Allergic reactions provoked by environmental mycobacteria

Abstract

The occurrence of non-specific tuberculin reactions in animals had a great supporting effect on research into the the ecology of mycobacteria. In the advanced phase of the eradication of tuberculosis, the tuberculin test is commonly used as an important diagnostic tool. In some regions however, animals which had shown positive reactions failed to show any evidence of tuberculosis at detailed post mortem examinations. These non-specific reactions resulted mainly from sensitisation with environmental mycobacteria (Worthington, 1967, Monaghan et al. 1994), but the origin of these mycobacteria could not be satisfactorily explained until their ecology had been studied. This was carried out in a large breeding farm for chickens in South Bohemia. More than 80% of the chickens gave a positive reaction when tested for avian tuberculin over three consecutive years. The autopsies revealed no tuberculous lesions, but it was possible to cultivate Mycobacterium intracellulare serotype 8 from the livers and spleens (Kazda & Dvorak, 1965, Kazda, 1966, Kubin et al. 1969). This mycobacterium provoked positive reactions to avian tuberculin in experimentally infected chickens. Its source was found to be moorland water used as drinking water for the chickens. The tanks used for storing the drinking water were exposed to sunshine during the summer months. The temperature of the water exceeded 30 °C, high enough for mycobacteria to thrive. When well water was introduced instead, the non-specific reactions disappeared within a few months (Kazda, 1967).