The pathology of tuberculosis lesions in allergic skin test (PPD tuberculin) positive cows and detection of tuberculosis agents with PCR in milk samples

Authors: ÇİĞDEM TUNCAY, FATİH HATİPOĞLU

Abstract: The aim of this study was to determine tuberculosis (Tb) agents in milk and the pathologic changes in the tissues and organs of 100 PPD Tb-positive cows that were intended for slaughter. Milk samples were taken before slaughtering and PCR analysis was conducted to detect the Tb agent. In postmortem examinations, the lungs, liver, mammary glands, spleen, kidneys, and heart were collected for macroscopic and histopathological examinations. Out of the 100 PPD positive cows, lesions of Tb were observed in 75 cows. In the microscopic examination, Tb was identified in the lungs (51 cases), liver (61 cases), and in both the liver and lungs (37 cases). Although mammary Tb was suspected in 32 cows in macroscopic examinations, in microscopic examinations these cases were evaluated as chronic pyogenic abscesses mastitis. No Tb agents were detected by PCR analysis in milk samples taken from the cows before slaughter. Therefore, periodical milk inspections are suggested for controlling agents in milk. In some of the Tb PPD positive animals (25 cases), no changes were detected; therefore, there is a need to improve tests with higher sensitivity for the antemortem diagnosis of Tb. Moreover, people involved in the livestock sector should be trained about Tb, hygiene rules, and disease-free herds.

Keywords: Tuberculosis, pathology, cow, PPD, PCR, milk

Full Text: PDF