Abstract:
Mycobacterium bovis, the causative agent of bovine tuberculosis (bTB), is a
multihost pathogen of public health and veterinary importance. We characterized
the M. bovis isolated at the human–livestock–wildlife interface of the
Serengeti ecosystem to determine the epidemiology and risk of cross-species
transmission between interacting hosts species. DNA was extracted from
mycobacterial cultures obtained from sputum samples of 472 tuberculosis
(TB) suspected patients and tissue samples from 606 livestock and wild animal
species. M. bovis isolates were characterized using spoligotyping and
Mycobacterial Interspersed Repetitive Units-Variable Tandem Repeats
(MIRU-VNTR) on 24 loci. Only 5 M. bovis were isolated from the cultured
samples. Spoligotyping results revealed that three M. bovis isolates from two
buffaloes (Syncerus caffer) and 1 African civet (Civettictis civetta) belonged to
SB0133 spoligotype. The two novel strains (AR1 and AR2) assigned as
spoligotype SB2290 and SB2289, respectively, were identified from indigenous
cattle (Bos indicus). No M. bovis was detected from patients with clinical
signs consistent with TB. Of the 606 animal tissue specimens and sputa of
472 TB-suspected patients 43 (7.09%) and 12 (2.9%), respectively, yielded
non-tuberculous mycobacteria (NTM), of which 20 isolates were M. intracellulare.
No M. avium was identified. M. bovis isolates from wildlife had 45.2%
and 96.8% spoligotype pattern agreement with AR1 and AR2 strains, respectively.
This finding indicates that bTB infections in wild animals and cattle
were epidemiologically related. Of the 24 MIRU-VNTR loci, QUB 11b
showed the highest discrimination among the M. bovis strains. The novel
strains obtained in this study have not been previously reported in the area,
but no clear evidence for recent cross-species transmission of M. bovis was
found between human, livestock and wild animals.
