PATHOGENS IN ANIMAL WASTES AND THE IMPACTS OF WASTE MANAGEMENT PRACTICES ON THEIR SURVIVAL, TRANSPORT AND FATE

Abstract

Concerns about potential animal waste pollution of the environment have focused mainly on water,and the potential impacts of nitrogen, phosphorous, and turbidity (suspended solids). However,contemporary issues associated with potential pollution impacts of livestock operations now includemicrobial pathogens, gaseous emissions (such as ammonia), and odors (odorants). Increasedawareness of zoonoses (pathogenic microbes of animal origin) in animal wastes is now recognizedas a public health concern, especially because of the occurrence of waterborne disease outbreaksapparently caused by fecal contamination of manure origin (for example, in Walkerton, Ontario, in2000). Identification and characterization of zoonotic animal pathogens is one of the key steps inreducing potential human exposures via water and other routes (foods, air and soil). Various bacteria,viruses, and protozoa exist in apparently healthy animals, but upon transmission to humansthese pathogens can cause illness and even death. Exposure of humans to these disease-causingpathogens of animal origin can occur via occupational exposure, water, food, air or soil. Some ofthe important pathways for pathogen transmission to humans are shown in Figure 1.<br><br>The fecal wastes and other wastes (such as respiratory secretions, urine, and sloughed feathers,fur or skin) of various agricultural (livestock) and feral animals often contain high concentrations ofhuman and animal pathogens (disease-causing microorganisms) (Strauch and Ballarini, 1994).Concentrations of some pathogens occur at levels of millions to billions per gram of wet weightfeces or millions per ml of urine. Per capita fecal production by agricultural animals such as cattleand swine exceeds that of humans. Furthermore, the trend for production facilities to harbor thousandsto tens of thousands of animals in relatively small spaces results in the generation of verylarge quantities of concentrated fecal and other wastes that must be effectively managed to minimizeenvironmental and public health risks.