BOZEMAN, Mont., Oct. 1 (UPI) -- U.S. scientists have linked the West Nile viral deaths of hundreds of pelican chicks in northeast Montana to an infestation of stable flies.
Veterinary entomologist Greg Johnson of Montana State University began studying the deaths at the Medicine Lake National Wildlife Refuge after discovering a bird with blood on its neck and some flies feeding on the blood in late July. Stable flies look like common house flies but they have a painful bite and come from a different family than do horse flies or deer flies.
Johnson collected about 1,300 flies and divided them into 60 groups. Eighteen of the groups tested positive for West Nile virus.
"This is the first report of stable flies feeding on wild birds, or pelicans for that matter, and the first report of stable flies infected with West Nile virus," Johnson said. "These results suggest stable flies might be involved in amplification and/or transmission of West Nile virus at the pelican colony and possibly could serve as a vector of West Nile virus to other pelicans."