Texas has reported the nation’s first case of equine West Nile virus this year, according to an article on the Houston Chronicle website. The articles said the case was confirmed in April in Grimes County, northwest of Houston.
According to the Texas Department of State Health Services, there have been two human cases of West Nile virus this year, and 11 mosquitoes trapped in five different counties have tested positive for the virus.
California, Mississippi and Tennessee all have reported human cases this year, according to the USDA.gov website
According to the University of Kentucky College of Agriculture, “West Nile virus (WNV), an arbovirus endemic in North America, is the causative agent of West Nile equine encephalomyelitis (WNEE) and an important consideration in the differential diagnosis of horses with signs of neurologic disease. WNV vaccination is important in the prevention of WNEE and is considered one of the core equine vaccinations by the American Association of Equine Practitioners. Core equine vaccinations are those indicated for use in all horses irrespective of use or geographic location in the USA."
Since the initial detection of West Nile virus in 1999 in New York, the virus has spread throughout the 48 contiguous states and the District of Columbia.
In 2012 there were 627 cases of West Nile virus in horses reported from 41 states, according to USDA/APHIS. The report they issued noted that was the highest number of equine cases for the past five years, “but still considerably lower than the number of cases reported during the 2002 WNV outbreak when 15,257 equine cases were reported.”
The states with the most equine cases of West Nile virus in 2012 were Texas (120), Louisiana (62), Pennsylvania (47), Mississippi (39), Iowa (35) and Indiana (30).
Cases reported since West Nile virus first appeared in the United States:
- 87 reported cases of equine West Nile virus in 2011
- 125 cases in 2010
- 276 cases in 2009
- 179 cases in 2008
- 468 cases in 2007
- 1,086 cases in 2006
- 1,088 cases in 2005
- 1,406 cases in 2004
- 5,181 cases in 2003
- 15,275 cases in 2002
- 738 cases in 2001
- 60 cases in 2000
- 25 cases in 1999.
Many states have web sites with West Nile virus surveillance reports. You can find a list on the USDA/APHIS website.