Lack of pasteurisation and pollution prove irritating

Professor John Hermon-Taylor and colleagues from St George's Hospital Medical School in London, UK, have found the strongest evidence yet that Chrohn's disease and irritable bowel syndrome (IBS) may be caused by the bacterium Mycobacterium avium subspecies paratuberculosis (MAP).

Crohn's disease can cause a variety of symptoms including lack of appetite, chronic diarrhoea, abdominal pain, fatigue, and weight loss. Irritable bowel syndrome causes more intermittent pain, constipation and diarrhoea. MAP is a bacterial infection found in livestock, which inflames the nerves of the gut. It has been suggested that MAP may be infecting humans via two routes.

The first is that current milk pasteurisation practices may not be killing the bacteria efficiently.

The second is that leachate from animal waste containing MAP is entering the water systems, evading filtration and chlorination, and ending up in drinking water. MAP has been found in 2% of pasteurised retail milk samples.

The study by Hermon-Taylor and team found that 92% of the 37 patients tested with Crohn's disease were infected with MAP. MAP also infected 26% of control patients with non-inflammatory bowel disease (nIBD) but without Crohn's disease. According to the Guardian, three patients with irritable bowel syndrome were all infected with MAP, which Professor Hermon-Taylor said was an unexpected finding. Hermon-Taylor's team has alerted the Chief Medical Officer (Professor Sir Liam Donaldson) to the result and Donaldson is organising an examination of the evidence.

Hermon-Taylor is currently working on a vaccine against MAP and investigating MAP in water supplies. The team does not recommend that people stop drinking milk, but does recommend that people with Crohn's and those at risk drink UHT milk until further information is available.