# Prevalence and characterization of Cryptosporidium in sika deer from Northern China

## TL;DR

This study finds that Cryptosporidium, a zoonotic parasite, infects sika deer in Northern China, with higher rates in young deer and potential for human transmission.

## Contribution

The study provides updated epidemiological data and genetic characterization of Cryptosporidium in sika deer in Northern China.

## Key findings

- Cryptosporidium infection rate in sika deer was 14.81% across four Chinese provinces.
- Young sika deer had significantly higher infection rates compared to adults.
- Cryptosporidium deer genotype and a zoonotic C. ubiquitum subtype were identified.

## Abstract

Cryptosporidium spp. are important zoonotic parasites that can cause moderate to severe diarrhea in humans and animals. However, the epidemiological data of Cryptosporidium in sika deer in China need to be updated. In this study, a total of 466 fecal samples were collected from sika deer in Shandong, Jilin, Liaoning, and Heilongjiang provinces. Nested PCR was used to amplify the SSU rRNA gene to detect Cryptosporidium spp. The results showed that the overall infection rate of Cryptosporidium spp. was 14.81%, with no significant differences among regions (p = 0.05). The highest infection rate was found in Heilongjiang Province (23.60%) and the lowest in Jilin Province (10.71%). The infection rate in summer (23.61%) seemed higher than that in autumn (13.20%), but the difference was not statistically significant (p = 0.30). Notably, young sika deer showed a significantly higher infection rate (28.21%) compared to adults (10.32%) (p < 0.0001). Sequence analysis identified two Cryptosporidium species/genotypes: Cryptosporidium deer genotype (98.55%) and Cryptosporidium ubiquitum (1.45%). Subtyping revealed that the C. ubiquitum isolate belonged to the zoonotic XIIa subtype. These findings provide new insights into the prevalence and genetic diversity of Cryptosporidium in sika deer and suggest that sika deer may act as a potential reservoir for zoonotic Cryptosporidium transmission.