Clinical presentation and diagnostics of cattle with suspected Johne’s disease

QR Microbiology;RA0421 Public health. Hygiene. Preventive Medicine;SF600 Veterinary Medicine

Baro Basora, Joan ; Ellis, Kathryn

University:University of Glasgow

Department:School of Veterinary Medicine

关键词: Johne's, paratuberculosis, cattle, ill thrift, diarrhoea, poor body condition, serology, PCR, culture, histology, ZN.;   

Others  :  http://theses.gla.ac.uk/71952/7/2019BaroBasoraMVM.pdf

来源: University of Glasgow

【 摘 要 】

Johne’s disease, caused by the bacteria Mycobacterium avium subsp. paratuberculosis (MAP), is a chronic, wasting condition of ruminants, which is characterized by the clinical signs of weight loss and diarrhoea. The economic losses associated with the disease in the cattle and sheep industry, worldwide spread and high prevalence make Johne’s disease an important disease to investigate. Additionally, MAP has been isolated from humans suffering of Crohn’s disease and zoonotic potential of MAP in humans is still under debate. Currently available diagnostic tests have impaired sensitivity, particularly in preclinical stages of disease and thus a prompt and effective identification of infected animals is difficult. The primary aim of this work was to analyse and describe the history, clinical presentation and diagnostic test results of cattle submitted to a veterinary teaching hospital that showed clinical signs consistent with Johne’s disease. The secondary aim was to compare diagnostic test results to the gold standard, faecal culture. Fifty-nine out of the 192 cattle referred over 18 months met the inclusion criteria for the study, which was poor body condition or a history of weight loss and diarrhoea. A total of 52 females and seven males, comprising 34 beef and 25 dairy cattle were studied. All cattle had a full clinical examination, biochemistry blood analysis, Johne’s blood serology and faecal PCR and culture. They were inspected post-mortem and the ileo-caecal valve and proximal lymph node were examined histopathologically using a haematoxylin-eosin (H/E) and Ziehl-Neelsen (ZN) staining. Results from clinical examination, albumin and globulin serum concentrations, Johne’s serology, PCR, post-mortem examination and histopathology examination were compared to faecal culture results. Thus, this study reported all the clinical and diagnostic test results commercially available for Johne’s disease in cattle, such study was not reported before. Results showed inconsistent results between PCR and culture tests. However, both blood serology and H/E slide examination tests had a specificity of 100%.This work should help inform clinicians on interpretation of Johne’s diagnostic testing in clinical cases and may have implications for Johne’s control programmes relying on the results from the diagnostic tests reported.