The Relation between Human Presence and Occurrence of<i>Glardia</i>Cysts in Streams in the Sierra Nevada, California

Suk, Thomas J.; Sorenson, Stephen K.; Dileanis, Peter D.

doi:10.1080/02705060.1987.9665163

Cited by 14 publications

(8 citation statements)

References 10 publications

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“…isolated from humans have some potential for infecting beavers and muskrats (7). Also, Suk et al (27) reported that surface water in recreational areas with high human usage had significantly higher levels of Giardia cysts in the water (44.9%) than did water from areas with low recreational use (17.2%). The media-popularized term "beaver fever," used in regard to the role of these animals as a source of cysts in waterborne giardiasis, may actually be a misnomer, since human usage of the watersheds may have led to the contamination of the drinking water (6).…”

Section: Discussionmentioning

confidence: 99%

Prevalence of Giardia spp. in beaver and muskrat populations in northeastern states and Minnesota: detection of intestinal trophozoites at necropsy provides greater sensitivity than detection of cysts in fecal samples

Erlandsen

Sherlock

Bemrick

et al. 1990

Appl Environ Microbiol

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Surveys of the prevalence of the intestinal protozoan Giardia spp. in animal populations have relied almost exclusively on the detection of cysts in fecal samples. We have determined the prevalence of Giardia spp. in beaver and muskrat populations in four northeastern states and Minnesota by using both the detection of trophozoites in mucosal scrapings from live-trapped animals at necropsy and the detection of cysts in fecal samples collected from kill-trapped animals. In muskrats the prevalence of Giardia infection was 36.6% by cyst detection in fecal samples (n = 790) from kill-trapped animals and 95.9% in live-trapped muskrats when the intestinal contents were analyzed for the presence of trophozoites (n = 219). Similarly, in beavers, Giardia infection was 9.2% by cyst detection in fecal samples (n = 662) from kill-trapped beavers and 13.7% in live-trapped animals examined for the presence of intestinal trophozoites (n = 302). The detection of trophozoites in mucosal scrapings from live-trapped animals consistently yielded a significantly higher prevalence for both muskrats and beavers than did the method based on detection of cysts in the fecal samples. The prevalence of Giardia infection in juvenile and adult live-trapped muskrats was similar (92.5 and 94.4%, respectively), but the prevalence in juvenile live-trapped beavers (23.2%) was significantly greater than that seen in the adult animals (12.6%). No difference in Giardia prevalence on the basis of sex was seen in either animal species. Regional variation, often statistically significant, was seen in the prevalence of Giardia in beavers in the northeastern states and Minnesota, but was not detected for muskrats.

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Section: Discussionmentioning

confidence: 99%

Prevalence of Giardia spp. in beaver and muskrat populations in northeastern states and Minnesota: detection of intestinal trophozoites at necropsy provides greater sensitivity than detection of cysts in fecal samples

Erlandsen

Sherlock

Bemrick

et al. 1990

Appl Environ Microbiol

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“…parasites (Giardia spp. ), even in watersheds that receive litt1e recreation use (Suk et al 1987). In the Sierra Nevada, Verner and Ritter (1983) found that Brown-headed Cowbirds (Molothrus ater) were positively associated with recreational packstock stations.…”

Section: Recreation Use and Its Managementmentioning

confidence: 99%

Threats to Wilderness Ecosystems: Impacts and Research Needs

Cole¹,

Landres²

1996

Ecological Applications

178

118

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One of the primary purposes of designated wilderness areas is protection of natural ecosystems. However, the ecological integrity of these most protected of public lands is threatened by direct and indirect effects of human activities both internal and external to wilderness. Accelerated research programs on threats to wilderness are needed to realize the purposes for which wilderness was established and to improve our understanding of natural ecosystems. This paper reviews current knowledge and critical research needs for some of the most significant threats to wilderness ecosystems: (1) recreational use and its management; (2) livestock grazing and its management; (3) fire management; (4) introduction of alien species; (5) diversion and impoundment of water; (6) emission of atmospheric pollutants; and (7) management of adjacent lands. Some of these threats cause highly disruptive localized impacts, whereas some have a more widespread effect. Other threats are highly significant because they threaten rare or irreplaceable ecological attributes. Ecological science needs to be applied to improve evaluations of wilderness conditions, improve efforts to protect wilderness ecosystems from further degradation, and improve efforts to restore the integrity of disturbed systems.

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“…6 Although concerns have been raised regarding Giardia in the Sierra, many authors have suggested that other fecal pathogens, such as enterotoxic Escherichia coli , may play a greater role in mountain-acquired illness. 6 –10…”

Section: Introductionmentioning

confidence: 99%

Risk Factors for Coliform Bacteria in Backcountry Lakes and Streams in the Sierra Nevada Mountains: A 5-Year Study

Derlet

Ger

Richards

et al. 2008

Wilderness Environ Med

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The Relation between Human Presence and Occurrence ofGlardiaCysts in Streams in the Sierra Nevada, California

Cited by 14 publications

References 10 publications

Prevalence of Giardia spp. in beaver and muskrat populations in northeastern states and Minnesota: detection of intestinal trophozoites at necropsy provides greater sensitivity than detection of cysts in fecal samples

Prevalence of Giardia spp. in beaver and muskrat populations in northeastern states and Minnesota: detection of intestinal trophozoites at necropsy provides greater sensitivity than detection of cysts in fecal samples

Threats to Wilderness Ecosystems: Impacts and Research Needs

Risk Factors for Coliform Bacteria in Backcountry Lakes and Streams in the Sierra Nevada Mountains: A 5-Year Study

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