Ovine Johne's Disease (OJD) is the description given to sheep suffering from a mycobacterium paratuberculosis (prognosis negative) 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 faecal matter, and is known to be spread by the transport of infected faecal 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. The question as to whether wildlife can carry OJD remains unanswered, but it is known that Bovine Johne's Disease, although a strain distinct from OJD, can be carried by sheep.  With present technology it is not possible to reliably diagnose OJD in individual live sheep.  Recent advances have reduced the unit cost and accuracy of testing with a "pooled faecal culture" (PFC) test.  If OJD is present the entire flock is assumed to be infected.

OJD in NSW AUSTRALIA   Losses up to 6% 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 1 August 1999, 49% of the 422 flocks confirmed as infected in NSW are in the central tablelands.   A further 930 flocks are classified as "suspect". (LAND; page 9, 16 September 1999).

Wool farmers who volunteer to have their flocks tested by the AAHC find themselves in a "lose-lose" situation.  It is financially preferable to shear an unknown status flock, accept any losses (where 1% to 5% loss p/a is normal) and hope (if OJD has infected the flock) that natural selection will produce a resistant sheep variety.

The alternative is to be tested & either be declared OJD free & still be at risk of infection from wildlife or other means, or be confirmed as having OJD.  If confirmed the options are do nothing & continue life as a pariah or become one of the 50 producers taking part in the latest variation to the government's "control & evaluation" program. (P. Austin, p 14 LAND; 24 June 1999).

The Crohns-Johnes link is a tenuous argument for eradicating Johnes from sheep.  From my reading, the chief concerns of organizations such as Para are that the spread of Crohn's into the population is via pasteurized milk, with meat being a lesser concern.

There is growing cynicism among farmers about the procedure of government & bureaucratic planning:

1. More than one neighbour has observed that government takes it's animal health advice from public servants who are employed to supervise animal health programmes.  For some decades these public officials managed the successful control program for footrot.  Perhaps too successful?  By the mid '90s many of these officials were facing retrenchment.  OJD has provided continuity.
2. From the concerns expressed by those who feed at the trough of the wool research levy (LAND, 10 Feb. 2000, letters) it seems that there is a real fear that wool producers might vote for a zero or low wool tax.   Farmers must fear that the minister might use his powers to override such a vote.
3. Other civil liberties being eroded or poached by rampant legislators are the right to own a gun or the right to choose whether to wear a seat belt.  In both instances there is mounting evidence that the legislation preventing gun ownership and the legislation enforcing seat belt wearing costs lives.

HEALTH ASPECTS.  Research has uncovered persuasive evidence that suggests that Johne's disease (JD) of ruminants and Crohn's disease (CD) in humans is caused by the same organism.   Evidence suggests that mycobacterium paratuberculosis is present in our food and possibly in our water supplies.  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.

In Ireland 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.

Karen Meyer in the USA has collected and published very persuasive evidence on her site "crohns.org".  The Animal Health Councils in Australia & the USA continue to refuse to act because, they state:

"there is no evidence of a causative relationship".

The Centre for Disease Control in Atlanta is unarguably the most important medical centre for the study and control of human diseases in the world.  During a meeting with members of Para, officials from the CDC made the following statement about Crohns:

CDC is taking this matter very seriously.  CDC is now making moves that are supportive of the need to identify risk factors for human infection

This response shows that market forces can be relied upon to deal efficiently with Johnes Disease.  The lesson to be learned is that legislators should limit their activities to offers of compensation for their own flawed quarantine legislation.  Oppressive regulation to close the barn door is not a suitable alternative to compensation for the initial legislative stupidity that left the door open.

I continue to advise my readers to move themselves and their loved ones to a "ruminant products" free diet.  Paratuberculosis is a particularly hardy microbe.  The evidence seems to indicate that UHT milk and matured cheese are "safe".  UHT appears to be safe because the heat kills the para bacterium.  Matured cheese seems to be safe because it's acidity kills the para bacterium over time.  And perhaps well seared meat?  And if your drinking water is sourced from a grazed reservoir, perhaps boiled water?

Created 1997, Previous upgrade 17 September 1999  14 November 1999, minor additions 1 January 2000, latest 11 February 2000.