Effects of immunosuppression on encephalitis virus infection in the house finch, Carpodacus mexicanus.
Immunosuppression of house finches was attempted by blood feeding Culex tarsalis Coquillett mosquitoes or by injecting birds with the corticosteroid dexamethasone or the immunosuppressant drug cyclophosphamide before and after inoculation with western equine encephalomyelitis or St. Louis encephalitis viruses. Mosquito bites (8-37 females blood feeding on each bird over a 3-d period) did not enhance the viremia response or increase the frequency of chronic infection. In contrast, dexamethasone and cyclophosphamide enhanced the amplitude and duration of the viremia response, but had no consistent effect on the antibody responses as measured by enzyme immunoassay or plaque reduction neutralization assay. Elevated viremias were followed by increases in the frequency of chronic infections with St. Louis encephalitis, but not western equine encephalomyelitis. Immunosuppression may provide a useful tool to study the chronic infection process of flaviviruses in vertebrates.
Reisen
William K
WK
Arbovirus Research Unit, Center for Vector-borne Disease Research, School of Veterinary Medicine, University of California, Davis, CA 95616, USA. arbo123@pacbell.net
Chiles
Robert E
RE
Green
Emily N
EN
Fang
Ying
Y
Mahmood
Farida
F
Martinez
Vincent M
VM
Laver
Thomas
T
D000818:Animals; D001715:Bird Diseases / Q000276:immunology / Q000517:prevention & control / Q000821:virology*; D003465:Culex / Q000821:virology*; D017931:DNA Primers; D004660:Encephalitis / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D004668:Encephalitis Viruses / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D005260:Female; D007165:Immunosuppression Therapy / Q000379:methods; D008297:Male; D016133:Polymerase Chain Reaction; D020308:Songbirds / Q000276:immunology* / Q000821:virology*; D014766:Viremia / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary
D017931:DNA Primers