Biology Professor Receives $856,000 Grant To Study Virus in Cliff Swallows

Thursday, November 18, 2004

Charles R. Brown, a biology professor at The University of Tulsa, has received a grant of $856,000 from the National Institutes of Health to study a virus that infects cliff swallows. The research may help understand the transmission of other viruses that affect humans, such as West Nile virus.

The four-year research grant is for a project titled “Population Dynamics of a Bird-Borne Arbovirus.” Goals include determining the extent of viral infection and how the virus reappears each year.

Brown says the transmission of most such viruses is poorly understood, in part because of the difficulty in finding and sampling both the hosts of the viruses and the vectors, such as mosquitoes, that spread the virus. Viruses carried by insects cause a variety of human illnesses, including encephalitis. Also unclear is how epidemics occur in some areas and how a virus persists between epidemics.

Brown will be specifically studying the Buggy Creek virus, named after the location where it was first discovered in western Oklahoma. The virus is known to live in the cliff swallow and is transmitted from bird to bird by the blood-sucking cimicid insect. It is not known if the virus affects the health of birds or humans, or if mosquitoes spread the virus to humans.

Field work will be done along the Platte River in Nebraska where Brown has conducted research for 23 years. Every summer, Brown and his research team band swallows and recapture previously banded birds to determine life span, health and migration patterns. Since 1982 about 158,000 birds have been banded. The birds live in colonies in mud nests usually found on bridges and cliffs.

Brown says his research project is ideal for investigating the transmission of such a virus because of the many years of data already available and because the sites of the virus infections can be reliably identified. This contrasts with other viral propagation, such as West Nile virus, in which an infected crow might be found, but it is not known where or how the bird was infected.

If a banded cliff swallow is identified as host to the virus, “we can correlate that to past data about that particular bird, such as age, weight, behavior and travel pattern,” says Brown. “With our system we should be able to predict where we can find viruses in the population as we will be able to see if there is a relation between colony size and the presence and transmission of the virus.” Nesting colonies range in size from a few nests to 6,000 nests.

When the swallows migrate to South America in the winter, the parasitic bugs burrow beneath the mud nests, re-emerging when the birds return in the spring, shortly before the breeding season in May and June.

The presence and distribution of the virus will be determined in three ways. Brown and his researchers will take blood or oral samples from birds. In addition, mosquitoes collected from traps near the nesting areas will be tested, and cimicid insects will also be tested.

The grant includes funds to hire a postdoctoral researcher. The new researcher’s first task will be to travel to Nebraska in winter to collect insects to sample for the virus. Lab work and analysis will be conducted at TU and at the Centers for Disease Control and Prevention in Fort Collins, Colo. Virus subtypes will be identified by genetic sequencing in Munich, Germany.

The Buggy Creek virus is similar to the one that causes Western equine encephalitis, a disease that is spread to horses and humans by infected mosquitoes, but which generally causes only flu-like symptoms in humans.