Non-tuberculous mycobacteria isolated from slaughter pigs in Mubende district, Uganda
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Date
2012
Journal Title
Journal ISSN
Volume Title
Publisher
BMC Veterinary Research
Abstract
The importance of infections caused by non-tuberculous mycobacteria (NTM) in animals and humans
has gained considerable recognition during the past few years. In the developed world, where pig production is
extensively practiced, studies on mycobacterial infections and related control strategies have received increasing
attention. The infections are reported to be caused by a wide spectrum of NTM. Unfortunately, these infections
have been less recognized in sub-Saharan Africa owing to lack of awareness and systematic studies. In this study we
aimed at isolating and identifying species of mycobacteria involved in causing infections in slaughter pigs in
Mubende district of Uganda. Furthermore we wanted to identify factors associated with infection prevalence in the
study area.
Methods: A total of 363 lymph nodes were collected and cultured for the presence of mycobacteria. Isolates were
identified by 16S rDNA gene sequencing. A questionnaire survey was administered to identify production related
factors associated with infection prevalence. Data were assembled and analysed using descriptive statistics and
mixed effects logistic regression analysis.
Results: Mycobacteria were detected in 39 % (143/363) of the examined lymph nodes, 63 % (59/93) of lymph
nodes with gross lesions typical of mycobacteriosis and 31% (84/270) of lymph nodes with no visible lesions.
Nineteen per cent of the isolated mycobacteria were identified as Mycobacterium (M) avium, of these 78% and 22%
were M. avium sub sp. Hominissuis and avium respectively. Other mycobacterial species included M. senuense (16%),
M. terrae (7%) and M. asiaticum (6%). This study found free range systems (OR = 3.0; P = 0.034) and use of water from
valley dams (OR = 2.0; P = 0.049) as factors associated with high prevalence of mycobacteria in slaughter pigs.
Conclusions: This study demonstrated a high prevalence of NTM infections among slaughter pigs in Mubende
district of Uganda. M. avium was the most prevalent of all NTM isolated and identified. Free range system of pig
management and valley dam water were the most significant factors associated with NTM prevalence in Mubende
district. These findings could be of a major public health concern given that it is in a predominantly pork
consuming population with 18% HIV/AIDS prevalence. Therefore, stringent post-mortem inspection at the slaughter
houses is of paramount importance to reduce human exposure.
Description
Keywords
Non-tuberculous mycobacteria, Slaughter pigs, Mubende district, Uganda
Citation
Muwonge et al.: Non-tuberculous mycobacteria isolated from slaughter pigs in Mubende district, Uganda. BMC Veterinary Research 2012 8:52. doi:10.1186/1746-6148-8-52