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A total of 738 strains of Mycobacterium avium complex (MAC) were examined in biological experiments on poultry by use of PCR methods with primers for detection of the insertion sequence IS901. Serotype strains of MAC from all known 28 serotypes were examined. Further strains were isolated from human immunodeficiency virus (HIV)-negative and HIV-positive patients, 6 animal species, 17 bird species, and the environment. Of 165 strains virulent for poultry, characterized by generalized tuberculosis, 164 strains contained IS901, a result which is statistically highly significant (P, 0.01). The remaining 573 strains were nonvirulent; however, IS901 was present in 24 strains. From among 20 strains of serotypes 1, 2, and 3, IS901 was found in 15 strains, only 5 of which were virulent for poultry. The remaining 111 strains, of serotypes 4 to 28, were nonvirulent and did not incorporate IS901. None of the 152 strains isolated from humans was virulent for poultry, including 12 strains which were IS901 positive.The importance of mycobacterial infections caused by strains of Mycobacterium avium complex (MAC) in animals and humans is continuously increasing (11,18). In the human population, the condition is aggravated by the spread of human immunodeficiency virus (HIV) infection. In AIDS patients, the incidence of disseminated mycobacterial infection caused by MAC strains can reach up to 55% (34, 47). In poultry, swine, and cattle farms and in farmed red deer, avian tuberculosis imposes the highest financial losses (5,9,30,39,40).In veterinary epidemiology, virulent strains inducing avian generalized tuberculosis are the most important. One of the oldest and most frequently used methods for virulence assessment of MAC strains in birds is the challenge assay with poultry; nevertheless, mice, guinea pigs, hamsters, and rabbits also have been used (2,8,10,31,42,43,51,52). Serotyping has partly replaced time-consuming experimentation on laboratory animals. Originally, serotypes 1 and 2, virulent for birds, were classified as M. avium, and 13 nonvirulent serotypes were classified as M. intracellulare (39,41). Later, a third virulent serotype of M. avium, serotype 3, was described (21). Piening et al. denominated those three MAC serotypes as the M. avium group, in accordance with previous studies. Strains of serotypes 12 to 20 were absolutely nonvirulent for poultry and were denominated as the M. intracellulare group. Strains of serotypes 4 to 6 and 8 to 11, causing changes only at the site of inoculation after intramuscular injection, were denominated as an intermediate MAC group (33).As further serotypes were continuously investigated, in 1979 the number of serotypes belonging to M. intracellulare increased to 25 (serotypes 4 to 28) (49, 50). However, research results obtained in the early 1980s led to a new approach to the taxonomic classification of each MAC serotype. DNA-DNA hybridization was used to show the relationship of strains of serotypes 1 to 6 and 8 to 11 (3). These and other results led in 1990 to the suggestion for...

Mycobacteria were isolated from 14 (4.5%) of 314 samples, containing 7791 adult Diptera, which were collected in the Czech Republic and Slovakia in 1997-2000. These flies were collected from three cattle herds with paratuberculosis, two pig herds with mycobacterial infections and one farm that kept both cattle and pigs and that did not have problems of mycobacterial infections. Mycobacterium intracellulare was isolated from Eristalis tenax Linnaeus (Diptera: Syrphidae) captured from a pig herd. Mycobacterium avium ssp. avium (serotype 8) was isolated from flies of the genera Drosophila Fallen (Diptera: Drosophilidae) and Musca Linnaeus (Diptera: Muscidae) originating from a pig herd. Mycobacterium spp. were isolated from Musca spp. and Mycobacterium fortuitum was isolated from dung flies of the genus Scatophaga Meigen (Diptera: Scatophagidae), Musca spp. and Stomoxys calcitrans Linnaeus (Diptera: Muscidae) captured in the same herd. Mycobacterium scrofulaceum was isolated from S. calcitrans from the farm with both cattle and pigs. Mycobacterium avium ssp. paratuberculosis was isolated from Scatophaga spp. collected from pastures grazed by one of the cattle herds and from Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae) and Lucilia caesar Linnaeus (Diptera: Calliphoridae) captured in a slaughterhouse, where cattle infected with paratuberculosis were slaughtered. Mycobacterium phlei was isolated from flies of the genus Lucilia captured at a waste bin. These data indicate that mycobacteria may be spread by adult flies that have been in contact with material contaminated with these pathogens.

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The organs of 30 insectivorous mammals and 62 rodents from areas inhabited by people or livestock where cattle paratuberculosis or mycobacterial infections of swine had been found to occur were examined by cultivation during the monitoring of occurrence and spread of mycobacterioses in cattle and swine. Mycobacteria were found in the organs of 3 insectivores (10%) and 6 rodents (9.7%). Mycobacterium chelonae was isolated from the organs of the lesser white-toothed shrew (Crocidura suaveolens) and the common vole (Microtus arvalis), and M. vaccae and M. avium subsp. avium (IS901+, serotype 1) from the organs of the common shrew (Sorex araneus). M. avium subsp. avium (IS901+, serotype 1) was also isolated from the organs of the yellow-necked mouse (Apodemus flavicollis). Slow-growing mycobacteria of group III (according to Runyon) were isolated from the organs of the mouse (Mus musculus sensu lato) and the yellow-necked mouse (A. flavicollis). These findings had no connection with the epizootological situation in the nearby livestock. M. fortuitum was isolated from the organs of the common vole (M. arvalis) caught in a field within easy reach of a swine breeding herd. M. fortuitum was also identified in the lymph nodes and droppings of this swine herd, as well as in the straw, scrapings from the floor of stalls, troughs and banisters, as well as from larvae and imagoes of dipterous insects. These results demonstrate the possibility that insectivores and small rodents can spread the causative agents of mycobacteria in wild and domestic animals.