Equine West Nile Virus (WNV) Up-Date 2007
As of September 11, Montana and California had reported the highest number of equine West Nile Virus (WNV) cases in the United States.
As of September 11, Montana and California had reported the highest
number of equine West Nile Virus (WNV) cases so far this year with 24
and 19, respectively. The USDA's Animal and Plant Health Inspection
Service tracks equine arboviruses through the National Animal Health
Surveillance System (NAHSS).
Other states reporting numerous cases included:
- Colorado (16);
- Texas (16);
- Missouri (13);
- New Mexico (11).
Reports detailing the incidence of cases down to the county level are
available on the NAHSS Web site, www.aphis.usda.gov/vs/nahss/equine.
Idaho had the highest incidence of equine WNV cases in 2006. The state reported 338 cases to the NAHSS (for more on this see www.TheHorse.com/ViewArticle.aspx?ID=7776). Other states reporting a high number of cases included Texas (111) and Arkansas (77).


