The activity of ozone against Plasmodium falciparum

Ozone has strong antimicrobial activity and reactive oxygen intermediates play an important role in the immune defense against microbial infections. We investigated the effect of ozone on the malaria parasite Plasmodium falciparum in vitro. A laboratory adapted P. falciparum strain was ozonated with 80 mug/ml ozone and the growth determined for 4 days. A strong growth inhibitory effect up to a factor of 2.6 to 6.7 on Day 4 was seen, depending on the basal parasitemia, A growth inhibitory effect was also observed when parasites were added after ozonation of the culture medium. Ozonated leucocytes co-incubated with P. falciparum did not inhibit parasite growth. The results show that ozone is active against intracellular infectious agents that do not come in direct contact with ozone.