Does MAP “Cause” Crohn’s Disease?
There seems to be universal agreement among researchers that Mycobacteria Avium Paratuberculosis (MAP), on its own, doesn’t “cause” Crohn’s Disease (see May 29 blog). This is based on strong genetic and immunological evidence suggesting the children and young adults who develop Crohn’s have either an inherited or acquired susceptibility to develop an abnormal immune reaction to MAP infection. However there is also overwhelming evidence that preventing MAP exposure in the first place greatly reduces a child’s chances of developing an incurable and often fatal illness. Owing to the government’s refusal to implement public health measures to effectively limit exposure, the US presently enjoys the distinction of having the highest incidence of Crohn’s in the world.
What the Evidence Shows
While the issue remains controversial, twenty years of research strongly suggests MAP plays some role in the etiology of Crohn’s. In fact if this were a civil liability case, the judge or jury would surely rule that the preponderance of evidence supports the connection. Among other findings are the following:
- While MAP is a common soil organism found nearly everywhere in the world, Crohn’s Disease is only found in cultures that drink milk – and is found in all cultures that drink milk, except for India (where milk is boiled);
- Crohn’s was virtually unknown prior to the early 1900s, when there was a transition from buying milk from a local dairy to a system of mass distribution, involving the pooling of milk from many different sources;
- MAP is found in the breast milk of nursing mothers with Crohn’s ;
- With improved DNA fingerprinting, MAP is found in the intestines of 80-90% of patients with Crohn’s Disease and only 4% of patients with other serious intestinal diseases;
- Patients with Crohn’s have MAP antibodies in their blood;
- Asian countries previously free of Crohn’s are experiencing an increased incidence as they begin drinking milk and keeping dairy herds.
Thanks to the efforts of Project Censored, Dr Chiodini and a few other brave scientists and doctors, in June 2007 the American Academy of Microbiology finally acknowledged the potential link between MAP and Crohn’s. While they agreed there was an urgent need for more research, they also argued (incomprehensibly) against food safety regulations to eliminate potential routes of exposure.
Déjà vu: Regulatory Agencies that Refuse to Regulate
As in the case of the banking regulators, whose inaction led to the economic collapse, federal food safety regulators continue to obstruct veterinary and medical researchers who have been fighting for twenty years for mandatory preventive measures to slow the spread of MAP. Despite dozens of studies from Europe showing otherwise, the Food and Drug Administration (FDA) persists in claiming MAP is eradicated by pasteurization. Likewise, the US Department of Agriculture (USDA) resists compulsory monitoring of herds for MAP or compulsory reporting of Johne’s Disease – or even compromise measures, such as mandatory testing of animals from infected farms or improved farmer education about MAP, Johne’s Disease and basic calf hygiene techniques that reduce MAP infection. Especially as recent surveys reveal that 50 per cent of American farmers have never even heard of MAP.
The Precautionary Principle
In the UK and EU, which follow the Precautionary Principle, public health agencies don’t believe children should continue to be exposed while we wait for unequivocal proof MAP plays a causal role in Crohn’s disease. This could take decades (especially as most US funders continue to decline research proposals to study MAP infection in humans). They feel (as do I) that it’s unconscionable to continue to expose children to a potentially fatal illness when simple and inexpensive public health measures could greatly reduce their risk of MAP infection.