Johne's disease in sheep

Johne's disease in sheep is an infectious and incurable wasting disease. It is caused by the bacteria Mycobacterium paratuberculosis.

Changes to the management of Johne's Disease in sheep in South Australia will begin to take effect from 1 July 2018, including the establishment of a new South Australian Ovine Johne's Disease Management Program.

Changes to the program that producers should note:

  • Johne's disease in sheep remains a notifiable disease and must be immediately reported to PIRSA Animal Health. See the reporting animal disease page for instructions if you suspect Johne's disease is present in sheep or other species.
  • National Vendor Declarations (NVDs) and National Sheep Health Declarations (NSHDs) are still compulsory.
  • There is will be increased ability for infected producers to trade sheep. Buyer beware means you need to check the status of animals BEFORE you purchase – check the NVD and NSHD
  • Movement restrictions into SA remain in place. The only change to South Australian entry requirements is the addition of Approved vaccinates for the OJD program

Visit the South Australian Ovine Johne's Disease Management Program page for more information.

Download the Endemic sheep disease management programs - frequently asked questions (PDF 412.2 KB or DOCX 158.8 KB).

Clinical signs

Johne's is an insidious and progressive disease. It is not easily detectable and often no clinical signs are evident for the first few years.

Clinically affected sheep progressively loose weight (wasting). Sheep with the clinical signs of the disease usually die or are euthanised within 3 to 8 months.

The classical clinical signs of Johne's disease is a distinct ‘tail' to the mob. The slight increase in deaths and wasting from Johne's disease may not be noticeable initially. It may be mistaken for sheep already in poor condition through being older in age or having internal parasite burdens.

The level of disease in flock is influenced by the environment and management practices. Higher rainfall and higher stocking rates usually results in higher levels of disease.

Infected sheep may carry and spread the disease without ever showing clinical signs. Healthy looking animals can be shedding the bacteria for a considerable length of time prior to them becoming clinically affected. This is as a result of the long incubation period.

It is more than likely Johne's disease is already well established within the flock when deaths are noticed that are obviously attributable to the disease.

Once the clinical phase occurs, the condition is always fatal.

Spread between animals

Johne's Disease usually enters a flock when:

  • new infected sheep enter a flock
  • stray infected sheep enter a flock
  • sheep eat pasture contaminated by faeces from infected sheep and other susceptible species
  • sheep drink water contaminated by faeces from infected sheep and other susceptible species
  • co-grazing with infected cattle and other species which are infected with Johne's disease (such as goats and alpacas).

More information

Page Last Reviewed: 06 Jul 2018
Top of page