Synonyms: Johne’s disease ,Chronic specific enteritis of cattle, Chronic bacterial enteritis of cattle
Chronic bacillary dysentery.
Paratuberculosis is a chronic infectious disease of cattle, sheep, and occasionally other animals caused by Mycobacterium paratuberc’Ulosis and characterized by recurrent diarrhea, progressive emaciation and thickening and corrugation of the intestinal mucosa.
M. paratuberculosis – small, short, thick rod, 0.5 by 1-2J.L, stains with usual acid-fast stains, considered Gram-positive, aerobic.
Difficult to culture; requires a growth factor as:
- Extracts of saprophytic acid-fast bacteria.
- Extracts from lymph nodes of calf.
- Habitat outside body is unknown but it is believed that it will live in pastures and premises contaminated with faeces for months.
- Killed by pasteurization temperatures.
- Susceptible to common disinfectants as:
- Sodium orthophenylphenate, 1/200 for 15 min.
- 3% liquor cresolis cularsi.
Antigenic relationship to:
- Avian tubercle bacillus.
- Some rare cases, mammalian tubercle bacillus.
- Widely prevalent in Europe, including England and the Channel Islands.
- Direct contact with faecal material.
- Contaminated food and water with faecal matter.
- Cattle, sheep primarily.
- Reported in deer, horse, mule, swine, monkey.
Factors affecting susceptibility:
- Not necessarily a disease of adults.
- Lesions and symptoms most often occur from 2-6 years of age.
- Calfhood is the period of greatest susceptibility to infection – difficult to infect calv–s over 4 months of age.
B. Sex – no relationship.
C. Con–ition – no relationship.
D. Feed–ng – fecal contamination of f–ed, water, and pastures increases infection hazard. e. Housing – premises contaminated wi–h feces are an important source of infection.
- Incubation period at least two years in natural infection.
- Three- types of infections.’
- 10-20% animals in her’ showing symptoms of profuse, diarrhea and emaciation.
- Occasional animal showing symptoms.
- Those reacting to johnin test but showing no lesions on postmortem.
- First distinctive symptom is chronic fetid diarrhoea without strainincularsetite is usually good and attitude lively.
- Milk flow decreases.
- Temperature is normal.
- Progressive diarrhoea.
- Diarrhoea macularsodic and is aggravated by a ration of green feed.
- No apparent disturbance of respiratory, urinary, or circulatory systems.
- Finally emaciation becomes extreme, eyes sunken, and recumbency constant. 11. Almost always fatal in a month to 2 years.
- Disease often becomes active after parturition.
- Organism ingested and passes through epithelium of intestine.
- Packets of organisms appear in mucosa and act as foreign body producing specific inflammatory reaction.
- Organisms carried to mesenteric lymph nodes by lymphatic system, acting as fore.ign bodies.
- Diarrhea in early stages caused by inflammatory reaction with resulting oedema.
- Diarrhea in later stages caused by developing fibrosis of intestine preventing reabsorption of water.
- Thickening and corrugation of intestinal mucosa due to fibrosis.
- Emaciation due to loss of intestinal functions.
- Chronic serous lymphadenitis of mesenteric lymph nodes – enlarged and soft.
- Thickened and corrugated intestinal mucosa.
- Occurs most frequently in first 20-30 feet of intestinal tract posterior to duodenum.
- Cecum frequently involved.
- Infiltration of monocytes into intestinal mucosa, submucosa, and villi.
- Lymphocytes and eosinophils collect around foci of large mononuclear phagocytes.
- Giant cells are formed.
- Infiltration of connective tissue in latter stages.
- No caseation necrosis or calcification in cattle; may be present in sheep.
- Microscopic appearance of mesenteric lymph nodes.
- Infiltration of monocytes cause lymph nodes to be enlarged and soft.
- Packets of acid-fast organism very evident.
History of Johne’s disease in herd or community.
- Chronic recurrent culars.
- Progressive cachexia.
- Thickened and corrugated intestinal mucosa.
- Inject 0.2 mI. intradermal johnin in caudal fold, vulva or skin side of neck.
- Read in 48 hrs.
Positive reaction is diffuse swelling 3 mm. or more in thickness.
Intradermal avian tuberculin used but not as satisfactory as intradermal johnin.
Temperature test using avian tuberculin.
- 3 pre-injection temperatures taken at 2-hour intervals.
- Omit animals with temperature at 103°F. or higher.
Inject 10 mI. tuberculin intravenously.
- Take temperature one hour after injection; then every hour for 12 hrs.
- Majority reactions occur 3-8 hrs. after injection.
- Positive reaction is rise of 1.5 degrees over pre-injection temperature.
- Physical reaction often present – diarrhea, chills, and dyspnea.
Close antigenic relationship of bacillus of Johne’s disease, bovine tuberculosis, and avian tuberculosis causes difficulties in accurate test results.
- Microscopic examination of piece of rectal mucosa for acid-fast organisms.
- Microscopic examination of section of affected intestinal tract and lymph nodes.
- Animals showing clinical symptoms rarely recover.
- Chronic progressive emaciation and death.
- Case – various antibiotic agents have been tried, resulting in improvement but not total recovery.
- Herd – none.