Manure and microbes: public and animal health problem

Most environmental concerns about waste manage-ment either have focused on the effects of nutrients, especially N and P, on water quality or have empha-sized odor problems and air quality. Microbes from manure are often low on the priority list for control and remediation, despite the fact that several out-breaks of gastroenteritis have been traced to livestock operations. The pathogens discussed in this paper include protozoans ( Cryptosporidium parvum, Giardia spp.), bacteria ( Listeria monocytogenes, Es-cherichia coli O157:H7, Salmonella spp., and Mycobacterium paratuberculosis) , and some enteric viruses. Clinical symptoms, prospects for zoonotic in-fection, and control methods other than the use of antimicrobials are considered. Recommendations to avoid disease transmission include taking steps to ensure the provision of clean, unstressful environ-ments to reduce disease susceptibility and the careful handling and spreading of manure from animals at high risk for infection, especially young calves. Com-posting and drying of manure decrease the number of viable pathogens. Environmental controls, such as filter strips, also reduce the risk of water contamina-tion. ( Key words: manure, pathogen, water quality, waste management