Oral melatonin improves the detection of parasitemia in malaria

Malaria is a growing global threat and a major cause of mortality in the tropics. The gold standard diagnosis is peripheral blood smear examination. It has been demonstrated that melatonin acts as messenger molecule in malaria pathophysiology. This concept was used to evolve a clinical study wherein use of exogenous melatonin could improve the chance of detection of the parasite.

In a prospective study, 80 consecutive patients seen in the Department of Medicine at Kasturba Hospital, Manipal, suspected to have malarial fever were enrolled with proper informed consent, and randomly assigned to the groups given oral melatonin 3mg (melatonin group, n = 40) or placebo (control group, n = 40). Blood samples were collected for peripheral smear examination at baseline and then at two, three, four and five hours after drug administration. The primary end point was the parasite detection index.

Baseline characteristics of patients were comparable. In the melatonin group, there was a significant increase of 0.0943 ± 0.22 in the mean parasite index from 0.217 ± 0.42 pre-melatonin to 0.3114 ± 0.5 post-melatonin (p = 0.001), compared to a difference of 0.0025 ± 0.22 in mean parasite index before and after placebo in the control group (p = 0.95). The maximum rise in parasite detection was seen at five hours after melatonin.

In a single centre study, for the first time, it has been shown that a significantly higher proportion of patients was diagnosed with malaria on peripheral smear after oral melatonin administration, maximal at five hours after administration of melatonin.