At least two horses in Churchill County are exhibiting symptoms of West Nile virus and a preliminary blood test on one has come back positive for the mosquito-borne disease. Final results of a more thorough test are expected back sometime today.
Nevada State Veterinarian David Thane said he is holding out judgment on what is afflicting some local equines until the official results are in.
"One of the problems with West Nile is it looks like several other things," Thain said.
Even preliminary tests are often misleading, he said, adding that vaccinations often trigger a false positive for West Nile infections.
Churchill County rancher Jerry Hoover is one horse owner anxiously awaiting results of blood drawn Wednesday from his year-old quarter horse, Todd.
Todd began acting odd Wednesday, Hoover said. He began "thrashing around, very disoriented, with no muscular control at all."
"It's like he was possessed."
Thursday Todd was more sedate, after receiving several anti-inflammatory injections. He couldn't stand and began to shake whenever he tried. Occasionally, the horse mustered enough strength to sit upright and drink, with his weight up on two front legs.
"I can't imagine the headache he must have," Hoover said. "I just don't know what to do for him."
If Todd does have the West Nile virus, his brain and spinal column are likely swelled to the point where he is suffering through a debilitating migraine. It's the migraine, Thane said, that can cause most symptoms in West Nile-infected horses.
The fever and headache can be so bad, Thane said, that horses become utterly confused and don't know where they are.
"Often times they appear to be blind, just because they're so out of it."
The virus was confirmed for the first time in Nevada on July 16, based on blood tests from a dead crow in Carson City. Tests confirmed on Tuesday that mosquitos in Fernley and Silver Springs are also carrying the virus. And the Associated Press reported Thursday that health officials in Washoe and Clark Counties have discovered one possible human case of the disease each.
While humans are about as likely to die from West Nile virus as they are to die from a lightning strike, horses are far more susceptible.
An estimated 30 percent of unvaccinated horses who show symptoms of West Nile die. But, while horses are more susceptible to the virus, they can be vaccinated where humans cannot.
"I'm scared that a lot of people are waiting until the last minute to vaccinate and they don't think (West Nile) has made it into the valley," Hoover said.
While horses are one of the few animals that can contract West Nile, they are not carriers of the virus. They cannot pass it on, not even to other mosquitos, Thane said.
Cory McConnell can be contacted at firstname.lastname@example.org