Bovis ISSN 2398-2993

Mycobacterium avium subsp paratuberculosis

Synonym(s): Johnes, MAP

Contributor(s): Veronica Fowler , Tammy Hassel

Introduction

Classification

Taxonomy

  • Kingdom: bacteria.
  • Phylum: actinobacteria.
  • Order: actinomycetales.
  • Suborder: corynebacterineae.
  • Family: mycobacteriaceae.
  • Genus: mycobacterium- closely related to Corynebacterium, Nocardia and Rhodococcus.

Etymology

  • GK: myces- a fungus; bakterion- a small rod.

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Clinical Effects

Epidemiology

Habitat

  • MAP has been found in several wild mammal species, including deer and rabbits.

Lifecycle

  • Infection with MAP most frequently occurs in the first few months of life but the clinical signs of the disease are not apparent until the animal is between two to five years old.
  • As a consequence of the long period of time between infection and the disease becoming apparent, an animal can spread the disease to many other herd mates before it begins to manifest clinical signs.

Transmission

  • MAP is shed in large amount in the feces of infected animals and can also be found in milk, particularly in colostrum Colostrum. Infections of calves commonly occur through drinking infected colostrum, by suckling teats that are soiled with contaminated feces or through licking or grooming behaviour in contaminated environments. Congenital infection (ie before birth) can also occur.

Pathological effects

  • Diarrhea, weight loss, decreased milk production, or roughening of the hair coat.
  • Ventral edema Ventral edema (swelling of the neck, chest, abdomen or legs) and submandilar edema (swelling of the lower jaw) due to abnormally low levels of protein in the blood.
  • The disease progressively damages the intestines and ultimately leads to death due to emaciation or dehydration. The lesions of paratuberculosis caused by the excessive production of pro-inflammatory cytokines by infected host cells rather than by a toxic effect of MAP.
  • Clinical disease is not normally observed in cattle less than two years of age. Cattle become infected as calves but the disease remains clinically silent until the animal ages.

Control

Control via animal

  • Affected animals should be isolated and if confirmed, positive slaughtered.
  • Calving yards or boxes should be kept as clean as possible to reduce the exposure of newborn calves to the infectious agent.
  • Feeding of pooled colostrum should be avoided.
  • Colostrum and waste milk should only be fed to calves if it has been pasteurised or taking from test negative dams Milk acidification.
  • Keep teats and udders of freshly calved cows as clean as possible.
  • Avoid co-grazing with other livestock that may be infected and control rabbits.
  • Prevent fecal contamination of feed and water supplies and keep troughs clean.

Control via chemotherapies

Control via environment

  • Provide mains water and fence off other water sources, particularly areas of stagnant water which may be used by wildlife.
  • Avoid co-grazing with other livestock that may be infected and control rabbits.

Vaccination

  • An inactivated MAP vaccine for animals under 4 weeks of age is licensed in the UK to control Johne's disease sheep and goats; however this vaccine is not licensed for use in cattle but may be used in extreme circumstances.
  • The vaccine can interfere with interpretation of the tuberculin skin test for bovine Tuberculosis Tuberculosis (TB).

Diagnosis

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Further Reading

Publications

Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Britton L E, Cassidy J P, O'Donovan J, Gordon S V & Markey B (2016) Potential application of emerging diagnostic techniques to the diagnosis of bovine Johne's disease (paratuberculosis). The Veterinary Journal 209, 32-39 PubMed.
  • Waddell L A, Rajić A, Stärk K D & McEwen S A (2016) The potential Public Health Impact of Mycobacterium avium ssp. paratuberculosis: Global Opinion Survey of Topic Specialists. Zoonoses Public Health 63 (3), 212-22 PubMed.
  • Stevenson K (2015) Genetic diversity of Mycobacterium avium subspecies paratuberculosisand the influence of strain type on infection and pathogenesis: a review. Journal of Veterinary Research 46 (1), pp 64 PubMed.
  • Grove-White D & Oultram J (2014) Principles of control of Johne's Disease in the dairy herdLivestock 19 (1), 14-19 VetMedResource.
  • Coad M, Clifford D J, Vordermeier H M & Whelan A O (2013) The consequences of vaccination with the Johne's disease vaccine, Gudair, on diagnosis of bovine tuberculosis. The Veterinary Record 172 (10), 266-266 PubMed.
  • Salem M, Heydel C, El-Sayed A, Ahmed S A, Zschöck M & Baljer G (2013) Mycobacterium
    avium subspecies paratuberculosis: an insidious problem for the ruminant
    industry.
    Trop Anim Health Prod 45 (2), 351-66 PubMed.
  • Sweeney R W, Collins M, Koets A P, McGuirk S M & Roussel A J (2012) Paratuberculosis (Johne's disease) in cattle and other susceptible species. Journal of Veterinary Internal Medicine 26 (6), 1239-1250 PubMed.

Other sources of information

  • Assessment of surveillance and control of Johne’s disease in farm animals in GB, SAC Veterinary Science Division.
  • OIE Terrestrial manual, Chapter 2.1.15 – Paratuberculosis (Johne’s disease).

Organisation(s)

  • APHA.
  • OIE.

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