Relapse pattern of Plasmodium vivax in Mumbai: a study of 283 cases of vivax malaria.

Objectives: To analyze the relapse pattern of Plasmodium vivax in the city of Mumbai.
Methods: 283 cases of smear positive vivax malaria were treated with full dose (25 mg/kg) chloroquine and were asked to follow up for at least one year. None of the patients received primaquine.
Results: Of the 150 cases who followed up for at least one year, 19 relapsed, 17/19 relapsed within the first 6 months; indicating that the relapse pattern in the city is predominantly of the tropical or Chesson strain type.
Conclusions: Vivax malaria patients should be monitored for at least six months. Those who do relapse should receive treatment with full dose chloroquine and 14 days of primaquine treatment.