James L. Hardy

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The nucleotide sequences of the small (S) genomic RNAs of six California (CAL) serogroup bunyaviruses (Bunyaviridae: genus Bunyavirus) were determined. The S RNAs of two California encephalitis virus strains, two Jamestown Canyon virus strains, Jerry Slough virus, Melao virus, Keystone virus and Trivittatus virus contained the overlapping nucleocapsid (N)(More)
St. Louis encephalitis (SLE) virus has become established in the Los Angeles Basin of California, where it most likely is maintained by horizontal transmission among Culex tarsalis Coquillet and passerine birds in park-riparian habitat. Viral transmission also was detected at low levels in residential habitat by the infrequent seroconversion of sentinel(More)
Viral mutants that appeared during long-term persistent infections of mosquito cell cultures (Aedes albopictus, A. dorsalis and Culex tarsalis) with St Louis encephalitis virus were characterized. Evidence was obtained for the presence of temperature-sensitive mutants in the A. dorsalis and C. tarsalis persistently infected cultures, and small plaque(More)
If global warming occurs in California, daily mean temperatures may increase by 3 to 5 degrees C, precipitation patterns will change, and sea level may rise 1 m. Studies were done on effect of temperature changes on survival of Culex tarsalis Coquillett, the primary vector of western equine encephalomyelitis (WEE) and St. Louis encephalitis (SLE) viruses,(More)
Adult Syrian hamsters were readily infected by intranasal inoculation with Modoc virus. Viremias were detected 2 to 6 days after infection and peak viremia titers (10(6.2) plaque-forming units/ml of blood) occurred 4 days postinoculation. All infected animals developed neutralizing and hemagglutination-inhibiting antibodies by 7 days, and complement-fixing(More)
The extrinsic incubation rate (inverse of the time in days from infection to median transmission) of western equine encephalomyelitis (WEE) and St. Louis encephalitis (SLE) viruses by laboratory strains of Culex tarsalis Coquillett increased as a linear function of incubation temperatures from 10 to 30 degrees C. The estimated temperatures for zero(More)
The mechanism for long-term maintenance of St. Louis encephalitis (SLE) virus in California is unknown. Two possibilities are 1) that the virus is maintained locally in discrete enzootic foci by one or more reservoir mechanisms, and/or 2) that the foci are ephemeral in nature and virus is reintroduced periodically from other enzootic areas by migratory(More)
Culex tarsalis was a less competent vector of western equine encephalomyelitis (WEE) virus after 2-3 weeks' extrinsic incubation at 32 degrees C than after incubation at 18 degrees or 25 degrees C. The high temperature itself was not directly detrimental to mosquito infection as all mosquitoes were initially infected, but subsequently some females were able(More)
The formation of the peritrophic membrane in adult female mosquitoes, Culex tarsalis, was examined by light and electron microscopy. The initial evidence of secretion of peritrophic membrane precursors occurred at 8-12 h after ingestion of the bloodmeal. Morphogenesis of the peritrophic membrane occurred within 12-16 h after the initial secretion;(More)