WHERE DOES IT OCCUR? 



Avian botulism has been reported from every continent except Antarctica. Outbreaks of 

 avian botulism have occurred in North America since the beginning of the century, if not 

 earlier. Most occurrences have been reported within the past 20 years. Most type C out- 

 breaks in the United States occur west of the Mississippi River; however, outbreaks have 

 occurred from coast to coast and .border to border. Type E outbreaks in birds are less fre- 

 quent and have been confined to the Great Lakes region. 



Major Waterfowl Botulism Outbreaks in the U.S. 



Year Estimated Loss Location 



1910 "Millions" Utah & California 



1925 100,000 Lake Malheur, Oregon 



1929 100-300,000 Great Salt Lake, Utah 



1941 250,000 Tulare Basin, California 



1952 4-5 Million Western United States 



1978 50,000 Montana 



1979 100,000 Montana 



1980 110,000 Great Salt Lake, Utah 



