Detection of chloroquine and artemisinin resistance molecular markers in Plasmodium falciparum: A hospital based study

High Plasmodium malariae Prevalence in an Endemic Area of the Colombian Amazon Region

Malaria is a worldwide public health problem; parasites from the genus Plasmodium are the aetiological agent for this disease. The parasites are mostly diagnosed by conventional microscopy-based techniques; however, their limitations have led to under-registering the reported prevalence of Plasmodium species. This study has thus been aimed at evaluating the infection and coinfection prevalence of 3 species of Plasmodium spp., in an area of the Colombian Amazon region. Blood samples were taken from 671 symptomatic patients by skin puncture; a nested PCR amplifying the 18S ssRNA region was used on all samples to determine the presence of P. vivax, P. malariae and P. falciparum. Statistical analysis determined infection and coinfection frequency; the association between infection and different factors was established. The results showed that P. vivax was the species having the greatest frequency in the study population (61.4%), followed by P. malariae (43.8%) and P. falciparum (11.8%). The study revealed that 35.8% of the population had coinfection, the P. vivax/P. malariae combination occurring most frequently (28.3%); factors such as age, geographical origin and clinical manifestations were found to be associated with triple-infection. The prevalence reported in this study differed from previous studies in Colombia; the results suggest that diagnosis using conventional techniques could be giving rise to underestimating some Plasmodium spp. species having high circulation rates in Colombia (particularly in the Colombian Amazon region). The present study’s results revealed a high prevalence of P. malariae and mixed infections in the population being studied. The results provide relevant information which should facilitate updating the epidemiological panorama and species’ distribution so as to include control, prevention and follow-up measures.

Comparative assessment on the prevalence of mutations in the Plasmodium falciparum drug-resistant genes in two different ecotypes of Odisha state, India

Considering malaria as a local and focal disease, epidemiological understanding of different ecotypes of malaria can help in devising novel control measures. One of the major hurdles in malaria control lies on the evolution and dispersal of the drug-resistant malaria parasite, Plasmodium falciparum. We herewith present data on genetic variation at the Single Nucleotide Polymorphism (SNP) level in four different genes of P. falciparum (Pfcrt, Pfmdr1, Pfdhfr, and Pfdhps) that confer resistance to different antimalarials in two different eco-epidemiological settings, i.e. Hilly-Forest (HF) and Riverine-Plain (RP), in a high malaria endemic district of Odisha state, India. Greater frequency of antimalarial resistance conferring SNPs and haplotypes was observed in all four genes in P. falciparum, and Pfdhps was the most variable gene among the four. No significant genetic differentiation could be observed in isolates from HF and RP ecotypes. Twelve novel, hitherto unreported nucleotide mutations could be observed in the Pfmdr1 and Pfdhps genes. While the Pfdhps gene presented highest haplotype diversity, the Pfcrt gene displayed the highest nucleotide diversity. When the data on all the four genes were complied, the isolates from HF ecotype were found to harbour higher average nucleotide diversity than those coming from RP ecotype. High and positive Tajima's D values were obtained for the Pfcrt and Pfdhfr genes in isolates from both the HF and RP ecotypes, with statistically significant deviation from neutrality in the RP ecotype. Different patterns of Linkage Disequilibrium (LD) among SNPs located in different drug-resistant genes were found in the isolates collected from HF and RP ecotypes. Whereas in the HF ecotype, SNPs in the Pfmdr1 and Pfdhfr were significantly associated, in the RP ecotype, SNPs located in Pfcrt were associated with Pfmdr1, Pfdhfr and Pfdhps. These findings provide a baseline understanding on how different micro eco-epidemiological settings influence evolution and spread of different drug resistance alleles. Our findings further suggest that drug resistance to chloroquine and sulfadoxine-pyrimethamine is approaching fixation level, which requires urgent attention of malaria control programme in India.