1978 EPORNITIC OF AVIAN CHOLERA ON THE CHESAPEAKE BAY

In an outbreak of avian cholera (Pasteurella multocida infection) in wildfowl on and around Chesapeake Bay during March and April of 1978, 31,295 carcasses were retrieved from Maryland and Virginia. Although other birds were involved, mortality was heavy among diving ducks (90% of the total), especially oldsquaw ducks (80% of the total). This is the second outbreak involving primarily diving ducks to be reported from this area of the Atlantic Flyway. It mimics in many respects the epornitic that occurred in 1970. Although mortality was heavy then, this occurrence appears much more severe and could be the largest recorded outbreak of avian cholera in North America.