MAP in the Environment

MAP in Food

MAP in Water


Mycobacterium avium subspecies paratuberculosis (MAP), which causes Johne's Disease in many species of ruminants, is endemic in the food animal herds of almost every developed country.

Since MAP is not classified as a human pathogen, meat, milk and other products from animals infected with MAP may be continually entering the human food chain. There is a wealth of evidence which appears to indicate that MAP is capable of surviving the food processing methods that we employ to protect us from disease, such as cooking and pasteurization. This scientific evidence is thoroughly reviewed and discussed in the MAP in dairy products,  MAP in beef products, and Marshfield Clinic Study - Retail Testing sections of our website.  

Another possible route of transmission of MAP from cattle to humans is via contaminated water supplies.  This is because MAP is shed onto pastures and will be washed off into ground and river waters.  Where such water is piped to households for human consumption, it may enable MAP to infect people by this route as well.

Additionally, Several other provocative questions must be answered:  

  •  Is MAP-infected water used to irrigate crops? 
  • Could fruits and vegetables be contaminated in processing plants where they are rinsed with MAP-infected water and processed for distribution to the public? 
  • Are we exposing our children to this pathogen by giving them fruit and vegetables contaminated with MAP as a result of this process? 

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The public deserves answers to these
very serious questions!

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Studies Being Conducted in the UK

The UK has taken the lead in conducting studies relating to MAP infection in water supplies.  At the present time there are two studies underway.   Sponsoring these studies are:

  • Natural Environment Research Council's Centre for Ecology and Hydrology (CEH)  - Funded by Medical Research Council (MRC) and National Environment Research Council (NERC) - Research Conducted by Professor Roger Pickup (CEH, Windemere) and Professor John Hermon-Taylor (St. George's Hospital Medical School, London
  • Department of Food Science, Queen's University Belfast - Research Conducted by Whan LB, Grant IR, Ball HJ, Scott R., Rowe UT.   (Lett Appl Microbiol 2001 Sep;33(3):227-31)

The research being conducted at Natural Environment Research Council's Centre for Ecology and Hydrology (CEH) by Professors Pickup and Hermon-Taylor, a five-year study, began in October, 2000.  Overall, there are three co-operative projects within the collabortive program of research.  They are evaluating whether runoff from cow pastures is contaminating drinking water supplies with MAP.   Quoting these researchers in an article printed in the IA Journal: 

"...Taken together, the results of this new research, will permit the design and implementation of measures to ensure that our animals are MAP-free, that our water is safe, and perhaps through vaccine production, that the risk of Crohn's disease is eventually eliminated." 

The research  completed and published in September 2001 at the Department of Food Science, Queen's University Belfast relates to the bactericidal effect of chlorine on MAP in drinking water.   The study's aim was:  "To determine whether this organism [MAP] can survive standard water treatment processes."  Two strains of M. paratuberculosis were subjected to various chlorine concentrations. 

The conclusion:  "The data showed that when initial inoculum levels were high, neither M. paratuberculosis strain was completely killed at the free chlorine concentrations and contact times applied."  [underline added for emphasis]

Further, "This work highlights the need for further research into the survival of M. paratuberculosis during water treatment."  

In light of this study which concludes that MAP survives standard water treatment processes, PARA urges immediate resesarch to ensure the protection of the public health!

What is being done in the U.S.?

Sadly, the U.S. is doing nothing to ascertain:   (1) Extent of MAP-infection of public water supplies; (2) Whether water used for crop irrigation is contaminating these food supplies; (3) What methods of water treatment will ensure killing of MAP, and ultimately employing those methods until such time that Johne's disease is eradicated from herds. 

The Environment Protection Agency (EPA) is the U.S. agency responsible for the safety of water.   They are aware of the problem as evidenced by an August 1999 document entitled "Mycobacteria:  Health Advisory".   (See Pages 4, 18-20)

Unfortunately, the U.S. is choosing to ignore the food AND water problems created by MAP in our environment.  MAP is on EPA's radar screen as an NTM, "Non-Tuberculosis Mycobacteria", yet they are taking no action to protect the public by conducting research in this area or issuing warnings to consumers.   Every U.S. citizen should be asking them WHY?   

(See PARA's Governments subsection on the EPA for further details about this agency and its responsibilities in this area.)


While it is possible for individuals to eliminate milk/dairy/beef products from their diet in an attempt to limit MAP exposure, it is nearly impossible to avoid drinking MAP-contaminated water from public water supplies, and equally as difficult to avoid foods that have potentially been infected with MAP via irrigation methods using infected water. 

There is an urgent need to determine what water treatment methods may be effective at eliminating MAP from water supplies.  We applaud the UK researchers for their extremely important work in determining the extent of MAP infection in public water supplies, and researching the efficacy of treatment methods to ensure killing of this dangerous pathogen.  

PARA is hopeful that the quote taken from Professor Pickup and Professor Hermon-Taylor holds true:  "The results of this new research, will permit the design and implementation of measures to ensure that our animals are MAP-free, that our water is safe, and perhaps through vaccine production, that the risk of Crohn's disease is eventually eliminated." 

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