Browsing by Author "MOHAMMED, ALI"

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    THE STATUS OF BOVINE TUBERCULOSIS IN SELECTED AREAS OF NORTH GONDAR ADMINISTRATIVE ZONE, ETHIOPIA
    (2006-06) MOHAMMED, ALI; Dr. Ademe Zerihun, Dr.Gezahagn Mamo
    Mycobacterium bovis (M. bovis) is one of the members of Mycobacterium tuberculosis complex, which infects both animals and man causing mammalian tuberculosis. A cross sectional and case control studies were conducted in Dembia and Gondar districts of North Gondar from September 2005 to April 2006 to determine the prevalence of bovine tuberculosis (BTB) and associated risk factors and assess the sources of infection of human tuberculosis (HTB). In the cross sectional study, cattle from extensive (310) and semi intensive (315) production systems were tested with the comparative intradermal tuberculin test (CID). In the case control study design, 50 human tuberculous patients (cases) and a similar number of patients visiting the hospital for some other health problems other than tuberculosis were interviewed about their hygienic practices, feeding habits and cattle management practices that would contribute to the transmission and maintenance of the disease. From each of the cases and control groups, 200 cattle owned or attended by them were tested with the CID test. Of all 1025 animals examined, 21% were positive. In the cross sectional study, assuming doubtful reactors as negative, prevalence was higher (16.8%) in semi-intensive production system than extensive (11.6%) and this difference was significant (p<0.05). Herd level prevalence was 37.7% and 56.3% in extensive and semi intensive production systems, respectively. It was also significant (p<0.001) between poor and good cattle management practices; cattle under poor management were 3.4 times more likely to be infected with BTB than those under good management. Other factors which were significantly (p<0.05) associated with prevalence were production system, breed, age, sex and body condition. In the multivariate logistic regression analysis, production system and management were significant (p<0.05). In the case-control study, out of the 200 animals tested that are owned by tuberculous human patients, 40 (20%) and from the same number of animals owned by non-tuberculous control groups, 22 (11%) were positive for the tuberculin test. The differences in prevalence of BTB in cattle owned by human TB cases and control group were significant (2=98.90, p<0.001). Of 50 TB cases, 66% and 34% were diagnosed as pulmonary and extra pulmonary tuberculosis, respectively. About 86% of the patients consume raw milk and milk products. The majority (58%) of HTB patients are between the ages 15 and 45 while 24% and 18% were below 15 and above 45 years, respectively. Cattle owners who consumed raw milk were at higher risk (OR = 14.33) of being infected with tuberculosis than those who consumed boiled milk. From the questionnaire survey, significant associations (p<0.05) with VIII cases were found when patients had physical contact with other clinical cases, drinks raw milk (2 =32.18; P<0.001) and are farmers compared to similar variables in the control group (2=25.01; P<0.001). In the bacteriological examination, Mycobacterium species were isolated from 26 (47.3%) sputum, 2 (15.4%) fine-needle aspirates (FNA) and 1(14.3%) peritoneal fluid of humans and 7 (7.1%) of 99 milk samples. The majority (88.5%) of sputum isolates were M. tuberculosis, and only one isolate (3.8%) was M. bovis while one isolate from milk was M. tuberculosis. Atypical mycobacteria were isolated from sputum (2), FNA (1) and milk (2). Among the isolates, 79.4% (23/29) and 10,3% (3/29) of the human isolates were M. tuberculosis and M. bovis, respectively. The rest 10.3% (3/29) were other mycobacterial species. On the other hand, 14.3% (1/7) and 57.1% (4/7) of the cattle isolates indicates were M. tuberculosis and M. bovis, respectively. The rest 28.6% (2/7) were other mycobacterial species. The findings in this study demonstrate the importance of BTB as a major health risk and cattle being one of the most important sources of infection. The findings of the present study using comparative intradermal tuberculin test and cultural examination of samples from humans and animals have shown that cattle may be important sources of infection to humans particularly of M. bovis infection.