UC Davis researchers solve century-old bluetongue virus mystery

Researchers at the University of California, Davis, have solved a century-old mystery by discovering that the bluetongue virus that affects cattle and sheep survives winter by reproducing in midges, which spread the virus.

They discovered that when temperatures turned cold and biting-midge populations fell, transmission of the disease dropped accordingly. Yet when the weather turned warmer the virus reappeared with the midges. The study was recently published in the journal PLOS ONE.

Bluetongue, which was first identified in the 1800s in southern Africa, derives its name from the swollen lips and tongue of infected sheep that can turn blue. It is estimated that the disease costs the U.S. cattle and sheep industries about $125 million a year.

James MacLachlan, veterinary professor at UC Davis

"This discovery has important ramifications for predicting the occurrence of bluetongue in livestock and, we hope, for eventually developing controls for the disease," James MacLachlan, a co-author of the study and veterinary professor at UC Davis, said in a statement.

Still, the researchers cautioned, the virus, which doesn't affect humans, may have other ways of surviving the winter that they are investigating.

- see the release
- check out the PLOS ONE abstract