Cryptosporidium spp. in wild rodents in the Poyang Lake region, China.

Cryptosporidium spp. are zoonotic protozoan parasites that cause diarrheal disease worldwide. Rodents can harbor diverse Cryptosporidium spp. and facilitate their transmission to the environment and other hosts, including humans. However, data on Cryptosporidium infection in wild rodents in the Poyang Lake region, China's largest freshwater lake, remain scarce. Here, we investigated Cryptosporidium spp. in 273 wild rodents collected from seven sites adjacent to villages around Poyang Lake between 2022 and 2024. The rodents were identified by cytochrome c oxidase subunit I (COI) gene sequencing as Apodemus agrarius (n = 148) and Rattus losea (n = 125). Nested PCR targeting the small subunit ribosomal RNA (SSU rRNA) gene revealed an overall Cryptosporidium spp. infection rate of 16.5% (45/273, 95% CI: 12.3-21.9%), with 20.3% (30/148, 95% CI: 14.2-27.8%) in A. agrarius and 12.0% (15/125, 95% CI: 6.9-19.0%) in R. losea. Sequence and phylogenetic analyses identified seven Cryptosporidium species/genotypes: C. apodemi, C. canis, C. muris, C. suis, C. ubiquitum, rat genotype II, and rat genotype III. Notably, the detection of four zoonotic species (C. canis, C. muris, C. suis, and C. ubiquitum) highlights the potential risk of zoonotic transmission of Cryptosporidium spp. from wild rodents to humans in this region. These findings underscore the need for systematic surveillance and control of Cryptosporidium spp. in wild rodent communities around Poyang Lake.