There is a history of inadequate treatments for cryptosporidiosis and a lack of understanding of the species that cause human disease. Against this background, we review the efficacy of antiparasitic agents, particularly nitazoxanide, which has led to increased treatment options, the potential for immunotherapy, and consider the role of highly active antiretroviral therapy in reducing the incidence of this opportunistic infection.
Nitazoxanide is effective for cryptosporidiosis in immunocompetent and probably immunocompromised patients (with an alteration in the duration of treatment or the dosing regimen). HIV-infected patients on highly active antiretroviral therapy have a dramatically lower incidence of cryptosporidiosis, attributable to the effects of intestinal immune reconstitution as well as the effect on the CD4 cell count. Protease inhibitors have a direct inhibitory effect on Cryptosporidium infection, suggesting a further reason for the reduction in the incidence of cryptosporidiosis and implying a further possible therapeutic modality.
Cryptosporidiosis remains a significant public health threat. Risk avoidance guidance could be viewed in the more relative terms of risk management depending on the degree of immunosuppression. Of established efficacy in immunocompetent patients, nitazoxanide is also useful for immunocompromised patients. Better prevention and treatment options mean that, in the immunocompromised, this disease is now less common. Immune reconstitution is the key to prevention. Further database mining of the Cryptosporidium genome will assist in the discovery of new genes, biochemical pathways and protective antigens that can be targeted to develop novel therapies for cryptosporidiosis.
aScottish Parasite Diagnostic Laboratory, Stobhill Hospital, Glasgow UK and bDepartment of Microbiology, Cork University Hospital, Wilton, Cork, Ireland
Correspondence to Huw V. Smith, Scottish Parasite Diagnostic Laboratory, Stobhill Hospital, Glasgow G21 3UW, UK Tel: +44 0141 201 3028; fax: +44 0141 201 3029; e-mail: email@example.com