Tuberculosis in swine co-infected withMycobacterium aviumsubsp.hominissuisandMycobacterium bovisin a cluster from Argentina

Abstract

SUMMARY In Argentina little is known about the epidemiology of tuberculosis (TB) infection in swine. We characterized the epidemiological dynamics of Mycobacterium avium complex (MAC) infection in a swine population of Argentina using molecular tools and spatial analysis techniques. Isolates (n = 196) obtained from TB-like lesions (n = 200) were characterized by polymerase chain reaction. The isolates were positive to either M. bovis (IS6110) (n = 160) or M. avium (IS1245) (n = 16) while the remaining 20 (10.2%) isolates were positive to both M. bovis and M. avium. The detection of both bacteria together suggests co-infection at the animal level. In addition, MAC-positive isolates (n = 36) were classified as M. avium subsp. avium (MAA) (n = 30) and M. avium subsp. hominissuis (MAH) (n = 6), which resulted in five genotypes when they were typed using mycobacterial interspersed repetitive unit, variable number of tandem repeats (MIRU-VNTR). One significant (P = 0.017) spatial clustering of genotypes was detected, in which the proportion of MAH isolates was larger than expected under the null hypothesis of even distribution of genotypes. These results show that in Argentina the proportion of TB cases in pigs caused by M. avium is larger than that reported in earlier studies. The proportion of M. bovis-MAC co-infections was also higher than in previous reports. These results provide valuable information on the epidemiology of MAC infection in swine in Argentina.

Genetic diversity ofMycobacterium aviumcomplex strains isolated in Argentina by MIRU-VNTR

“…On the other hand, previous studies carried out also in Buenos Aires Province, but not in the exact region of this study, reported mycobacterioses in pigs caused by MAC. In that study, most of the cases were caused by MAA (n: 30) instead of MAH (n: 6) [14]. However, although it has been postulated the possible zoonotic role of MAH, the INMV patterns found for MAH isolates from pigs in Buenos Aires Province, were different from those found in the present study [14].…”

“…The four subspecies of M. avium are: (a) MAP that contains IS900 [7]; (b) M. avium subsp. avium (MAA), which contains IS901 and could affect humans [11][12][13][14]; (c) MAS (M. avium subsp. silvaticum) that also has IS901 [15]; and (d) M. avium subsp.…”

Estimates of the global and continental burden of animal tuberculosis in key livestock species worldwide: A meta-analysis study

“…When comparing Africa and Europe, the prevalence estimates may be influenced by the fact that the population density of pigs in Europe is much higher than in Africa [ 32 ], therefore Europe could be investing more resources in monitoring TB or in other trade-relevant disease in this species that enables TB suspicion and confirmation. However, South America, which shows on most of the sub-continent values of pig population density similar to those found in Africa [ 32 ], has an estimate which clearly weights data from two studies [ 41 , 42 ], both from Argentina. A single occurrence in Asia was retrieved in which the prevalence is 1.26%.…”

Increased B and T Cell Responses in M. bovis Bacille Calmette-Guérin Vaccinated Pigs Co-Immunized with Plasmid DNA Encoding a Prototype Tuberculosis Antigen

“…Furthermore, extensive information on swine leukocyte antigens is available and it is possible to predict cytotoxic T cell epitopes. Like humans, swine are a natural host to Mycobacterium species [ 54 ] and wild boar and free-range pigs can be infected by Mycobacterium tuberculosis complex and contribute to the spread of bovine tuberculosis [ 55 ]. Swine develop similar pathological lesions to those seen in humans following M .…”