Paratuberculosis

paratuberculosis [¦par·ə·tə‚bər·kyə′lō·səs]

(veterinary medicine)

Johne's disease

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Paratuberculosis 

(also Johne’s disease), a chronic infectious disease of ruminants characterized by specific changes in the intestine. It is prevalent in many countries of Europe, America, Australia, and Southeast Asia. The mortality rate is 10 to 25 percent. The causative agent is an acid-alcohol-Antiformin-resistant bacillus belonging to the genus Mycobacterium. The bacteria can survive eight to 12 months outside their host, but they die within 30 minutes in milk heated to 63°C. The disease afflicts sheep, cattle, reindeer, and, less commonly, goats, camels, and yaks.

Clearly diseased animals and those with a latent course of paratuberculosis discharge the bacteria into the environment with feces, milk, urine, and semen. Cleaning equipment and feed can transmit the bacteria. Factors that contribute to the spread of the disease include improper feeding, unsatisfactory maintenance, and overworking of the animals. Infection occurs in both the stabling and pasturing periods, generally in regions with acidic, waterlogged, or saline soils, where the grasses are lacking in phosphorous and calcium salts. Bacteria enter the intestinal mucosa and mesenteric lymph nodes, where they induce a proliferative inflammation. Intestinal involvement results in profound functional disturbances and chronic poisoning.

Animals suffering from paratuberculosis are sluggish, emaciated, and unproductive. Profuse diarrhea is a characteristic clinical symptom. Epizootiological data, clinical symptoms, and results of laboratory studies and allergy skin tests are used to make the diagnosis. Specific therapy and prevention have not been worked out. If paratuberculosis is detected, the farm is declared infected and sanitary measures are instituted. General prevention involves meeting the zoohygienic demands for the maintenance and feeding of animals.

REFERENCE

Shchurevskii, V. E. Paratuberkulez sel’skokhoziaistvennykh zhivotnykh. Moscow, 1971.