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EY Lukianova-Hleb et al. Hemozoin-generated vapor nanobubbles for transdermal reagent- and needle-free detection of malaria. Proc Natl Acad Sci U S A
Successful diagnosis, screening, and elimination of malaria critically depend on rapid and sensitive detection of this dangerous infection, preferably transdermally and without sophisticated reagents or blood drawing. . . .
KJ Vogel et al. Phylogenetic investigation of Peptide hormone and growth factor receptors in five dipteran genomes. Front Endocrinol (Lausanne)
Peptide hormones and growth factors bind to membrane receptors and regulate a myriad of processes in insects and other metazoans. . . .
J Rydzak et al. Human erythrocyte glycophorin C as the receptor for EBA-140 Plasmodium falciparum merozoite ligand. Postepy Hig Med Dosw (Online)
Erythrocyte invasion by the blood-stage Plasmodium falciparum parasites is a multistep process involving specific interactions between parasites and red blood cells. . . .
R Sundararajan et al. Barriers to Malaria Control among Marginalized Tribal Communities: A Qualitative Study. PLoS One
Malaria infection accounts for over one million deaths worldwide annually. . . .
DV Canyon et al. Insights in public health: systems thinking: basic constructs, application challenges, misuse in health, and how public health leaders can pave the way forward. Hawaii J Med Public Health
The strengthening of health systems is fundamental to improving health outcomes, crisis preparedness, and our capacity to meet global challenges, such as accelerating progress towards the Millennium Development Goals, reducing maternal and child mortality, combating HIV, malaria and other diseases, limiting the effects of a new influenza pandemic, and responding appropriately to climate change. . . .
F Carlini et al. HLA-G UTR Haplotype Conservation in the Malian Population: Association with Soluble HLA-G. PLoS One
The HLA-G molecule plays an important role in immunomodulation. . . .
Development and application of an AllGlo probe-based qPCR assay for detecting knockdown resistance (kdr) mutations in Anopheles sinensis
Background: Anopheles sinensis is one of the most important malaria vectors in China and other Southeast Asian countries. High levels of resistance have been reported in this species due to the long-term use of insecticides, especially pyrethroids, for public health and agricultural purposes. Knockdown resistance (kdr) caused by a single base pair mutation in the gene encoding the sodium channel is strongly associated with pyrethroid insecticide resistance in many Anopheles mosquitoes. There are few methods currently available for detecting kdr mutations in An. sinensis. Methods: A novel AllGlo probe-based qPCR (AllGlo-qPCR) method was developed to screen for the predominant kdr mutations in An. sinensis mosquitoes from the Jiangsu Province. The results from AllGlo-qPCR, allele-specific PCR (AS-PCR), and TaqMan-MGB probe-based qPCR (TaqMan-qPCR) were compared. A comparative analysis of the equipment required, ease of use and cost of the available methods was also performed. Finally, the AllGlo-qPCR method was used to detect the frequencies of kdr mutations from the other four provinces in central China. Results: Six kdr genotypes were detected in An. sinensis from the Jiangsu Province by DNA sequencing. The AllGlo-qPCR method detected all of the kdr genotypes with a high level of accuracy (97% sensitivity and 98% specificity). AllGlo-qPCR correctly determined the kdr genotypes of 98.73% of 158 An. sinensis samples, whereas TaqMan-qPCR and AS-PCR correctly identified 96.84% and 88.61% of mutations, respectively. Furthermore, the AllGlo-qPCR method is simpler to perform, requires less equipment, and exhibits a moderate expense cost comparing with the other tested methods of kdr mutation detection. Samples collected from four of the other provinces in central China showed a high frequency of kdr mutation in An. sinensis, as detected by the established AllGlo-qPCR method. Conclusion: The novel AllGlo-qPCR method developed for kdr mutation detection in An. sinensis exhibits greater specificity and sensitivity than currently available methods and is more cost-effective; therefore, it represents a useful tool for entomological surveillance.
Education attainment of head of households associated with insecticide-treated net utilization among five to nineteen-year old individuals: evidence from the malaria indicator survey 2010 in Zambia
Background: Education attainment may be a factor potentially influencing health-seeking behaviour of individuals. The effect of the level of education attainment of head of households of five to nineteen year old individuals in Zambia on ITN utilization was investigated. Methods: Data stem from the 2010 Malaria Indicator Survey, which covered the entire Zambia, was used in this study. Of the total number of five to 19-year olds (n = 7,429), only 65% (4, 810) met the inclusion criteria for this study. The education level of the head of households was taken as a household variable and was categorized as "never been to school" for those who had never enrolled in school, Primary for Grades 1 to 7, Secondary for Grades 8 to 12 and Tertiary for beyond Grade 12. Multivariate Logistic regression was used to determine adjusted odds ratios that estimated the effect of education on ITN utilization after controlling for residence, sex, age group and other background factors. Results: Overall (n = 4,810), 48.5% were males and 51.5% were females with the median age of 10 years and 11 years respectively. The ITN utilization among the five to 19 year old individuals from households with the head having Primary and Secondary education were not statistically significant from those who came from households where the head had never been to school. However, those who came from households with the head having tertiary education attainment were 1.7 times more likely to have slept under an ITN a night before the survey than those from households headed by individuals who never attended school or had primary education. (AOR, 1.69; 95% CI, 1.19-2.41). Of the eligible population, 35% were excluded from the study due to incomplete records. Conclusion: The findings suggest that tertiary education of the head of head of the household might be important in influencing health behaviour of the members of households. Therefore, health education messages focussing on strategies that aim to increase ITN utilization need to account for these differential variations associated with education attainment in communities.
Malaria elimination without stigmatization: a note of caution about the use of terminology in elimination settings
This commentary offers a note of caution about the negative social impact that may be inadvertently generated through malaria elimination activities. In particular, the commentary is concerned with the practice of describing people who remain at risk of malaria in low transmission settings as 'hotpops' or 'reservoirs of infection.' The authors argue that since those at risk of malaria in elimination settings are often already socially marginalized - such as migrants, indigenous groups, ethnic minorities and poor rural communities - that care should be taken to avoid implementing programmes in ways that may inadvertently add to the social stigmatization of those most at risk of malaria in a low transmission setting. Programmes should avoid using language that identifies particular groups as a source of infection, and instead begin a broader shift in orientation toward engaging constructively with communities within elimination strategies. Programmes should promote monitoring and evaluation to ensure that unintended negative consequences such as stigma do not occur; advocate for appropriate resourcing (human, financial, other) to minimize the risk of short cuts being used to achieve an end game that may discriminate against specific groups; and strengthen community engagement activities in elimination setting to avoid targeting stigmatized groups and to empower communities to prevent outbreaks and re-introduction of malaria. In this way malaria elimination can be achieved without stigmatization.
Therapeutic efficacy and safety of artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in North-Eastern Tanzania
Background: The World Health Organization recommends that regular efficacy monitoring should be undertaken by all malaria endemic countries that have deployed artemisinin combination therapy (ACT). Although ACT is still efficacious for treatment of uncomplicated malaria, artemisinin resistance has been reported in South-East Asia suggesting that surveillance needs to be intensified by all malaria endemic countries. This study assessed the efficacy and safety of artemether-lumefantrine (AL) for the treatment of uncomplicated falciparum malaria in Muheza district of north-eastern Tanzania, an area where the transmission has significantly declined in recent years. Methods: Eighty eight children (aged 6 months to 10 years) with uncomplicated falciparum malaria were recruited into the study. The patients were treated with standard doses of AL and followed up for 28 days. The primary end point was parasitological cure on day 28 while the secondary end points included: improvement in haemoglobin levels and occurrence, and severity of adverse events. Results: A total of 163 febrile patients were screened, out of which 88 patients (56 under-fives and 32 aged >=5 years) were enrolled and 79 (89.8%) completed the 28 days of follow-up. There were no cases of early treatment failure whilst 40 (78.4%) under-fives and 21(75.0%) older children had adequate clinical and parasitological response (ACPR) before PCR correction. Late clinical failure was seen in 5.6% (n = 51) and 3.6% (n = 28) of the under-fives and older children respectively; while 15.7% and 21.6% had late parasitological failure in the two groups respectively. After PCR correction, ACPR was 100% in both groups. Reported adverse events included cough (49.7%), fever (20.2%), abdominal pain (10.1%), diarrhoea (1.3%), headache (1.3%) and skin rashes (1.3%). Conclusion: This study showed that AL was safe, well-tolerated and efficacious for treatment of uncomplicated falciparum malaria. Since Muheza has historically been a hotspot of drug resistance (e.g. pyrimethamine, chloroquine, and SP), surveillance needs to be continued to detect future changes in parasite sensitivity to ACT.
Label-free microfluidic enrichment of ring-stage Plasmodium falciparum-infected red blood cells using non-inertial hydrodynamic lift
Background: Understanding of malaria pathogenesis caused by Plasmodium falciparum has been greatly deepened since the introduction of in vitro culture system, but the lack of a method to enrich ring-stage parasites remains a technical challenge. Here, a novel way to enrich red blood cells containing parasites in the early ring stage is described and demonstrated. Methods: A simple, straight polydimethylsiloxane microchannel connected to two syringe pumps for sample injection and two height reservoirs for sample collection is used to enrich red blood cells containing parasites in the early ring stage (8-10 h p.i.). The separation is based on the non-inertial hydrodynamic lift effect, a repulsive cell-wall interaction that enables continuous and label-free separation with deformability as intrinsic marker. Results: The possibility to enrich red blood cells containing P. falciparum parasites at ring stage with a throughput of ~12,000 cells per hour and an average enrichment factor of 4.3 +/- 0.5 is demonstrated. Conclusion: The method allows for the enrichment of red blood cells early after the invasion by P. falciparum parasites continuously and without any need to label the cells. The approach promises new possibilities to increase the sensitivity of downstream analyses like genomic- or diagnostic tests. The device can be produced as a cheap, disposable chip with mass production technologies and works without expensive peripheral equipment. This makes the approach interesting for the development of new devices for field use in resource poor settings and environments, e.g. with the aim to increase the sensitivity of microscope malaria diagnosis.
Nature, Vol. 513, No. 7518. (18 September 2014), pp. 431-435, doi:10.1038/nature13468
Qingfeng Zhang, Nicolai Siegel, Rafael Martins, Fei Wang, Jun Cao, Qi Gao, Xiu Cheng, Lubin Jiang, Chung-Chau Hon, Christine Scheidig-Benatar, Hiroshi Sakamoto, Louise Turner, Anja Jensen, Aurelie Claes, Julien Guizetti, Nicholas Malmquist, Artur Scherf
Qingfeng Zhang, Nicolai Siegel, Rafael Martins, Fei Wang, Jun Cao, Qi Gao, Xiu Cheng, Lubin Jiang, Chung-Chau Hon, Christine Scheidig-Benatar, Hiroshi Sakamoto, Louise Turner, Anja Jensen, Aurelie Claes, Julien Guizetti, Nicholas Malmquist, Artur Scherf
Stable malaria incidence despite scaling up control strategies in a malaria vaccine-testing site in Mali
Background: The recent decline in malaria incidence in many African countries has been attributed to the provision of prompt and effective anti-malarial treatment using artemisinin-based combination therapy (ACT) and to the widespread distribution of long-lasting, insecticide-treated bed nets (LLINs). At a malaria vaccine-testing site in Bandiagara, Mali, ACT was introduced in 2004, and LLINs have been distributed free of charge since 2007 to infants after they complete the Expanded Programme of Immunization (EPI) schedule and to pregnant women receiving antenatal care. These strategies may have an impact on malaria incidence. Methods: To document malaria incidence, a cohort of 400 children aged 0 to 14 years was followed for three to four years up to July 2013. Monthly cross-sectional surveys were done to measure the prevalence of malaria infection and anaemia. Clinical disease was measured both actively and passively through continuous availability of primary medical care. Measured outcomes included asymptomatic Plasmodium infection, anaemia and clinical malaria episodes. Results: The incidence rate of clinical malaria varied significantly from June 2009 to July 2013 without a clear downward trend. A sharp seasonality in malaria illness incidence was observed with higher clinical malaria incidence rates during the rainy season. Parasite and anaemia point prevalence also showed seasonal variation with much higher prevalence rates during rainy seasons compared to dry seasons. Conclusions: Despite the scaling up of malaria prevention and treatment, including the widespread use of bed nets, better diagnosis and wider availability of ACT, malaria incidence did not decrease in Bandiagara during the study period.
Detection of Plasmodium knowlesi DNA in the urine and faeces of a Japanese macaque (Macaca fuscata) over the course of an experimentally induced infection
Background: Diagnostic techniques based on PCR for the detection of Plasmodium DNA can be highly sensitive and specific. The vast majority of these techniques rely, however, on the invasive sampling of blood from infected hosts. There is, currently, considerable interest in the possibility of using body fluids other than blood as sources of parasite DNA for PCR diagnosis. Methods: Urine and faeces were obtained from a Plasmodium knowlesi infected-Japanese macaque (Macaca fuscata) over the course of an experimentally induced infection. P. knowlesi DNA (PkDNA) extracted from urine and faeces were monitored by nested PCR targeting the P. knowlesi specific cytochrome b (cytb) gene. Results: Urinary PkDNA was detected on day 2, but was not amplified using DNA templates extracted from the samples on day 4, day 5 and day 6. Subsequently, urinary PkDNA was detected from day 7 until day 11, and from day 20 until day 30. PkDNA in faeces was detected from day 7 until day 11, and from day 20 until day 37. Moreover, real-time quantitative PCR showed a remarkable increase in the amount of urinary PkDNA following anti-malarial treatment. This might have been due to the release of a large amount of PkDNA from the degraded parasites as a result of the anti-malarial treatment, leading to excretion of PkDNA in the urine. Conclusions: The cytb-PCR system using urine and faecal samples is of potential use in molecular epidemiological surveys of malaria. In particular, monkey faecal samples could be useful for the detection of zoonotic primate malaria in its natural hosts.
Analysis of polymorphisms in Plasmodium falciparum genes related to drug resistance: a survey over four decades under different treatment policies in Brazil
Background: Anti-malarial resistance in Plasmodium falciparum remains an obstacle for malaria control. Resistance-associated genes were analysed in Brazilian samples over four decades to evaluate the impact of different treatment regimens on the parasite genetic profile. Methods: Samples were collected on filter paper from patients infected in the Amazon region from 1984 to 2011. DNA was extracted with Chelex(R) 100 and monoinfection confirmed by PCR. SNPs in the pfcrt, pfmdr1, pfdhfr and pfdhps genes were assessed by PCR-RFLP. The pfmdr1 copy number was estimated using real time quantitative PCR with SYBR(R) Green. Parasite response was assessed ex vivo with seven concentrations of each anti-malarial. Patients were treated according to Brazilian guidelines: quinine plus tetracycline or mefloquine in period 1 and ACT in period 2. Results: All 96 samples presented the pfcrt 76T mutant throughout the assessed periods. In addition, all isolates showed ex vivo chloroquine resistance. The pfmdr1 86Y was detected in 1.5% of samples in period 1, and in 25% in period 2. All samples presented the pfmdr1 1246Y. The analysis of pfmdr1 copy number showed amplification in 37.3% in period 1 and in 42% in period 2. Mutations in pfdhfr were shown as follows: 51I in all samples in period 1 and in 81.2% in period 2; 59R in 6.4% in period 2. The pfdhfr 108N and the pfdhps 437G were seen in all samples along time; the pfdhps 540E in 93.7% in period 1 and in 75% in period 2. Conclusions: The 76T mutation associated to chloroquine resistance is still present in the parasite population, although this anti-malarial was withdrawn from the chemotherapy of P. falciparum in Brazil in the mid-1980s. All isolates assayed ex vivo for chloroquine showed resistant phenotype and 76T. No association was observed between pfmdr1 mutations and resistance to quinine, mefloquine and artemisinin derivatives. Additionally, the pfdhfr 108N mutation was detected in all samples throughout the evaluated periods, demonstrating fixation of the mutant allele in the parasite population. Changes in Brazilian national guidelines for the malaria chemotherapy in the last 27 years yielded a discreet genetic impact in the parasite population.
Background: Accurate malaria stratification is essential for effective targeting of interventions but represents a particular challenge in pre-elimination settings. In these settings transmission is typically sufficiently low and spatially heterogeneous to warrant a need for estimates of malaria risk at sub-district or village level but is also likely to be sufficiently high to render the type of decision support systems appropriate to the final stages of malaria elimination impractical. In such a scenario it is arguably more feasible to strengthen existing passive malaria surveillance systems so that routinely generated case data can provide an effective basis for stratifying malaria risk. This paper explores the utility of routine malaria surveillance data for the stratification of malaria risk in Cambodia, where the target is malaria elimination by 2025. Methods: A malaria information system (MIS) was developed to generate timely, routine data on temporal and spatial variations in malaria cases reported through public health facilities and village malaria workers (VMWs). The MIS was implemented across all malaria endemic districts in the country during 2010-11. In 2012 MIS data were extracted and assessed on the basis of coverage and completeness. Village-level incidence estimates for 2011 were generated using predefined data inclusion criteria. Results: In 2011, the MIS covered 681 health facilities and 1,489 VMW villages; the overall completeness of monthly reporting was 82% and 97% for health facilities and VMWs respectively. Using these data it was possible to estimate malaria incidence for 89% of villages covered by the MIS. The resulting stratification highlights the highly heterogeneous nature of malaria transmission in Cambodia and underlines the importance of village-level data for effective targeting of interventions, including VMWs. Challenges associated with implementing the MIS and the implications of these for developing viable and sustainable MIS in Cambodia and elsewhere are discussed. Conclusions: This study demonstrates the operational feasibility of introducing a system to routinely generate village level malaria case data in Cambodia. Although resulting incidence estimates are subject to various limitations and biases the data provide an objective, repeatable basis for a dynamic system of stratification which is appropriate for guiding the transition between malaria pre-elimination and elimination phases.
Determinants of mortality, intensive care requirement and prolonged hospitalization in malaria - a tertiary care hospital based cohort study from South-Western India
Background: There is a remarkable dearth of literature on less pronounced outcomes in malaria, namely prolonged hospitalization and intensive care requirement. Limitations on routine clinical applicability of the World Health Organization's (WHO) guidelines for determination of severity in malaria does result in underestimation of the true burden of clinicians' perceived severity in malaria. This study was conducted to evaluate the clinico-laboratory and malarial severity features to determine their association with mortality, prolonged hospitalization and requirement of intensive care outcomes. Methods: A tertiary care hospital based retrospective study was conducted from the year 2007 to 2011 among microscopically proven adult malaria patients. Logistic regression analysis was performed to determine the factors associated with mortality, more than seven days hospitalization, intensive care and other supportive requirements. Results: Of a total of 922 malaria cases studied, more than seven days of hospitalization was the most frequent (21.8% (201), 95% CI = 19.1-24.5%) followed by intensive care requirement (8.6% (79), 95% CI = 6.8-10.4%) and in-hospital mortality (1.2% (11), 95% CI = 0.5-1.9%). Odds of mortality were significantly higher with cerebral malaria, pulmonary oedema/acute respiratory distress syndrome (PE/ARDS), liver dysfunction, severe anaemia, renal failure, respiratory distress, metabolic acidosis and leucocytosis. More than seven days hospitalization had inverse association with mortality. Plasmodium falciparum infection, more than three days of history of fever, haemoglobinuria, renal failure, shock, leucocytosis, severe thrombocytopaenia and every 10 mmHg fall in systolic blood pressure were the independent predictors of more than seven days of hospitalization. More than three days of history of fever, cerebral malaria, PE/ARDS, renal failure, metabolic acidosis, hyperparasitaemia, leucocytosis and severe thrombocytopaenia were independently associated factors with intensive care requirement. Conclusions: For routine clinical settings, severity definition for malaria needs to be redefined or modified from the existing WHO guidelines. Leucocytosis and severe thrombocytopaenia should be identified as severity determinant in malaria. Patients having more than three days history of fever, leucocytosis, severe thrombocytopaenia and renal failure are more likely to require either prolonged hospitalization and/or intensive care. PE/ARDS alone in Plasmodium vivax may result in mortality, whereas multiorgan involvement is common in P. falciparum related mortalities.
A randomized trial of artesunate-amodiaquine versus artemether-lumefantrine in Ghanaian paediatric sickle cell and non-sickle cell disease patients with acute uncomplicated malaria
Background: Sickle cell disease (SCD) is a genetic disorder common in malaria endemic areas. In endemic areas, malaria is a major cause of morbidity and mortality among SCD patients. This suggests the need for prompt initiation of efficacious anti-malarial therapy in SCD patients with acute malaria. However, there is no information to date, on the efficacy or safety of artemisinin combination therapy when used for malaria treatment in SCD patients. Methods: Children with SCD and acute uncomplicated malaria (n = 60) were randomized to treatment with artesunate-amodiaquine (AA), or artemether-lumefantrine (AL). A comparison group of non-SCD children (HbAA genotype; n = 59) with uncomplicated malaria were also randomized to treatment with AA or AL. Recruited children were followed up and selected investigations were done on days 1, 2, 3, 7, 14, 28, 35, and 42. Selected clinical and laboratory parameters of the SCD patients were also compared with a group of malaria-negative SCD children (n = 82) in steady state. Results: The parasite densities on admission were significantly lower in the SCD group, compared with the non-SCD group (p = 0.0006). The parasite reduction ratio (PRR) was lower, clearance was slower (p < 0.0001), and time for initial parasitaemia to decline by 50 and 90 % were longer for the SCD group. Adequate clinical and parasitological response (ACPR) on day 28 was 98.3 % (58/59) in the SCD group and 100 % (57/57) in the non-SCD group. Corresponding ACPR rates on day 42 were 96.5 % (55/57) in the SCD group and 96.4 % (53/55) in the non-SCD group. The fractional changes in haemoglobin, platelets and white blood cell counts between baseline (day 0) and endpoint (day 42) were 16.9, 40.6 and 92.3 %, respectively, for the SCD group, and, 12.3, 48.8 and 7.5 %, respectively, for the non-SCD group. There were no differences in these indices between AA- and AL-treated subjects. Conclusions: The parasite clearance of SCD children with uncomplicated malaria was slower compared with non-SCD children. AA and AL showed similar clinical and parasitological effects in the SCD and non-SCD groups. The alterations in WBC and platelet counts may have implications for SCD severity.Trial registration: Current controlled trials ISRCTN96891086.
Single genome amplification and direct amplicon sequencing of Plasmodium spp. DNA from ape fecal specimens
Protocol Exchange (2010), doi:10.1038/nprot.2010.156