Are and Gene Mutations Associated with Chloroquine-Resistant Parasites?

(1) Background: Malaria remains a significant global public health issue. Since parasites quickly became resistant to most of the available antimalarial drugs, treatment effectiveness must be constantly monitored. In Brazil, up to 10% of cases of vivax malaria resistant to chloroquine (CQ) have been registered.

Chloroquine- Resistant Haplotypes in Brazilian Endemic Areas Four Decades after CQ Withdrawn.

(1) Background: Malaria is a public health problem worldwide. Despite global efforts to control it, antimalarial drug resistance remains a great challenge. In 2009, our team identified, for the first time in Brazil, chloroquine (CQ)-susceptible parasites in isolates from the Brazilian Amazon.

Mutations in Huambo, Angola.

Artemisinin (ART) is recommended as the first-line drug for infections combined with a long-acting partner drug. The emergence of resistance to ART (ARTR) is a concern for malaria. The most feared threat remains the spread of ARTR from Southeast Asia to Africa or the independent emergence of ARTR in Africa, where malaria accounts for 93% of all malaria cases and 94% of deaths.

Correction: Balancing selection and high genetic diversity of Plasmodium vivax circumsporozoite central region in parasites from Brazilian Amazon and Rio de Janeiro Atlantic Forest.

[This corrects the article DOI: 10.1371/journal.pone.

Balancing selection and high genetic diversity of Plasmodium vivax circumsporozoite central region in parasites from Brazilian Amazon and Rio de Janeiro Atlantic Forest.

Circumsporozoite protein (CSP) is the primary pre-erythrocytic vaccine target in Plasmodium species. Knowledge about their genetic diversity can help predict vaccine efficacy and the spread of novel parasite variants. Thus, we investigated pvcsp gene polymorphisms in 219 isolates (136 from Brazilian Amazon [BA], 71 from Rio de Janeiro Atlantic Forest [AF], and 12 from non-Brazilian countries [NB]).

Extensive genetic diversity of Plasmodium vivax dbp-II in Rio de Janeiro Atlantic Forest and Brazilian Amazon Basin: evidence of positive selection.

Background: Plasmodium vivax is the most widespread human malaria parasite outside Africa and is the predominant parasite in the Americas. Increasing reports of P. vivax disease severity, together with the emergence of drug-resistant strains, underscore the urgency of the development of vaccines against P.

Analytical validation of real-time quantitative PCR assays for optimum diagnosis of vivax malaria.

Background: The prompt diagnosis of plasmodial species for effective treatment prevents worsening of individual health and avoids transmission maintenance or even malaria reintroduction in areas where Plasmodium does not exist. Polymerase chain reaction (PCR) allows for the detection of parasites below the threshold of microscopic examination.

Objective: Our aim was to develop a real-time PCR test to reduce diagnostic errors and increase efficacy.

Low-grade sulfadoxine-pyrimethamine resistance in Plasmodium falciparum parasites from Lubango, Angola.

Background: Malaria is a major parasitic disease, affecting millions of people in endemic areas. Plasmodium falciparum parasites are responsible for the most severe cases and its resistance to anti-malarial drugs is notorious. This is a possible obstacle to the effectiveness of intermittent preventive treatment (IPT) based on sulfadoxine-pyrimethamine (SP) cures administrated to pregnant women (IPTp) during their pregnancy.

Plasmodium vivax mdr1 genotypes in isolates from successfully cured patients living in endemic and non-endemic Brazilian areas.

Background: Plasmodium vivax is the most widely distributed species causing the highest number of malaria cases in the world. In Brazil, P. vivax is responsible for approximately 84 % of reported cases.

Molecular markers of antifolate resistance in Plasmodium falciparum isolates from Luanda, Angola.

Background: Plasmodium falciparum malaria remains a leading health problem in Africa and its control is seriously challenged by drug resistance. Although resistance to the sulphadoxine-pyrimethamine (SP) is widespread, this combination remains an important component of malaria control programmes as intermittent preventive therapy (IPT) for pregnant women and children. In Angola, resistance patterns have been poorly characterized, and IPT has been employed for pregnant women since 2006.

Brazilian Plasmodium falciparum isolates: investigation of candidate polymorphisms for artemisinin resistance before introduction of artemisinin-based combination therapy.

Background: This study was performed to better understand the genetic diversity of known polymorphisms in pfatpase6 and pfmdr1 genes before the introduction of ACT in Brazil, in order to get a genotypic snapshot of Plasmodium falciparum parasites that may be used as baseline reference for future studies.

Methods: Parasites from P. falciparum samples collected in 2002, 2004 and 2006-2007 were genotyped using PCR and DNA sequencing at codons 86, 130, 184, 1034, 1042, 1109 and 1246 for pfmdr1 gene, and 243, 263, 402, 431, 623, 630, 639, 683, 716, 776, 769 and 771 for pfatpase6 gene.

Plasmodium falciparum isolates from Angola show the StctVMNT haplotype in the pfcrt gene.

Background: Effective treatment remains a mainstay of malaria control, but it is unfortunately strongly compromised by drug resistance, particularly in Plasmodium falciparum, the most important human malaria parasite. Although P. falciparum chemoresistance is well recognized all over the world, limited data are available on the distribution and prevalence of pfcrt and pfmdr1 haplotypes that mediate resistance to commonly used drugs and that show distinct geographic differences.

Chloroquine and sulphadoxine-pyrimethamine sensitivity of Plasmodium falciparum parasites in a Brazilian endemic area.

Background: The goal of the present study was the characterization of Plasmodium falciparum genes associated to malaria drug resistance (pfcrt, pfdhfr and pfdhps), in samples from two Brazilian localities.

Methods: Parasites from 65 P. falciparum samples were genotyped using nested-PCR and direct DNA sequencing.