zoonoses and communicable diseases common to ... - PAHO/WHO

112 BACTERIOSESand M. fortuitum. Strains similar to M. fortuitum, but differing in several biochemicalcharacteristics, were isolated from swine with lymphadenitis; the name M.porcinum has been proposed for these strains (Tsukamura et al., 1983).MAC bacteria can sometimes be isolated from the apparently healthy lymphnodes of a large percentage of animals inspected in slaughterhouses (Brown andNeuman, 1979).In the US, any mycobacterial lesion is considered tuberculous for purposes ofinspecting pork. Economic losses due to tuberculosis were US$ 2.3 million in 1976,but fell 73% in 1988 (Dey and Parham, 1993).CATS AND DOGS: In cats, nodular lesions, with or without fistulation, are seen in thecutaneous and subcutaneous tissues, primarily on the venter. M. fortuitum is amongthe mycobacteria identified; on one occasion, M. xenopi was also found. This diseaseshould be distinguished from “cat leprosy,” whose etiologic agent is M. lepraemuriumand which is probably transmitted by rat bite. The cutaneous or subcutaneousnodules of “leprosy” can localize in any part of the body (White et al., 1983). Skininfections caused by nontuberculous mycobacteria also occur in dogs. Although dogsare resistant to MAC, 10 cases were confirmed in basset hounds; their susceptibilitymay be due to a genetic immunodeficiency (Carpenter et al., 1988).OTHER SPECIES: In addition to infections caused by the prevalent tuberculosismycobacteria (M. tuberculosis and M. bovis), infections caused by nontuberculousmycobacteria, such as various MAC serotypes, also occur in nonhuman primateskept in captivity. The infection is predominantly intestinal and manifests as diarrheaand emaciation. Lesions in these animals differ from those caused by M. tuberculosisand M. bovis in that tubercles do not form and necrosis and giant cells are absent.The lamina propria of the intestine is infiltrated by epithelioid cells (Thoen et al.,1981). In a cage of macaques (Macaca arctoides), MAC infection was prevalentamong various diseases and caused the death of 44 of 54 animals over a period oftwo-and-a-half years. The lesions found upon autopsy indicated an enteric origin forthe disease process. Histopathological examination and clinical laboratory examinationssuggested that the common basis of the diseases was an immunologic abnormality(Holmberg et al., 1985).Infection due to nontuberculous mycobacteria also occurs in other animal specieskept in captivity. In poikilotherms, the disease may be caused by various species ofmycobacteria, such as M. chelonae, M. marinum, M. fortuitum, and M. avium.An infection due to M. ulcerans was described in koalas (Phascolarctos cinereus)on Raymond Island (Australia). The animals had ulcers on the flexor muscles oftheir extremities. This is the first confirmation of infection due to M. ulcerans in animalsother than man (Mitchell and Johnson, 1981).Disease among aquarium or aquiculture fish may be caused by several mycobacteria,particularly M. marinum and M. fortuitum. The clinical symptoms are variableand may resemble other diseases, with emaciation, ascites, skin ulcerations, hemorrhages,exophthalmos, and skeletal deformities. Upon necropsy, grayish whitenecrotic foci are found in the viscera. Exposure to M. marinum in fish kept in aquariumsmay cause skin infections in man (Leibovitz, 1980; Martin, 1981).Unculturable mycobacteria that can be confused with M. leprae have been foundin several animal species, such as frogs in Bolivia (Pleurodema cinera and P. marmoratus)and water buffalo in Indonesia (Bubalus bubalis).