Investigation of an Outbreak of Mycobacteriosis in Serbia

After a number of pigs imported to Serbia reacted positively to avian and/or bovine tuberculin, Mycobacter avium subsp. hominissuis was found in porcine and environmental samples from the Lithuanian breeding herd and that peat in Lithuania was a source of infection in these pigs, according to researchers based in Norway.

5 January 2012

3 minute read

By: Jackie Linden

A high proportion of pigs imported to Serbia from a Lithuanian breeding herd reacted positively against avian and/or bovine tuberculin. The pigs were euthanised and lesions characteristic for mycobacterial infection were detected. An investigation of potential mycobacteriosis in the pigs imported to Serbia and the possible source of infection in the Lithuanian herd were therefore initiated, according to Angelika Agdestein of the Norwegian Veterinary Institute in Oslo and co-authors at other institutes in Norway as well as Serbia and Lithuania. Their paper was published in BMC Veterinary Research.

Formalin fixed, paraffin embedded lymph nodes from tuberculin positive animals were examined by real-time PCR for IS1245 and IS6110. IS1245 was detected in 55 per cent and IS6110 in 11 per cent of the samples. Seven of the 10 IS6110-positive samples were positive for IS1245.

Eleven lymph nodes from 10 pigs and 15 environmental samples were collected from the Lithuanian breeding herd and cultured for mycobacteria. M. avium subsp. hominissuis was detected in all lymph nodes and from eight samples of peat and sawdust. Isolates with identical and related IS1245- and IS1311 RFLP profiles were detected from swine and peat.

Agdestein and co-authors conclude that their study demonstrated cross reactions between avian and bovine tuberculin in pigs. Real-time PCR indicated infection with M. avium in the Serbian pigs. However, as a small proportion of the lymph nodes were positive for IS6110, infection with bacteria in the M. tuberculosis complex could not be ruled out.

Analyses confirmed the presence of M. avium subsp. hominissuis in porcine and environmental samples from the Lithuanian breeding herd. The results indicate peat as a source of M. avium subsp. hominissuis infection in these pigs, and that the pigs imported to Serbia were infected with M. avium subsp. hominissuis.

Reference

Agdestein A., T.B. Johansen, V. Polacek, B. Lium, G. Holstad, D. Vidanovic, S. Aleksic-Kovacevic, A. Jørgensen, J. Zultauskas, S.F. Nilsen and B. Djønne. 2011. Investigation of an outbreak of mycobacteriosis in pigs. BMC Veterinary Research, 7:63. doi:10.1186/1746-6148-7-63