Experimental Infection in Mice with Cryptosporidium Isolated from Humans.

Cryptosporidium is a genus of protozoa that infects the gastrointestinal and respiratory epithelium of various host species. The aim of this study was to perform experimental infection in conventional mice with three Cryptosporidium species isolated from humans. The three Cryptosporidium species, namely Cryptosporidium canis, Cryptosporidium parvum, and Cryptosporidium ryanae, were obtained from fecal samples collected from patients hospitalized in an infectious disease hospital. The mice, from 10-day-old litters kept with their mother, were divided into three groups and orally infected with one of the Cryptosporidium species. The first oocysts were identified in the feces of the mice four days post-infection. The infection was successful with all three Cryptosporidium species, but the infection level (expressed as the number of oocysts per microscopic field) was low. The infection was detected using a rapid immunochromatographic test 40 days post-infection. Furthermore, starting on the 17th day after infection, the mothers also tested positive on the rapid immunochromatographic test, having been negative until that point. It was concluded that mice could represent a source of infection for the three Cryptosporidium species in other susceptible species, including humans. No behavioral changes or diarrhea were observed in any of the experimental cases.