Spontaneous occurrence of antibodies against pathogenic amoebae of the limax group in domestic animals.

Sera of 1 218 animals were examined using indirect haemagglutination reaction with antigens of Naegleria fowleri and Acanthamoeba culbertsoni. Rabbit sera (214 samples) gave negative reaction with both antigens. Bovine sera (593 samples) reacted positively in 1.5%, particularly with the antigen of A. culbertsoni. Out of the 411 pigs examined 12% were positive with one or both of the antigens. In one of the pig farms of a modern type the positivity with one or both of the antigens. In one of the pig farms of a modern type the positivity was as much as 32.2%. The titres of positive animal sera have never been higher than 1 : 320. The amoebae of the limax group do not seem to be involved in the pathogenesis of diseases of cattle and rabbits. A sporadic occurrence of peracute cases is possible. In case of a sudden death, animals with symptoms of encephalitis or pneumonia should be examined for the presence of amoebae. Hypersensitivity should be considered as a possible cause of pig diseases.