Anti-cryptosporidial activity of Camellia sinensis (green tea extract) in experimentally infected immunocompromised mice

Cryptosporidium parvum, an Apicomplexan parasite, is an important cause of diarrheal disease, especially in immunodeficient hosts. Nevertheless, there is no entirely successful therapeutic agent against cryptosporidiosis to date. Hence, this study aims to test the potential prophylactic and therapeutic effect of Camellia sinensis (green tea extract) in dexamethasone immunosuppressed mice versus the nowadays used drug, Nitazoxanide (NTZ). Parasitological and molecular methods were used to characterize Cryptosporidium oocysts before infection. Fifty bred female Swiss Albino mice were divided into 5 groups; group I (GI)(GTP): immunosuppressed and prophylactically treated with green tea extract for 5 days prior to infection, group II (GII)(GTT): immunosuppressed, infected with Cryptosporidium parvum and treated with green tea extract, group III (GIII)(NT): immunosuppressed, infected and treated with NTZ, group IV (GIV)(PC): immunosuppressed and infected (Positive control), group V (GV)(NC): immunosuppressed and non-infected (Negative control). Furthermore, parasitological examination for oocysts in the stool, and histopathological examination for the small intestine and liver specimens were performed for the study groups. Cryptosporidium oocysts used for induction of infection proved to be Cryptosporidium parvum genotype 2. Moreover, a significant oocyst reduction in fecal samples correlated with an improvement of histopathological changes in the small intestinal and liver tissues in GI(GTP), GII (GTT) and GIII(NT) groups. Besides, the GII(GTT) group showed the best improvement in parasitological and histopathological parameters among the test groups. This study revealed that Camellia sinensis (green tea extract) has potential activity against cryptosporidiosis and could serve as a promising prophylactic and therapeutic anti-cryptosporidial agent.