Experimental Infection in Mice with <i>Cryptosporidium</i> Isolated from Humans.

Abstract

<i>Cryptosporidium</i> 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 <i>Cryptosporidium</i> species isolated from humans. The three <i>Cryptosporidium</i> species, namely <i>Cryptosporidium canis</i>, <i>Cryptosporidium parvum</i>, and <i>Cryptosporidium ryanae</i>, 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 <i>Cryptosporidium</i> species. The first oocysts were identified in the feces of the mice four days post-infection. The infection was successful with all three <i>Cryptosporidium</i> 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 <i>Cryptosporidium</i> species in other susceptible species, including humans. No behavioral changes or diarrhea were observed in any of the experimental cases.