Experimental infection of horses with West Nile virus.
A total of 12 horses of different breeds and ages were infected with West Nile virus (WNV) via the bites of infected Aedes albopictus mosquitoes. Half the horses were infected with a viral isolate from the brain of a horse (BC787), and half were infected with an isolate from crow brain (NY99-6625); both were NY99 isolates. Postinfection, uninfected female Ae. albopictus fed on eight of the infected horses. In the first trial, Nt antibody titers reached >1:320, 1:20, 1:160, and 1:80 for horses 1 to 4, respectively. In the second trial, the seven horses with subclinical infections developed Nt antibody titers >1:10 between days 7 and 11 post infection. The highest viremia level in horses fed upon by the recipient mosquitoes was approximately 460 Vero cell PFU/mL. All mosquitoes that fed upon viremic horses were negative for the virus. Horses infected with the NY99 strain of WNV develop low viremia levels of short duration; therefore, infected horses are unlikely to serve as important amplifying hosts for WNV in nature.
Bunning
Michel L
ML
Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. mbunning@cdc.gov
Bowen
Richard A
RA
Cropp
C Bruce
CB
Sullivan
Kevin G
KG
Davis
Brent S
BS
Komar
Nicholas
N
Godsey
Marvin S
MS
Baker
Dale
D
Hettler
Danielle L
DL
Holmes
Derek A
DA
Biggerstaff
Brad J
BJ
Mitchell
Carl J
CJ
D000330:Aedes / Q000502:physiology / Q000821:virology; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology; D001715:Bird Diseases / Q000821:virology; D001921:Brain / Q000821:virology; D002522:Chlorocebus aethiops; D005260:Female; D006734:Horse Diseases / Q000097:blood / Q000276:immunology / Q000635:transmission / Q000821:virology; D006736:Horses / Q000097:blood / Q000276:immunology / Q000821:virology*; D007303:Insect Vectors / Q000502:physiology / Q000821:virology; D008297:Male; D012463:Saliva / Q000276:immunology / Q000821:virology; D020308:Songbirds / Q000821:virology; D014709:Vero Cells; D014766:Viremia / Q000097:blood / Q000276:immunology / Q000635:transmission / Q000821:virology; D014901:West Nile Fever / Q000097:blood / Q000276:immunology / Q000635:transmission* / Q000821:virology; D014902:West Nile virus / Q000276:immunology / Q000502:physiology*
D000914:Antibodies, Viral