West Nile virus: Still a threat
West Nile virus remains a threat to horses. However, with the right vaccine and preventive measures, it's not too late for horse owners to help protect their horses against this life-threatening disease.
West Nile encephalomyelitis is an inflammation of the central nervous system that is caused by an infection with WNV. It is transmitted by mosquitoes--which feed on infected birds or other animals--to horses, humans and other mammals. So far in 2012, 31 states have reported 157 cases of WNV in horses, with Louisiana and Texas having the most confirmed cases--26 and 16, respectively.
The number of reported WNV cases fell from 1,069 in 2006 to 146 in 2010, and the decline is said by health experts to reflect both vaccination and naturally acquired immunity.
"It is a good sign that the number of cases has declined over the last decade, however there has been an increasing number of both human and equine cases, especially over the last couple months," said Tom Lenz, DVM, MS, senior director, equine technical services, Pfizer Animal Health.
Vaccination remains the most effective way to help protect horses against West Nile and other encephalic or mosquito-borne diseases, such as Eastern equine encephalomyelitis and Western equine encephalomyelitis. A trusted vaccine is available to help offer demonstrated protection against WNV and, Eastern and Western equine encephalomyelitis and tetanus--WEST NILE-INNOVATOR + EWT--all in a single vaccine. According to the American Association of Equine Practitioners guidelines, WNV is considered a core vaccination, along with Eastern equine encephalomyelitis, Western equine encephalomyelitis, tetanus and rabies.
In conjunction with vaccination, use good techniques for managing mosquitoes. This includes:
--Destroying any mosquito breeding habitats by removing all potential sources of stagnant water.
--Cleaning and emptying any water-holding container, such as water buckets, water troughs and plastic containers, on a weekly basis.
Remember that WNV does not always lead to signs of illness. Horses that do become clinically ill, the virus infects the central nervous system and may cause symptoms such as loss of appetite and depression. Other clinical signs may include fever, weakness or paralysis of hind limbs, impaired vision, ataxia, aimless wandering, walking in circles, hyper-excitability or coma.5 Horse owners should contact a veterinarian immediately if they notice signs or symptoms of WNV infection in their horses, especially if they are exhibiting neurological signs. The case fatality rate for horses exhibiting clinical signs of WNV infection is approximately 33 percent.
No matter the location, horses can be at risk. By providing proper vaccination and helping to manage mosquito populations, horse owners can do their part to help prevent WNV infections.
For more information on the WEST NILE-INNOVATOR line of vaccines contact your Pfizer Animal Health representative, visit https://animalhealth.pfizer.com/sites/pahweb/us/en/products/Pages/West_Nile_Innovator.aspx or call 855-4AH-PFIZER (855-424-7349).