Avian Cholera Outbreaks

Avian cholera is caused by the bacterium Pasteurella multocida, which can kill in as little as six hours. The
disease is fatal to roughly half of the infected birds. Healthy birds can be infected by live bacteria released by
dead or dying birds, as well as seemingly healthy birds that have been carrying the disease. Dense concentrations of waterfowl enhance transmission opportunities, so avian cholera can sometimes spread through a wetland quickly, killing thousands of birds in a single outbreak.

National Wildlife Health Center scientists, in collaboration with state, national, international, and non-governmental agencies, conducted research for three years to determine, finally, that the prevalence of cholera in the wild is probably due to disease carriers, birds that previously contracted the disease and survived. Scientists also determined that exposure to the cholera bacteria, Pasteurella multocida, can occur in bird populations in seemingly disease-free areas. These results are significant because experts previously believed almost all infected birds died due to the swift and lethal nature of avian cholera.