Resistance of infection by Plasmodium vivax to chloroquine in Bolivia.

Arletta Añez,Manuel Moscoso,Sonia Gutierrez,Carlos Ascaso,Viviana Melgar,Cecilia Garnica,Ángel Laguna,Mauren Cuba

doi:10.1186/s12936-015-0774-4

Arletta Añez, Manuel Moscoso + Show 6 more

Open Access

https://doi.org/10.1186/s12936-015-0774-4

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Journal: Malaria journal	Publication Date: Jul 1, 2015
Citations: 36	License type: cc-by

Affiliation: University of Barcelona, Departamento de Salud

Abstract

BackgroundChloroquine (CQ) over three days plus primaquine (PQ) for seven days is the treatment of choice of infections by Plasmodium vivax in Bolivia, where 95% of the cases of malaria are attributed to this species. The aim of this study was to evaluate the therapeutic efficacy of CQ in this setting.MethodsPatients in the Amazon region of northern Bolivia, were included in the study from May to November 2011 and the therapeutic efficacy of CQ was evaluated over a 28-day follow-up period. Patients with P. vivax mono-infection received 25 mg/Kg body weight of CQ over three days. The concentrations of CQ + desethylchloroquine (DCQ) in blood were determined at days 7 and 28 of follow up; at follow-up and on the day of treatment failure was administered PQ.ResultsOne hundred patients fulfilled the inclusion criteria, two were lost to follow up and another two were later excluded for protocol violation. Of the 96 patients who completed the follow up 10 showed TF; one presented continued parasitaemia until day 7 of follow up, three on day 21 and six on day 28 of follow up. The geometric mean of CQ + DCQ on day 7 was 321.7 ng/ml (range 197–535 ng/ml). In six patients with TF the CQ + DCQ concentrations in blood on the day of TF were >100 ng/ml. The rate of resistance was 6.5%.ConclusionThe present study demonstrates the presence of resistance to CQ in the treatment of malaria by P. vivax in the Amazon region of Bolivia. New clinical trials are needed to establish alternative treatments against these parasites in this region of South America.

Highlights

Chloroquine (CQ) over three days plus primaquine (PQ) for seven days is the treatment of choice of infections by Plasmodium vivax in Bolivia, where 95% of the cases of malaria are attributed to this species
Study site The study was developed in the department of Beni, in the municipality of Riberalta, in the north of the Amazonia of Bolivia where 18% of the diagnoses of malaria and 21% of the cases of malaria by P. vivax are reported in Bolivia [11]
From May to November 2011, 656 cases of malaria by P. vivax were reported out of a total of 5,290 cases evaluated in the urban area of Riberalta

Summary

Introduction

Chloroquine (CQ) over three days plus primaquine (PQ) for seven days is the treatment of choice of infections by Plasmodium vivax in Bolivia, where 95% of the cases of malaria are attributed to this species. In South America, 60% [1] of the cases of malaria are due to Plasmodium vivax while, in Bolivia, 93% correspond to this parasite and the remaining 7% to Plasmodium falciparum. In Bolivia, the first-line therapeutic schedule for infections by P. vivax includes 25 mg/Kg body weight of chloroquine (CQ) for three days plus 3.5 mg of primaquine (PQ) for 7 days. In Latin America, the first cases of resistance to CQ in infections by P. vivax were reported in Guyana in 1996, with three patients maintaining parasitaemia in the presence of adequate serum levels of CQ [6]. Confirmed resistance according to the serum levels of CQ and its main metabolite desethylchloroquine (DCQ) has only been reported in Peru with a rate of 1.2% [7] and in Brazil with 5.2% [8]

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