Australian  SPIN

July 2003
Ovine Mycobacterium paratuberculosis
 SYNOPSIS. As a wool producer I am concerned with OJD (Ovine Johne's Disease), both from health and commercial aspects.  This document was intended to reflect information about OJD.  I have expanded that intent to reflect information about mycobacterium paratuberculosis, the bacteria that is present wherever there is Johne's disease.  Johne's disease is a disease of ruminants.  The Veterinary Science faculty of the University of Wisconsin USA seems to have a most comprehensive site on Johne's Disease at  Frequently Asked Questions about Johne's Disease.  The NSW Department of agriculture has placed a rather comprehensive "Agnote" (which it appears to be updating) called "Frequently asked questions on OJD".  The NSW Farmer's association has an OJD page that gives up to date information on the politics surrounding regulation.

Ovine Johne's Disease (OJD) is the description given to sheep suffering from a mycobacterium paratuberculosis infection.   The symptoms are a general "wasting" of infected animals over a period of years. OJD is often mistaken for a range of other problems (abscess, worms, fluke, and dietary deficiency).  OJD is known to be spread by ingestion of pasture contaminated with infected fecal matter, and is known to be spread by the transport of infected fecal matter in waterways. Young animals are more susceptible, and it appears that they can be infected by mother's milk. The bacterium has been reported to persist for longer than one year on the pasture.

Inter species transmission may mean that once Johnes disease has entered the local environment, it becomes virtually impossible to eradicate.  This conclusion might be drawn when it is considered that Bovine Johne's Disease, although a strain distinct from OJD, can be carried by sheep, and by the report by Primary Industries and Resources South Australia (PIRSA) that: Interim laboratory results from veterinary research on Kangaroo Island have shown that two kangaroos and two wallabies have tested positive for the presence of Ovine Johne’s disease (OJD) bacteria.

With present technology it is not possible to reliably diagnose OJD in individual live sheep.  Recent advances have reduced the unit cost and improved the accuracy of testing with a "pooled fecal culture" (PFC) test.  If OJD is present the entire flock is assumed to be infected.

OJD in NSW AUSTRALIA   Losses up to 9% have been reported in Australia.  In NZ and other countries where the disease is endemic anecdotal evidence is that losses stabilize in the range 1% to 3% p/a.  OJD was first detected in Australia circa 1980 in the central tablelands of NSW, and as of the end of 2000 there were 505 properties confirmed as infected in NSW. ( LAND p7, 26 April 2001).

The NSW Farmer's association has recommended (OJD update May 03) that:

  1. A "risk assessment" scale be provided.
  2. Trading be permitted based on vendor declarations and buyer's risk assessment.
  3. Farmers be permitted to self police trading in local regions.
  4. The restricted Guidare & successor vaccines be made commercially available.
  5. OJD remain a notifiable disease, but without regulatory consequences.
  6. Other states be consulted.

More than three years have passed since the Yass RLPB suggested that reliance on market forces and vendor declarations (backed by the Fair Trading Act) would best control the spread of OJD.   Two years ago it was suggested on these pages that vaccine be provided on a commercial basis.  We see here the reluctance of government to unmake regulations.

HUMAN HEALTH ASPECTS.  Research has uncovered persuasive evidence that suggests that Johne's disease (JD) of ruminants and presently incurable Crohn's disease (CD) in humans is caused by the same organism. (See e.g. Michael Greger MD in the USA.)     Crohn's is a particularly nasty disease that attacks the intestines producing both severe inflammation resulting in excruciating pain during digestion and uncontrolled bowel movements.

Evidence suggests that mycobacterium paratuberculosis is present in our food and possibly in our water supplies.  Alan Kennedy has uncovered and detailed research which would tend to make any normal hypochondriac like myself think seriously about giving up pasteurized milk products for life.  His summary is particularly succinct.

The Veterinary Science faculty at the University of Wisconsin USA has published a page on the Zoonotic Potential of Johne's disease titled Association of M.paratuberculosis and Crohn's disease. Karen Meyer et al in the USA have collected and published very persuasive evidence on the site

More recent sites displaying research on the Johnes/Crohns link are the "paratuberculosis organization" site, whose sponsors offer membership for $50.00 US, and the Crohn's & Colitis Foundation of America who seek charitable (offline) donations.

Producer organizations continue to dither because, as they state:

"there is no evidence of a causative relationship".
"The lack of evidence of a causative relationship

is not evidence of the lack of a causative relationship."

The evidence seems to indicate that pasteurizing (for 15 seconds at 72C) does not kill para, but that UHT milk and matured cheese are "safe".   Matured cheese is thought to be safe because it's acidity kills the para bacterium over time.  And perhaps well seared meat?

Created 1997, upgrades 14 November 1999, minor additions 1 January 2000,  February 00June 00July 00end 00 May 01