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United States Department of Agriculture

Agricultural Research Service

Title: Giardia and Cryptosporidium in animals and in the environment: Progress on research to safeguard human health

item Fayer, Ronald

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 10, 2007
Publication Date: October 17, 2007
Citation: Fayer, R. 2007. Giardia and Cryptosporidium in animals and in the environment: Progress on research to safeguard human health. Lecture at the University of Foggia, October 17-21, 2007, Bari, Italy. p. 1.

Technical Abstract: Cryptosporidiosis and giardiasis are gastrointestinal diseases of humans and many animals caused by protozoan parasites. Cryptosporidium has become a very important pathogen in drinking water, detected in over 90% of the surface waters tested in the United States and found in surface waters worldwide. Giardia is the most prevalent cause of protozoan diarrhea worldwide. Feces containing oocysts or cysts from infected humans, livestock and other domesticated animals, and wildlife are the ultimate source of zoonotic and anthroponotic Cryptosporidium and Giardia in the watershed. Dispersal of feces to surface and ground water, application to farmland, gardens, or lawns, and transmission by mechanical vectors can carry the infective oocyst stage to drinking water supplies, food crops, or directly to susceptible persons and animals. To reduce or eliminate transmission we must know which species pose a risk to humans and animals, we must know the sources (hosts) of these organisms, and we must have accurate methods for detect to detect the organisms in environmental specimens. Intervention can be accomplished by eliminating organisms, reducing prevalence of host infection, and decreasing planned environmental loading. We can intervene at the source by decreasing levels of infection or prevalence in animal hosts and by treating or containing the feces. But it is important to clearly and precisely identify the species and genotype of the parasite and this cannot be accomplished by microscopy alone. The number of organisms in the environment can be greatly reduced using proper manure management practices associated with land application, composting, aerobic or anaerobic digestion, holding lagoons, insect control, runoff control, and limiting animal access to surface waters. Although approximately 90% of human feces are discharged directly into surface waters in developing countries, most feces are processed in wastewater treatment facilities in industrialized countries. But, leaky septic systems and undersized or malfunctioning treatment facilities frequently have been identified as sources of surface water contamination. The important species, methods to accurately identify the organisms, methods of managing cattle, wildlife, birds and flies the physical and chemical disinfection methods, and the potential use of biological control agents will be discussed in detail.

Last Modified: 8/28/2016