Rodent-adapted infection in humans: Seven new cases and review of the literature.

Cases of cryptosporidiosis in humans have been reported with strong indication of transmission from rodents. Here, we report seven new human cases of cryptosporidiosis involving rodent-adapted species ( [ = 1], [ = 4; previously known as chipmunk genotype I], [ = 1], and [n = 1]) and review cases of human infection caused by these four species published to date. The seven new cases were detected in Denmark within a period of twelve months from 2022 to 2023. Only the and cases were associated with travel outside Denmark. The total number of human cases of cryptosporidiosis due to and documented to date globally are still limited (4 and 7, respectively), whereas cases involving and have been detected to a larger extent (43 and 63 cases, respectively). The four new cases of were all of the XIVaA20G2T1 subtype, which is the only subtype identified so far in Scandinavia, and which is a subtype not yet found outside of Scandinavia. The new case was identified as the XVaA3g subtype. The case was subtyped as IXbA6. No subtype data were produced for due to lack of a subtype assay. Review of existing data suggests the presence of and primarily in northern countries and and primarily in warmer climates. While our data may further support the role of as a cause of zoonotic disease, case descriptions should be obtained where possible to determine if species primarily adapted to rodents are the likely cause of symptoms or just an incidental finding.