In the years 1981 and 1982 when a mass mortality of wild and domestic water birds was observed on the Starý pond, eleven diseases or just died birds were examined by the neutralization test for botulotoxin and four sludge samples for the presence of Clostridium botulinum. C. Botulinum toxin of C type was detected in four wild ducks (Anas platyrhynchos) from September 1981 and July 1982 and in one gull (Larus ridibundus) and July 1982. The highest titres (of mice i. p. LD50/g) of botulotoxin in ducks were 10(6.3) in the intestinal contents, 10(6.1) in the liver tissue and 10(5.1) in the stomach contents. In one duck we detected, besides the C type, a smaller botulotoxin amount of A type. Therefore we can recommend a complete serotypifying for the cases of botulism in water birds. Out of four sludge samples collected in September 1982 one sample was negative, whereas in three samples the C botulotoxin was demonstrated after propagation and one C. botulinum strain of C type was isolated.

Thermal sensitivity of Clostridium botulinum type C toxin