Author, Donkey, Bureaucrats, Administrators
53,803
edits
Changes
no edit summary
Line 41:
Line 41:
===[[Intestines Proliferative Enteritis - Pathology#Paratuberculosis (Johnes disease)|Johne's Disease (paratuberculosis)]]===
−*[[Intestines Proliferative Enteritis - Pathology#Paratuberculosis (Johnes disease)|Johne's Disease]] is a chronic, contagious enteritis of ruminants
−*Caused by ''M avium'' subsp. ''paratuberculosis''
−*Epidemiology
−**Transmitted to young calves by ingestion of mycobacteria in faeces of infected adults
−**Organisms viable in environment for long periods
−**Long incubation period with clinical signs appearing in cattle over 2 years of age
−**Subclinical carriers can occur, shedding organisms in their faeces
−*Pathogenesis and pathogenicity
−**''M avium'' subsp. ''paratuberculosis'' is an intracellular pathogen
−**Mycobacteria are ingested by macrophages in the Peyer's patches
−**Survival and replication of mycobacteria in macrophages initiate an immune-mediated granulomatous reaction
−**Lymphocytes and macrophages accumulate in the lamina propria and submucosa, resulting in marked thickening and folding of the intestinal wall
−**Mesenteric lymph nodes are enlarged
−**A protein-losing enteropathy results, along with failure to absorb nutrients and water
−*Clinical signs
−**Diarrhoea, initially intermittent, and weight loss in cattle
−**Weight loss in sheep and goats
−**Rapidly fatal with weight loss and diarrhoea in some deer
−*Diagnosis
−**All diagnostic procedures have faults but include:
−**Microscopy of rectal biopsies
−**Faecal culture
−**Serology of serum including complement fixation tests, agar-gel immunodiffusion test and an ELISA
−**Histopathology of intestines and lymph nodes
−**Isolation and identification of mycobacteria from faeces and tissues
−**Ziehl-Neelson-positive smears
−**Intradermal tuberculin test
−**DNA probes for detection in faeces
−*Control
−**Slaughter of affected animals
−**Detection and slaughter of subclinical shedders using faecal culture, DNA probes and ELISA
−**Good hygiene to protect young calves
−**Separation and isolation of calves from affected dams
−**Inactivated adjuvanted vaccines are available and reduce shedding of mycobacteria but do not eliminate infection
[[Mycobacterium lepraemurium]]
[[Mycobacterium lepraemurium]]
+[[Mycobacterium avium subsp. paratuberculosis]]
−[[Category:Bacteria]][[Category:Gram_positive_bacteria]][[Category:Rods]]
[[Category:Bacteria]][[Category:Gram_positive_bacteria]][[Category:Rods]]