We describe the MalariaGEN Pf7 data resource, the seventh release of Plasmodium falciparum genome variation data from the MalariaGEN network. It comprises over 20,000 samples from 82 partner studies in 33 countries, including several malaria endemic regions that were previously underrepresented. For the first time we include dried blood spot samples that were sequenced after selective whole genome amplification, necessitating new methods to genotype copy number variations. We identify a large number of newly emerging crt mutations in parts of Southeast Asia, and show examples of heterogeneities in patterns of drug resistance within Africa and within the Indian subcontinent. We describe the profile of variations in the C-terminal of the csp gene and relate this to the sequence used in the RTS,S and R21 malaria vaccines. Pf7 provides high-quality data on genotype calls for 6 million SNPs and short indels, analysis of large deletions that cause failure of rapid diagnostic tests, and systematic characterisation of six major drug resistance loci, all of which can be freely downloaded from the MalariaGEN website.
gh or yaniweh@ug. edu.gh.Plasmodium malariae and Plasmodium ovale are increasingly gaining public health attention as the global transmission of falciparum malaria is decreasing. However, the absence of reliable Plasmodium species-specific detection tools has hampered accurate diagnosis of these minor Plasmodium species. In this study, SYBR Greenebased real-time PCR assays were developed for the detection of P. malariae and P. ovale using cooperative primers that significantly limit the formation and propagation of primersdimers. Both the P. malariae and P. ovale cooperative primer-based assays had at least 10-fold lower detection limit compared with the corresponding conventional primers. More important, the cooperative primer-based assays were evaluated in a cross-sectional study using 560 samples obtained from two health facilities in Ghana. The prevalence rates of P. malariae and P. ovale among the combined study population were 18.6% (104/560) and 5.5% (31/560), respectively. Among the Plasmodium-positive cases, P. malariae and P. ovale mono-infections were 3.6% (18/499) and 1.0% (5/499), respectively, with the remaining being co-infections with Plasmodium falciparum. The study demonstrates the public health importance of including detection tools with lower detection limits in routine diagnosis and surveillance of nonfalciparum species. This will be necessary for comprehensively assessing the effectiveness of malaria interventions and control measures aimed toward global malaria elimination.
Sulfadoxine-pyrimethamine (SP) is used as malaria chemoprophylaxis for pregnant women and children in Ghana. Plasmodium falciparum resistance to SP is linked to mutations in the dihydropteroate synthase gene (pfdhps), dihydrofolate reductase gene (pfdhfr) and amplification of GTP cyclohydrolase 1 (pfgch1) gene. The pfgch1 duplication is associated with pfdhfr L164, a crucial mutant for high level pyrimethamine resistance which is rare in Ghana. The presence of amplified pfgch1 in Ghanaian isolates could be an indicator of the evolution of the L164 mutant. This study therefore determined the pfgch1 copy number variations and SP resistance mutations in clinical isolates from Ghana. One hundred and ninety-two (192) blood samples collected from children aged ≤14 years with uncomplicated malaria in 2013–14 and 2015–16 were used. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the pfgch1 copy number and nested PCR-Sanger sequencing used to detect mutations in pfdhps and pfdhfr genes. Twelve parasites (6.3%) harbored double copies of the pfgch1 gene out of the 192 samples. Of the 12, 75% had the pfdhfr I51-R59-N108, 92% had the pfdhps G437 mutant, 8% had the pfdhps E540 and 67% had the SP resistance haplotype IRNG. No L164 was detected in samples with amplified pfgch1. The rare T108 mutant associated with cycloguanil resistance showed predominance (60%) over N108 in the 2015–16 isolates. The observation of parasites with increased copy number of pfgch1 gene is indicative of the future evolution of the rare quadruple pfdhfr mutant, I51-R59-N108-L164, in Ghanaian parasites. Mutant pfdhps isolates also had increased gch1 copy number suggestive that it may also facilitate sulphadoxine resistance. The selection of parasites with pfgch1 gene amplification will enhance the sustenance and persistence of parasites with SP resistance in the country. Policy makers need to begin the search for a replacement chemoprophylaxis drug for malaria vulnerable groups in Ghana.
gametocytes develop over 9-12 days while sequestered in deep tissues. On emergence into the bloodstream, they circulate for varied amounts of time during which certain host factors might influence their further development. We aimed to evaluate the potential association of patient clinical parameters with gametocyte development and carriage via in vivo methods. Seventy-two patients were enrolled from three hospitals in the Volta region of Ghana in 2016. Clinical parameters were documented for all patients, and gametocyte prevalence by microscopy was estimated at 12.5%. By measuring RNA transcripts representing two distinct gametocyte developmental stages using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR), we obtained a more precise estimate of gametocyte carriage while also inferring gametocyte maturation. Fifty-three percent of the study participants harbored parasites expressing transcripts of the immature gametocyte-specific gene (), whereas 36% harbored RNA-positive parasites, which is enriched in mid and mature gametocytes, suggesting the presence of more immature stages. Linear logistic regression showed that patients older than 5 years but less than 16 years were more likely to carry gametocytes expressing both and compared with younger participants, and gametocytemia was more likely in mildly anemic individuals compared with those with severe/moderate anemia. These data provide further evidence that a greater number of malaria patients harbor gametocytes than typically estimated by microscopy and suggest a possible association between age, fever, anemia, and gametocytemia.
Background Chronic Sedentary lifestyles have been linked to increased odds of stress, elevated anxiety and diminished wellbeing, inducing cytokine production and predispose to hypertension and other cardiovascular diseases. In endemic areas, Plasmodium falciparum and hepatitis B virus (HBV) infections can trigger pro-inflammatory cytokine responses. However, the impact of these infections on cytokine response profiles in individuals engaged in chronic sedentary activities is unknown. This study was aimed at addressing these concerns using a predominantly sedentary population of traders in the Tamale metropolis of Ghana. Method Four hundred respondents were categorized, based on their number of working years (< or ≥ 5 years) and number of working hours per day (< or ≥ 10 h), into sedentary (≥5 years + ≥ 10 h) and non-sedentary (≥ 5 years + < 10 h, < 5 years + ≥ 10 h and < 5 years + < 10 h) groups. The participants were tested for P. falciparum and HBV infections using polymerase chain reaction. Blood pressure and cytokines responses were measured. Associations and comparison analysis between variables were determined, and test statistics with p < 0.05 were considered statistically significant. Results Infection status included: un-infected (93.5%), P. falciparum mono-infected (1.0%), HBV mono-infected (3.0%) or P. falciparum /HBV co-infected (2.5%). Majority of the participants, 57.0% (n = 228) were involved in chronic sedentary life style. That notwithstanding, sedentary lifestyle was independent of the infection groups (χ2 = 7.08, p = 0.629). Hypertension was diagnosed in 53.8% of respondents and was independent of infection status (X2 = 6.33, p = 0.097). Pro-inflammatory (TNF-α, IL-1β, IL-6, IL-8 and IL-12) and anti-inflammatory (IL-10, IL-7 and IL-13) cytokine responses were similar among individuals with different sedentary working time and between hypertensive and non-hypertensive individuals (p > 0.05 for all comparisons). Among individuals with different infection status, pro-inflammatory (TNF-α; p = 0.290, IL-1β; p = 0.442, IL-6; p = 0.686, IFN-γ; p = 0.801, IL-8; p = 0.546, IL-12; p = 0.154) and anti-inflammatory (IL-10; p = 0.201, IL-7; p = 0.190, IL-13; p = 0.763) cytokine responses were similar. Conclusion Our data suggest that asymptomatic infections of P. falciparum and HBV together with a high prevalence of hypertension did not have any significant impact on cytokine response profiles among predominantly sedentary traders in the Tamale metropolis of Ghana.
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