Zoonotic Cryptosporidium spp. in Wild Rodents and Shrews

Rauni Kivistö,Otso Huitu,Heikki Henttonen,Jukka Niemimaa,Sofia Kämäräinen

doi:10.3390/microorganisms9112242

Rauni Kivistö, Otso Huitu + Show 3 more

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https://doi.org/10.3390/microorganisms9112242

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Abstract

There has been a significant increase in the number of reported human cryptosporidiosis cases in recent years. The aim of this study is to estimate the prevalence of Cryptosporidium spp. in wild rodents and shrews, and investigate the species and genotype distribution to assess zoonotic risk. Partial 18S rRNA gene nested-PCR reveals that 36.8, 53.9 and 41.9% of mice, voles and shrews are infected with Cryptosporidium species. The highest prevalence occurred in the Microtus agrestis (field vole) and Myodes glareolus (bank vole). Interestingly, bank voles caught in fields were significantly more often Cryptosporidium-positive compared to those caught in forests. The proportion of infected animals increases from over-wintered (spring and summer) to juveniles (autumn) suggesting acquired immunity in older animals. Based on Sanger sequencing and phylogenetic analyses, Apodemus flavicollis (yellow-necked mouse) is commonly infected with zoonotic C. ditrichi. Voles carry multiple different Cryptosporidium sp. and genotypes, some of which are novel. C. andersoni, another zoonotic species, is identified in the Craseomys rufocanus (grey-sided vole). Shrews carry novel shrew genotypes. In conclusion, this study indicates that Cryptosporidium protozoan are present in mouse, vole and shrew populations around Finland and the highest zoonotic risk is associated with C. ditrichi in Apodemus flavicollis and C. andersoni in Craseomys rufocanus. C. parvum, the most common zoonotic species in human infections, was not detected.

Highlights

IntroductionPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
The aim of this study is to estimate the prevalence of Cryptosporidium spp. in Finnish wild small mammals using nested-PCR based on the partial 18S rRNA gene and to further investigate Cryptosporidium species occurring in the samples, and assess their potential zoonotic risk based on the literature
Apodemus flavicollis (36.4%) and Alexandromys oeconomus were commonly infected with Cryptosporidium species

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. In Finland and other Fennoscandian countries (Norway and Sweden), there has been a significant increase in the number of reported human cryptosporidiosis cases in recent years [1]. According to the Finnish Institute for Health and Welfare, the number of reported human cryptosporidiosis cases has increased by more than 40-fold since 2000; from four cases reported in 2000 (on average 12 cases per year from 2000 to 2010) to 571 cases in. The majority of human cryptosporidiosis cases are caused by C. hominis, mainly transmitted from human to human and C. parvum, which is a zoonotic species and a common cause of diarrhea in calves, in Finland. A small proportion of the human cases are caused by other Cryptosporidium species, which usually remain unidentified

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