An outbreak of fatal duck sickness among a resident flock of mixed mallard, Peking white, and mallard-Peking white crossed ducks was investigated and proved to be caused by botulism type C intoxication. The incident was deemed unusual because it occurred on a flowing river in the apparent absence of the usual conditions associated with avian botulism. Furthermore, Clostridium botulinum could not be demonstrated in bottom samples from the shallow water at the site of the outbreak. Although a comprehensive scheme was followed for detection and isolation of C. botulinum type C, and ample evidence of the toxic anaerobe in enrichment cultures was obtained, examination of approximately 125 isolates failed to yield the toxic anaerobe in pure culture. A possible association between this outbreak of avian botulism and an alteration in the aquatic environment occasioned by the building of a high dam, with the attendant rise in water levels and decreased river flow rate, is suggested but can not be definitely proved. Interested workers should be alert to the possibility of botulism in unusual or recently altered environments and the attractive hazard to migratory fowl posed by afflicted resident waterfowl.

Sera from 41 mule deer (Odocoileus hemionus) in Yosemite National Park, California, were tested for neutralizing antibody to 17 arboviruses which are known or suspected to occur in California. Antibody titers to California encephalitis, Trivittatus, Cache Valley, or Jerry Slough viruses were detected in 4 of the sera. Deer may be useful indicator hosts for the presence of arbovirus activity in a geographic area.

Gulls were force fed Clostridium botulinum type E toxin. Their susceptibility varied with the strain of C. botulinum type E toxin, and the LD₅₀, for gulls to a toxic strain was calculated to be approximately 20,000 mouse MLD. Type E botulinal toxin was present in dead alewives taken from the beach and water of Lake Michigan, and thus a vehicle for waterbird intoxication is available.