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By Sherry F. Pruitt

One West Nile virus hypothesis developed by Arkansas State University researchers has been disproved based on test results from some 300 bird samples.

Researchers are also sampling mosquitoes, which is just as important as sampling birds, in an effort to prevent the virus in humans.

Dr. Jim Bednarz, professor of biological sciences, said one of the researchers' hypotheses was that the West Nile virus could have been brought in through spring migration, but the data do not support the theory.

Bednarz, Dr. Jeannette Loutsch, assistant professor of cell biology and virology, and Dr. Tom Risch, assistant professor of environmental biology, began last spring sampling hundreds of birds and hundreds of mosquitoes in an effort to understand the pathways of West Nile virus from animals to humans in Arkansas, particularly the Delta, which is a high potential area for West Nile.

Bednarz said he caught six birds Tuesday, collected blood samples and other data and banded the red-winged blackbirds, yellow-billed cuckoos, mockingbirds and a barn swallow.

However, most of the laboratory research is being conducted on spring 2003 samples collected from residential and migratory birds, Loutsch said.

Of the 1,200 bird samples taken last year, 338 samples were analyzed in two ways. What was learned by looking at two parts of the ribonucleic acid (RNA), a genetic material, she said, is that all their samples were negative for West Nile.

The reason tests were conducted in two different ways is because RNA is fragile and breaks apart easily, she explained.

Loutsch said the work is "tedious because lots of things can go wrong" when working with RNA.

Now ASU researchers are thinking that perhaps the birds acquire West Nile here and take it somewhere else or the birds get it here and it remains here, Bednarz explained.

Loutsch said researchers also are looking at mosquitoes, but that research is more difficult because of their small size.

Arkansas Biosciences Institute funding allowed Loutsch to purchase an automated device for genetic analysis -- a first for ASU. She is utilizing new techniques in her research.

In the laboratory Loutsch is taking blood from 1,000 mosquitoes and trying 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, Bednarz explained.

By working together, Bednarz said, researchers hope to "map out the pathways" then "break connections as far as controlling the virus ... in the Delta."

Loutsch acknowledged that few researchers are looking at healthy birds for answers.

Bednarz's proposal was funded by an Arkansas Biosciences Institute grant. The study was funded under the title of "Vector Ecology of West Nile Virus: An Assessment of Human Risk in the Delta Region of Arkansas."