Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: March 28, 2002
Publication Date: April 1, 2002
Citation: Trout, J.M., Higgins, J.A., Shelton, D.R., Fayer, R. 2002. Tracking fecal pathogens from cattle and wildlife in the Chesapeake Bay. BARC Poster Day.
Contamination of surface waters with fecal pathogens that pose a risk of infection to humans and animals is an ongoing concern. However, determining the sources of such contamination and the contribution of animal agriculture is often a difficult task. Several closely related studies have been conducted to examine levels of contamination as well as to investigate possible sources of infectious organisms. A survey of beef cattle indicated that of 7-14 month-old calves up to 54% and 29% were infected with Giardia and Cryptosporidium, respectively. Wildlife surveys showed the following percent of animals positive for Cryptosporidium and Giardia respectively: beaver, 12%, 20%; deer, 5.5%, 0%; fox, 12.5%, 3.4%; muskrat, 22.3%, 77.7%; otter, 9.3%, 6.3%; raccoon, 0%, 2%. Thus, the highest prevalences of both pathogens were found in beaver and muskrat populations, two species closely associated with surface water. Oysters have been used as indicators of water contamination and were collected from various locations around the Bay where pathogen-contaminated runoff was likely to enter the water. Cryptosporidium was found in oysters collected from all locations, however, Giardia was not detected in any of the oysters. To determine if cattle were the primary source of pathogens in the water, bovine enterovirus (BEV, a non-pathogenic agent common in cattle) was examined as an indicator of bovine fecal contamination. BEV was detected in the cattle, the water, and the oysters, suggesting that cattle may indeed be responsible for water contamination. BEV was also detected in deer and even wild goose feces, indicating its usefulness as a point source indicator may be limited. The complexity of the foregoing results related to the epidemiologic determination of relationships between sources of pathogens and their distribution in the environment indicates the inherent difficulty in assessing the role of agriculture in spread of human and animal pathogens.