Myristica fragrans Houtt. methanol extract as a promising treatment for Cryptosporidium parvum infection in experimentally immunosuppressed and immunocompetent mice.

Background and aim: Cryptosporidiosis is a major waterborne disease affecting ruminants and humans worldwide. It causes diarrhea and neonatal mortality in buffalo calves, and watery diarrhea and mortality in children and immunodeficient patients. This study aimed to investigate the efficacy of Myristica fragrans methanolic extract in treatment of C. parvum infection in comparison with nitazoxanide (NZX) (a Food and Drug Administration-approved drug control) in immunosuppressed and immunocompetent mice.

Materials and methods: One hundred laboratory-bred male Swiss albino mice were equally divided into immunocompetent and immunosuppressed groups. Each group was further divided into five subgroups: (1) non-infected and non-treated control, (2) infected and non-treated control (infected with Cryptosporidium parvum oocysts 3 × 10³), (3) NZX-treated (100 mg/kg, 200 μL/mouse), (4) M. fragrans Houtt. methanol extract-treated (500 mg/kg), and (5) combination-treated (NZX + M. fragrans extract). Number of oocysts/g of feces, serum immunoglobulin (Ig) G level, and interferon (IFN)-γ, and interleukin (IL)-4 levels were used to evaluate the therapeutic effect.

Results: C. parvum oocyst shedding in stool samples was significantly decreased in all treatment groups, with 79.7%, 81.2 %, and 85.5 % reduction in immunocompetent mice treated with NZX, M. fragrans, and their combination, respectively. In immunosuppressed mice, oocyst shedding was reduced by 77.7%, 80.5 %, and 83.7 % upon NZX, M. fragrans, and their combination treatments, respectively. The serum IgG level was lowest in mice treated with a mixture of M. fragrans and NZX, followed by those treated with NZX, and was highest in mice treated with M. fragrans alone. Regarding cytokine levels, all groups treated with M. fragrans had low levels of IFN-γ and IL4 on day 21 post-infection.

Conclusion: Collectively, the treatment of cryptosporidiosis with M. fragrans extract was successful in mice, as demonstrated by the measured parameters. M. fragrans reduced C. parvum oocyst shedding and serum IgG, IFN-γ, and IL-4 levels in immunocompetent and immunosuppressed mice.