# Molecular Epidemiological Survey of Cryptosporidium in Ochotona curzoniae and Bos grunniens of Zoige County, Sichuan Province

## TL;DR

This study found Cryptosporidium parasites in plateau pikas and yaks in Zoige County, revealing new species and highlighting zoonotic risks.

## Contribution

The study reports the first detection of an unidentified Cryptosporidium species in plateau pikas and provides insights into regional zoonotic risk.

## Key findings

- Cryptosporidium was detected in 8.3% of samples from plateau pikas and yaks in Zoige County.
- An unidentified Cryptosporidium species was found in plateau pikas, while C. bovis and C. ryanae were found in yaks.
- Maixi town had the highest Cryptosporidium detection rate at 32.4%.

## Abstract

Cryptosporidium is an important zoonotic parasite that infects a wide range of animals, causing diarrhea, growth retardation, and economic losses in livestock. Although Cryptosporidium has been reported in some regions of Aba Prefecture, there is limited research on the prevalence and distribution of Cryptosporidium spp. in Ochotona curzoniae (plateau pika) and Bos grunniens (yak) in Zoige County. Therefore, the current study aimed to investigate the species and genotypes of Cryptosporidium in O. curzoniae and B. grunniens, and to reveal their potential zoonotic risk in Zoige County of Sichuan Province, China. The results that overall prevalence rate of Cryptosporidium in Zoige County was 8.3% (20/242), and three different Cryptosporidium species were involved, including C. bovis, C. ryanae, and an unidentified Cryptosporidium sp.; among them, an unidentified Cryptosporidium sp. was detected in O. curzoniae, and C. bovis and C. ryanae were detected in B. grunniens. These findings demonstrate that Cryptosporidium infections are present in both O. curzoniae and B. grunniens in Zoige County, with notable differences in infection rates and species composition, and provide valuable data on the epidemiology of Cryptosporidium in the region and offer scientific support for the healthy development of the livestock industry and public health management.

In order to investigate the infection status of Cryptosporidium in O. curzoniae and B. grunniens in Zoige County, Sichuan Province, fecal samples from B. grunniens and gastrointestinal contents from captured O. curzoniae were collected between March and December 2023 from five townships (Dazhasi, Axi, Hongxing, Tangke, and Maixi). Genomic DNA was extracted, and nested PCR targeting the small subunit (SSU) rRNA gene of Cryptosporidium was performed. PCR-positive products were sequenced, trimmed, aligned, and subjected to phylogenetic analysis to determine species and genotypes. A total of 242 samples were obtained, of which 20 were Cryptosporidium SSU rRNA-positive, yielding an overall detection rate of 8.3% (20/242). The detection rates of O. curzoniae and B. grunniens were 7.0% (8/114) and 9.4% (12/128), respectively. Among the five sampling sites, Maixi town exhibited the highest detection rate (32.4%, 11/44), followed by Hongxing town (15.2%, 7/46) and Tangke town (4.6%, 2/44). Phylogenetic analysis detected an unidentified Cryptosporidium sp. in O. curzoniae, while C. bovis (n = 10) and C. ryanae (n = 2) were detected in B. grunniens. These findings demonstrate that Cryptosporidium infections are present in both O. curzoniae and B. grunniens in Zoige County, with notable differences in infection rates and species composition. Continued surveillance of Cryptosporidium in local livestock and wildlife is warranted to provide critical data for regional public health management.