Paratuberculosis (ParaTB) in cattle and Crohn's disease in humans are both chronic inflammatory bowel diseases. The causative agent for ParaTB has been identified; however, the etiological agent for Crohn's disease remains elusive. A number of studies researching a potential link between the two diseases have been unable to confirm that the diseases share a common pathogen. Since the involvement of the ParaTB pathogen with Crohn's disease cannot be excluded, the possibility is that ParaTB may be a zoonosis, and therefore, increased efforts must be made to control the transmission of ParaTB.
Mycobacteriumavium paratuberculosis (MAP) is the bacterium that causes ParaTB in ruminants and its presence can also be detected in milk and milk products. Today, ParaTB - also known as Johne's disease - is a worldwide animal health problem and the existence of the disease in cattle can have a serious, negative, economic impact on the milk and dairy product industry.
Does MAP play a role in Crohn's disease?
Crohn's disease (CD) is an inflammatory bowel disease in humans. It is a complex affliction dependant on genetic, environmental, and geographical factors. The disease has an autoimmune component that is thought to be triggered by a bacterial or viral infection. Symptoms include diarrhoea and weight loss - comparable to that of ParaTB.
There have been a number of studies that suggest that MAP may be a cause of Crohn's disease. This is of particular concern as an emerging food safety issue because the organism may be spread to humans through inadequately pasteurized milk and dairy products. Whether MAP can cause Crohn's disease has been the subject of many studies with inconclusive results. MAP has been on the pathogen suspect list for Crohn's disease since it was first reported at the beginning of the 20th century. While in some studies MAP DNA has been detected in gut samples of CD patients - but not in patients with other inflammatory afflictions of the bowels - and MAP can be isolated and cultured from biopsies obtained from some Crohn's disease patients, other studies failed to find such an association. Furthermore, epidemiological studies have shown that areas with a high incidence of ParaTB do not also have an increased prevalence of Crohn's disease. On the other hand, the successful treatment of Crohn's disease patients with antibiotics directed at the Mycobacterium species has been reported by research groups from the United States (US) and Australia, supporting the theory that there is a direct involvement of MAP in Crohn's disease. Recently, the US Food and Drug Administration have allowed clinical trials with a combination of antibiotics for the treatment of Crohn's disease. As the etiological origin of Crohn's disease remains unclear, it would be unwise to dismiss the contribution of MAP to the pathogenesis of at least a subset of Crohn's disease patients. As long as there is a suspected link between ParaTB and Crohn's disease in humans, it is essential that ParaTB disease control in cattle be pursued with increased vigilance.
Prionics currently offers reliable and sensitive Parachek® test kits for the diagnosis of ParaTB infected animals. Recognizing that presence of ParaTB may have an impact on food safety and ultimately human health, Prionics was pleased to announce in early 2007 approval from the US Department of Agriculture for its Parachek® test to be used on bovine milk samples.
