Susceptibility of greater sage-grouse to experimental infection with West Nile virus.
Populations of greater sage-grouse (Centrocercus urophasianus) have declined 45-80% in North America since 1950. Although much of this decline has been attributed to habitat loss, recent field studies have indicated that West Nile virus (WNV) has had a significant negative impact on local populations of grouse. We confirm the susceptibility of greater sage-grouse to WNV infection in laboratory experimental studies. Grouse were challenged by subcutaneous injection of WNV (10(3.2) plaque-forming units [PFUs]). All grouse died within 6 days of infection. The Kaplan-Meier estimate for 50% survival was 4.5 days. Mean peak viremia for nonvaccinated birds was 10(6.4) PFUs/ml (+/-10(0.2) PFUs/ml, standard error of the mean [SEM]). Virus was shed cloacally and orally. Four of the five vaccinated grouse died, but survival time was increased (50% survival=9.5 days), with 1 grouse surviving to the end-point of the experiment (14 days) with no signs of illness. Mean peak viremia for the vaccinated birds was 10(2.3) PFUs/ml (+/-10(0.6) PFUs/ml, SEM). Two birds cleared the virus from their blood before death or euthanasia. These data emphasize the high susceptibility of greater sage-grouse to infection with WNV.
Clark
Larry
L
United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado 80521, USA. larry.clark@aphis.usda.gov
Hall
Jeffrey
J
McLean
Robert
R
Dunbar
Michael
M
Klenk
Kaci
K
Bowen
Richard
R
Smeraski
Cynthia A
CA
D000818:Animals; D000835:Animals, Wild / Q000276:immunology / Q000821:virology; D001715:Bird Diseases / Q000276:immunology* / Q000821:virology; D004198:Disease Susceptibility / Q000662:veterinary; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D046094:Galliformes; D007279:Injections, Subcutaneous / Q000662:veterinary; D011897:Random Allocation; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D015996:Survival Rate; D013997:Time Factors; D014765:Viral Vaccines / Q000276:immunology*; D014766:Viremia / Q000662:veterinary; D014901:West Nile Fever / Q000276:immunology / Q000401:mortality / Q000662:veterinary* / Q000821:virology; D014902:West Nile virus / Q000472:pathogenicity*
D014765:Viral Vaccines