Prevalence and Genotypes of Cryptosporidium in Wildlife Populations Co-Located in a Protected Watershed in the Pacific Northwest, 2013 to 2016.

Xunde Li,Sarah Silkie,Chengling Xiao,Tran Nguyen,Yone Akagi,Edward R Atwill,Ann Levy

doi:10.3390/microorganisms8060914

Abstract

Between October 2013 and May 2016, 506 scat samples were collected from 22 species of wildlife located in a protected watershed of a major municipal water supply in the Pacific Northwest, USA. Overall prevalence of Cryptosporidium in the wildlife scat was 13.8% (70/506), with 15 species of wildlife found positive for Cryptosporidium. Prevalence of Cryptosporidium varied among species of wildlife, with higher prevalences observed in cougars (50.0%), mountain beavers (40.0%), and bobcats (33.3%), but none of these species are riparian-dependent. Genotyping of Cryptosporidium by sequencing PCR amplicons from the 18S rRNA gene were successful for seven species of wildlife, including bobcat, unknown predator, black-tailed deer, deer mouse, snowshoe hare, mountain beaver, and western spotted skunk. BLAST and phylogenetic analyses indicated that multiple species and genotypes of Cryptosporidium were present, with some isolates possibly co-circulating within and between wildlife populations in this protected watershed. Evidence of oocyst exchange between infected prey and their predators was also found. During the study period, several zoonotic Cryptosporidium species and genotypes that are uncommon in humans were detected in bobcat (99.58% identical to Cryptosporidium felis), unknown predator (100% identical to Cryptosporidium canis), snowshoe hare (100% identical to Cryptosporidium sp. skunk genotype), and mountain beaver (100% identical to Cryptosporidium ubiquitum). Novel sequences were also found in mountain beaver. To our knowledge, this is the first published report of a unique genotype or species of Cryptosporidium in mountain beaver (Aplodontia rufa).

Highlights

Parasites of the genus of Cryptosporidium infect virtually all vertebrate groups, with some species exhibiting host specificity [1,2]
Because sources of drinking water such as lakes, reservoirs, rivers, and groundwater can be contaminated by waterborne pathogens shed by wild and domestic animals, the prevalence and distribution of zoonotic species of Cryptosporidium in wildlife located within watersheds that provide source water for municipal drinking water is of public health importance [5]. The objective of this project was to determine the prevalence and diversity of known species and novel genotypes of Cryptosporidium in the resident and migratory wildlife populations located in a major, protected watershed in the Pacific Northwest; such data would contribute to a better assessment of Cryptosporidium health risks from human exposure to this parasite through drinking water
In Canada, a lower prevalence of 0.94% for Cryptosporidium was found in wildlife, with scat from 6 of 19 wildlife species testing positive at locations along tributaries of the North Saskatchewan River in Alberta [36]

Summary

Introduction

Parasites of the genus of Cryptosporidium infect virtually all vertebrate groups, with some species exhibiting host specificity [1,2]. A massive waterborne outbreak of cryptosporidiosis occurred in Milwaukee, Wisconsin, in 1993, which was transmitted through the public water supply to affect over 400,000 people [10]. A similar community outbreak of cryptosporidiosis infected about 13,000 people in Georgia in 1987, due to contamination of the public water supply [11]. A community outbreak of cryptosporidiosis associated with surface water-supplied municipal water occurred in Baker City, Oregon in 2013, in which 2780 people were infected [12]. Active and passive surveillance for waterborne Cryptosporidium spp. oocysts have detected this parasite in numerous municipal and rural watersheds around the world. In the USA., detection of Cryptosporidium spp. oocysts in water have been widely reported, such as during base- and storm-flow conditions for the Potomac River watershed [18], in surface water in the Wachusett Reservoir watershed in central Massachusetts [19], during storm flow conditions from watersheds in New York [20], popular swimming sites in central California [21], and in rivers in Washington State [22]

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Discussion

Conclusion