Treatment & diagnosis of Crohn's Disease

Diagnosis of human MAP infection

Currently, there are no available diagnostic tests which have been proven to be capable of diagnosing MAP infection in humans. (We need to state that at the outset because we are asked quite often about where patients can go to get blood tests for diagnosing MAP infection.)


If Mycobacterium avium subspecies paratuberculosis (MAP) is the cause of some cases of Crohn's disease, then it may be possible to diagnose that MAP infection, in one of the following ways

  • Immune reaction. By taking a sample of the patient's blood, and testing it for the presence of antibodies and/or other immune reactions to MAP in blood or tissue.

  • Tissue Sample. By taking a tissue sample, by biopsy, from the patient and testing it for the presence of MAP.

  • Fecal sample. By taking a sample of the patient's feces and testing it for the presence of MAP.

Diagnostics are Improving

Heretofore, one of the problems plaguing research has been the inadequate tests for diagnosing Human MAP infection.   In recent years there have only been a few researchers dedicating themselves to this crucial area of research, and we wish to thank them for their persistence, in spite of many frustrating years of working with shoestring budgets.  Thankfully, funding is becoming available for this area of research, and we are very optimistic that great strides will be made regarding diagnostics development. 

Due to collaborative efforts of researchers at the National Institutes of Health (NIH) and Centers for Disease Control (CDC)  and globally, it is exciting to report that this crucial area of research is "moving forward" to quote one CDC representative.  We anticipate there will be many new developments to report in the coming months given there is intensified interest, coupled with research monies, in this area. 

Important Research in Diagnosing Human MAP Infection

While the following bulleted items are by no means a summary of ALL work done in the area of MAP infection, these are among the most significant: 

  • Breast Milk Study - In their study entitled "Isolation of Mycobacterium avium supbsp. paratuberculosis from breast milk of Crohn's disease patients" (American Journal of Gastroenterology 2000 Apr; 95(4):1094-95), Dr. Saleh A. Naser and Dr. Ira Shafran report finding MAP in the breast milk of lactating Crohn's disease patients.  The researchers point to their results as "...further demonstrating the gross similarity between humans diagnosed with Crohn's disease and Johne's Disease mammals infected with MAP."  (Please see PARA's report "Suspect Crohn's bug found in breast milk" for more details.)
  • As published in the September issue of Digestive Diseases Science (Dig Dis Sci 2002 Sep;47(9):2079-81; Shafran, Piromalli, Decker, Sandoval, Naser, El-Zaatari), researchers at the University of Central Florida, Orlando, Florida conclude:  "This investigation further establishes the utility of p35 and p36 recombinant clones for the diagnosis of CD, and reveals the complimentary role of ASCA and p35 and p36 for effective detection of CD.  Larger studies are needed to investigate the combined use of these serological markers for the diagnosis of CD."   
  • As published in the December issue of the Journal of Clinical Microbiology, Dr. Michael Collins and associates report the result of a study that demonstrates an "association" between MAP and Crohn's disease. The study involved patients in the U.S. and Denmark, who were tested using six different assays normally used on animals. See the abstract of this paper, or transcript and audio of an overview presented to the National Johne's Working Group (NJWG) of the U.S. Animal Health Association in October 2000

Please visit the Scientific Articles section of our website for a complete listing of all research published regarding MAP and Crohn's disease, including studies relating to diagnostics.

The Need for Clinical Trials

Although several groups of investigators are attempting to develop diagnostics which can diagnose MAP infection in Crohn's disease, none of these tests have been subjected to sufficient clinical trials to prove their effectiveness. Thus, these tests cannot yet be relied upon to diagnose Crohn's disease or MAP infection. Just as drug treatments must be subjected to blinded and controlled trials before their use can be recommended, so also diagnostic tests must be subjected to clinical trials that are

  • Controlled. A successful diagnostic test must prove to be specific to the disease being tested. For this reason, both patients and healthy control subjects must be examined using the same test.

  • Blind. In order to prevent investigator bias, personnel administering the test must be unaware of the identity and the state of health of the patient being tested. It is only at the completion of the trial that clinical diagnoses are compared with results of the diagnostic test, and a correlation is sought.

  • Multi-center. To increase diversity and eliminate regional bias of the study, trials of diagnostic tests should be conducted by multiple independent laboratories.

Since there are diagnostic tests under development for diagnosing MAP infection in Crohn's disease, it is important that double-blind, controlled, multi-center clinical trials of such diagnostic tests begin as soon as possible.

The Future of Diagnostics

Diagnostics are being improved at a rapid pace, and we are optimistic that reliable tests will become available in the not-too-distant future.  These tests have the potential to be less invasive, more reliable and more cost-effective than existing diagnostics for Crohn's disease.

Improved diagnostics will be a huge stride forward in that once MAP can be accurately diagnosed, an important foundation will be laid for treating patients and eliminating MAP from the environment. 

Source:   Contact PARA:
Paratuberculosis Awareness & Research Association, 1999-2003.