[Sources of cattle infection with atypical mycobacteria and the frequency of their isolation from healthy slaughter animals in Cienfuegos Province, Cuba]. / Iztochnitsi za infektirane na govedata s atipichni mikobakterii i chestota na izoliraneto im ot zaklani zdravi zhivotni v provintsiia Sienfuegus v Kuba.

Studied were a total of 322 samples of water, feed, and grass vegetation with soil from a region where there were records of unspecific tuberculin reactions with cattle. Investigations were also carried out on viscera and lymph nodes of 120 slaughtered cattle. It was found that the atypical acid-fast mycobacteria were widely spread in some regions of Cuba: 42.5% were found in grass samples, 37.5%--in soil samples, 35.0%--in water ones, and 9.6% in feed samples. Atypical mycobacteria were isolated in 35.0% of the cases with internal organs and lymph nodes of slaughtered healthy animals. Established were as many as ten species of such bacteria, prevailing being M. aquae B, M. aquae A, M. smegmatis, and M. phlei. Suggested is the preparation of an allergen from selected strains of atypical mycobacteria to carry out differential tuberculin tests where suspected tuberculin reactions were recorded in the practice.

[Role of atypical mycobacteria in the occurrence of nonspecific tuberculin reactions in cattle]. / Roliata na niakoi atipichni mikobakterii za poiava na nespetsifichni tuberkulinovi reaktsii pri govedata.

Bacteriologic investigations were carried out with a total of 295 cattle of the Holstein-Zebu breed that responded positively to tuberculin. Mycobacterium bovis was isolated from 66 animals, and 12 species of atypical mycobacteria were isolated from 94 animals. Parallel studies were comparatively made of the intradermal reaction test and the bacterial findings. Three groups of calves were infected with various atypical mycobacteria, and their response was followed up with the use of the avian and the bovine type of tuberculin on the 100 th day of infection. It was found that the unspecific tuberculin response of cattle in Cuba were not uncommon, and the best proportion of such reactions were shown to be due to the involvement of atypical mycobacteria. The investigated cattle with a positive response to bovine tuberculin at a single intradermal test were harbouring M. bovis in 66 cases (22.3 per cent), atypical mycobacteria in 94 cases (32.1 per cent), and Actinomyces bovis in 7 cases (2.3 per cent). In 128 of the cases (43.3 per cent) both the morphologic and the bacteriologic findings were negative. The cases with a stronger response at the single intradermal tuberculin test in which the skin fold enlarged over 6.5 mm corresponded to a larger extent to the actual specific infection in the animals than to an infection caused by atypical mycobacteria, however, this could not be absolutely stated for all animals. Following a muscular as well as an oral infection of calves with atypical mycobacteria the allergic response was enhanced from the 40 th up to the 100 th day, the positive reaction to avian tuberculin becoming stronger than to bovine tuberculin.(ABSTRACT TRUNCATED AT 250 WORDS)