As if the threat of West Nile virus were not enough, Dallas County residents now have yet another threat to worry about: East Nile virus.

Dr. Donny Buster, a veterinarian at Selma Animal Hospital, reported a possible case of East Nile virus or equine encephalitis Monday. Buster said it won’t be known for certain if the animal suffered from equine encephalitis, West Nile virus or the less familiar East Nile virus until lab tests are returned.

Actually, East Nile virus is nothing new, according to Buster.

Both strains are transmitted by mosquitoes and can affect humans, birds, horses and certain other mammals.

A third strain of the disease &045;&045; the Venezuelan variety &045;&045; has largely fallen away in recent years.

Buster said the afflicted horse was located in the River Road area, near International Paper’s Riverdale Mill plant. &uot;By the time I got there it was down on the ground and couldn’t get up,&uot; he said.

While West Nile virus often causes only flu-like symptoms in a healthy human, it usually proves fatal to horses. East Nile virus is even more virulent, according to Buster.

He emphasized that the only fail-safe prevention was vaccination. Horses being vaccinated for the first time receive two shots four weeks apart and a yearly booster shot thereafter.

He warned that attempting to prevent infection with insecticides is often ineffective. &uot;You’d just about have to quit your job and spray ’em all day long if you rely on insecticides,&uot; Buster said. &uot;We’re trying to get the word out. It might help somebody.&uot;

According to the Centers for Disease Control in Atlanta, there were 4,000 reported cases of human West Nile virus infection in 2002. Symptoms include fever, headaches and body aches.