Prevalence Of Plasmodium Falciparum Research Articles

A survey of malaria prevalence and antimalarial preventive measures amongst students of University of Lagos, Nigeria

The prevalence of malaria parasite and antimalarial preventive measures among students of University of Lagos, Nigeria was carried out between November 2014 and February 2015. Blood samples were collected from 400 students (with age ranging from 15-46year) by finger pricking and analyzed microscopically and by Rapid Diagnostic Test kit. Semi-structured questionnaire probing into their knowledge of the cause of malaria, ability to recognize signs and symptoms, treatment seeking behaviour was distributed to the respondents. The prevalence of Plasmodium falciparum by microscopy was significantly lower (p=0.0000042). More than three quarters of the respondents (88.5%) had a good knowledge of the cause of malaria and were able to identify signs and symptoms of malaria which included headache (51.5%), fever (26%), dizziness (9.5%). Also more than half of the students (202) visit hospital when they recognize such signs while others visit Pharmaceutical outlets (130), drug hawkers (37) or use herbal remedy (31).Malaria preventive measures employed by students ranges from the use of Long-Lasting Insecticide Treated Bednets (74), topical mosquito repellant cream (65) to cleaning the environment (54). Furthermore, half of the students (50%) reported having malaria bouts twice per year, 35% once annually while 15% could not remember how often they have it. These bouts of various frequencies resulted in 360 (90%) of the students being absent from school from less than 10 days to more than 20 days. Proactively placing preventive measures would negate cascades of effects amongst the students. Continuous studies should be carried out to assess the prevalence of malaria in different foci of Nigeria and the level of awareness on the benefits of use of preventive measures should be emphasized among community members if Nigeria and Africa as a whole will meet the elimination target by 2030.

Population genetics structure of Plasmodium vivax circumsporozoite protein during the elimination process in low and unstable malaria transmission areas, southeast of Iran

In Iran, the prevalence of Plasmodium falciparum and Plasmodium vivax has dropped after a national malaria elimination program was launched. To estimate the likelihood of success and to measure the outcome of malaria intervention tools during elimination programs (2008–2012), the population genetic surveys of Iranian P. vivax isolates (n=60) were carried out using the CSP genetic marker. The results were compared with a similar work that was carried out during a control phase (2000–2003) in the same study areas. Based on PCR-RFLP analysis, 49 (81.67%) of 60 studied samples were VK210 and 11 (18.33%) were VK247 with no mixed genotypes. However, 10.97% of P. vivax isolates of control phase harbored the mixed genotypes. Sequencing analysis of 50 pvcsp gene showed 14 distinct haplotypes, of which 11 and 3 were VK210 and VK247 types, respectively. However, during the control phase, 19 distinct subtypes (11 VK210 and 8 VK247) were reported. Also, 7 of 11 VK210 and the VK247F subtypes were new, and 3 out of 7 new VK210 and VK247F were isolated from the patients with Pakistani nationality. The lower nucleotide diversity per site (π=0.02017±0.00436 and π=0.04525±0.00255) and haplotype diversity (Hd=0.513±0.093 and Hd=0.691±0.128) as well as lower In/Del haplotype [Hd(i)=0.243 and 0] and nucleotide diversity [π(i)=0.00078 and 0] were recorded for VK210 and VK247of the elimination samples, respectively. In conclusion, the comparison of PRMs and RATs in CRR along with the polymorphism analysis of the sequence lengths, SNPs, and In/Del polymorphisms in all analyzed samples showed lower genetic diversity for PvCSP in the elimination samples. Also, although there is a turnover of P. vivax parasite genotypes in the study areas, reduction in genetic diversity and transmission was detected due to scaling-up of the intervention tools during an elimination program in Iran. This notable challenge of the elimination program must be taken into account and controlled by active surveillance for limiting both reintroductions of new allelic forms as well as the spread of drug-resistant parasite to prevent any disease outbreaks.

Absence of Association Between Sickle Trait Hemoglobin and Placental Malaria Outcomes.

Heterozygous hemoglobin S (HbAS), or sickle trait, protects children from life-threatening falciparum malaria, potentially by attenuating binding of Plasmodium-infected red blood cells (iRBCs) to extracellular ligands. Such binding is central to the pathogenesis of placental malaria (PM). We hypothesized that HbAS would be associated with reduced risks of PM and low birth weight (LBW). We tested this hypothesis in 850 delivering women in southern Malawi. Parasites were detected by polymerase chain reaction in placental and peripheral blood, and placentae were scored histologically for PM. The prevalence of HbAS was 3.7%, and 11.2% of infants were LBW (< 2,500 g). The prevalence of Plasmodium falciparum was 12.7% in placental and 8.5% in peripheral blood; 24.4% of placentae demonstrated histological evidence of P. falciparum HbAS was not associated with reduced prevalence of P. falciparum in placental (odds ratio [OR]: 1.27, 95% confidence interval [CI]: 0.50-3.23, P = 0.61) or peripheral blood (OR: 2.53, 95% CI: 1.08-2.54, P = 0.03), prevalence of histological PM (OR: 0.97, 95% CI: 0.40-2.34, P = 0.95), or prevalence of LBW (OR: 0.82, 95% CI: 0.24-2.73, P = 0.74). Mean (standard deviation) birth weights of infants born to HbAS (2,947 g [563]) and, homozygous hemoglobin A (2,991 g [465]) mothers were similar. Across a range of parasitologic, clinical, and histologic outcomes, HbAS did not confer protection from PM or its adverse effects.

Plasmodium falciparum parasitaemia and clinical malaria among school children living in a high transmission setting in western Kenya.

BackgroundMalaria among school children is increasingly receiving attention, yet the burden of malaria in this age group is poorly defined. This study presents data on malaria morbidity among school children in Bungoma county, western Kenya.MethodThis study investigated the burden and risk factors of Plasmodium falciparum infection, clinical malaria, and anaemia among 2346 school children aged 5–15 years, who were enrolled in an individually randomized trial evaluating the effect of anthelmintic treatment on the risks of malaria. At baseline, children were assessed for anaemia and nutritional status and information on household characteristics was collected. Children were followed-up for 13 months to assess the incidence of clinical malaria by active detection, and P. falciparum infection and density evaluated using repeated cross-sectional surveys over 15 months.ResultsOn average prevalence of P. falciparum infection was 42 % and ranged between 32 and 48 % during the five cross-sectional surveys. Plasmodium falciparum prevalence was significantly higher among boys than girls. The overall incidence of clinical malaria was 0.26 episodes per person year (95 % confidence interval, 0.24–0.29) and was significantly higher among girls (0.23 versus 0.31, episodes per person years). Both infection prevalence and clinical disease varied by season. In multivariable analysis, P. falciparum infection was associated with being male, lower socioeconomic status and stunting. The risk of clinical malaria was associated with being female.ConclusionThese findings show that the burden of P. falciparum parasitaemia, clinical malaria and anaemia among school children is not insignificant, and suggest that malaria control programmes should be expanded to include this age group.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-016-1176-y) contains supplementary material, which is available to authorized users.

Microscopic and molecular evidence of the presence of asymptomatic Plasmodium falciparum and Plasmodium vivax infections in an area with low, seasonal and unstable malaria transmission in Ethiopia.

BackgroundThe presence of asymptomatic infections has serious implications for malaria elimination campaigns. Since asymptomatic carriers do not seek treatment for their infection and may become gametocyte carriers, they undoubtedly contribute to the persistence of malaria transmission in a population. The presence of asymptomatic parasitemias was noted in areas with seasonal malaria transmission. In Ethiopia there is a paucity of data regarding the prevalence of asymptomatic malaria carriage. This study was undertaken to assess the presence and prevalence of asymptomatic Plasmodium falciparum and Plasmodium vivax infections in south-central Oromia, Ethiopia.MethodsA total of 1094 apparently healthy individuals ≥ 2 years of age in south-central Oromia, Ethiopia, an area with seasonal and unstable malaria transmission, were screened for the presence of asymptomatic plasmodial infections. Finger-prick blood samples were taken from each participant for blood film preparation for microscopy and the rapid diagnostic test (RDT). Blood samples were also spotted on Whatman 3MM filter paper for parasite DNA extraction.ResultsThe prevalence of asymptomatic Plasmodium carriage (P. falciparum, P. vivax and mixed species) was 5.0 % (55/1,094) as determined by microscopy, while the prevalence as determined using RDT was 8.2 % (90/1,094). PCR was done on 47 of 55 microscopy-confirmed and on 79 of 90 RDT-confirmed samples. PCR detected parasite DNA in 89.4 % (42/47) of the microscopy-positive samples and in 77.2 % (61/79) of the RDT-positive samples. No significant difference was observed in the prevalence of asymptomatic P. falciparum or P. vivax infections in the study area (P > 0.1). However, the prevalence of asymptomatic parasitaemia was significantly associated with gender (OR = 0.47, P = 0.015; being higher in males than females) and age (X2 = 25, P < 0.001; being higher in younger than in older individuals). Age and parasite densities had an inverse relationship.ConclusionsThis study confirms the presence of asymptomatic P. falciparum and P. vivax infections in south-central Oromia, an area with low, seasonal and unstable malaria transmission in Ethiopia. Of 55 microscopically confirmed asymptomatic infections, P. falciparum monoinfection accounted for 45.5 % and of 90 RDT positive asymptomatic infections, 66.7 % were P. falciparum. Although not statistically significant, P. falciparum accounted for a relatively large number of the asymptomatic infections as determined by both tests. The prevalence of asymptomatic parasitaemia was highest in the younger age group. HRP-2-based RDTs specific for P. falciparum showed high false positivity rate compared to Plasmodium lactate dehydrogenase (pLDH) specific to P. vivax. Although microscopy and RDT detected substantial numbers of asymptomatic infections in apparently healthy inhabitants, the use of a highly sensitive molecular diagnostics offers a more accurate assessment of the magnitude of asymptomatic infections.

Co-endemicity of Plasmodium falciparum and Intestinal Helminths Infection in School Age Children in Rural Communities of Kwara State Nigeria.

BackgroundMalaria and intestinal helminths co-infection are major public health problems particularly among school age children in Nigeria. However the magnitude and possible interactions of these infections remain poorly understood. This study determined the prevalence, impact and possible interaction of Plasmodium falciparum and intestinal helminths co-infection among school children in rural communities of Kwara State, Nigeria.MethodsBlood, urine and stool samples were collected from 1017 primary school pupils of ages 4–15 years. Stool samples were processed using both Kato-Katz and formol-ether concentration techniques and microscopically examined for intestinal helminths infection. Urine samples were analyzed using sedimentation method for Schistosoma haematobium. Plasmodium falciparum was confirmed by microscopy using thick and thin blood films methods and packed cell volume (PCV) was determined using hematocrit reader. Univariate analysis and chi-square statistical tests were used to analyze the data.ResultsOverall, 61.2% of all school children had at least an infection of either P. falciparum, S. haematobium, or intestinal helminth. S. haematobium accounted for the largest proportion (44.4%) of a single infection followed by P. falciparum (20.6%). The prevalence of malaria and helminth co-infection in the study was 14.4%. Four species of intestinal helminths were recovered from the stool samples and these were hookworm (22.5%), Hymenolepis species (9.8%), Schistosoma mansoni (2.9%) and Enterobius vermicularis (0.6%). The mean densities of P. falciparum in children co-infected with S. haematobium and hookworm were higher compared to those infected with P. falciparum only though not statistically significant (p = 0.062). The age distribution of both S. haematobium (p = 0.049) and hookworm (p = 0.034) infected children were statistically significant with the older age group (10–15 years) recording the highest prevalence of 47.2% and 25% respectively. Children who were infected with S. haematobium (RR = 1.3) and hookworm (RR = 1.4) have equal chances of being infected with P. falciparum as children with no worm infection. On the other hand children infected with Hymenolepis spp. (p<0.0001) are more likely to be infected with P. falciparum than Hymenolepis spp. uninfected children (RR = 2.0)ConclusionsThese findings suggest that multiple parasitic infections are common in school age children in rural communities of Kwara State Nigeria. The Hymenolepis spp. induced increase susceptibility to P. falciparum could have important consequences on how concurrent infections affect the expression or pathogenesis of these infections.

High Rates of Asymptomatic, Sub-microscopic Plasmodium vivax Infection and Disappearing Plasmodium falciparum Malaria in an Area of Low Transmission in Solomon Islands.

IntroductionSolomon Islands is intensifying national efforts to achieve malaria elimination. A long history of indoor spraying with residual insecticides, combined recently with distribution of long lasting insecticidal nets and artemether-lumefantrine therapy, has been implemented in Solomon Islands. The impact of these interventions on local endemicity of Plasmodium spp. is unknown.MethodsIn 2012, a cross-sectional survey of 3501 residents of all ages was conducted in Ngella, Central Islands Province, Solomon Islands. Prevalence of Plasmodium falciparum, P. vivax, P. ovale and P. malariae was assessed by quantitative PCR (qPCR) and light microscopy (LM). Presence of gametocytes was determined by reverse transcription quantitative PCR (RT-qPCR).ResultsBy qPCR, 468 Plasmodium spp. infections were detected (prevalence = 13.4%; 463 P. vivax, five mixed P. falciparum/P. vivax, no P. ovale or P. malariae) versus 130 by LM (prevalence = 3.7%; 126 P. vivax, three P. falciparum and one P. falciparum/P. vivax). The prevalence of P. vivax infection varied significantly among villages (range 3.0–38.5%, p<0.001) and across age groups (5.3–25.9%, p<0.001). Of 468 P. vivax infections, 72.9% were sub-microscopic, 84.5% afebrile and 60.0% were both sub-microscopic and afebrile. Local residency, low education level of the household head and living in a household with at least one other P. vivax infected individual increased the risk of P. vivax infection. Overall, 23.5% of P. vivax infections had concurrent gametocytaemia. Of all P. vivax positive samples, 29.2% were polyclonal by MS16 and msp1F3 genotyping. All five P. falciparum infections were detected in residents of the same village, carried the same msp2 allele and four were positive for P. falciparum gametocytes.Conclusion P. vivax infection remains endemic in Ngella, with the majority of cases afebrile and below the detection limit of LM. P. falciparum has nearly disappeared, but the risk of re-introductions and outbreaks due to travel to nearby islands with higher malaria endemicity remains.

Plasmodium falciparum in the southeastern Atlantic forest: a challenge to the bromeliad-malaria paradigm?

BackgroundRecently an unexpectedly high prevalence of Plasmodium falciparum was found in asymptomatic blood donors living in the southeastern Brazilian Atlantic forest. The bromeliad-malaria paradigm assumes that transmission of Plasmodium vivax and Plasmodium malariae involves species of the subgenus Kerteszia of Anopheles and only a few cases of P. vivax malaria are reported annually in this region. The expectations of this paradigm are a low prevalence of P. vivax and a null prevalence of P. falciparum. Therefore, the aim of this study was to verify if P. falciparum is actively circulating in the southeastern Brazilian Atlantic forest remains.MethodsIn this study, anophelines were collected with Shannon and CDC-light traps in seven distinct Atlantic forest landscapes over a 4-month period. Field-collected Anopheles mosquitoes were tested by real-time PCR assay in pools of ten, and then each mosquito from every positive pool, separately for P. falciparum and P. vivax. Genomic DNA of P. falciparum or P. vivax from positive anophelines was then amplified by traditional PCR for sequencing of the 18S ribosomal DNA to confirm Plasmodium species. Binomial probabilities were calculated to identify non-random results of the P. falciparum-infected anopheline findings.ResultsThe overall proportion of anophelines naturally infected with P. falciparum was 4.4% (21/480) and only 0.8% (4/480) with P. vivax. All of the infected mosquitoes were found in intermixed natural and human-modified environments and most were Anopheles cruzii (22/25 = 88%, 18 P. falciparum plus 4 P. vivax). Plasmodium falciparum was confirmed by sequencing in 76% (16/21) of positive mosquitoes, whereas P. vivax was confirmed in only 25% (1/4). Binomial probabilities suggest that P. falciparum actively circulates throughout the region and that there may be a threshold of the forested over human-modified environment ratio upon which the proportion of P. falciparum-infected anophelines increases significantly.ConclusionsThese results show that P. falciparum actively circulates, in higher proportion than P. vivax, among Anopheles mosquitoes of fragments of the southeastern Brazilian Atlantic forest. This finding challenges the classical bromeliad-malaria paradigm, which considers P. vivax circulation as the driver for the dynamics of residual malaria transmission in this region.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-015-0680-9) contains supplementary material, which is available to authorized users.

Prevalence of Malaria and Associated Factors among Patients Attending at Hallaba Health Center, Southern Ethiopia

Back ground: Malaria is usually an important hazard in order to open health and economic progress inside the African continent. Throughout sub-Saharan the African continents, 90% of all demise largely below 5 youngsters tend to be due to malaria. Yearly you can find in relation to 270-480 million circumstances associated with malaria leading to in relation to one million demise, largely inside The African continent as well as especially within 5 youngsters. Almost all of the full division of Ethiopia is actually malarious, doing malaria the best open health problem inside Ethiopia. The purpose of this particular review seemed to be to look into your frequency as well as associated factors among patients attending at Hallaba health center based on thick and thin blood film examination. Thus, this research was launched to determine the prevalence of malaria and associated factors among patients who attended at Hallaba health center. Methods: Health center based cross sectional study was conducted from April 19 to June 21, 2009 at Hallaba health center on a total of 204 individuals who were selected conveniently. Structured questionnaire was used to obtain socio-demographic and other data. Then the data were entered and analyzed by using SPSS software. Statistical tables and graphs were used to present the result. Chi-square tests and OR (95% CI) were used to test the association. Results: The analyses showed that the highest prevalence of malaria was found between age group of 0-19 year. There was association between age group and prevalence of malaria (X2= 77.07, P<0.005) and also there was association between prevalence of malaria and sign and symptom like fever (OR=11.84%, 95%CI, 4.62-30.27, P<0.005). Vomiting (OR=8.29, 95% CI 3.39-20.49, P<0.005).Chills (OR=8.76, 95% CI 3.71-20.70, P<0.005) Joint and back pain (OR=3.85, 95%CI 1.26-11.94, P<0.005), headache (OR=75.17, 95% CI 21.12-270.43, P<0.005). Conclusion: Those with inadequate socio-economic conditions are really linked to malaria contamination. On the result it can be concluded that most of the respondents were infected with Plasmodium vivax. The respondents' knowledge or having information about malaria has no association with the prevalence of malaria. Age, altitude, rainfall and socio-economic factors contribute to high prevalence of malaria at Hallaba health Center. This kind of facts is vital to style increased strategic involvement with the lessening connected with malaria pandemic in Halaba town. Generally, from the result of this study it can concluded that the prevalence of Plasmodium vivax and Plasmodium falciparum is different from the national figure.

Baseline health conditions in selected communities of northern Sierra Leone as revealed by the health impact assessment of a biofuel project.

As biofuel projects may be associated with positive and negative effects on people's health and wellbeing, a health impact assessment was performed for the Addax Bioenergy Sierra Leone (ABSL) project. We present data from the baseline health survey, which will provide a point of departure for future monitoring and evaluation activities. In December 2010, a cross-sectional survey was carried out in eight potentially affected communities. A broad set of clinical and parasitological indicators were assessed using standardised, quality-controlled procedures, including anthropometry and prevalence of anaemia, Plasmodium falciparum and helminth infections. Complete datasets were obtained from 1221 individuals of 194 households and eight schools. Of children aged <5 years (n=586), 41.8% were stunted, 23.2% were underweight and 4.8% were wasted. Very high prevalences of anaemia and P. falciparum were found in children aged 6-59 months (n=571; 86.1% and 74.0%, respectively). Overall, 73.7% of women of reproductive age (n=395) were anaemic. In school-aged children (n=240), 27.9% had light- to moderate-intensity hookworm infections, whereas Ascaris lumbricoides, Trichuris trichiura and Schistosoma mansoni were rare (<3% each). The detailed description of the baseline health conditions, in combination with future health surveys, will deepen the understanding of how a biofuel project impacts on community health in a rural setting in sub-Saharan Africa.

Malaria transmission in Bissau, Guinea-Bissau between 1995 and 2012: malaria resurgence did not negatively affect mortality.

IntroductionAs Plasmodium falciparum prevalence decreases in many parts of Sub-Saharan Africa, so does immunity resulting in larger at risk populations and increased risk of malaria resurgence. In Bissau, malaria prevalence decreased from ∼50% to 3% between 1995 and 2003. The epidemiological characteristics of P. falciparum malaria within Bandim health and demographic surveillance site (population ∼100000) between 1995 and 2012 are described.Methods and FindingsThe population was determined by census. 3603 children aged <15 years that were enrolled in clinical trials at the Bandim health centre (1995–2012) were considered incident cases. The mean annual malaria incidence per thousand children in 1995–1997, 1999–2003, 2007, 2011, 2012 were as follows; age <5 years 22→29→4→9→3, age 5–9 years 15→28→4→33→12, age 10–14 years 9→15→1→45→19. There were 4 campaigns (2003–2010) to increase use of insecticide treated bed nets (ITN) amongst children <5 years. An efficacious high-dose chloroquine treatment regime was routinely used until artemisinin based combination therapy (ACT) was introduced in 2008. Long lasting insecticide treated bed nets (LLIN) were distributed in 2011. By 2012 there was 1 net per 2 people and 97% usage. All-cause mortality decreased from post-war peaks in 1999 until 2012 in all age groups and was not negatively affected by malaria resurgence.ConclusionThe cause of decreasing malaria incidence (1995–2007) was probably multifactorial and coincident with the use of an efficacious high-dose chloroquine treatment regime. Decreasing malaria prevalence created a susceptible group of older children in which malaria resurged, highlighting the need to include all age groups in malaria interventions. ACT did not hinder malaria resurgence. Mass distribution of LLINs probably curtailed malaria epidemics. All-cause mortality was not negatively affected by malaria resurgence.

Patterns of malaria indices across three consecutive seasons in children in a highly endemic area of West Africa: a three times-repeated cross-sectional study.

ObjectivesTo study the manifestations of Plasmodium infection, and its relations with the malaria disease, especially when comparing dry and rainy seasons in a hyperendemic area of West Africa.MethodsThe study was carried out in an area where malaria transmission is high, showing important seasonal variations. One thousand children, representing the total child population (1–12 year old), were observed transversally at the end of three consecutive seasons (dry/rainy/dry). The usual indicators, such as parasite density, splenomegaly, anaemia, or febrile disease were recorded and analysed.ResultsThe prevalence of Plasmodium falciparum was high in all age groups and seasons, constantly around 60%. The high transmission season (rainy) showed higher rates of anaemia and spleen enlargement and, in the youngest children only, higher parasite densities. There were also differences between the two dry seasons: in the first one, there was a higher rate of fever than in the second one (p < 0.001). Low parasite density (<2,000 p/μl) was never associated with fever during any season, raising some concern with regard to the usefulness of parasite detection. The possible origins of fever are discussed, together with the potential usefulness of analyzing these indices on a population sample, at a time when fever incidence rises and malaria is one potential cause among others. The distinction to be made between the Plasmodium infection and the malaria disease is highlighted.ConclusionsThese data confirm previous hypotheses of a strong difference in malaria infection and disease between dry and rainy seasons. The most relevant seasonal indicator was not mainly parasite rate and density but anaemia, spleen enlargement, prevalence and possible origin of fever.RecommendationsIn any situation (i.e. fever or not) and especially during the dry season, one must consider that detection of parasites in the blood is only evidence of a Plasmodium infection and not necessarily of a malaria disease. In such a situation, it seems suitable to obtain, through national malaria teams, a well-defined situation of transmission and prevalence of Plasmodium infection following zones and seasons, in order to adapt control strategies. For researchers, a systematic management of data separately for dry and rainy season appears mandatory.

Malaria has retreated but is not yet defeated: low Plasmodium falciparum prevalence and artemisinin resistance in north Cambodia

A cross-sectional population-based survey using a two-stage cluster sampling was conducted in the rural districts of Chhaeb and Chey Saen, from September to October 2013. In each district, 30 clusters of 10 households were randomly selected, totalling 1275 participants in Chhaeb and 1224 in Chey Saen. Prevalence of Plasmodium spp carriage was assessed by real-time PCR on 5 μL dried blood spot. P. falciparum positive samples were screened for a recently identified artemisinin resistance molecular marker (K13 mutation). Additionally, 2 mL venous blood was collected in 491 participants from two villages to enable evaluation of the PCR-detection rate using different blood volumes. The study was approved by the Cambodian National Ethics Committee and the MSF Ethics Review Board.

Characterization of drug resistance associated genetic polymorphisms among Plasmodium falciparum field isolates in Ujjain, Madhya Pradesh, India.

BackgroundSince 2011, artesunate + sulphadoxine-pyrimethamine (ASP), instead of chloroquine, has been recommended for treatment of uncomplicated malaria in India. In Ujjain, central India, with an annual parasite index <0.1, the prevalence of drug-resistant Plasmodium falciparum is unknown. In other parts of India chloroquine and sulphadoxine-pyrimethamine-resistant P. falciparum is prevalent. The aim of this study was to determine the prevalence of anti-malarial drug resistance-associated genetic polymorphisms in P. falciparum collected in Ujjain in 2009 and 2010, prior to the introduction of ASP.MethodsBlood samples from 87 patients with P. falciparum mono-infection verified by microscopy were collected on filter-paper at all nine major pathology laboratories in Ujjain city. Codons Pfcrt 72–76, pfmdr1 1034–1246, pfdhfr 16–185, pfdhps 436–632 and pfnhe1 ms4760 haplotypes were identified by sequencing. Pfcrt K76T and pfmdr1 N86Y were identified by restriction fragment length polymorphism, and pfmdr1 gene copy number by real-time PCR.ResultsSulphadoxine-pyrimethamine resistance-associated pfdhfr 108 N and 59R alleles were found in 75/78 (96%) and 70/78 (90%) samples, respectively, and pfdhps 437G was found in 7/77 (9%) samples. Double mutant pfdhfr 59R + 108 N were found in 62/76 (82%) samples. Triple mutant pfdhfr 59R + 108 N and pfdhps 437G were found in 6/76 (8%) samples. Chloroquine-resistance-associated pfcrt 76 T was found in 82/87 (94%). The pfcrt 72–76 haplotypes found were: 80/84 (95%) SVMNT, 3/84 (4%) CVMNK and 1/84 (1%) CVMNT. Pfmdr1 N86 and 86Y were identified in 70/83 (84%) and 13/83 (16%) samples, respectively. Pfmdr1 S1034 + N1042 + D1246 were identified together in 70/72 (97%) of successfully sequenced samples. One pfmdr1 gene copy was found in 74/75 (99%) successfully amplified samples.ConclusionThis is the first characterization of key anti-malarial drug resistance-associated genetic markers among P. falciparum collected in Ujjain, Madhya Pradesh, India. The results indicate that the efficacy of standard dose chloroquine at the time of the study was likely to be poor, whereas ASP was likely to be efficacious, supporting the changed drug treatment policy. However, P. falciparum with reduced susceptibility to sulphadoxine-pyrimethamine is highly prevalent, highlighting the need for continuous surveillance of ASP efficacy in the study area.

Parasite prevalence in a village in Burkina Faso: the contribution of new techniques.

Parasites are a major public health problem in developing countries. A coproparasitological and immunoparasitological study was conducted in Burkina Faso, in the rural village of Touguri, in November and December 2011. The coproparasitologic analysis was conducted in the pediatric population and seroprevalence surveys were conducted in the adult population to research intestinal, blood, and helminth parasites. The coproparasitologic study was performed on stool samples using two diagnostic methods - standard microscopy and the FLOTAC technique. The total of 49 stool samples analyzed were obtained from children between two months and eleven years of age. The serology study was carried out to evaluate the prevalence of P. falciparum, Echinococcus spp., Tenia solium, and A. lumbricoides using different immunological techniques such as ELISA and Western Blot techniques. The study population included 85 adult patients between 15 and 70 years of age. Results of coproparasitological analyses showed Hymenolepis nana as the only helminth found, in 28.6% of the total number of patients. Results of serological evaluation revealed a practically null prevalence of Echinococcus, Taenia solium, and Ascaris lumbricoides, and a 77.64% prevalence of Plasmodium falciparum. Despite the small number (especially in terms of coprological samples) of individuals examined, this study showed that the parasite prevalence in a rural area of Burkina Faso has a significant impact in the general population, particularly in children. Another finding was that FLOTAC had a higher sensitivity than the widely used ethyl ether-based concentration technique for coprological sample analysis.

Indoor residual spraying in combination with insecticide-treated nets compared to insecticide-treated nets alone for protection against malaria: a cluster randomised trial in Tanzania.

Insecticide-treated nets (ITNs) and indoor residual spraying (IRS) of houses provide effective malaria transmission control. There is conflicting evidence about whether it is more beneficial to provide both interventions in combination. A cluster randomised controlled trial was conducted to investigate whether the combination provides added protection compared to ITNs alone. In northwest Tanzania, 50 clusters (village areas) were randomly allocated to ITNs only or ITNs and IRS. Dwellings in the ITN+IRS arm were sprayed with two rounds of bendiocarb in 2012. Plasmodium falciparum prevalence rate (PfPR) in children 0.5-14 y old (primary outcome) and anaemia in children <5 y old (secondary outcome) were compared between study arms using three cross-sectional household surveys in 2012. Entomological inoculation rate (secondary outcome) was compared between study arms. IRS coverage was approximately 90%. ITN use ranged from 36% to 50%. In intention-to-treat analysis, mean PfPR was 13% in the ITN+IRS arm and 26% in the ITN only arm, odds ratio = 0.43 (95% CI 0.19-0.97, n = 13,146). The strongest effect was observed in the peak transmission season, 6 mo after the first IRS. Subgroup analysis showed that ITN users were additionally protected if their houses were sprayed. Mean monthly entomological inoculation rate was non-significantly lower in the ITN+IRS arm than in the ITN only arm, rate ratio = 0.17 (95% CI 0.03-1.08). This is the first randomised trial to our knowledge that reports significant added protection from combining IRS and ITNs compared to ITNs alone. The effect is likely to be attributable to IRS providing added protection to ITN users as well as compensating for inadequate ITN use. Policy makers should consider deploying IRS in combination with ITNs to control transmission if local ITN strategies on their own are insufficiently effective. Given the uncertain generalisability of these findings, it would be prudent for malaria control programmes to evaluate the cost-effectiveness of deploying the combination. www.ClinicalTrials.gov NCT01697852 Please see later in the article for the Editors' Summary.

Characterization of malaria transmission during military crisis in urban area of Bouake, Central Cote d’Ivoire

Background: During the past 10 years, Cote d’Ivoire has experienced a serious military and political crisis that disrupted the environment of towns and villages. From the change of the initial environment emerge new landscapes favourable to tropical diseases vectors and pests. To investigate the real situation of malaria in a war zone, a survey was conducted from April 2008 to March 2009 in the urban area of Kennedy in Bouake, central Cote d’Ivoire. Methods & Materials: Entomological data were collected from the human landing catches and parasitological data were obtained from blood smear and thick film in children aged 0 to 15 years, following a clinical examination. Results: The Culicidae fauna collected is characterized by three main malaria vectors, An. gambiae, A. funestus, An nili. However, An. gambiae and An. funestus transmitted Plasmodium with means sporozoite rates of 2.8% and 12.5%, respectively. The aggressive rates of both vectors were 29 and 0.7 b/m/n respectively. The endemicity of the study area estimated by the entomological inoculation rate (EIR) was 296 infected bites/man/year (ib/m/y) for An. gambiae and 33 ib/m/y for An. funestus. Mean prevalence of Plasmodium falciparum was estimated to 83% and Plasmodium falciparum is responsible for 100% of infections. Conclusion: During the political contributed to modify transmission ecology of Plasmodium in urban Bouake as malaria vectors found previously in rural areas were collected in this high urbanized area of Kennedy in Bouake.

Impact of long-lasting, insecticidal nets on anaemia and prevalence of Plasmodium falciparum among children under five years in areas with highly resistant malaria vectors

BackgroundThe widespread use of insecticide-treated nets (LLINs) leads to the development of vector resistance to insecticide. This resistance can reduce the effectiveness of LLIN-based interventions and perhaps reverse progress in reducing malaria morbidity. To prevent such difficulty, it is important to know the real impact of resistance in the effectiveness of mosquito nets. Therefore, an assessment of LLIN efficacy was conducted in malaria prevention among children in high and low resistance areas.MethodsThe study was conducted in four rural districts and included 32 villages categorized as low or high resistance areas in Plateau Department, south-western Benin. Larvae collection was conducted to measure vector susceptibility to deltamethrin and knockdown resistance (kdr) frequency. In each resistance area, around 500 children were selected to measure the prevalence of malaria infection as well as the prevalence of anaemia associated with the use of LLINs.ResultsObserved mortalities of Anopheles gambiae s.s population exposed to deltamethrin ranged from 19 to 96%. Knockdown resistance frequency was between 38 and 84%. The prevalence of malaria infection in children under five years was 22.4% (19.9-25.1). This prevalence was 17.3% (14.2-20.9) in areas of high resistance and 27.1% (23.5-31.1) in areas of low resistance (p = 0.04). Eight on ten children that were aged six - 30 months against seven on ten of those aged 31–59 months were anaemic. The anaemia observed in the six to 30-month old children was significantly higher than in the 31–59 month old children (p = 0.00) but no difference associated with resistance areas was observed (p = 0.35). The net use rate was 71%. The risk of having malaria was significantly reduced (p < 0.05) with LLIN use in both low and high resistance areas. The preventive effect of LLINs in high resistance areas was 60% (95% CI: 40–70), and was significantly higher than that observed in low resistance areas (p < 0.05).ConclusionThe results of this study showed that the resistance of malaria vectors seems to date not have affected the impact of LLINs and the use of LLINs was highly associated with reduced malaria prevalence irrespective of resistance.

The effect of insecticide-treated bed nets on the incidence and prevalence of malaria in children in an area of unstable seasonal transmission in western Myanmar

BackgroundInsecticide-treated bed nets (ITN) reduce malaria morbidity and mortality consistently in Africa, but their benefits have been less consistent in Asia. This study’s objective was to evaluate the malaria protective efficacy of village-wide usage of ITN in Western Myanmar and estimate the cost-effectiveness of ITN compared with extending early diagnosis and treatment services.MethodsA cluster-randomized controlled trial was conducted in Rakhine State to assess the efficacy of ITNs in preventing malaria and anaemia in children and their secondary effects on nutrition and development. The data were aggregated for each village to obtain cluster-level infection rates. In total 8,175 children under 10 years of age were followed up for 10 months, which included the main malaria transmission period. The incidence and prevalence of Plasmodium falciparum and Plasmodium vivax infections, and the biting behaviour of Anopheles mosquitoes in the area were studied concurrently. The trial data along with costs for current recommended treatment practices were modelled to estimate the cost-effectiveness of ITNs compared with, or in addition to extending the coverage of early diagnosis and treatment services.ResultsIn aggregate, malaria infections, spleen rates, haemoglobin concentrations, and weight for height, did not differ significantly during the study period between villages with and without ITNs, with a weighted mean difference of −2.6 P. falciparum episodes per 1,000 weeks at risk (95% Confidence Interval −7 to 1.8). In areas with a higher incidence of malaria there was some evidence ITN protective efficacy. The economic analysis indicated that, despite the uncertainty and variability in their protective efficacy in the different study sites, ITN could still be cost-effective, but not if they displaced funding for early diagnosis and effective treatment which is substantially more cost-effective.ConclusionIn Western Myanmar deployment of ITNs did not provide consistent protection against malaria in children living in malaria endemic villages. Early diagnosis and effective treatment is a more cost effective malaria control strategy than deployment of ITNs in this area where the main vector bites early in the evening, often before people are protected by an ITN.

Ordered Accumulation of Mutations Conferring Resistance to Sulfadoxine-Pyrimethamine in the Plasmodium falciparum Parasite

Monitoring the prevalence of drug resistant Plasmodium falciparum is essential for effective malaria control. Resistance to pyrimethamine and sulfadoxine increases as mutations accumulate in the parasite genes encoding dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps), respectively. Although parasites are exposed to these antifolate drugs simultaneously, it remains virtually unknown whether dhfr and dhps mutations accumulate along interrelated paths. We investigated the order of step-wise accumulation in dhfr and dhps by cumulative analyses using binomial tests in 575 P. falciparum isolates obtained from 7 countries in Asia and Melanesia. An initial step in the accumulation of mutations preferentially occurred in dhfr (2 mutations), followed by 1 mutation in dhps. In a subsequent step, mutations were estimated separately for 5 dhfr/dhps-resistant lineages identified using 12 microsatellites flanking dhfr and dhps. Among these lineages, we found 3 major mutational paths, each of which follows a unique stepwise trajectory to produce the most highly resistant form with 4 mutations in dhfr and 3 in dhps. The ordered accumulation of mutations in dhfr and dhps elucidated here will assist in predicting the status and progression of antifolate resistance in malaria-endemic regions where antifolate drugs are used for intermittent preventive treatment.