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Abstract Background The incidence of malaria in the Americas has decreased markedly in recent years. Honduras and the other countries of Mesoamerica and the island of Hispaniola have set the goal of eliminating native malaria by the year 2020. To achieve this goal, Honduras has recently approved national regulations to expand the possibilities of a shortened double dose primaquine (PQ) treatment for vivax malaria. Considering this new shortened anti-malarial treatment, the high frequency of G6PDd genotypes in Honduras, and the lack of routinely assessment of the G6PD deficiency status, this study aimed at investigating the potential association between the intake of PQ and haemolysis in malaria-infected G6PDd subjects. Methods This was a prospective cohort and open-label study. Participants with malaria were recruited. Plasmodium vivax infection was treated with 0.25 mg/kg of PQ daily for 14 days. Safety and signs of haemolysis were evaluated by clinical criteria and laboratory values before and during the 3rd and 7th day of PQ treatment. G6PD status was assessed by a rapid test (CareStart™) and two molecular approaches. Results Overall 55 participants were enrolled. The frequency of G6PD deficient genotypes was 7/55 (12.7%), where 5/7 (71.4%) were hemizygous A− males and 2/7 (28.6%) heterozygous A− females. Haemoglobin concentrations were compared between G6PD wild type (B) and G6PDd A− subjects, showing a significant difference between the means of both groups in the 3rd and 7th days. Furthermore, a statistically significant difference was evident in the change in haemoglobin concentration between the 3rd day and the 1st day for both genotypes, but there was no statistical difference for the change in haemoglobin concentration between the 7th day and the 1st day. Besides these changes in the haemoglobin concentrations, none of the patients showed signs or symptoms associated with severe haemolysis, and none needed to be admitted to a hospital for further medical attention. Conclusions The findings support that the intake of PQ during 14 days of treatment against vivax malaria is safe in patients with a class III variant of G6PDd. In view of the new national regulations in the shortened treatment of vivax malaria for 7 days, it is advisable to be alert of potential cases of severe haemolysis that could occur among G6PD deficient hemizygous males with a class II mutation such as the Santamaria variant, previously reported in the country.

Abstract Background Malaria remains a public health problem in some countries of Central America. Rapid diagnostic tests (RDTs) are one of the most useful tools to assist in the diagnosis of malaria in remote areas. Since its introduction, a wide variety of RDTs have been developed for the detection of different parasite antigens. PfHRP2 is the most targeted antigen for the detection of Plasmodium falciparum infections. Genetic mutations and gene deletions are important factors influencing or affecting the performance of rapid diagnostic tests. Methods In order to demonstrate the presence or absence of the pfhrp2 and pfhrp3 genes and their flanking regions, a total of 128 blood samples from patients with P. falciparum infection from three Central American countries were analysed through nested or semi-nested PCR approaches. Results In total, 25.8 and 91.4% of the isolates lacked the region located between exon 1 and exon 2 of pfhrp2 and pfhrp3 genes, respectively. Parasites from the three countries showed deletions of one or both genes. The highest proportion of pfhrp2 deletions was found in Nicaragua while the isolates from Guatemala revealed the lowest number of pfhrp2 deletions. Parasites collected from Honduras showed the highest proportion of phfrp3 absence (96.2%). Twenty-one percent of isolates were double negative mutants for the exon 1–2 segment of both genes, and 6.3% of isolates lacked the full-length coding region of both genes. Conclusions This study provides molecular evidence of the existence of P. falciparum isolates lacking the pfhrp2 and pfhrp3 genes, and their flanking regions, in Honduras, Guatemala and Nicaragua. This finding could hinder progress in the control and elimination of malaria in Central America. Continuous evaluation of RDTs and molecular surveillance would be recommended.

Countries could use the monitoring of drug resistance in malaria parasites as an effective early warning system to develop the timely response mechanisms that are required to avert the further spread of malaria. Drug resistance surveillance is essential in areas where no drug resistance has been reported, especially if neighbouring countries have previously reported resistance. Here, we present the results of a four-year surveillance program based on the sequencing of the pfcrt gene of Plasmodium falciparum populations from endemic areas of Honduras. All isolates were susceptible to chloroquine, as revealed by the pfcrt “CVMNK” genotype in codons 72-76.