Isolation and Molecular Identification of Mycobacterium Bovis in Cattle Slaughtered in Makurdi and Otukpo Abattoirs, Benue State, Nigeria
Isolation and Molecular Identification of Mycobacterium Bovis in Cattle Slaughtered in Makurdi and Otukpo Abattoirs, Benue State, Nigeria.
Abstract
Bovine tuberculosis (BTB) is a disease of high economic relevance within the context of livestock farming as it directly affects animal productivity and also influences international trade in animal products.
The aim of this study was to determine the species of Mycobacterium isolated from cattle carcasses in Makurdi and Otukpo abattoirs.
A total of 63 cattle suspected of BTB were sampled from a total of 587 cattle inspected at the abattoirs. Samples were processed and Ziehl-Neelsen microscopy were carried out based on recommended procedure.
Processed tubercle lesions were cultured on Lowenstein-Jensen media with or without pyruvate and incubated for 8 to 12 weeks at 37°C. Region of difference (RD) typing of isolates was carried out as recommended.
Out of a total of 587 cattle samples that were examined, 63 (10.7%) had BTB lesions,47 (74.0%) were positive for acid-fast bacilli. Lynph nodes and lungs were more affected than other organs.
Samples from liver, spleen, kidney, heart and pleural surface gave 100% growth on Lowenstein-Jensen slant while lymph nodes and lungs gave 68.2% and 81.3% growth respectively.
More growth were seen on media containing pyruvate than glycerol. RD typing of 40 isolates identified the presence of 36 RD1, and absence of 36 RD4, 36 RD9 and 33 RD 12.
Therefore, 36 (90.0%) of the isolates were identify as M. bovis, while the other isolates were identified as non- tuberculous mycobacteria (NTM).
The annual prevalence of bovnie tuberculosis in cattle slaughtered in Markudi abattoirs from 2008 to 2012 was 1.9%. A prevalence of 2.9% was recorded in Otukpo abattoir from 2010 to 2012.
Introduction
Background Of Study
Bovine tuberculosis (BTB) is a chronic bacterial disease of cattle characterized by respiratory disease (O’Reilly and Daborn, 1995) with production of progressive granulomatous lesions affecting organs in the chest and abdominal cavity (Shitaye et al., 2006).
The disease is caused by the Mycobacterium bovis in cattle (Smith et al., 2006), a member of the Family Mycobacteriaceae (Metchock et al., 2005) and belong to the Genus Mycobacterium (Smith et al., 2011).
The species is a member of the group Mycobacterium tuberculosis complex (MTC), these include Mycobacterium tuberculosis, Mycobacterium africanum, Mycobacterium bovis (along with the M. bovis-derived bacillus Calmette-Guerin (BCG) vaccine strains).
Mycobacterium microti, Mycobacterium bovis subsp. caprae (M. caprae), Mycobacterium tuberculosis subsp. Canettii (Brosch et al., 2002; Mostowy et al., 2002) and Mycobacterium pinnipedii (Niemann et al., 2005).
Bovine tuberculosis caused by other members of the MTC has been reported (Cadmus et al., 2010; Jenkins et al., 2011; Smith et al., 2011; Schrenzel, 2012)
The organism was discovered by Robert Koch in 1882, it an aerobic acid- fast, non motile, non-capsulated, non-spore forming bacillus (Grange, 2006).
Mycobacteria are obligate intracellular pathogens that can infect several animals species, although M. bovis is principally an animal pathogen which is closely related to M. tuberculosis and has the broadest host range of any pathogenic Mycobacterial species (Schrenzel, 2012).
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