Volume 25 , Issue 2 , December 2023 , Pages 215-226
Shorsh Gharib Rashid 1 ; Rizgar Raheem Sulaiman 2 ; Nahla Mohammed Saeed 3
1 Department of Zoonotic Disease Control, Directorate of Health, Ministry of Health, Sulaimani City, Kurdistan Region, Iraq
2 Department of Clinic and Internal Medicine, College of Veterinary Medicine, University of Sulaimani, Sulaimani City, Kurdistan Region, Iraq
3 Department of Microbiology, College of Veterinary Medicine, University of Sulaimani, Sulaimani City, Kurdistan Region, Iraq
Background: Mycobacterium bovis (M. bovis) causes bovine tuberculosis (BTB), is an
endemic disease in cattle and poses a high risk of spreading to humans. Objective: This
study aimed to determine M. bovis in cattle and assess the similarities between cattle and
humans through molecular methods and histopathological examinations. Methodology:
Randomly, blood samples from 411 healthy appearance cows (1% of the target
population) in five districts in Sulaimani province, Iraq, were collected from January to
March 2022. Sera were obtained immediately and used for ELISA test to determine M.
bovis. Additionally, the disease prevalence was confirmed by gross lesions at the
slaughterhouse and histopathological examination of collected lymph nodes. Moreover, a
PCR assay was used to detect M. bovis in suspected cow samples and previously
diagnosed human samples. Gene sequencing and phylogenetic tree analysis were also
done to determine the molecular differences between animal and human M. bovis.
Results: Using an ELISA test, 46 (11.11%) of 414 samples were positive, while 368
(88.89%) were negative without significant differences between the districts (p>0.05).
According to postmortem lesions at the slaughterhouse, only three cows were infected
with TB, and typical gross lesions were calcified necrotic and multiple well-demarcated
granulomas. The molecular test using two primers (CSB2 and oxyR gene) revealed that
M. bovis was found in animal and human extra-pulmonary lymph nodes with no
molecular change. Conclusion: Healthy cows harbored M. bovis, the causative agent of
a contagious disease that spreads and causes a persistent health problem in humans.