Cryptosporidium species are related to protozoan parasites that infect the gastrointestinal tract
of a wide variety of animals, including humans. The host immune status is crucial for determining
the susceptibility to infection, the outcome and the severity of the disease. Nitazoxanide®
is the only FDA approved drug to treat such opportunistic infection, yet demonstrates limited
and immune-dependent efficacy. The present work studied the effect of combination therapy in
treating cryptosporidiosis, plus exploring the possible modulating effect on the local adaptive
immune response in experimental dexamethasone immunocompromized mice model. The results
showed that combination of selenium supplementation with ivermectin® or nitazoxanide
improved the oocysts reduction percentage compared to groups receiving single anti-parasitic
therapeutic drugs alone. Also, combination of ivermectin with nitazoxanide gave the best oocysts
reduction rates with the lowest score of ileitis severity. But, local expression of CD4 T
cells was down-regulated and unlikely could not be elevated enough even after all treatment
types. CD8 was up regulated in all treated groups as compared with non-treated control group,
indicating its possible role in reducing the serious threats of such opportunistic infection.