Pathogenic mycobacteria and water

Abstract

The spectrum of waterborne infectious disease is changing due to dramatic changes in our society and environment. In 1990s, the major concern of the water utilities was to deal with coliform bacteria in the drinking water. But more recently, waterborne mycobacterial spp have assumed significance owing to their role in causing disseminated infections in immunocompromised people, such as in AIDS patients. Mycobacterium avium is a free-living environmental mycobacterium that can cause localized disease in the lungs, lymph glands, skin, wounds or bones. Drinking water is the major source of M. avium infection because the practice of disinfecting water using chlorine allows M. avium, which is chlorine resistant, to flourish in the absence of any competition. M. avium also exists in a symbiotic relationship with certain species of amoebae that may be fundamental to its transmission. M. bovis, on the other hand, is not a free-living environmental mycobacterium, but has a broad host range including wildlife, domestic livestock and humans. There are evidences of it being transmitted between the wildlife, livestock and humans, specifically under water-scarce environment. More recently, a link between Buruli ulcer (BU), a disease caused by M. ulcerans, and a biting aquatic insect has been reported. This leads to the speculation that BU is a vector-borne disease and that water may be an important environment for the proliferation of the vector. This chapter examines water as a route of infection for different types of mycobacterial diseases in humans and their health impacts on humans. Thus, appropriate public health measures must be developed to control the spread of mycobacterial diseases through water.