Editor's note: This is the final installment of a 2-part series about Arkansas State University research on West Nile virus.

By Sherry F. Pruitt

Sun education editor

Sampling mosquitoes is just as important as sampling birds for Arkansas State University researchers in the effort to prevent West Nile virus in humans.

Sampling mosquitoes for West Nile has begun on the ASU campus. Arkansas Biosciences Institute funding has allowed Dr. Jeannette Loutsch, assistant professor of cell biology and virology, to purchase an automated machine for genetic analysis -- a first for ASU. She will utilize new techniques in her research.

In the laboratory, Loutsch will take blood from 1,000 mosquitoes and try to identify upon which bird host the mosquitoes fed. In mosquitoes, they are looking for incidents of West Nile, which species carry West Nile and in which environments it occurs, Dr. Jim Bednarz, professor of biological sciences, explained.

"I'm the one who's going to be analyzing the samples that they've collected. Right now, we have 1,000 bird samples that we are going to be in the process of extracting from their blood -- whether or not they have West Nile virus," Loutsch said. "That technique is going to take a little bit of manipulation because the virus itself -- if it's there -- should be floating around in the liquid part of their blood ..."

Loutsch said she is in the process of starting the isolation of the West Nile ribonucleic acid (RNA).

"It has an RNA core of genetic material we're going to try to identify using some new technology -- whether or not the RNA is present in the serum samples of the birds," she stated.

She said that she and about seven undergraduate and graduate students expect to start with a process of extracting the virus out of the mosquito, as well as the bird deoxyribonucleic acid (DNA).

"We have two different samples of mosquitoes now: some that we're going to test specifically just for West Nile. The other set -- we'll specifically look for what kind of bird were bitten," Loutsch said.

"We're looking at mosquitoes' blood meals. The interesting aspect will be to determine what host mammals or birds they've been feeding on," Bednarz explained.

"Mosquitoes will feed on anything that gives off CO2. We need to do that differentiation. We're basically going to start by taking those samples, looking to see if we can find a gene that is specific to the bird..." Loutsch said.

She indicated that she and the students will identify the type of bird using a combination of techniques and look to pair two types of DNA.

"We'll take some DNA from a known bird and compare it to our unknown bird and see if we can't get it down to a species," she said.

Several studies have revealed that some bird species, such as blue jays and crows, are at high risk for West Nile.

In addition, researchers will test bird species that have never been tested.

"So we're going to have to figure what their pattern would look like, looking at our known bird sample so we can make assumptions about birds that have not been identified or previously published.

The end result, Loutsch said, is to identify birds that are at risk so that people in the Delta can avoid areas where the birds are located or take precautions in those areas.

"To me, this is a neat project because of the collaboration of all of the disciplines" -- a bird ecologist, Bednarz; a molecular biologist, Loutsch; and an animal biologist, Dr. Tom Risch, Bednarz said.

Although it is preliminary, Bednarz indicated that Risch, assistant professor of environmental biology, has discovered something new.

"They put mosquitoes traps up high in the forest and low where humans hang out -- ground level. It's very preliminary, but they seem to be getting different communities of mosquitoes," Bednarz explained. "This -- to our knowledge -- hasn't been discovered before. There could be an enzootic cycle where the virus is just being passed from bird to mosquito to bird to mosquito, so the virus could be held up in the mosquitoes and the birds, which are in the canopy of the forest for a while. Then every so often, a mosquito might come down and bite a mammal or a bird that puts it at the surface level and exposes humans."

The finding, Bednarz said, could mean they are dealing with a different community of mosquitoes at different heights in the forest.

Loutsch said West Nile does not affect most healthy, normal people and animals. However, horses that have been bitten may develop a form of encephalitis.

"As far as we can tell, it has to go through a mosquito," she said. "They're finding antibodies to West Nile in people who've never really been sick. It's the elderly and the immuno-compromised people ... that are at a greater risk than most people. It doesn't mean that people don't have to take precautions."