Synonyms

No known synonym

Name of the disease in English

Johne's disease, Paratuberculosis

The disease in brief

The disease is important in many ways because it is contagious and incurable; it is due to Mycobacterium avium subsp. paratuberculosis (MAP), a bacteria resistant in the environment and which tends to persist in an infected herd. Contamination of a bovine occurs more easily at a young age, before or after weaning; the disease is not visible until adulthood, usually after 2 years, most cases being 4-5 years old. Inapparent infection can be spread throughout the herd. The economic losses are high in an infected herd, linked to mortality and the consequences of subclinical infection: weight loss, growth retardation, inability to sell breeding stock because the disease is a very frequent cause of legal buyer / seller conflicts. Links between bovine paratuberculosis and Crohn's disease (CD) in humans have been suggested, but appear to be ruled out today.

A herd certification considered to be at low risk of infection has been implemented and collective control is under way in several regions.

Be careful, infection can lead to false positives during tuberculinations.

Clinic & diagnosis

The disease should be suspected when an adult cattle, often emaciated, presents with diarrhea which is often very watery and without fever. A trough edema in a lean adult bovine is also a suspicion of paratuberculosis, which will of course have to be confirmed.

Typical sign of the disease

No description

Pictures

See below

Diagnostic formulas

No description

Differential diagnosis

- Copper deficiency N72

- Fascioliasis N51

- Polyparasitism, strongylosis, fluke or paramphistomiasis-3 PA10.1

- Mucous membrane disease - chronic form = runting disease. DG44.2

- Renal amyloidosis UR18

- Chronic peritonitis N358

- Chronic salmonellosis ...

Confirm a suspicion?

To confirm a clinical case, a stool sample can be used for different analyzes:

- Ziehl-Nielsen staining allows confirmation of most cases at low cost. It makes it possible to highlight AFB (acid-alcohol-resistant bacilli) in clusters.

- The PCR method allows the detection of the genetic material of MAP

- Stool culture requires a response time of more than 3 months and is ill-suited to the situation.

A blood sample on a dry tube allows an Elisa test to be carried out demonstrating contact with the bacteria. This is the earliest test.

Prognosis and treatment

The disease is incurable. All processing is unnecessary.

Prevention

The prevention of paratuberculosis is organized in many regions by the GDS; a control plan is committed for more than 5 years: it aims to reduce economic losses by eliminating visible disease and reducing infection.

Prevention combines measures of different kinds:

- Screening for subclinical infection in adults; it is essential when the clinical incidence is high.

- Protection of young people raised on the farm through strict hygiene of food and housing, and the rapid separation of mother and calf from a dairy herd 

- Vaccination (derogatory because it crosses with tuberculosis) is an effective means of protecting young people, especially in nursing herds.

See control plan used by GDS22: HYDG-1

References

Adjou K., Belbis G., Millemann Y., Ravary-Plumioën B. - Cours National Veterinary School of Alfort-2016-238p.