Mosquito Transmission of Venezuelan Equine Encephalomyelitis Virus from Experimentally Infected Dogs


Dogs experimentally infected with the Trinidad strain of Venezuelan equine encephalomyelitis (VEE) virus served as donor hosts for the infection of Aedes triseriatus mosquitoes, 10 percent of which then transmitted the disease to guinea pigs by bite 21 days later. A. aegypti which fed simultaneously did not become infected.

The infection in dogs caused a frank febrile response and hemagglutination-inhibition antibody formation. Significant virus concentrations were demonstrated in the blood, brain, and testicle. Although death occurred in 6 of the 10 challenged animals, overt signs of illness were minimal. The two uninoculated dogs which were in contact with the challenged dogs became infected, but neither died.

Microscopic study of the brains disclosed various alterations, which, although not diagnostic, are considered compatible with VEE infection.

Author Notes

U. S. Army Medical Unit, Fort Detrick, Md.

U. S. Army Biological Laboratories, Fort Detrick, Md.