Evidence of Self-Medication with Chloroquine before Consultation for Malaria in the Southern Pacific Coast Region of Colombia.

Self-medication with antimalarial drugs is a major factor in the development of drug resistance, exerting subtherapeutic drug pressure on circulating parasite populations. Data on self-medication with antimalarials from the Southern Pacific coast region of Colombia, where 4-aminoquinolines resistance and political instability prevail, are vital to elimination strategies. We present results of an exploratory study of 254 individuals having malaria symptoms who sought malaria diagnosis in two hospitals in Tumaco, Department of Nariño, Colombia.

Single nucleotide polymorphisms in Plasmodium falciparum V type H(+) pyrophosphatase gene (pfvp2) and their associations with pfcrt and pfmdr1 polymorphisms.

Background: Chloroquine resistance in Plasmodium falciparum malaria has been associated with pfcrt 76T (chloroquine resistance transporter gene) and pfmdr1 86Y (multidrug resistance gene 1) alleles. Pfcrt 76T enables transport of protonated chloroquine out of the parasites digestive vacuole resulting in a loss of hydrogen ions (H(+)). V type H(+) pyrophosphatase (PfVP2) is thought to pump H(+) into the digestive vacuole.

High-throughput analysis of antimalarial susceptibility data by the WorldWide Antimalarial Resistance Network (WWARN) in vitro analysis and reporting tool.

Assessment of in vitro susceptibility is a fundamental component of antimalarial surveillance studies, but wide variations in the measurement of parasite growth and the calculation of inhibitory constants make comparisons of data from different laboratories difficult. Here we describe a Web-based, high-throughput in vitro analysis and reporting tool (IVART) generating inhibitory constants for large data sets. Fourteen primary data sets examining laboratory-determined susceptibility to artemisinin derivatives and artemisinin combination therapy partner drugs were collated from 11 laboratories.

Long term persistence of clonal malaria parasite Plasmodium falciparum lineages in the Colombian Pacific region.

Background: Resistance to chloroquine and antifolate drugs has evolved independently in South America, suggesting that genotype - phenotype studies aimed at understanding the genetic basis of resistance to these and other drugs should be conducted in this continent. This research was conducted to better understand the population structure of Colombian Plasmodium falciparum in preparation for such studies.

Results: A set of 384 SNPs were genotyped in blood spot DNA samples from 447 P.

Sentinel network for monitoring in vitro susceptibility of Plasmodium falciparum to antimalarial drugs in Colombia: a proof of concept.

Drug resistance is one of the principal obstacles blocking worldwide malaria control. In Colombia, malaria remains a major public health concern and drug-resistant parasites have been reported. In vitro drug susceptibility assays are a useful tool for monitoring the emergence and spread of drug-resistant Plasmodium falciparum.

Large variation in detection of histidine-rich protein 2 in Plasmodium falciparum isolates from Colombia.

Most rapid diagnostic tests (RDTs) available use histidine-rich protein 2 (HRP2) as a target. However, it has been reported that sequence variations of this protein affects its sensitivity. Currently, there is insufficient evidence for HRP2 variability in Plasmodium falciparum isolates from Colombia and its relationship with RDT performance.

Origin and dissemination across the Colombian Andes mountain range of sulfadoxine-pyrimethamine resistance in Plasmodium falciparum.

The therapeutic efficacy of sulfadoxine-pyrimethamine (SP) in treating uncomplicated Plasmodium falciparum malaria is unevenly distributed in Colombia. The Andes mountain range separates regions in the west where malaria is endemic from those in the east and constitutes a barrier against gene flow and the dispersal of parasite populations. The distribution of dhfr and dhps genotypes of 146 P.

Global sequence variation in the histidine-rich proteins 2 and 3 of Plasmodium falciparum: implications for the performance of malaria rapid diagnostic tests.

Background: Accurate diagnosis is essential for prompt and appropriate treatment of malaria. While rapid diagnostic tests (RDTs) offer great potential to improve malaria diagnosis, the sensitivity of RDTs has been reported to be highly variable. One possible factor contributing to variable test performance is the diversity of parasite antigens.

Short report: polymorphisms in the pfcrt and pfmdr1 genes of Plasmodium falciparum and in vitro susceptibility to amodiaquine and desethylamodiaquine.

The potential role of polymorphisms in the pfcrt and pfmdr1 genes and in vitro susceptibility to amodiaquine and desethylamodiaquine were explored in 15 chloroquine-resistant Colombian Plasmodium falciparum isolates. Single nucleotide polymorphisms in the pfcrt gene, including a newly reported mutation (S334N), were seen in isolates with decreased susceptibility to amodiaquine and desethylamodiaquine. The lowest susceptibility found to amodiaquine was observed in an isolate carrying a pfcrt and pfmdr1 Dd2-like haplotype, whereas a pfcrt haplotype related to the 7G8 Brazilian strain was found in a Colombian isolate with the lowest susceptibility to desethylamodiaquine.

In vitro susceptibility of P. falciparum populations from Colombia and Tanzania to a new synthetic peroxide (OZ277).

Sensitivity of Plasmodium falciparum populations from Colombia (N = 38) and Tanzania (N = 45) to the newly developed, fully synthetic peroxide OZ277 was investigated using a standard isotopic microtest. OZ277 showed excellent activity against chloroquine-resistant isolates in Colombia with median IC(50) [range] values of 2.5 ng/mL [0.

Susceptibility of Colombian Plasmodium falciparum isolates to 4-aminoquinolines and the definition of amodiaquine resistance in vitro.

There are wide variations in the threshold used to define in vitro resistance of Plasmodium falciparum to amodiaquine (AQ), probably due to differences in methodology and interpretation. In vitro susceptibility data of Colombian P. falciparum strains to AQ and N-desethylamodiaquine is used to illustrate the need to standardized methodologies and compare inhibitory concentrations, instead of resistant/susceptible phenotypes, when studying the mechanisms of resistance to AQ and monitoring drug susceptibility trends in the field.

Polymorphisms in cg2 and pfcrt genes and resistance to chloroquine and other antimalarials in vitro in Plasmodium falciparum isolates from Colombia.

Polymorphisms in Plasmodium falciparum cg2 and pfcrt genes and their association with chloroquine resistance in vitro in Colombian parasites were evaluated in this study. Association of chloroquine resistance with resistance to other antimalarial drugs in vitro was also examined. Polymerase chain reactions (PCR) for kappa and omega cg2 regions and nested PCR and digestion with ApoI enzyme for K-76T pfcrt point mutation defined corresponding polymorphisms in 83 samples collected between 1995 and 1999.