Lab Tests Samples, Confirms Wnv in Two Horses in Utah

By Sun Advocate

Tests conducted on horses in Grand and Salt Lake counties confirmed the two animals were infected with west Nile virus.
Test samples were taken from the horses after animals exhibited symptoms of the virus.
The samples were tested at the Utah Veterinary Diagnostic Laboratory in Logan.
Last year, 34 horses in six Utah counties contracted west Nile virus. Approximately half of the animals in question died or were euthanized because of the illness.
In addition to the incidents involving the horses, the Utah Department of Health has confirmed five human cases of west Nile virus in the state. The virus is not transmissible from horses to humans, emphasized the officials.
The Utah Department of Agriculture and Food urges Carbon County residents to protect horses by vaccinating the animals for west Nile virus
The UDAF also encourages all Utahns to take necessary precautions to prevent human cases of the virus
The UDAF has been advising horse owners to administer two vaccination shots for the several weeks. It is now advisable to administer a booster shot for added protection.
The vaccine is available from local veterinarians.
“We are one of the last states in the Intermountain West to report West Nile Virus in a horse,” indicated Dr. Michael Marshall.
“I believe our dry climate and our education efforts have helped postpone the onset of WNV this year,” added the Utah state veterinarian.
Utah has now joined Wyoming, Colorado, New Mexico, Arizona, Nevada and Idaho as states reporting west Nile virus infections.
The most common sign of the virus in horses is weakness, usually in the hindquarters, pointed out state officials.
Weakness may be indicated by a widened stance, stumbling, leaning to one side and toe dragging. In extreme cases, paralysis may follow.
Fever is sometimes evident as are depression and fearfulness.
West Nile virus causes encephalitis and affects the central nervous system.
Carbon County residents who suspect viral infection in animals should contact veterinarian immediately
Approximately one-third of the horses showing signs of the illness will die.
Eighty percent of WNV infections in horses occur in August and September. Vaccination after exposure may not protect animals against the disease.
The equine vaccine requires two doses and takes approximately five weeks to offer protection. Once vaccinated, yearly booster shots are necessary.
Residents can protect horses by applying approved repellants to the animals and controlling mosquitoes as well as the insects’ breeding areas.
Owners may also protect horses by putting the animals in a barn or enclosed structure.
The UDAF also encourages local residents to insect-proof homes. And when venturing outdoors into areas with mosquitoes, people should wear protective clothing and use insect repellant containing DEET.
As an added precaution, Carbon County citizens can install or repair screens in residences and inspect yards for standing water that can provide mosquito-breeding habitat.
There is currently no human vaccine to protect Carbon County residents and Utahns at locations across the state from becoming infected with west Nile virus, explained the state officials.
West Nile virus has spread rapidly across the country since first being discovered in New York in 1999.
The most common way people and animals can contract the disease is through a mosquito bite.
Only about 20 percent of people infected with the virus show symptoms of the illness. The symptoms of west Nile virus infection include headaches, body aches and a mild fever.
Less than 1 percent of the individuals infected with the virus will develop a serious illness like encephalitis and meningitis.
People older than 50 years of age and individuals who have existing health problems are the most likely to develop the severe forms of the illness, pointed out the state officials.
Tests on blood samples taken from the sentinel chickens were also conducted at the Utah Veterinary Diagnostic Laboratory in Logan.
Several bird species serve as the reservoirs for the disease. Mosquitoes transmit the disease from the reservoir species transmit the virus to other birds, horses, humans and animals. Horses and humans are dead-end hosts for the disease. As deadend hosts, infected horses and humans cannot transmit the west Nile virus.