Southeast Texas calf infected with West Nile

By LORI COPE | East Texas Edition

November 21, 2002 -- When a 4-week-old Brahman calf near Wharton was having mini-seizures, difficulty standing and getting up, stiffness, and a drifting eye, Dr. Carlos Bonnot knew it could be a variety of illnesses - but West Nile Virus?

A blood sample has confirmed the virus, commonly associated with horses, is present in the calf.

Dr. Carlos Bonnot, one of the veterinarians at Wharton Veterinary Clinic, said upon first examination of the calf on Oct. 21, he wasn't sure what was causing the symptoms. Running down his differential list of possibilities, the vet knew it could have been any kind of encephalitis, a case of rabies, a toxicity ... even a brain abscess.

But "there had been two cases of West Nile Virus in horses in the general area," Bonnot said. The blood sample confirmed the fact that young bovine had the virus.

From the USDA Animal and Plant Health Inspection Service (APHIS) website, it is noted that "cows may show antibodies to the virus, which means they have contracted it without showing any clinical signs or becoming ill."

But because the calf was so young, the virus hit him with a good punch. "His immune system was immature ... and the cow didn't have any antibodies to the virus to pass along in her colostrum," Bonnot said on Nov. 14.

So obviously the calf was bitten by a mosquito - the insect which transmits the virus which causes encephalitis, or inflammation of the brain.

"This is an isolated case," Bonnot stressed. "Unless we see an increase of cattle showing central nervous (system) disorders" and confirmations of the virus, there is no reason for producers in the area to vaccinate their cattle.

"This, I believe, is maybe the first (WNV case in cattle) in Texas," he added. The veterinarian said he has information that a few cattle in the Midwest have been diagnosed with WNV.

The calf in Wharton has not succumbed to the illness, Bonnot said. "It never lost its appetite. It's still nursing." The calf was treated with anti-inflammatory drugs and fluids.