Abd Rashid, Ain Izzati (2020) Gross and histopathological changes in organs of cattle seropositive to bovine tuberculosis. [Project Paper] (Submitted)
![[img]](http://psaspb.upm.edu.my/style/images/fileicons/text.png) |
Text
lp FPV 2020 36.pdf Download (1MB) |
Abstract
Bovine tuberculosis is caused by Mycobacterium bovis. It is an infectious disease that is transmitted via the respiratory or oral route, and produces granulomatous tubercle, which is a typical chronic lesion. The aim of this study was to describe the pathological changes in dairy cattle seropositive to bovine tuberculosis. A total of 20 sero-positive and 5 sero-negative adult dairy cattle were randomly selected from 6 farms. All positive animals showed positive reactions to both γ-IFN (BOVIGAM®) and comparative intradermal tuberculin tests. The positive animals were culled by slaughtering and the carcasses were immediately examined for gross lesions, particularly the granulomatous tubercle lesions in two body systems, the respiratory and gastro-intestinal systems. The respiratory system involved the lungs, the mediastinal and retropharyngeal lymph nodes while the gastro-intestinal system involved the intestines and mesenteric lymph node. Following gross examination, samples of the organs were fixed in 10% buffered formalin and histological sections were stained with hematoxylin and eosin (H&E) to examine the lesions and were also stained with Ziehl-Neelsen staining to detect the presence of acid-fast bacilli in tissues. The results revealed a poor correlation between the comparative intradermal tuberculin test and the presence of granulomatous tubercle lesions. Only 13 (65%) positive animals had the lesion either grossly, histopathology or both. The lesions were found in the respiratory system and none of the cattle had gross tubercle lesion in the gastro-intestinal tract. However, histological examination revealed a strong correlation between gross and histopathology lesion (p<0.05; r = 0.873) where 92% reactors with gross tubercle showed the evidence of granulomatous histopathology. Ziehl-Neelsen staining of organ smears revealed the presence of acid-fast bacilli in 11 (55%) of the 20 reactors while 5 (25%) were identified with the presence of acid-fast bacilli in the tissue sections of lungs and mediastinal lymph node. Hence, detection of the acid-fast bacilli in tissue section was moderate but significantly (r = 0.56; p<0.05) correlation with organ smear. Furthermore, the acid-fast bacilli were observed mainly in the stages III and IV of the granulomatous tubercles. The stage of granulomatous tubercle was significant (p<0.05) but at a moderate correlation with the presence of acid-fast bacilli in organ tissue (r = 0.53). The presence of gross tubercle lesion was moderate but significantly (p<0.05) correlated with the detection of acid-fast bacilli in organ smear (r = 0.53) and tissue (r = 0.48). Thus, this study concluded that relying on seropositive results alone could increase the occurrence of false positive animals. Hence, conducting a thorough ante-mortem and post-mortem tests are important in confirming cases of bovine tuberculosis.
| Item Type: | Project Paper |
|---|---|
| Faculty: | Faculty of Veterinary Medicine |
| Depositing User: | Ms Nurhaznita Mahmood |
| Date Deposited: | 23 Oct 2023 06:37 |
| Last Modified: | 23 Oct 2023 06:37 |
| URI: | http://psaspb.upm.edu.my/id/eprint/1508 |
Actions (login required)
 |
View Item |