Experimental Inoculation of House Sparrows (Passer Domesticus) With Buggy Creek Virus

Abstract

ABSTRACT:We performed experimental inoculations of house sparrows (Passer domesticus) with Buggy Creek virus (BCRV), a poorly known alphavirus (Togaviridae) vectored primarily by the swallow bug (Hemiptera: Cimicidae: Oeciacus vicarius) that is an ectoparasite of the cliff swallow (Petrochelidon pyrrhonota) and house sparrow. Viremias were detected by plaque assay in two of six birds on days 1-3 postinoculation; viremia was highest on day 2. Viral RNA was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) in blood of six of 12 birds ranging from day 1 to day 15 postinoculation. Infectious BCRV was detected in nasopharyngeal swab samples from two birds by plaque assay. Three control birds that were housed with viremic individuals showed evidence of BCRV RNA in blood (by RT-PCR), suggesting possible bird-to-bird transmission of this virus. Viral RNA also was detected by RT-PCR in brain and skin tissue of six birds on necropsy at the end of the 16-day experiment. Introduced house sparrows are apparently a competent amplifying host for BCRV, and their presence year-round at cliff swallow colonies may facilitate persistence of the virus locally, especially when cliff swallows abandon a site temporarily. The findings that BCRV can be shed orally, that it persists in bird skin, and that control birds could apparently be infected by conspecifics suggest that this virus may be transmitted from bird to bird in the crowded conditions of many cliff swallow colonies.

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

“…At 15 days postinoculation, tissue samples were obtained from brain, spleen, liver, lungs, and skin of 15 birds and tested by RT-PCR for BCRV. Viral RNA was detected in brain tissue of four birds and in skin of four birds (Huyvaert et al, 2008). In a comprehensive study of arboviruses in California, Milby and Reeves (1990) sampled 1,308 birds and obtained 15 isolations of WEEV.…”

“…data). Huyvaert et al (2008) experimentally inoculated 16 adult House Sparrows with BCRV. No birds showed clinical signs of infection, and the birds were not necropsied.…”

“…Eastern equine encephalitis virus and Highlands J virus (HJV), an alphavirus in the Western equine encephalomyelitis virus (WEEV) complex, cause clinical illness and death in pen-raised Chukars (Alectoris chukar; Ranck et al, 1965) and domestic turkeys . Experimental infection studies with wild passerine birds and alphaviruses generally have shown low mortality and transient to no morbidity in adults of most species (Komar et al, 1999;Reisen et al, 2003;Huyvaert et al, 2008), although response to experimental infection can vary by species. For example, European Starlings (Sturnus vulgaris) inoculated with EEEV died more frequently than other species tested (Komar et al, 1999), and White-crowned Sparrows (Zonotrichia leucophrys), Goldencrowned Sparrows (Zonotrichia atricapilla), Tricolored Blackbirds (Agelaius tricolor), and Red-winged Blackbirds (Agelaius phoeniceus) died when inoculated with passaged strains of WEEV, whereas other passerines, including House Sparrows (Passer domesticus), were unaffected by experimental virus infection (Hardy and Reeves, 1990).…”

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

“…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. 16 Although some information on WNV pathology is known for relatively young individuals of several raptor species, 17,18 we know almost nothing about the clinical pathology of arboviruses in nestling passerine birds, 16 possibly because nestlings or recently fledged passerines are rarely found dead or exhibiting clinical pathology attributable to arboviruses.…”

Seasonal Variation and Age-Related Correlates of Buggy Creek Virus (Togaviridae) Infection in Nestling House Sparrows

“…Samples that were initially BCRV positive by RT-PCR were subjected to plaque assay on Vero cells as described by Huyvaert et al (2008), with the exception of using yeastextract lactalbumin instead of M-199 growth media. Viremia titers were determined by serial dilution.…”