PATHOLOGICAL INVESTIGATION OF BOVINE TUBERCULOSIS IN RANGPUR DISTRICT IN BANGLADESH

Abstract

Bovine tuberculosis (bTB) is one of the most economically important zoonotic diseases and tuberculin test has been widely used to detect its prevalence worldwide. This study was designed to investigate the pathological condition of bovine tuberculosis (BTB) using caudal fold tuberculin test in different dairy farms and free ranging cattle in Rangpur district during january - December. 2012. A total of 240 cattle (over the age of 6 months) were selected to have tuberculin test by bovine PPD (purified protein derivative) at caudal fold area in intradermal route regardless of age and sex. In the present study, 9 (3.75%) out of 240 cattle showed tuberculin positive reaction ( distinct and visible swelling) and 7( 2.92 %) cattle showed suspicious reaction (indistinct and invisible swelling). Out of 98 male cattle 3 (3.06%) and out of 142 female cattle 6 (4.22%) showed tuberculin positive reaction. The percentage of female cattle reactors were somewhat higher than the percentage of male cattle in CFT test and younger animals (7months- 3 years) were found more susceptible to tuberculosis than older animals. Grossly congested and consolidated lungs containing fairly distinctly demarcated caseous yellowish nodules throughout both parts of the lungs and divided macroscopically into haemorrhagic, fibrotic lesion and localized type. The spleen was enlarged but grossly nodular lesions were not seen. Histopathologically granulomatous nodular lesions with caseous necrotic mass surrounded by various reactive cells and fibrous connective tissues were found in lungs pursued by necropsy of selected tuberculin positive animal. The study dictates a positive correlation among the caudal fold tuberculin test, gross and histopathological study of the visceral organs.