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

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).

Diverse Genotypes and Species of Cryptosporidium in Wild Rodent Species from the West Coast of the USA and Implications for Raw Produce Safety and Microbial Water Quality

“…In the US, detection of Cryptosporidium spp. oocysts in watersheds has been reported on the east [ 38 , 39 , 40 ] and west coast (California [ 41 ], Washington [ 42 ], Oregon [ 27 ]). Given that Cryptosporidium in wild rodents such as deer mice, yellow-bellied marmots, and mountain beavers can be >99.75% homologous to C. parvum , C. ubiquitum, or other zoonotic species or genotypes of Cryptosporidium , along with the observation that rodents like deer mice can shed very high concentrations (>10 8 ) of oocysts per g feces [ 24 ], reasonable control measures may be needed to prevent high population densities of rodents occurring in close proximity to recreational water sources or municipal drinking water supplies that can pose a risk for waterborne transmission to humans and other animals.…”

“…Based on the literature of Cryptosporidium spp. in wild rodent hosts trapped from the west coast of the US [ 15 , 20 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ] and through online queries for DNA sequences of Cryptosporidium from this region of the US in the publicly accessible GenBank ( , accessed on 28 December 2020), 36 total isolates were identified, resulting in 22 unique sequences of the 18S rRNA gene of Cryptosporidium . These DNA sequences of Cryptosporidium isolates were from multiple deer mice ( Peromyscus maniculatus ), a house mouse ( Mus musculus ), mountain beavers ( Aplodontia rufa ), yellow-bellied marmots ( Marmota flaviventris ), a long-tailed vole ( Microtus longicaudus ), multiple California ground squirrels ( Otospermophilus beecheyi ), Belding’s ground squirrels ( Urocitellus beldingi ), and a golden-mantled ground squirrel ( Callospermophilus lateralis ).…”

“…from wild rodents trapped on the west coast of the US; second, the phylogenetic relationships between Cryptosporidium from wild rodents and named reference Cryptosporidium species in mammals (including humans) and known reference zoonotic genotypes. Depending on the availability of the 18S rRNA gene sequences of Cryptosporidium in the GenBank, reference sequences for the second phylogenetic analysis were selected as previously described [ 27 ] and based on: (1) sequences of isolates representing described Cryptosporidium species from mammals; (2) sequences of isolates from known zoonotic genotypes; (3) sequences previously used by other investigators for species description or as reference sequences; (4) sequence length (longer sequence available for each species; i.e., ≥700 bp); and (5) sequences not originating from cloned PCR products due to the potential for erroneous sequence data generated from cloning PCR products [ 29 , 30 ]. Phylogenetic trees were constructed using the Vector NTI Advance 11 based on a pairwise alignment.…”

“…The aim of this work was to consolidate the diversity of Cryptosporidium spp. and genotypes shed in the feces of wild rodents that we and other researchers have documented over the past decade of research [ 15 , 20 , 22 , 23 , 24 , 25 , 26 , 27 ] and to update the phylogenetic relationships of unique Cryptosporidium sequences from wild rodents on the west coast of the United States (US); this information will reveal new public health implications for food safety and water quality for the different species and genotypes of Cryptosporidium in wild rodents from this geographical region of the US.…”

Editorial for the Special Issue: Epidemiology, Transmission, Cell Biology and Pathogenicity of Cryptosporidium

“…Cryptosporidium was detected in 1.7% of the samples tested, with the presence of two zoonotic species ( C. parvum and C. andersoni ) and one avian genotype ( Cryptosporidium goose genotype II). The research article by Li et al [ 3 ] provided information about the prevalence and diversity of species and genotypes of Cryptosporidium in the resident and migratory wildlife populations located in a major, protected watershed in the Pacific Northwest. The overall prevalence of Cryptosporidium in the wildlife scat reached 13.8%, with 15 species of wildlife found to be positive for the parasite.…”