A Survey of Mycobacteriosis of Feral Pigs in the Northern Territory

Abstract

Seven hundred and fifty-one feral pigs from the subcoastal plains of the Northern Territory were examined. The sample population consisted of 52.4% females and 47.6% males. They ranged in age from newborn piglets to mature animals of over 72 months. Of the pigs examined 47.7% had macroscopic abscesses and of these 80.2% were probably caused by mycobacteria. Tissues from 193 pigs were examined bacteriologically and 93 strains of mycobacteria were isolated. These were typed as M. bovis (37 strains); M. avium serotype 2 (1); M. intracellulare serotypes 6 (2), 7 (3), 9 (1) and 18 (1); M. intracellulare double serotypes 6 + 12 (1), 8 + 12 (1), and 11 + 12 (1); M. intracellulare unclassified serotype (4); M. scrofulaceum serotype 41 (1); M. scrofulaceum unclassified serotype (7); M. gordonae (2); M. Kansasii (1); M. simiae (2); M. szulgai (2); M. vaccae (1); and M. xenopi (2). Additionally, 3 strains were unidentifiable members of the M. avium-M. intracellulare-M. scrofulaceum (MAIS) complex, one strain was a Runyon's group IV and 4 strains were typed as members of the genus Rhodococcus. Five strains were non-viable on subculture and 10 did not conform to any currently recognised species of mycobacteria. Of the 93 strains, 3 were isolated from tissue that did not contain macroscopic lesions, viz. M. simiae, Runyon's group IV and an unidentifiable member of the MAIS complex. It was concluded that the feral pig is probably an end host for both M. bovis and atypical mycobacteria and not a significant source of infection for cattle. M. bovis is not a significant cause of mortality in feral pigs but mycobacterioses are a significant cause of morbidity. With increasing age, the proportion of pigs having lesions increased whereas the proportion of lesions from which mycobacteria could be isolated decreased.

Wild boar (Sus scrofa) as a possible vector of mycobacterial infections: review of literature and critical analysis of data from Central Europe between 1983 to 2001

“…Med. -Czech, 48, 2003 (3): 51-65 number of tuberculous lesions from which mycobacteria were isolated fell (Corner et al, 1981). Ray et al (1972) also describe the more frequent isolation of mycobacteria from the tissue of wild boar without tuberculous lesions.…”

“…Clinically the disease (above all bovine tuberculosis) in pigs manifests itself only in swelling of the mandibular lymph nodes. Pathological and anatomical changes are mostly represented only by yellowish tuberculous nodules with central necrosis and calcification above all in the submandibular and retropharyngeal lymph nodes, and also on the pleura and sometimes on the peritoneum (Corner et al, 1981;Serraino et al, 1999;Bollo et al 2000). Ray et al (1972) followed the dependence of the emergence of a certain form of tuberculome in pigs on an isolated mycobacterial species.…”

“…The low isolation of mycobacteria from tuberculous lesions also indicates a certain degree of resistance of this species of animals to mycobacterial infection (Corner et al, 1981). Mycobacterioses in wild boar caused by other species of mycobacteria (M. a. avium, M. intracellulare and others) are not a cause of increased mortality, but cause increased morbidity (Corner et al, 1981;Tweddle and Livingstone, 1994;Serraino et al, 1999). According to Tato et al (2001 -pers.…”

“…considerably high. In the northern part of Australia the organs of 193 wild boar from six areas were examined between 1973 and 1976 for mycobacteria, with a positive result in 88 (45.6%) wild boar (Corner et al, 1981). Of the 93 mycobacterial isolates, M. bovis was the most frequently isolated species from tuberculous and tuberculoid lesions (37 isolates).…”

Genetic characterization ofMycobacterium aviumisolates recovered from humans and animals in Australia

“…The organism is present in the environment, may be found in the faeces of healthy people [3], and can be isolated from granulomas in animals [4,5] and in human patients without any predisposing conditions [6,7]. It is considered to be an opportunistic pathogen in humans, and has been reported to cause disseminated infection in up to 50 % of patients with AIDS in the USA [8,9], and in 17% of such patients in Australia [10,11].…”