To date, only one randomized controlled trial has been conducted evaluating the effect of treating helminths on markers of HIV-1 progression. In this small unblinded study conducted in Zimbabwe, individuals with schistosomiasis (both with and without HIV-1 infection) were randomized to receive praziquantel at inclusion or after a delay of 3 months. The study found that the HIV-1 infected individuals receiving early treatment of schistosomiasis had no change in plasma HIV-1 RNA levels compared to an increase in HIV-1 RNA levels in the delayed treatment group. However, several other observational studies evaluating the effect of treating helminth co-infection have found that successful eradication of helminths had no effect on plasma HIV-1 RNA levels or even led to transient increases in viral load. We are currently conducting a systematic review for the Cochrane Library evaluating all of the available data examining the effect of treating helminths of HIV-1 RNA levels and CD4 counts.