Morphological Changes in Geese after Experimental and Natural Infection with Mycobacterium Avium Serotype 2

Pavlas M., Vlasta Patlokov:l and J. Zajicek: Morphological Changes in Geese after Experimental and Natural Infection with Mycobacterium avium Serotype 2. Acta vet. Brno, 52, 1983: 163-167. Pathomorphological changes in two groups of 10 geese infected experimentally with Mycobacterium avium serotype 2 by either the intravenous or the oral route were localized most frequently in the liver. The resistance of geese to M. avium was high particularly in the group infected orally where tuberculous lesions were demonstrated in 3 birds in the liver and in one bird each in the intestine, lung and spleen. Similar results were obtained in slaughter geese infected naturally with M. avium. Serological examination by means of rapid agglutination with blood and serum proved a better diagnostic tool than tuberculin testing; it detected tuberculosis in 80 per cent of intravenously infected birds and in 20 per cent of orally infected birds with tuberculosis of the liver but failed to do so in geese having solitary tubercles in the liver, spleen or lung after oral infection. The high resistance of geese to M. avium particularly after oral infection does not exclude the possibility of their contracting avian tuberculosis. However, massive infection is required to produce the disease and the transfer of infection is less frequent than in gallinaceous birds. Mycobacterium avium, goose, susceptibility, morphological changes, diagnosis, avian tuberculosis. Mycobacterium avium is presently the most important pathogenic mycobacterium in the epizootiology of tuberculosis in birds. Among water-fowls, geese and ducks are generally regarded as relatively resistant to avian tuberculosis. Tuberculous lesions in geese and ducks have been found mainly in the liver, intestine and spleen, and less frequently in other organs. Tuberculosis of bones is very rare in geese (KlimeS 1970). Of geese showing positive reactions to avian tuberculin, 94.4 per cent were reported to hwe tuberculous lesions in the liver, 27.7 per cent in the lung, 22.2 per cent in the spleen, 11.1 per cent in the intestine and 5.5 per cent in the kidney (Shchepilov 1957). In the Czech Socialist Republic, a study on geese including slaughter and dead birds from large and small flocks showed that in tuberculous geese, 96 per cent of tuberculous lesions were in the spleen, 48 per cent in the liver and only occasional lesions were found in the lung and intestine (Rachac 1981). Liver and spleen lesions were also most frequent in geese after experimental infection with M. avium. Histological changes in the liver and spleen were demonstrated as early as 12 days and necrotic foci 21 days after infection, whereas the intestine showed only solitary tuberculous lesions (Cerny 1982). The last-named investigator found no tuberculous lesions in ducks exposed to avian tuberculosis by contact for 250 days. In the U.S.S.R. natural infection with M. avium in geese and ducks kept together with tuberculous birds was described by Matyzhev (1958). On gross examination, tuberculous lesions in slaughter or dead geese may be confused with non-specific changes produced by causative agents of aspergillosis, pseudotuberculosis and salmonellosis as well as by micrococci and further agents of non-specific disease such as leucosis and sarcomatosis. FleS:lr et al. (1976) examining 519 specimens from slaughter geese with gross le-