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United States Department of Agriculture

Agricultural Research Service

Title: Control and Intervention Strategies to Combat Parasite Transmission Through the Environment

Authors
item Bosch, Albert - MICRO. UB, SPAIN
item Poel, Wim - NIOPH, NETHERLANDS
item Bidawid, Sabah - HEALTH CANADA, CA
item Wolk, Donna - U. OF ARIZONA
item Smith, Huw - STOBHILL HSPTL,SCOTLAND
item Trout, James

Submitted to: International Association for Food Protection
Publication Type: Abstract Only
Publication Acceptance Date: December 31, 2003
Publication Date: August 10, 2004
Citation: Bosch, A., Poel, W., Bidawid, S., Wolk, D., Smith, H., Trout, J.M. 2004. Control and intervention strategies to combat parasite transmission through the environment[Abstract]. International Association for Food Protection Annual Meeting. p. 165.

Technical Abstract: There are numerous pathways by which parasites can be transmitted throughout the environment. From human, wildlife, and livestock sources, fecal material containing parasites can be deposited directly onto the land or into surface water. Processed human waste may also be land applied. Additionally mechanical vectors such as birds and insects which forage in fecal material can acquire and transport parasites within the environment. There are two primary intervention points that can be targeted to disrupt these transmission cycles. One is by treating the source of the parasites, the infected animals. The second is to treat or contain the potentially infectious animal waste. Reduction of infections in livestock can be accomplished by various management techniques, such as attention to sanitation, control of potential mechanical vectors, reduced exposure to infected wildlife, and when economically feasible, but use of therapeutic drugs. Numerous treatments have been attempted on animal waste in the hope of killing Cryptosporidium oocysts and Giardia cysts, however, the success rates have generally been low due to the highly resistant nature of these structures. Only the most toxic chemicals have demonstrated high efficacy and thus these agents are not generally adaptable for use in the environment. Some treatments such as aerobic and anaerobic digestion appear to be promising as the parasites lose their infectivity very rapidly at temperatures above 40C. Additionally controlling runoff to decrease the entry of fecal material into surface water can help to limit environmental dissemination of infectious organisms. It may also be possible to use biological controls such as predatory microorganisms, some of which have been shown to ingest parasites in laboratory experiments. While no single approach is likely to result in completely blocking parasite transmission through the environment, a combination of approaches could result in a reduction of the occurrence of parasites in the environment, thus reducing the risk of human infection.

Last Modified: 7/30/2014
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