Repurposing disulfiram in a promising combination therapy for cryptosporidiosis in immunocompromised mice.

Cryptosporidiosis remains a major health concern, particularly in immunocompromised individuals, due to limited effective treatment options. Nitazoxanide (NTZ) is currently the only FDA-approved drug for cryptosporidiosis, yet its efficacy is significantly reduced in immunosuppressed hosts. This study evaluated the therapeutic potential of disulfiram, an FDA-approved drug for alcoholism, alone and in combination with NTZ, against Cryptosporidium infection in immunocompromised mice. Forty immunosuppressed Swiss albino mice were divided into five equal groups: uninfected controls, infected untreated, NTZ-treated, disulfiram-treated, and combination-treated (NTZ + disulfiram). All infected mice were orally inoculated with ∼10⁴ Cryptosporidium oocysts and were treated with NTZ (250 mg/kg/day) and/or disulfiram (25 mg/kg/day) for 10 consecutive days. Efficacy was assessed through parasitological, histopathological, and ultrastructural analyses. The combination therapy achieved the highest fecal oocyst reduction: 34.3 % after one week and 88.3 % after two weeks. In comparison, NTZ and disulfiram monotherapies achieved 24 % and 76 % reductions, respectively, at two-weeks mark. In intestinal contents, the combination therapy resulted in 62.6 % oocyst reduction versus 11.4 % for NTZ and 36.2 % for disulfiram at week two post treatment. Histopathological analysis revealed near-complete mucosal restoration in the combination group, whereas monotherapies showed limited or moderate recovery. Transmission electron microscopy confirmed full epithelial regeneration only in the dual therapy group, with intact microvilli, normal mitochondria, and restored cellular junctions. In conclusion, disulfiram, particularly when combined with NTZ, demonstrated enhanced anti-cryptosporidial efficacy and may serve as a promising adjunct therapy, mostly for immunocompromised patients.