| Summary: | <p>Abstract</p> <p>Background</p> <p>Malaria is a potentially severe disease widely distributed in tropical and subtropical regions worldwide. Clinically, the progression of the disease can be life-threatening if it is not promptly diagnosed and properly treated. Through treatment, the radical cure of <it>Plasmodium vivax</it> infection can be achieved, thus preventing potential relapses and the emergence of new cases outside the Amazon region in Brazil. Surveillance for therapeutic failure in non-endemic areas is advantageous, as it is unlikely that recurrence of the disease can be attributed to a new malaria infection in these regions.</p> <p>Methods</p> <p>An observational study of 53 cases of <it>P. vivax</it> and mixed (<it>P. vivax</it> and <it>Plasmodium falciparum</it>) malaria was conducted at a travel medicine centre between 2005 and 2011 in Rio de Janeiro and a descriptive analysis of the potential factors related to recurrence of <it>P. vivax</it> malaria was performed. Groups with different therapeutic responses were compared using survival analysis based on the length of time to recurrence and a set of independent variables thought to be associated with recurrence.</p> <p>Results</p> <p>Twenty-one relapses (39.6%) of <it>P. vivax</it> malaria were observed. The overall median time to relapse, obtained by the Kaplan-Meier method, was 108 days, and the survival analysis demonstrated an association between non-weight-adjusted primaquine dosing and the occurrence of relapse (p < 0.03). Primaquine total dose at 3.6 mg/kg gave improved results in preventing relapses.</p> <p>Conclusions</p> <p>A known challenge to individual cure and environmental control of malaria is the possibility of an inappropriate, non-weight-based primaquine dosing, which should be considered a potential cause of <it>P. vivax</it> malaria relapse. Indeed, the total dose of primaquine associated with non-occurrence of relapses was higher than recommended by Brazilian guidelines.</p>
|
|---|