A snow leopard, an elephant, horses and birds have all fallen victim to West Nile virus.

But research might show swine, sheep and cattle to be immune.

Wayne Rowley, professor of entomology, said there is a slim chance of West Nile affecting livestock other than horses.

West Nile is relatively new to the area, Rowley said. The first reported case of West Nile in the United States occurred in the summer of 1999, according to the Iowa Department of Public Health.

“About half a dozen birds” from the Bronx Zoo in New York died from the virus, said Dr. Dennis Riordan, veterinarian at Blank Park Zoo in Des Moines. Since then the virus has been moving west; it was first discovered in Iowa in September 2001.

Riordan said the most activity is taking place in the South and Southeast “where the mosquito population is the largest.”

However, zoo officials are still concerned about the virus in Iowa.

“We are doing whatever we can to protect our animals,” Riordan said.

The Blank Park Zoo has administered vaccinations to all the animals possible. “The flamingoes are high risk,” as are all the other birds, Riordan said.

He said the reason birds are at high risk, even though they have been vaccinated, is because “there are no effective vaccinations for birds.” Riordan said he hopes the animals will be “naturally exposed and develop an immunity.”

The only way for officials to know if immunity has been developed is to retest blood samples.

As part of an American Zoo and Aquarium Association surveillance project, Riordan did a baseline blood sample for all of the zoo’s mammal and bird species. At the end of the summer when the animals are brought back indoors, they will be retested for antibodies protecting against West Nile.

“Blood samples are really the only way to know,” Riordan said.

The effects of the virus are still being investigated. Rowley and Kenneth Platt, professor of veterinary microbiology and preventive medicine, are working on a grant proposal to fund a study to conclude the implications of West Nile in livestock. The results are not expected until later this year.

The recent outbreaks of West Nile have mainly been a cause of concern in “wild birds, especially crows,” according to the Iowa Department of Public Health. Rowley said blue jays, hawks, owls and eagles are susceptible to the virus. Chickens are also susceptible, but the seven confirmed cases involving chickens, the infected animals were have been test subjects.

The effects in livestock are completely unknown at this point. To date there have been 112 infected horses in Iowa reported to the Iowa Department of Public Health. No reports have been made concerning livestock such as cattle, swine or sheep.

Rowley said there are two main reasons for the lack of reports in livestock – either the virus doesn’t affect livestock or the symptoms are not showing.

Symptoms of the virus range from mild flu-like fever and headache to fatal encephalitis, which is swelling of the tissue lining the brain.

Rowley said it is always a possibility livestock could be infected by West Nile. He said he didn’t know if the virus is capable of infecting livestock.

Rowley said it is not a likely scenario, however.

“My guess is that [the virus] doesn’t have much effect on livestock other than horses,” he said. “There has been an incredible amount of West Nile activit. If it did affect them it would most likely have shown up by now.”