PATHOGENS IN ANIMAL WASTES AND THE IMPACTS OF WASTE MANAGEMENT PRACTICES ON THEIR SURVIVAL, TRANSPORT AND FATE
National Center for Manure and Animal Waste Management: White Paper Summaries
Sobsey, M.D., Khatib, L.A., Hill, V.R., Alocilja, E., Pillai, S.
Manure and other wastes (such as respiratory secretions, urine and sloughed feathers, fur or skin) of various agricultural (livestock) animals often contain high concentrations (millions to billions per gram of wet weight feces) of human pathogens (disease-causing microorganisms). Per capita fecal production by agricultural animals such as cattle and swine far exceeds that of humans, and the trend for production facilities to harbor thousands to tens of thousands of animals in relatively small spaces results in the generation of very large quantities of concentrated fecal wastes that must be effectively managed to minimize environmental and public health risks. Definitive or reference methods to recover and detect many of the pathogens in animal manures and their treated residual solids and liquids have not been reported, especially for emerging pathogens, such as hepatitis E virus, bacteria such as E. coli O157:H7 and Yersinia enterocolitica, and parasites such as Giardia lamblia and Cryptosporidium parvum. Therefore, the extent to which these pathogens are removed or inactivated in animal waste treatment processes or management systems remains uncertain due to limitations associated with the pathogen recovery and detection methods. The development, evaluation and application of reliable, sensitive and affordable methods to recover and detect pathogens in animal manures and their treated residual solids and liquids is recommended. In principle, methods are available to recover and detect some indicator microbes in animal manures and their treated residual solids and liquids. However, the methods for some indicators, such as bacterial viruses (coliphages) and spores of Clostridium perfringens, have not been adequately verified and collaboratively tested in these types of samples. Such verification and performance characterization studies are recommended. Also recommended are comparative studies on the removal, inactivation and fate of indicator microbes and animal pathogens in manure treatment processes and management systems. If such studies show that the indicator microbes reliably reflect or predict the responses of the animal pathogens in manure treatment processes and management systems, it then becomes possible to use them in practical, rapid and affordable monitoring and surveillance activities to assess treatment process and system performance and the pathogen quality of the treated residuals.