FLUORESCENT ANTIBODY TESTS IN PRE-CLINICAL EXPERIMENTAL MYCOBACTERIUM JOHNEI INFECTIONS IN CATTLE

Antibodies detectable by the fluorescent antibody test developed in animals experimentally infected with M. johnei orally, between 3 and 12 months after dosing. The FA test was found to be positive 3 times more often than the CF test up to 22 to 24 months after dosing, when the animals were killed and their infections assessed. The fluorescent antibody levels were shown to vary from month to month and in some cases weekly, but tests on individual sera were reproducible. The incidence of fluorescent antibodies in cattle which had not been experimentally infected with M. johnei but came from a similar source, was 8·5 per cent. The possible causes of such reactions are discussed. © 1968.