Close kinship within multiple-genotype malaria parasite infections

Malaria infections containing multiple parasite genotypes are ubiquitous in nature, and play a central role in models of recombination, intra-host dynamics, virulence, sex ratio, immunity and drug resistance evolution in Plasmodium. While these multiple infections (MIs) are often assumed to result from superinfection (bites from multiple infected mosquitoes), we know remarkably little about their composition or generation. We isolated 336 parasite clones from eight patients from Malawi (high transmission) and six from Thailand (low transmission) by dilution cloning. These were genotyped using 384 single-nucleotide polymorphisms, revealing 22 independent haplotypes in Malawi (2–6 per MI) and 15 in Thailand (2–5 per MI). Surprisingly, all six patients from Thailand and six of eight from Malawi contained related haplotypes, and haplotypes were more similar within- than between-infections. These results argue against a simple superinfection model. Instead, the observed kinship patterns may be explained by inoculation of multiple related haploid sporozoites from single mosquito bites, by immune suppression of parasite subpopulations within infections, and serial transmission of related parasites between people. That relatedness is maintained in endemic areas in the face of repeated bites from infected mosquitoes has profound implications for understanding malaria transmission, immunity and intra-host dynamics of co-infecting parasite genotypes

Population Structure Shapes Copy Number Variation in Malaria Parasites.

If copy number variants (CNVs) are predominantly deleterious, we would expect them to be more efficiently purged from populations with a large effective population size (Ne) than from populations with a small Ne. Malaria parasites (Plasmodium falciparum) provide an excellent organism to examine this prediction, because this protozoan shows a broad spectrum of population structures within a single species, with large, stable, outbred populations in Africa, small unstable inbred populations in South America and with intermediate population characteristics in South East Asia. We characterized 122 single-clone parasites, without prior laboratory culture, from malaria-infected patients in seven countries in Africa, South East Asia and South America using a high-density single-nucleotide polymorphism/CNV microarray. We scored 134 high-confidence CNVs across the parasite exome, including 33 deletions and 102 amplifications, which ranged in size from <500 bp to 59 kb, as well as 10,107 flanking, biallelic single-nucleotide polymorphisms. Overall, CNVs were rare, small, and skewed toward low frequency variants, consistent with the deleterious model. Relative to African and South East Asian populations, CNVs were significantly more common in South America, showed significantly less skew in allele frequencies, and were significantly larger. On this background of low frequency CNV, we also identified several high-frequency CNVs under putative positive selection using an FST outlier analysis. These included known adaptive CNVs containing rh2b and pfmdr1, and several other CNVs (e.g., DNA helicase and three conserved proteins) that require further investigation. Our data are consistent with a significant impact of genetic structure on CNV burden in an important human pathogen

GENERAL CHARACTERISTICS OF PATIENTS WITH SHOULDER PROBLEMS

Amaç: Omuz ekleminden ve özellikle de eklem çevresindeki yumuşak dokulardan kökenalan problemler üst ekstremite ağrılarının en önemli nedenini oluşturur. Çalışmamızın amacıomuz ağrısı yakınması ile başvuran hastaların klinik özelliklerinin değerlendirilmesidir.Gereç ve yöntem: Omuz ağrısı yakınması ile başvuran 709 hastanın 744 omuzuretrospektif olarak değerlendirildi.Bulgular: Hastaların yaş ortalaması 55,16  10,88 yıl idi ve 395 hastada sağ, 279 hastadasol ve 35 hastada her iki omuz etkilenmişti. Vakaların %35,4'ünde travma öyküsü mevcuttu.Klinik ve radyolojik olarak yapılan değerlendirmelerde hastaların %45'inde subakromiyalsıkışma sendromu, %39,4'ünde rotator kaf rüptürü, %1,5'inde bisipital tendinit, %6,5'indeakromioklavikuler eklem dejenerasyonu, %2,2'sinde kalsifik tendinit, %5'inde donuk omuzve %0,4'ünde glenohumeral eklem artrozu saptandı. Subakromiyal sıkışma sendromu olanhastalar ile rotator kaf rüptürü olan hastaların karşılaştırılmasında rüptürü olan hastalarınyaş ortalamalarının daha yüksek ve "American Shoulder Elbow Score" (ASES) skorlarınındaha düşük olduğu ancak "Constant" skorları arasında herhangi bir fark olmadığı görüldü.Bu iki grup etiolojideki travma açısından değerlendirildiğinde rotator kaf rüptürü olan gruptatravma öyküsünün subakromiyal sıkışma sendromlu hastalara göre anlamlı olarak dahafazla olduğu ve travma öyküsünün rotator kafta rüptür riskini 2,9 kat arttırdığı görüldü.Sonuç: Omuz ağrısı nedenleri arasında rotator kaf sorunları çok önemli bir yer tutmaktadır.Travma ve yaş rotator kafta rüptür insidansını arttırmaktadır.Objective: Problems originating from the shoulder joint and periarticular soft tissues arethe most important causes of upper limb pain. The aim of this study was to investigate theclinical charactersitic patients.Material and method: Seven hundred forty-four shoulders 709 patients wereretrospectively studied.Results: The mean age of the patients was 55.16  10.88 years. Right shoulder wasinvolved in 395 patients, left in 279, and both shoulders in 35 patients. Thirty-five percenthad a history of trauma. According to clinical and radiological assessments, 45 % of patientswere diagnosed as subacromial impingement syndrome, 39.4 % roator cuff tears, 1.5 %bicipital tendinitis, 6.5 % degeneration of the acromioclavicular joint, 2.2 % calcific tendinitis,5 % frozen shoulder, and 0.4 % osteoarthritis of the glenohumeral joint. When the patientswith subacromial impingement syndrome were compared with the patients with rotator cuff tears, the mean age of the patients with rotator cuff tears was significantly higher andAmerican Shoulder Elbow Scores (ASES) were lower than the patients with subacromialimpingement syndrome. There were no significant differences between the Constant scores.Significantly more patients with rotator cuff tears had a history of trauma than patients withsubacromial impingement syndrome, and trauma increased the risk of rotator cuff tears 2.9times.Conclusion: Rotator cuff problems is one of the most common causes of shoulder painand functional limitations. Trauma and age are risk factors for rotator cuff rupture

Is sulphadoxine-pyrimethamine (SP) still useful as the first-line antimalarial drug in Malawi or it must be quickly withdrawn from the antimalarial repertoire?

In recent years our efforts to control malaria successfully have been severely hampered by widespread and highlevel resistance to front-line antimalarial drugs. In 1993,Malawi had to replace chloroquine (CQ) with sulphadoxinepyrimethamine (SP) as the first-line antimalarial owing to unacceptably high rates of CQ failure. Thirteen years after this change in treatment policy, Malawi is faced with a scenario that calls for yet another switch to a different first-line antimalarial

An evaluation of molecular markers for Plasmodium falciparum in vitro resistance to antimalarial drugs

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

In vitro antimalarial susceptibility profile and PRCRT/PFMDR-1 genotypes of Plasmodium falciparum field isolates from Malawi

We measured in vitro antimalarial drug susceptibility of 84 Plasmodium falciparum field isolates from Blantyre, Southern Malawi, using the WHO microtest and the lactate dehydrogenase assay. We also genotyped these isolates to investigate whether variation in their absolute drug sensitivity is associated with specific sets of pfcrt and pfmdr-1 mutations harbored by parasites. Our results show that nearly a decade after the withdrawal of chloroquine (CQ) as a first-line antimalarial in Malawi, most isolates are now sensitive to CQ and none is CQ-resistant as predicted by their drug sensitivity phenotype and pfcrt genotype. We also found that these isolates are uniformly sensitive to a range of quinoline-based antimalarials and artemisinin derivatives. These findings reinforce previous reports about a reduction in the proportion of CO-resistant parasites after the withdrawal of CQ in 1993 and pave the way for reassessing the clinical usefulness of CQ, artemisinins and other quinoline-based antimalarials in Malawi

Molecular surveillance for drug-resistant Plasmodium falciparum malaria in Malawi

We assessed the presence of point mutations associated with resistance to chloroquine (CQ) and sulphadoxine-pyrimethamine (SP) in 178 Plasmodium falciparum infections from three geographically distinct sites in Malawi. We confirm that CQ-resistance mutations are now rare in Malawi, being detectable at very low frequencies (2-4%) in infections from two of the three study sites. We also show that over 90% of infections from each of the three study sites carry a set of three dihydrofolate reductase (dhfr) and two dihydropteroate synthase (dhps) mutations strongly associated with SP treatment failure. In this short communication, we present these molecular data and discuss their implications for Malawi's first-line antimalarial treatment policy. (C) 2007 Elsevier B.V. All rights reserved

High-resolution single-cell sequencing of malaria parasites.

Single-cell genomics is a powerful tool for determining the genetic architecture of complex communities of unicellular organisms. In areas of high transmission, malaria patients are often challenged by the activities of multiple Plasmodium falciparum lineages, which can potentiate pathology, spread drug resistance loci and also complicate most genetic analysis. Single-cell sequencing of P. falciparum would be key to understanding infection complexity, though efforts are hampered by the extreme nucleotide composition of its genome (∼80% AT-rich). To counter the low coverage achieved in previous studies, we found that accurate, near-complete single-cell genome capture is possible by targeting DNA-rich late-stage parasites by Fluoresence-Activated Cell Sorting and whole genome sequencing. Our method routinely generates near-complete capture of the 23Mb P. falciparum genome (mean breadth of coverage 90.7%) at high efficiency. Data from 48 single-cell genomes derived from a polyclonal infection sampled in Chikhwawa, Malawi allowed for unambiguous determination of haplotype diversity and recent meiotic events, information that will aid public health efforts. [Abstract copyright: © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.