On January 27, 2017, in Yakima, Washington State and federal wildlife-diagnostic centers confirmed an outbreak of avian cholera near the Tri-Cities. At that time, they reported more than 1,200 dead ducks from the previous week.
Numbers for this wildlife mortality event continue to rise.
This avian cholera-related die-off also showed up in the US Wildlife Health Information Sharing Partnership – event reporting system (WHISPers), a multi-agency data collection of wildlife “morbidity or mortality events in North America” and is online here. WHISPers currently lists the number of deaths at approximately 2,005 ducks, herons, grebes, and other waterfowl/birds, all within the Walla Walla WA area. According to WHISPers, avian cholera deaths began around January 21, 2017 and do not yet have an end-date.
Washington Department of Fish and Wildlife’s Kyle Spragens and Dr. Katie Haman, issued disease and reporting information along with the avian cholera announcement, which is included below.
The disease was confirmed in dead ducks found near Burbank, Washington, and tested by the USGS National Wildlife Health Center and the Washington Animal Disease Diagnostic Lab. The birds tested negative for avian influenza, a different disease fatal to waterfowl and other birds.
Avian cholera is caused by the bacterium Pasteurella multocida and is one of the most common diseases among ducks, geese and other wild North American waterfowl, said Katie Haman, a wildlife veterinarian at the Washington Department of Fish and Wildlife (WDFW):
“Humans are not at a high risk for infection with the bacterial strain causing avian cholera, though infections in humans are possible. We advise people to avoid handling sick or dead birds, and to report any they find.”
According to the USGS National Wildlife Health Center, the bacteria kill waterfowl swiftly, sometimes in as few as 6-12 hours after infection. Live bacteria released into the environment by dead and dying birds can subsequently infect healthy birds. Avian cholera is highly contagious and spreads rapidly through bird-to-bird contact, ingestion of food or water containing the bacteria, or scavenging of infected carcasses.
Said Kyle Spragens, WDFW waterfowl manager:
“As a result, avian cholera can spread quickly through a wetland and kill hundreds to thousands of birds in a single outbreak. The bacteria are hardy and can survive in water for several weeks and in soil for several months.”
WDFW and the US Fish and Wildlife Service are working to minimize the spread of the disease through careful carcass collection and disposal to reduce the amount of bacteria in the environment.
Signs displayed by infected birds include lethargy, convulsions, swimming in circles, and erratic flight. They may also show mucous discharge from the mouth and nose, and soiling of the feathers around the vent, eyes, and bill.
Wildlife managers encourage waterfowl hunters in Walla Walla, Franklin, and Benton counties to clean and disinfect gear, such as waders and decoys to help minimize potential further spread of the bacteria.
A 10 percent bleach solution or warm soapy water can be used for disinfection. Leaving the gear in direct sunlight for several hours will also kill the bacteria. Waterfowl hunters are advised to use gloves when cleaning harvested birds, and if white spots are seen on the liver, err on the side of caution and discard the bird directly into a garbage bag.
Although bacteria from wild birds do not typically cause infections in mammals, dog owners should prevent contact between their pets and sick or dead birds encountered. Additionally, vehicles that have accumulated mud should be run through a commercial car wash.
For more information on avian cholera, see:
- Field manual chapter on avian cholera — www.nwhc.usgs.gov/publications/field_manual/chapter_7.pdf
- Fact sheet on avian cholera — www.nwhc.usgs.gov/publications/fact_sheets/pdfs/cholera091102.PDF.