http://pacmisc.net/ Aggregated malaria articles from multiple sources en-uk Tue, 7 Sep 2010 05:00:38 GMT Tue, 7 Sep 2010 05:00:38 Hand Blasted 1.0 Not edited very much web@pacmisc.net http://pacmisc.net/?2069 The Pacific Malaria Initiative Support Centre (PacMISC) has just posted the two thousandth article on the latest malaria news and science. The articles are a collection of news and science gathered from over 150 sources including the Malaria Journal, PLoS, Nature, Journal of Infectious Diseases and Science. The collection officially started in April 2009 with the opening of the PacMISC website but includes a small selection of articles dating back to 2000.<br>PacMISC produces a weekly "<em>This Week in Malaria</em>" email newsletter which is a digest of the malaria news and scientific articles posted during the week. You can sign up to receive the weekly email from the PacMISC web site.
Read More Sun, 5 Sep 2010 14:00:00 GMT http://pacmisc.net/?2069 PacMI http://pacmisc.net/?2061 The diagnosis of malaria in biological fluids other than blood using non-invasive, rapid diagnostic techniques provides a valuable approach in case management and epidemiological studies of malaria. Rapid detection of Plasmodium falciparum lactate dehydrogenase (pLDH) in saliva samples from 130 of 144 children with microscopically confirmed P. falciparum infection was evaluated using Optimal-IT dipsticks. Genotyping of parasites was also performed in saliva and blood samples from a cohort of patients by polymerase chain reaction (PCR). The sensitivity of the dipstick in whole-blood, whole-saliva, or supernatant of spun saliva samples was 97.2%, 77.9%, and 48.4%, respectively. The sensitivity of the dipstick in whole-saliva samples was significantly higher than in supernatant of spun saliva samples (P < 0.0005). Mutant T76 allele was detectable in 60% and 57% of blood and saliva samples, respectively. This finding shows rapid detection of pLDH in patient saliva.
Read More Sat, 4 Sep 2010 18:00:00 GMT http://pacmisc.net/?2061 Science http://pacmisc.net/?2068 Malaria is one of the worst sicknesses to affect humankind. For centuries there was no specific treatment, and it was not until the seventeenth century that Spanish colonisers brought back from Peru tree bark from which quinine was later extracted. In the twentieth century, synthetic alternatives to quinine were developed. Of these, chloroquine was the most successful, but by the 1970s widespread resistance had developed and the world was left without an effective treatment for malaria. During the same decade Chinese scientists extracted from sweet wormwood plant the drug artemisinin, which has proved to be very effective against chloroquine-resistant malarial parasites. The use of a combination therapy including artemisinin has made it possible to contemplate the eradication of malaria. Efforts to produce a stable and inexpensive supply of artemisinin are under way.
Read More Sat, 4 Sep 2010 17:00:00 GMT http://pacmisc.net/?2068 Science http://pacmisc.net/?2065 Every so often, the tide turns in a field of science. In malaria research, for a while an approach called "rational design" held sway, with great optimism that new drugs would emerge from understanding the biology of the malaria parasite at the molecular level. On page 1175 of this issue, however, Rottmann et al. (1) take our thinking back up to the level of the parasite.
Read More Sat, 4 Sep 2010 16:00:00 GMT http://pacmisc.net/?2065 Science http://pacmisc.net/?2059 From April 2005 to April 2006, a phase 2 malaria vaccine trial in Kenya enrolled 400 children aged 12-47 months. Each received mixed supervised and unsupervised artemether-lumefantrine for uncomplicated malaria, using a standard six-dose regimen, by weight. Children were followed for detection of parasitemia and clinical malaria. A median of two negative malaria blood films occurred during every recurrent parasitemia (RP) episode, suggesting reinfection over late recrudescence. Median time to RP after starting artemether-lumefantrine was 37 days (36-38). Of 2,020 evaluable artemether-lumefantrine treatments, there were no RPs in 99% by day 14, 71% by day 28, and 41% by day 42. By World Health Organization standards, 71% of treatment courses had adequate responses. Although recrudescence in some cannot be ruled out, our cohort had a shorter median time to RP compared with other artemether-lumefantrine treatment studies. This underscores patient counseling on completing all treatment doses for optimal protection from RP.
Read More Sat, 4 Sep 2010 16:00:00 GMT http://pacmisc.net/?2059 Science http://pacmisc.net/?2056 Despite enormous efforts to combat malaria the disease still afflicts up to half a billion people each year of which more than one million die. Currently no approved vaccine is available and resistances to antimalarials are widely spread. Hence, new antimalarial drugs are urgently needed. The results suggest that the set of essential enzymes predicted by our flux balance approach represents a promising starting point for further drug development.
Read More Sat, 4 Sep 2010 15:00:00 GMT http://pacmisc.net/?2056 Science http://pacmisc.net/?2067 Spiroindolones were discovered as promising antimalarial drug candidates through a high-throughput screening approach that should be applicable to a range of neglected infectious diseases. Rottmann et al. present the preclinical profile for an optimized spiroindolone drug candidate, NITD609. They obtained evidence for a decrease in drug sensitivity in strains of the malaria parasite Plasmodium falciparum bearing amino acid mutations in the P-type ATPase, indicating possible mechanisms of action and/or resistance.
Read More Sat, 4 Sep 2010 14:00:00 GMT http://pacmisc.net/?2067 http://pacmisc.net/?2066 Franois Nosten has built an unmatched international resume in malaria. The Shoklo Malaria Research Unit, which he founded 25 years ago on the politically sensitive and occasionally violent border between Thailand and Myanmar, formerly Burma, not only provides basic health services to tens of thousands of poor people, but it's also one of the most respected and prolific clinical malaria research centers in the world. With more than 230 published papers, including co-authorship of a report on page 1175 of this issue of Science, Nosten ranks as one of the 10 most-cited researchers in his field.
Read More Sat, 4 Sep 2010 14:00:00 GMT http://pacmisc.net/?2066 Media http://pacmisc.net/?2064 Recent reports of increased tolerance to artemisinin derivativesthe most recently adopted class of antimalarialshave prompted a need for new treatments. The spirotetrahydro--carbolines, or spiroindolones, are potent drugs that kill the blood stages of Plasmodium falciparum and Plasmodium vivax clinical isolates at low nanomolar concentration. Spiroindolones rapidly inhibit protein synthesis in P. falciparum, an effect that is ablated in parasites bearing nonsynonymous mutations in the gene encoding the P-type cation-transporter ATPase4 (PfATP4). The optimized spiroindolone NITD609 shows pharmacokinetic properties compatible with once-daily oral dosing and has single-dose efficacy in a rodent malaria model.
Read More Sat, 4 Sep 2010 14:00:00 GMT http://pacmisc.net/?2064 Science http://pacmisc.net/?2063 We compare, contrast, and evaluate methods to quantify genetic markers of antimalarial drug resistance. Frequency estimates should be reported along with crude prevalence. There are four main potential methods to estimate frequencies in blood samples: simple counting of single nucleotide polymorphisms (SNPs) and haplotypes in samples with multiplicity of infection (MOI) = 1; SNP counting in samples with MOI <= 2; SNP and haplotypes counting in samples with unambiguous genotypes; statistical inference using SNP and MOI data from all samples. Large differences between the methods became apparent when analyzing field data with high MOI. Simple counting dramatically reduced sample size and estimate precision, and we show that analysis of unambiguous samples is biased, leaving maximum likelihood or similar statistical inference as the only practical option. It is essential to account for genotyping missing minor clones; ignoring this phenomenon resulted in a 2-fold underestimation of SNPs and haplotypes present at low frequencies.
Read More Sat, 4 Sep 2010 14:00:00 GMT http://pacmisc.net/?2063 Science http://pacmisc.net/?2062 Catches of Anopheles gambiae and An. arabiensis with the Ifakara Tent Trap-model B (ITT-B) correlate better with human landing catches than any other method but fail to reduce the proportion of blood-fed mosquito caught, which indicates that users are exposed to bites during collection. An improved C model (ITT-C) was developed and evaluated by comparing with ITT-B in semi-field and full-field conditions in southern Tanzania. The sensitivity of the ITT-C was approximately two times that of the ITT-B: relative rate (95% confidence interval) = 1.92 (1.52-2.42), 1.90 (1.48-2.43), and 2.30 (1.54-3.30) for field populations of An. arabiensis, Culex spp., and Mansonia spp., respectively. The ITT-C caught 73% less blood-fed An. arabiensis than the ITT-B in open field experiments and none in semi-field experiments, which confirmed that the C design is a safe trapping method. Validation of ITT-C by comparison with human landing catches and parasitologic measures of human infection status may be necessary to confirm that this design produces consistent and epidemiologically meaningful results.
Read More Sat, 4 Sep 2010 14:00:00 GMT http://pacmisc.net/?2062 Science http://pacmisc.net/?2060 Parasite dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) are known target enzymes of antifolate drugs used for the treatment and prophylaxis of persons with malaria. We sequenced the Plasmodium vivax dihydrofolate reductase (pvdhfr) and dihydropteroate synthase (pvdhps) genes to examine the prevalence and extent of point mutations in isolates from malaria-endemic countries. Double mutations (S58R and S117N) or quadruple mutations (F57L/I, S58R, T61M, and S117T) in the pvdhfr gene were found in isolates from Thailand (96.4%) and Myanmar (71.4%), but in only one isolate (1.0%) from Korea, where sulfadoxine-pyrimethamine has never been used. The pvdhfr point mutations correlated strongly with the pvdhps point mutations and ranged from single to triple mutations (S382A, A383G, and A553G), among isolates from Thailand, Myanmar, and Korea. These findings suggests that the prevalence of mutations in pvdhfr and pvdhps in P. vivax isolates from different malaria-endemic countries is associated with selection pressure imposed by sulfadoxine-pyrimethamine.
Read More Sat, 4 Sep 2010 14:00:00 GMT http://pacmisc.net/?2060 Science http://pacmisc.net/?2058 Zambia national survey, administrative, health facility, and special study data were used to assess progress and impact in national malaria control between 2000 and 2008. Zambia malaria financial support expanded from US$9 million in 2003 to US$ ~40 million in 2008. High malaria prevention coverage was achieved and extended to poor and rural areas. Increasing coverage was consistent in time and location with reductions in child (age 659 months) parasitemia and severe anemia (53% and 68% reductions, respectively, from 2006 to 2008) and with lower post-neonatal infant and 14 years of age child mortality (38% and 36% reductions between 2001/2 and 2007 survey estimates). Zambia has dramatically reduced malaria transmission, disease, and child mortality burden through rapid national scale-up of effective interventions. Sustained progress toward malaria elimination will require maintaining high prevention coverage and further reducing transmission by actively searching for and treating infected people who harbor malaria parasites.
Read More Sat, 4 Sep 2010 14:00:00 GMT http://pacmisc.net/?2058 Science http://pacmisc.net/?2057 Clinical malaria incidence was determined over 18 months in a cohort of 553 children living in a peri-urban area near Cotonou. Three cross-sectional surveys were also carried out. Malaria incidence showed a marked seasonal distribution with two peaks: the first corresponding to the long rainy season, and the second corresponding to the overflowing of Lake Nokoue. The overall Plasmodium falciparum incidence rate was estimated at 84/1,000 person-months, and its prevalence was estimated at over 40% in the two first surveys and 68.9% in the third survey. Multivariate analysis showed that girls and people living in closed houses had a lower risk of clinical malaria. Bed net use was associated with a lower risk of malaria infection. Conversely, children of families owing a pirogue were at higher risk of clinical malaria. Considering the high pyrethroids resistance, indoor residual spraying with either a carbamate or an organophospate insecticide may have a major impact on the malaria burden.
Read More Sat, 4 Sep 2010 14:00:00 GMT http://pacmisc.net/?2057 Science http://pacmisc.net/?2055 To systemically review the evidence from clinical trials comparing the use of crystalloids and colloids for fluid resuscitation in children with severe infection. The current evidence on choice of fluids for resuscitation in children with infections is weak. While existing trials have provided important evidence in malaria and dengue, resuscitation in children with paediatric sepsis, for which colloids could theoretically be of benefit, has not been studied. The evidence from existing studies is not robust enough to make any definitive recommendations over the choice of resuscitation fluid and a definitive trial is required to address this.
Read More Sat, 4 Sep 2010 14:00:00 GMT http://pacmisc.net/?2055 Science http://pacmisc.net/?2053 As floods continued to ravage the south of Pakistan last week, health workers have expressed concern about the rise in the number of suspected malaria cases that have been reported.World Health Organization data show that 3.7 million people have been treated in areas affected by the floods since they began on 29 July. The cases include just over 500000 of acute diarrhoea (13% of the total number of cases), 520000 of acute respiratory infection (14%), 693000 of skin infections (19%), and 94000 of suspected malaria.
Read More Sat, 4 Sep 2010 14:00:00 GMT http://pacmisc.net/?2053 Media http://pacmisc.net/?2050 Scientists have identified new scent receptors in mosquitoes that could help develop more agents to lure, repel and kill the insects.
Read More Fri, 3 Sep 2010 06:40:58 GMT http://pacmisc.net/?2050 Media http://pacmisc.net/?2052 Pregnancy-associated malaria (PAM) is a serious consequence of the adhesion to the placental receptor chondroitin sulfate A (CSA) of Plasmodium falciparum-infected erythrocytes (PE) expressing the large cysteine-rich multi-domain protein var2CSA. Women become resistant to PAM, and develop strain-transcending immunity against CSA-binding parasites. The identification of var2CSA regions that could elicit broadly neutralizing and adhesion-blocking antibodies is a key step for the design of prophylactic vaccine strategies. Methodology Escherichia coli expressed var2CSA DBL domains were refolded and purified prior to immunization of mice and a goat. Thu, 2 Sep 2010 14:00:00 GMT http://pacmisc.net/?2052 Science http://pacmisc.net/?2051 Malaria remains one of the world's greatest killers and a vaccine is urgently required. There are no established correlates of protection against malaria either for natural immunity to the disease or for immunity conferred by candidate malaria vaccines. The RTS,S/AS02A vaccine offers significant partial efficacy against malaria.mRNA expression of five key cytokines interferon-gamma (IFN-?), monokine induced by gamma (MIG), interleukin-10 (IL-10), transforming growth factor- (TGF-) and forkhead box P3 (FoxP3) in peripheral blood mononuclear cells were measured by real-time RT-PCR before and after vaccination with RTS,S/AS02A and Modified Vaccinia virus Ankara encoding the circumsporozoite protein (MVA-CS) in healthy malaria-nave adult volunteers. Thu, 2 Sep 2010 14:00:00 GMT http://pacmisc.net/?2051 Science http://pacmisc.net/?2048 The United Nations forecasts that by 2050, more than 60% of the African population will live in cities. Thus, urban malaria is considered an important emerging health problem in that continent. Remote sensing (RS) and geographic information systems (GIS) are useful tools for addressing the challenge of assessing, understanding and spatially focusing malaria control activities. The objectives of the present study were to use high spatial resolution SPOT (Satellite Pour l'Observation de la Terre) satellite images to identify some urban environmental factors in Dakar associated with Anopheles arabiensis densities, to assess the persistence of these associations and to describe spatial changes in at-risk environments using a decadal time scale.
Read More Thu, 2 Sep 2010 14:00:00 GMT http://pacmisc.net/?2048 Science