Johne's disease: how to spot and report the disease

Overview

Johne's disease is a chronic infectious wasting condition of cattle and other ruminants caused by Mycobacterium avium subspecies paratuberculosis, commonly known as Map. It is related to other mycobacteria that cause tuberculosis such as M. bovis (bovine TB) and M. tuberculosis (in human).

Mycobacteria can infect multiple species of animals although there is no conclusive evidence that Map itself is a public health risk.

The disease progressively damages the intestines of affected animals, and in cattle this results in profuse and persistent diarrhoea, severe weight loss, loss of condition and infertility. Affected animals eventually and inevitably die.

In dairy herds, the presence of Johne's disease will significantly reduce milk yields well before other signs of the disease can be found. Johne's disease is not a notifiable disease in Great Britain (England, Scotland and Wales), but it is notifiable in Northern Ireland.

Johne’s disease is a so-called “iceberg disease” because it spreads slowly and silently. This enables it to become very prevalent and one of the most impactful diseases of cattle production.

Useful information on managing Johne’s Disease is available from:

• Cattle Health Certification Standards (CHeCS)
• The National Johne’s Management Plan through Action Johne’s