Prevalence and risk factors of Cryptosporidium in humans in China: A systematic review and meta-analysis

Cryptosporidium is a globally distributed protozoan parasite and a major cause of diarrheal disease, particularly among immunocompromised individuals. Despite its growing recognition as an important zoonotic pathogen, large-scale epidemiological data specific to the Chinese population remain scarce. We systematically retrieved articles on the occurrence of Cryptosporidium in humans in China through searches of PubMed, Web of Science, ScienceDirect, Chinese National Knowledge Infrastructure, Wanfang Data, and VIP Chinese Journal Database, with the literature search current through May 15, 2025, following PRISMA guidelines. A total of 193 studies were included, covering data from 27 provinces. A total of 193 studies were included, covering data from 27 provinces, with a total sample size of 249,142 individuals, of whom 11,339 tested positive. Pooled prevalence and 95 % confidence intervals (CI) were estimated using a random-effects model. Funnel-plot inspection and Egger's test indicated small-study effects/publication bias (p = 0.0082); trim-and-fill adjustment suggested some missing studies but produced broadly consistent adjusted estimates, so findings are reported with appropriate caution. The pooled prevalence of Cryptosporidium infection in humans in China was estimated at 5.0 %. Higher infection rates were observed in Northwestern China (6.61 %, 95 % CI: 3.20-11.13) and among individuals aged 17-30 years (8.43 %, 95 % CI: 3.55-14.61), and a significant decline in prevalence was noted in studies conducted after 2015. C. parvum and C. hominis were identified as the main infecting species, while other Cryptosporidium species (C. meleagridis, C. canis, C. felis, C. viatorum, C. baileyi, C. andersoni, C. bovis and C. suis) were only sporadically detected. In addition, higher infection rates occurred in HIV-positive individuals (7.63 %, 95 % CI: 5.34-10.28) and rural populations (5.18 %, 95 % CI: 3.46-7.23). These findings highlight the need for improved surveillance, accurate diagnostics, and targeted prevention strategies in high-risk regions and populations, with attention not only to young children but also to adults, who may face overlooked exposure risks.