West Nile Virus linked to Grand Forks horse illness

North Dakota apparently has its first recorded case of West Nile Virus (WNV) infection. The state veterinarian, Dr. Larry Schuler, announced Thursday, that preliminary tests have confirmed that a horse in Grand Forks had been infected with the virus.North Dakota apparently has its first recorded case of West Nile Virus (WNV) infection. The state veterinarian, Dr. Larry Schuler, announced Thursday, that preliminary tests have confirmed that a horse in Grand Forks had been infected with the virus.

Story originally posted by Horsecity.com Staff

North Dakota apparently has its first recorded case of West Nile Virus (WNV) infection.

The state veterinarian, Dr. Larry Schuler, announced Thursday, that preliminary tests have confirmed that a horse in Grand Forks had been infected with the virus.

"The National Veterinary Services Laboratory in Ames, IA, informed me today that a polymerase chain reaction (PCR) test came back positive for West Nile Virus on samples taken from the horse," Schuler said. "Based on this result and on results of other tests conducted by the North Dakota State University Veterinary Diagnostic Laboratory and the National Veterinary Services Laboratory, there can be little doubt that the West Nile Virus is here.

WNV causes a form of encephalitis, an inflammation of the brain. Birds serve as a host for the virus, which is then spread by mosquitoes to other birds and animals, including horses and humans. Neither humans nor horses can spread the disease.

Schuler urged horse owners to contact their veterinarians if their animals display symptoms of the disease, such as loss of appetite, head tremors, muscle twitches or inability to stand."

"It is very important to call your veterinarian immediately, so he or she can collect samples for diagnostic testing," Schuler said. "Laboratory confirmation is particularly important both for treating the animal and for tracking the movement of disease."

Schuler said horse owners should also ask their veterinarians about immunizing their animals against the disease. A vaccine is now available, but it must be administered twice within a three- to six-week period to be effective. Although the symptoms of WNV are similar to those of Western Equine Encephalitis and Eastern Equine Encephalitis, the vaccines against those diseases are ineffective against WNV.

"Horse and stable owners should also take measures to reduce mosquito populations near their premises," Schuler said. "Draining or treating stagnant water, mowing grass and weeds, applying repellents and putting up screens can protect your home or stable from mosquitoes."

WNV is common in parts of Africa, eastern Europe, west Asia and the Middle East. The first confirmed cases in the United States were in 1999, when several birds in New York City were found to have died of the disease. Although the origin of the U.S. infection is unknown, the virus samples here most closely resemble those from Middle Eastern sources.

In the past two years, the disease has spread to more than 20 states. Last year, more than 730 horses, donkeys or other members of the equine family were diagnosed with the disease in the U.S. About 20 percent of the animals died or had to be destroyed because of the severity of their illness. By the end of 2001, a total of 149 total human cases of WNV illness, including 18 fatalities, had been reported and confirmed in the U.S.

Schuler said the horse in Grand Forks was treated by an area veterinarian on June 30 and was euthanized several days later. The veterinarian conducted an autopsy on the animal, and sent tissue samples to the NDSU.

Schuler said horse owners can log onto the North Dakota Department of Agriculture website at www.agdepartment.com for a fact sheet on the West Nile Virus and horses. Information is also available on the U.S. Department of Agriculture website at www.aphis.usda.gov/oa/wnv/.

Fact sheets about West Nile virus and human health can be accessed at the Department of Health website at www.health.state.nd.us/disease/arbovirus or at the Centers for Disease Control and Prevention website at www.cdc.gov.