill and dead House Sparrow nestlings support the earlier studies of Hayes et al (1977) and Scott et al (1984), where only brain tissue was tested for virus.…”

“…Fifteen of the 18 nestlings (83.3%) found ill or dead were positive for BCRV by virus isolation and RT-PCR from tissues. Studies of WEEV and BCRV have shown little isolation of active virus in adult birds, with most field-collected isolates obtained from brain tissue or blood of nestlings (Holden et al, 1973b;Scott et al, 1984;McLean et al, 1989;Milby and Reeves, 1990;O'Brien and Brown, unpubl. data).…”

“…However, nestlings are difficult to locate for virus sampling, and sick or dead nestlings with sequelae attributable to viruses are not typically discovered in field studies (McLean, 2006). Infection studies involving altricial nestling birds are rare, and challenges in husbandry of nestlings make following the clinical progression of disease and attributing mortality to virus infection problematic (Holden et al, 1973a;Scott et al, 1990;Mahmood et al, 2004).…”

Prevalence and Pathology of West Nile Virus in Naturally Infected House Sparrows, Western Nebraska, 2008

“…29 House sparrow nestlings testing positive for WEEV in a Texas survey tended to be clustered by nest, with virus concurrently detected in oral sampling, which indicates possible contact transmission of WEEV between birds in nests. 12 Direct transmission of BCRV was demonstrated in an experimental inoculation study involving house sparrows, 15 perhaps through fecal contamination of water or food sources. The two nestlings examined by necropsy had feces on the ventral body surface, indicating they may have become unable to preen or perhaps to properly defecate out of the nest entrance because of morbidity from virus infection, which could further expose nest mates to WNV.…”

“…For example, WNV-infected young white leghorn chicks ( Gallus gallus domesticus ) exhibited greater viremias and more severe clinical response than older ones. 10 Western equine encephalomyelitis virus (WEEV) caused low to no mortality in adult house sparrows ( Passer domesticus ) in experimental infection studies 4,11 but is fatal to sparrow nestlings when they are infected naturally in the field 12 or experimentally infected in the laboratory. 4 Adult house sparrows inoculated with Buggy Creek virus (BCRV), an alphavirus in the WEEV antigenic complex, 13,14 develop transient to no viremia 15 and are not found viremic in field surveys (O'Brien V and Brown C, unpublished data), but field-sampled nestling house sparrows have high viremias and often die of virus infection.…”