By JENNIFER STOCKINGER
Staff Writer

A horse at a location near Brainerd has the first confirmed case of West Nile virus in the state this year, the Minnesota Board of Animal Health announced Thursday.

The infected five-year-old pregnant mare boarded at a horse facility near Brainerd and became so ill that it had to be euthanized. Testing the infected horse for the West Nile virus was completed recently at the University of Minnesota Veterinary Diagnostic Laboratory in St. Paul and confirmed at the Minnesota Department of Health Laboratory in Minneapolis.

Ann Domagala, veterinarian at AnnCo Veterinary Services in Brainerd, who treated the infected horse, said today that the horse did not show any clinical signs of the West Nile virus, such as muscle trembling or dragging of the feet. She said she had an appointment with the horse April 14 for a routine check-up and to conduct a blood test on the horse for Coggin's Disease. This blood test was needed in order for the horse to be moved to a local breeding and training facility to be foaled.

"The mare appeared a little lethargic that day, but was eating, drinking and moving easily around the paddock," said Domagala. "Neither myself or the owner were alarmed, thinking that she was probably a little uncomfortable because she was carrying a large foal."

Domagala said within five days following the check-up, the horse began showing signs of pneumonia that included a high temperature and rapid breathing.

"This horse began to deteriorate that day (April 19)," said Domagala. "The horse was down on the ground and having convulsions. There were no signs of recovery. The horse owner, the owner of the facility that boarded the horse and I made the decision to put the horse down.

"We tried to save the foal, but it was too early (in the pregnancy)."

Domagala would not release the names of the horse owner or the horse boarding facility. Kristine Petriny, assistant director of Minnesota Board of Animal Health, also would not release the names. Petriny said the owners did not want to be contacted.

Domagala said the horse was vaccinated for the West Nile virus last April, but it did not receive a booster vaccination this year. She said the horse owner had problems last year with the vaccination and decided this year, with the horse expecting, that it would not be vaccinated.

Domagala said she was not expecting to see such an early case of the West Nile virus, but said when she was treating the infected horse that the virus did cross her mind.

"I don't know if I'd say if I'm surprised (about the early virus case)," said Domagala. "We have mosquitoes in Minnesota in April. We just need to keep an eye on it."

Domagala said the infected horse was boarded with other horses, but could not say if the other horses were infected by West Nile virus. She said many times the host of the virus will seek out one animal and leave the rest alone.

Last year, 993 horses in the state tested positive for the virus, and 30 percent died.

State animal health officials said the virus did appear earlier than expected. Most cases appear mid-July through mid-September.

"It is highly unusual, but not impossible to have a positive case so early in the year," said Dave Neizel, epidemiologist for the state health department. "This horse was probably infected by an adult mosquito that overwintered with the virus, emerged and for some reason found the horse as its host.

The virus causes a form of encephalitis, an inflammation of the brain and spinal cord. Birds serve as the host for the virus, which is spread by mosquitoes to other birds and animals, including horses and humans. Humans and horses cannot spread the disease, reported state animal health officials.

Officials said horse owners can reduce the risk of the West Nile virus by vaccinating the horse as soon as possible; eliminate mosquito zones by mowing long grass, draining stagnant water puddles and removing items, such as old tires and tine cans that can serve as breeding grounds for mosquitoes; change water in drinking troughs weekly; and to minimize horses' exposure by using repellents and placing screens in stables.

State officials set up mosquito traps on the horse boarding facility near Brainerd Thursday, said Domagala.

Horse owners who notice any signs of the West Nile virus should contact their veterinarian. Signs of the virus include loss of appetite, lethargy, hindquarter weakness, involuntary muscle contractions, loss of coordination, head tilt, convulsions, paralysis and coma.

Any case of the West Nile virus must be reported to the state animal health department at (651) 296-2942.