Efficacy of nitazoxanide and paromomycin in biliary tract cryptosporidiosis in an immunosuppressed gerbil model

Objectives: To evaluate the efficacy of nitazoxanide and paromomycin in biliary tract cryptosporidiosis in an immunosuppressed Mongolian gerbil (Meriones unguiculatus) model. Methods: Gerbils (1-month-old) were dexamethasone-immunosuppressed for 10 days and challenged orally with 10(5) Cryptosporidium parvum oocysts. From day 0 to day 12 post-infection, one group (n = 14) was treated with 200 mg/kg/day nitazoxanide and another (n = 15) with 100 mg/kg/day paromomycin. Infection and efficacy of nitazoxanide and paromomycin were assessed by measuring oocyst shedding in faeces, biliary tract and ileum histological examination. Results: In nitazoxanide-treated and paromomycin-treated groups as compared with untreated animals (P < 0.05), oocyst shedding was partially suppressed in a similar manner (P > 0.05). Parasites were present in histological sections of the ileal mucosa of 16/16 infected untreated animals versus 3/14 and 6/15 in the nitazoxanide-treated and the paromomycin-treated groups, respectively (P < 0.05). In addition, gall bladder infection was less frequent in nitazoxanide-treated (2/14, P < 0.01) and paromomycin-treated (5/15, P = 0.07) animals than in untreated controls (9/16). No histological alteration of biliary mucosa was observed in both treated and untreated infected gerbils. Conclusions: Present data support the efficacy of nitazoxanide and, to a lesser extent, paromomycin on biliary C. parvum infection in gerbils, and prompt further investigation of the potential clinical benefits of nitazoxanide in treating human biliary cryptosporidiosis.