Mycobacterium Avium and Mycobacterium intracellulare Infections in Slaughtered Pigs in Makurdi, North-Central Nigeria: An Emerging Zoonosis

Mycobacterium avium and Mycobacterium intracelluare (Mycobacterium avium complex) infections in 462 randomly selected slaughtered pigs in Makurdi were determined over a period of 6 months to access the disease burden and potentials for human infection. Standard methods of acid-fast microscopy, culture and biochemical tests were used. Twelve (2.6%) of the 462 pigs slaughtered over a period of 6 months were infected with Mycobacterium avium/intracellulare (Mycobacterium avium complex). The infections were observed in all the months with an average monthly rate of 2.0%. Of the number infected, 7 (58.3%) were female and 5 (41.7%) were male with sex specific incidence rate of 3.3 and 2.0% respectively. Seventy-five percent of the infected were old while 25% were young ones with age group specific incidence rates of 5.5 and 1.0% respectively. Breed specific incidence rate of 5.9% for local breed was significantly (p<0.05) higher than 1.4% for exotic and cross breeds combined. One hundred and seventy three (37.4%) pigs from Makurdi and other parts of Benue State, were more affected than the 289 (62.6%) from other parts of Nigeria with respective source specific rate of 6.2 and 2.4%. Respondents indicated that most of the pigs were reared by extensive and semi-intensive systems with very few on intensive systems. The chance of human infection via consumption of infected carcass or contaminated food and water is high. The need for urgent diagnosis and control of the infection is highlighted.