Severe strongyloidiasis during interferon plus ribavirin therapy for chronic HCV infection

Ribavirin is a nucleoside analogue, recently introduced in hepatitis C virus (HCV) therapy, that has postulated immunomodulatory and immunosuppressive action. Strongyloidiasis is an helmintic infection caused by Strongyloides stercoralis, endemic in tropical countries. Severe strongyloidiasis has been demonstrated after immunosuppression by corticosteroids evolving some fatal cases. Here, we describe two cases of severe strongyloidiasis coincident with ribavirin plus interferon therapy for treating HCV infection. The review of our monotherapy protocol with interferon did not disclose any case of symptomatic strongyloidiasis pointing to a possible role of ribavirin in modifying immune response to S. stercoralis. We propose a careful screening for S. stercoralis before initiating ribavirin therapy or even empiric antihelmintic treatment.