Comparative study of the prophylactic and therapeutic effects of paromomycin, recombinant IL-12 alone or in combination against Cryptosporidium parvum infection in immunosuppressed mice.

Administration of paromomycin (100 mg/kg orally) for 10 days, rIL-12 (0.5 ug/mouse s.c.) for 3 consecutive days or combination of both was evaluated before and after infection with C. parvum using immunosuppressed mice model. A total of 110 suckling albino mice were immunosuppressed by hydrocortisone acetate and infected with 10(6) Cryptosporidium oocysts. Assesment of drug efficacy was done by estimating the oocyst count in stool using modified Ziehl Neelsen technique, the histopathological examination of terminal ileum and determination of serum level of IFN-gamma and calculation of the cure rate. The combination of paromomycin and rIL-12 was more effective than either drug alone. The cure rate was 86.7% when the regimen used prophylactically and 73.3% when the combination administered. Regression of the histopathological changes in comparison to the control group was noted. Moreover the combination regimens produced significant higher level of IFN-gamma suggesting that both rIL-12 and Paromomycin can act additively or synergistically in the prevention of C. parvum infection most probably through activation of INF-gamma production.