Levels Of Malaria Transmission Research Articles

Malaria prevalence and transmission in the Zakpota sub-district of central Benin: baseline characteristics for a community randomised trial of a new insecticide for indoor residual spraying

BackgroundMalaria transmission is known to be perennial and heterogeneous in Benin. Studies assessing local malaria prevalence, transmission levels and vector characteristics are critical for designing, monitoring and evaluating new vector control interventions in community trials. We conducted a study in the Zakpota sub-district of central Benin to collect baseline data on household characteristics, malaria prevalence, vector characteristics and transmission dynamics in preparation for a randomised controlled trial to evaluate the community impact of VECTRON™ T500, a new broflanilide indoor residual spraying (IRS) product.MethodsA total of 480 children under 5 years of age from the 15 villages of the sub-district were tested for malaria by rapid diagnostic tests (RDTs). Mosquitoes were collected by human landing catches (HLCs), pyrethrum spray catches (PSCs) and Centers for Disease Control and Prevention miniature light traps (CDC-LTs) in selected houses in each village to assess vector density, composition, vector infectivity and prevalence of insecticide resistance markers. Bioassays were performed to detect vector susceptibility to pyrethroids, broflanilide (6 µg/bottle) and clothianidin (90 µg/bottle).ResultsA total of 9080 households were enumerated in the 15 study villages. Insecticide-treated net (ITN) usage was > 90%, with 1–2 ITNs owned per household. Houses were constructed mainly with cement (44%) and mud (38%) substrates or a mixture of cement and mud (18%), and 60% of them had open eaves. The overall prevalence of P. falciparum infection was 19% among surveyed children: 20% among females and 18% among males. The haemoglobin rate showed an anaemia (< 11 g/dl) prevalence of 66%. Anopheles coluzzii and An. gambiae sensu stricto (s.s.) were the two vector species present at an overall proportion of 46% versus 54%, respectively. The human biting rate was 2.3 bites per person per night (b/p/n) and biting occurred mostly indoors compared with outdoors (IRR = 0.776; P = 0.001). The overall proportion of outdoor biting was 44% and exceeded indoor biting in three villages. The sporozoite rate was 2% with a combined yearly entomological inoculation rate (EIR) of 16.1 infected bites per person per year (ib/p/y). There was great variability in malaria transmission risk across the villages, with EIR ranging from 0 to 29.3 ib/p/y. The vector population showed a high intensity of resistance to pyrethroids across the study villages but was largely susceptible to broflanilide and clothianidin.ConclusionsThis study found high levels of malaria prevalence, vector density and transmission in the Zakpota sub-district despite the wide use of insecticide-treated nets. The vector population was mostly indoor resting and showed a high intensity of pyrethroid resistance but was generally fully susceptible to broflanilide. These findings demonstrated the suitability of the study area for the assessment of VECTRON™ T500 in a community randomised trial.Graphical

Genomics reveals heterogeneous Plasmodium falciparum transmission and selection signals in Zambia

BackgroundGenomic surveillance is crucial for monitoring malaria transmission and understanding parasite adaptation to interventions. Zambia lacks prior nationwide efforts in malaria genomic surveillance among African countries.MethodsWe conducted genomic surveillance of Plasmodium falciparum parasites from the 2018 Malaria Indicator Survey in Zambia, a nationally representative household survey of children under five years of age. We whole-genome sequenced and analyzed 241 P. falciparum genomes from regions with varying levels of malaria transmission across Zambia and estimated genetic metrics that are informative about transmission intensity, genetic relatedness between parasites, and selection.ResultsWe provide genomic evidence of widespread within-host polygenomic infections, regardless of epidemiological characteristics, underscoring the extensive and ongoing endemic malaria transmission in Zambia. Our analysis reveals country-level clustering of parasites from Zambia and neighboring regions, with distinct separation in West Africa. Within Zambia, identity by descent (IBD) relatedness analysis uncovers local spatial clustering and rare cases of long-distance sharing of closely related parasite pairs. Genomic regions with large shared IBD segments and strong positive selection signatures implicate genes involved in sulfadoxine-pyrimethamine and artemisinin combination therapies drug resistance, but no signature related to chloroquine resistance. Furthermore, differences in selection signatures, including drug resistance loci, are observed between eastern and western Zambian parasite populations, suggesting variable transmission intensity and ongoing drug pressure.ConclusionsOur findings enhance our understanding of nationwide P. falciparum transmission in Zambia, establishing a baseline for analyzing parasite genetic metrics as they vary over time and space. These insights highlight the urgency of strengthening malaria control programs and surveillance of antimalarial drug resistance.

Evolution and spread of Plasmodium falciparum mutations associated with resistance to sulfadoxine–pyrimethamine in central Africa: a cross-sectional study

Efficacy of sulfadoxine-pyrimethamine, the malaria chemoprophylaxis used in pregnant women, and in children when combined with amodiaquine, is threatened by the accumulation of mutations in the Plasmodium falciparum dihydropteroate synthase (pfdhps) and dihydrofolate reductase (pfdhfr) genes. Data on the prevalence of resistant alleles in central Africa and the new pfdhps I431V mutation, particularly associated with other mutations to form the pfdhps vagKgs allele, are scarce. We explored the frequency and geographical distribution of pfdhps and pfdhfr mutations in central Africa in 2014-18, and assessed the evolutionary origin of the vagKgs allele. Samples were collected at 18 health-care centres in seven countries (Angola, Cameroon, Central African Republic, Democratic Republic of the Congo, Gabon, Nigeria, and Republic of the Congo) from patients who showed possible symptoms of malaria between March 1, 2014, and Oct 31, 2018. Samples that were positive for P falciparum were transported to a laboratory in Toulouse, France, and genotyped. The frequency of pfdhfr and pfdhps mutations was studied in 1749 samples. Microsatellites in pfdhps flanking regions and whole-genome analysis compared with parasite genomes from the data-sharing network MalariaGEN were performed on samples carrying the vagKgs allele. Mapping of the prevalence of single nucleotide polymorphisms and corresponding alleles of pfdhfr and pfdhps showed a substantial spread of alleles associated with sulfadoxine-pyrimethamine resistance in central Africa during the 2014-18 period, especially an increase going west to east in pfdhps alleles carrying the K540E and A581G mutations. A high prevalence of the pfdhps I431V mutation was observed in Cameroon (exceeding 50% in the northern region) and Nigeria. Genomic analysis showed a recent African emergence and a clonal expansion of the most frequent pfdhps vagKgs allele. Reduced sulfadoxine-pyrimethamine efficacy due to increased resistance is a worrying situation, especially because the malaria transmission level is high in central Africa. Although the resistance phenotype remains to be confirmed, the emergence and spread of the vagKgs allele in west and central Africa could challenge the use of sulfadoxine-pyrimethamine. Toulouse Institute for Infectious and Inflammatory Diseases.

A High Proportion of Malaria Vector Biting and Resting Indoors despite Extensive LLIN Coverage in Côte d'Ivoire.

Malaria is still a leading cause mortality in Côte d'Ivoire despite extensive LLINs coverage. We present the results of an entomological survey conducted in a coastal and in an inland village with the aim to estimate Anopheles gambiae sensu lato (s.l.) female's abundance indoor/outdoor and Plasmodium falciparum infection rate and analyze the occurrence of blood-feeding in relation to LLINs use. Pyrethrum spray (PSC) and window exit traps (WT) collections were carried out to target endophagic/endophilic and endophagic/exophilic females, respectively. Data on LLINs use in sampled houses were collected. (1) high levels of malaria transmission despite LLINs coverage >70% (~1 An. gambiae s.l. predicted mean/person/night and ~5% Plasmodium falciparum infection rate); (2) 46% of females in the PSC sample were blood-fed, suggesting that they fed on an unprotected host inside the house; (3) 81% of females in WT were unfed, suggesting that they were leaving the house to find an available host. Model estimates that if everyone sleeps under LLINs the probability for a mosquito to bite decreases of 48% and 95% in the coastal and inland village, respectively. The results show a high proportion of mosquito biting and resting indoors despite extensive LLINs. The biological/epidemiological determinants of accounting for these results merit deeper investigations.

Investigating Practices Among Fish Farmers That Predispose Them To Malaria Infection: An Analytical Cross Section Survey In Mongu And Limulunga Districts Of Western Province, Zambia

Malaria is a parasitic disease that is transmitted between humans through the bite of the infected female Anopheles mosquito. Zambia has recently experienced a growing demand for fish, which is largely triggered by the growing population and an emergent urban middle class within Zambia and neighbouring countries. Various fish farming practices are carried out on small-scale, smallholder and commercial levels. Western Province is among the provinces in Zambia where fish farming is done. In 2014, Zambia became the sixth largest producer of farmed fish (mainly breams – a local name for tilapia) in Africa and the largest in the Southern African Development Community (SADC) and between 2012 and 2015, the malaria prevalence started to climb from 12.6 to 15.6 per cent in Western Province of Zambia. This study set out to investigate the practices of fish farmers that predispose them to malaria infection in Mongu (45) and Limulunga (30) districts of the western province of Zambia. The data collection tool was an interviewer-administered questionnaire (demographic characteristics, malaria knowledge, and fish farming practices). The data were analysed using the Statistical Package for Social Sciences (SPSS) version 22. Out of a total of 75 fish farmers, 83% of the participants had good knowledge of malaria while 17% had poor knowledge, and an association was found between the two highest levels of education (Tertiary and Secondary) and knowledge on malaria according to the chi-squared test (p&lt;0.005) and also showed that 73% (n=55) had their ponds near their houses and 3% (n=20) had their ponds far from their houses. Practices such as not draining ponds, working around the ponds at night without protective clothing, and having ponds near households predispose fish farmers to malaria infection in Mongu and Limulunga districts in Western Province, Zambia. Collectively, 21% of fish farmers practice unsafe fish farming, which could potentially increase malaria transmission levels in Western Province, Zambia.

Plasmodium malariae contributes to high levels of malaria transmission in a forest–savannah transition area in Cameroon

BackgroundMalaria control efforts are highly skewed towards Plasmodium falciparum while overlooking other Plasmodium species such as P. malariae. A better understanding of the role of Plasmodium species other than P. falciparum is needed to strengthen malaria elimination initiatives. The aim of the present study was to elucidate the contribution of P. malariae to malaria transmission in Cameroon.MethodsThe study was conducted in the Ngatti Health District, a forest–savannah transition area in the Adamawa Region, Cameroon. A total of 497 individuals aged from 1 to 85 years were diagnosed with malaria in November 2020 using a rapid diagnostic test (RDT) and microscopy. Adult mosquitoes were collected between September 2019 and March 2020 by indoor aspiration and identified morphologically and molecularly. The infection status of Plasmodium spp. was also determined by quantitative PCR, and dried blood spots were collected from 156 participants with the aim to detect different Plasmodium species by nested PCR.ResultsThe overall Plasmodium prevalence was 50.3%, 51.8% and 64.7%, as detected by microscopy, the RDT and PCR, respectively. Based on the PCR results, P. falciparum was the most prevalent species (43%); followed by co-infections P. falciparum/P. malariae (17%), P. falciparum/P. ovale (1.3%), P. falciparum/P. ovale/P. malariae (1.3%); and then by P. malariae mono-infection (2.5%). The same trend was observed using microscopy, with 35% of participants infected with P. falciparum, 11% co-infected with P. falciparum/P. malariae and 4% infected with P. malariae. The prevalence and parasite density of malaria infection varied significantly with age group (P < 0.05), with the highest prevalence rate observed in children aged 6–10 years (P = 0.0001) while the density of Plasmodium infection increased significantly in children aged < 5 years compared to the other age groups (P = 10−3). Among the 757 Anopheles mosquitoes collected, 737 (97.35%) were An. funestus sensu stricto, 15 (1.9%) were An. gambiae and 5 (0.6%) were An. hancocki. The Plasmodium species recorded at the head/thorax level were P. falciparum and P. malariae, with a sporozoite infection rate of 8.4%; the highest sporozoite infection rate was recorded at Mibellon village (13.6%).ConclusionThe results of this study reveal the significant contribution of P. malariae, in addition to P. falciparum, to the high malaria transmission rate in this region. These findings highlight the need to deploy initiatives to also tackle this Plasmodium species to eliminate malaria in the region.Graphical

Impact of malaria control interventions on malaria infection and anaemia in low malaria transmission settings: a cross-sectional population-based study in Sudan.

The past two decades were associated with innovation and strengthening of malaria control interventions, which have been increasingly adopted at large scale. Impact evaluations of these interventions were mostly performed in moderate or high malaria transmission areas. This study aimed to evaluate the use and performance of malaria interventions in low transmission areas on malaria infections and anaemia. Data from the 2016 Sudan malaria indicator survey was used. Multi-level logistic regression analysis was used to assess the strength of association between real-life community-level utilization of malaria interventions [diagnosis, artemisinin-based combination therapies (ACTs) and long-lasting insecticidal nets (LLINs)] and the study outcomes: malaria infections and anaemia (both overall and moderate-to-severe anaemia). The study analysis involved 26,469 individuals over 242 clusters. Malaria infection rate was 7.6%, overall anaemia prevalence was 47.5% and moderate-to-severe anaemia prevalence was 4.5%. The average community-level utilization was 31.5% for malaria diagnosis, 29.9% for ACTs and 35.7% for LLINs. The odds of malaria infection was significantly reduced by 14% for each 10% increase in the utilization of malaria diagnosis (adjusted odds ratio (aOR) per 10% utilization 0.86, 95% CI 0.78-0.95, p = 0.004). However, the odds of infection was positively associated with the utilization of LLINs at community-level (aOR per 10% utilization 1.20, 95% CI 1.11-1.29, p < 0.001). No association between malaria infection and utilization of ACTs was identified (aOR per 10% utilization 0.97, 95% CI 0.91-1.04, p = 0.413). None of the interventions was associated with overall anaemia nor moderate-to-severe anaemia. There was strong evidence that utilization of malaria diagnosis at the community level was highly protective against malaria infection. No protective effect was seen for community utilization of ACTs or LLINs. No association was established between any of the interventions and overall anaemia or moderate-to-severe anaemia. This lack of effectiveness could be due to the low utilization of interventions or the low level of malaria transmission in the study area. Identification and response to barriers of access and low utilization of malaria interventions are crucial. It is crucial to ensure that every suspected malaria case is tested in a timely way, notably in low transmission settings.

Knowledge, attitudes, and practices of Anopheles mosquito control through insecticide treated nets and community-based health programs to prevent malaria in East Sumba Island, Indonesia.

With an estimated 241 million human cases and 627,000 deaths in 2020, malaria remains a significant and ongoing global health challenge. This study employs a qualitative approach to investigate knowledge, attitudes, and practices surrounding mosquito control and prevention methods in East Sumba Regency, Indonesia. While malaria is under control in much of Indonesia, transmission in Sumba Island remains high, with incidence as high as 500 per 1000 population in some areas. A qualitative study was undertaken to explore use of insecticide treated nets, (ITNs), traditional Sumbanese mosquito control methods, and the role of women, integrated health service posts, (posyandu) and community-based health workers (kaders) in combatting malaria and controlling mosquitoes. Focus group discussions (n = 7) were conducted in East Sumba Island stratified by urban/rural location and level of malaria transmission. Key informant interviews (n = 14) were conducted with religious leaders, health workers, and women's group leaders. Results indicate that environmental conditions, such as high temperatures, were common deterrents to regular ITN use. Furthermore, our results suggest that community embedded health workers, kaders, and health service posts, posyandu, play an important role in information dissemination related to mosquitoes and mosquito-borne diseases as well as the distribution and use of ITNs in East Sumba Island. The role of the posyandu and kaders could be expanded to improve malaria prevention by integration with educational campaigns, aiding ITN distributions, and malaria diagnosis and treatment. This study is the first to examine mosquito-borne disease-related knowledge, attitudes, and practices in East Sumba Island, Indonesia. Results could improve mosquito control and malaria prevention by providing insights into local knowledge of Anopheles mosquitoes and malaria as well. Tailoring mosquito control and malaria prevention strategies around local knowledge and perceptions is likely to be more acceptable and sustainable.

DNA recovery from used malaria RDT to detect Plasmodium species and to assess Plasmodium falciparum genetic diversity: a pilot study in Madagascar

BackgroundRapid diagnostic tests (RDT) are widely used for malaria diagnosis in Madagascar, where Plasmodium falciparum is the predominant species. Molecular diagnosis is essential for malaria surveillance, but requires additional blood samples for DNA extraction. Used RDTs is an attractive alternative that can be used as a source of DNA. Plasmodium falciparum genetic diversity and multiplicity of infection, usually determined by the genotyping of polymorphic regions of merozoite surface proteins 1 and 2 genes (msp1, msp2), and the repeated region RII of the glutamate-rich protein gene (glurp) have been associated with malaria transmission levels and subsequently with the impact of the deployed control strategies.Thus, the study aims to use RDT as DNA source to detect Plasmodium species, to characterize Plasmodium falciparum genetic diversity and determine the multiplicity of infection.MethodsA pilot study was conducted in two sites with different epidemiological patterns: Ankazomborona (low transmission area) and Matanga (high transmission area). On May 2018, used RDT (SD BIOLINE Malaria Ag P.f/Pan, 05FK63) were collected as DNA source. Plasmodium DNA was extracted by simple elution with nuclease free water. Nested-PCR were performed to confirm Plasmodium species and to analyse P. falciparum msp1, msp2 and glurp genes polymorphisms.ResultsAmongst the 170 obtained samples (N = 74 from Ankazomborona and N = 96 from Matanga), Plasmodium positivity rate was 23.5% (40/170) [95% CI 17.5–30.8%] by nested-PCR with 92.2% (37/40) positive to P. falciparum, 5% (2/40) to Plasmodium vivax and 2.5% (1/40) to P. falciparum/P. vivax mixed infection. Results showed high polymorphisms in P. falciparum msp1, msp2 and glurp genes. Multiple infection rate was 28.6% [95% CI 12.2–52.3%]. The mean of MOI was 1.79 ± 0.74.ConclusionThis pilot study highlighted that malaria diagnosis and molecular analysis are possible by using used malaria RDT. A large-scale study needs to be conducted to assess more comprehensively malaria parasites transmission levels and provide new data for guiding the implementation of local strategies for malaria control and elimination.Trial registration Retrospectively registered

Impact of Malaria Diagnostic Technologies on the Disease Burden in the Sub-Saharan Africa.

Worldwide, transmission of emerging and reemerging malaria infections poses a significant threat to human health in the Sub-Saharan Africa, one that can quickly overwhelm public health resources. While the disease burden of malaria in the Sub-Saharan Africa appears to be on a gradual decline, it is characterized by spatial and temporal variability occasioning a sorry state for the Global South Countries. New evidence on long-term complications of malaria heightens our awareness of its public health impact. Given the likelihood of misdiagnosis, and the unknown levels of malaria transmission across different landscapes, many missed opportunities for prevention occur. Africa's population growth, unplanned urbanization, habitat destruction, and trans-border travel are contributing to a rise in the calamitous epidemiology of malaria. Despite empirical statistics demonstrating a downward trend in the malaria disease burden attributable to the scale-up of multiple control strategies, including new diagnostic technologies, malaria remains a global threat to human health in Sub-Sahara Africa. Malaria is a severe public health threat globally, despite several advancements and innovations in its control. Six species of the genus Plasmodium including Plasmodium malariae, Plasmodium falciparum, Plasmodium cynomolgi, Plasmodium knowlesi, Plasmodium ovale, and Plasmodium vivax are known to infect humans. However, greatest disease burden and fatalities are caused by Plasmodium falciparum. Globally, about 3 billion individuals are at risk of contracting malaria disease every year, with over 400,000 fatalities reported in the Sub-Saharan Africa. World Health Organization (WHO) 2018 malaria report indicated that approximately 405,000 mortalities and 228 million cases were reported worldwide, with Africa carrying the highest disease burden. Over the last decade, there has been a significant decline in malaria deaths and infections, which may be related to the availability of effective diagnostic techniques. However, in certain areas, the rate of decline has slowed or even reversed the gains made so far. Accurate diagnosis, adequate treatment, and management of the disease are critical WHO-set goals of eliminating malaria by 2030. Microscopy, rapid diagnostic tests (RDTs), nucleic acid amplification tests (NAATs), and biosensors are all currently accessible diagnostic methods. These technologies have substantial flaws and triumphs that could stymie or accelerate malaria eradication efforts. The cost, ease, accessibility, and availability of skilled persons all influence the use of these technologies. These variables have a direct and indirect ramification on the entire management portfolio of patients. Despite the overall decline in the malaria disease burden driven partly by new diagnostic technologies, a sobering pattern marked by limited number of studies and spatial as well as temporal heterogeneity remains a concern. This review summarizes the principle, performance, gaps, accomplishments, and applicability of numerous malaria diagnostic techniques and their potential role in reducing the malaria disease burden in Sub-Saharan Africa.

Plasmodium falciparum and Plasmodium vivax Adjust Investment in Transmission in Response to Change in Transmission Intensity: A Review of the Current State of Research.

Malaria parasites can adjust the proportion of parasites that develop into gametocytes, and thus the probability for human-to-vector transmission, through changes in the gametocyte conversion rate. Understanding the factors that impact the commitment of malaria parasites to transmission is required to design better control interventions. Plasmodium spp. persist across countries with vast differences in transmission intensities, and in sites where transmission is highly seasonal. Mounting evidence shows that Plasmodium spp. adjusts the investment in transmission according to seasonality of vector abundance, and transmission intensity. Various techniques to determine the investment in transmission are available, i.e., short-term culture, where the conversion rate can be measured most directly, genome and transcriptome studies, quantification of mature gametocytes, and mosquito feeding assays. In sites with seasonal transmission, the proportion of gametocytes, their densities and infectivity are higher during the wet season, when vectors are plentiful. When countries with pronounced differences in transmission intensity were compared, the investment in transmission was higher when transmission was low, thus maximizing the parasite’s chances to be transmitted to mosquitoes. Increased transmissibility of residual infections after a successful reduction of malaria transmission levels need to be considered when designing intervention measures.

Genetic diversity and population structure of the human malaria parasite Plasmodium falciparum surface protein Pfs47 in isolates from the lowlands in Western Kenya.

Plasmodium falciparum parasites have evolved genetic adaptations to overcome immune responses mounted by diverse Anopheles vectors hindering malaria control efforts. Plasmodium falciparum surface protein Pfs47 is critical in the parasite’s survival by manipulating the vector’s immune system hence a promising target for blocking transmission in the mosquito. This study aimed to examine the genetic diversity, haplotype distribution, and population structure of Pfs47 and its implications on malaria infections in endemic lowlands in Western Kenya. Cross-sectional mass blood screening was conducted in malaria endemic regions in the lowlands of Western Kenya: Homa Bay, Kombewa, and Chulaimbo. Dried blood spots and slide smears were simultaneously collected in 2018 and 2019. DNA was extracted using Chelex method from microscopic Plasmodium falciparum positive samples and used to genotype Pfs47 using polymerase chain reaction (PCR) and DNA sequencing. Thirteen observed haplotypes of the Pfs47 gene were circulating in Western Kenya. Population-wise, haplotype diversity ranged from 0.69 to 0.77 and the nucleotide diversity 0.10 to 0.12 across all sites. All the study sites displayed negative Tajima’s D values although not significant. However, the negative and significant Fu’s Fs statistical values were observed across all the study sites, suggesting population expansion or positive selection. Overall genetic differentiation index was not significant (FST = -0.00891, P > 0.05) among parasite populations. All Nm values revealed a considerable gene flow in these populations. These results could have important implications for the persistence of high levels of malaria transmission and should be considered when designing potential targeted control interventions.

Spatio-temporal Epidemiology of Malaria Mortality in Nigeria: Why the war against poverty must be won

Malaria is a major parasitic disease in the world including Nigeria which currently bears the brunt of the global malaria mortality burden. This paper responds to the need for all countries in the world including Nigeria to understand the geographical distribution and drivers of malaria mortality with the aim of consolidating the gains of global malaria elimination. The thrust of this paper therefore was to examine the geographical distribution, spatial clustering and determinant(s) of malaria mortality in Nigeria from 2006 to 2010. Retrospective data used in this research were obtained from published sources and were analysed with the aid of statistical and spatial analytical tools. Very noticeable state variations were observed in the pattern of malaria mortality, and strong and persistent clustering of malaria-related deaths was found in northwest Nigeria particularly Kano State due to high levels of malaria transmission. Lastly, there was a significant and differential effect of poverty on its geographical distribution; with the greatest effect felt in the north of Nigeria. In order to reduce death toll associated with the disease, the war against poverty must not only be intensified but should be mainstreamed into the national malaria control programme.

Genetic Diversity of Plasmodium falciparum Glutamate Rich Protein in Patients Attending the Merauke Hospital in Papua Province, Indonesia

Malaria remains an important health problem in Indonesia with the highest transmission in Papua Province, an easternpart of this country. The genetic diversity of malaria parasites is the main problem in understanding several aspects ofmalaria infections and the dynamics of their transmission, which also play a role in the development of a vaccine.Plasmodium falciparum is the deadliest of the human malaria parasites. Plasmodium falciparum glutamate-rich protein(Pfglurp) is one of the many erythrocytic stages antigens currently under development for a vaccine. The Pfglurp gene hasbeen extensively used as a marker to investigate the genetic diversity, Multiplicity of Infection (MOI), the level of malariatransmission, immunity against malaria, as well as a discriminatory instrument to distinguish new from recrudescentinfections of the field parasite population. Thus, this genotyping study aimed to find out the genetic population ofP.falciparum at the Merauke District, Province of Papua, Indonesia. DNA samples were isolated from Dried Blood Spots(DBS) obtained from P.falciparum infected patients in the Regional Public Hospital of Merauke, Province of Papua, Indonesiaduring May 2019-July 2019. The isolated DNAs were then amplified for nested Polymerase Chain Reaction (PCR) prior toPfglurp genotyping. The glurp gene was identified in all 51 DBS samples of P.falciparum-infected patients, and 18 variants ofallele were found. Among them, 45.10% were found to bear multigenotype infections. The size of the dominant allele(12.5%) was 701-750 bp. The MOI was 1.58. The genetic population of P.falciparum in Merauke Hospital has contained ahigher percentage of multigenotypes compared with monogenotypes indicating the high transmission of malaria in thestudied area.

Malaria Is Associated With Kaposi Sarcoma-Associated Herpesvirus Seroconversion in a Cohort of Western Kenyan Children.

We aimed to determine whether Plasmodium falciparum infection affects age of Kaposi sarcoma-associated herpesvirus (KSHV) seroconversion in Kenyan children. Kenyan children (n = 144) enrolled at age 1 month, from 2 sites with different levels of malaria transmission (stable/high vs unstable/low) were followed to age 24 months. Plasma was tested for KSHV antibodies using enzyme-linked immunosorbent assay (ELISA; K8.1 and LANA) and a multiplex bead-based assay (K8.1, K10.5, ORF38, ORF50, and LANA) and whole blood tested for P. falciparum DNA using quantitative PCR. Cox proportional hazards models were used to assess associations between P. falciparum DNA detection, malaria annualized rate (P. falciparum detections/person-years), and enrollment site (malaria-high vs malaria-low) with time to KSHV seroconversion. KSHV seroprevalence was 63% by age 2 years when assessed by multiplex assay. Children with P. falciparum were at increased hazards of earlier KSHV seroconversion and, among children with malaria, the hazard of becoming KSHV seropositive increased significantly with increasing malaria annualized rate. Children from the malaria-high transmission region had no significant difference in hazards of KSHV seroconversion at 12 months but were more likely to become KSHV seropositive by age 24 months. Malaria exposure increases the risk for KSHV seroconversion early in life.

Plasmodium falciparum and P. malariae: infection rates in the population of Northern Imbo Plain, Burundi.

Background:Burundi is cited among countries where malaria remains endemic. Notably, malaria is highly endemic in Imbo region, a lowland lying astride Lake Tanganyika. Among key malaria riposte interventions includes the promotion of Long-Lasting Insecticidal Nets (LLINs), but its incidence rate has not reduced. In this paper, we present the distribution of malaria species in 2 settings within Imbo region by accounting for the seasonal variations and the mostly infected populations.Methods:The study was conducted from 2 Health Care Centres of Murambi and Rugombo in Cibitoke District, Northern Burundi. Blood samples were collected on blood slides and the samples were used to confirm the presence of malaria parasites by microscopy.Results:The study observed an average malaria parasite prevalence of 32.5% across the selected site. Majority of patients 459(95.2%) were infected by P. falciparum while 8(1.7%) patients were infected by P. malariae. Patients from Murambi were more infected than those from Rugombo. P. falciparum was the most highly prevalent specie in the 2 localities. High prevalence was observed in children aged between 2 and 5 years. Among older participants P. falciparum still predominated and mixed infections were rather the least prevalent.Conclusion:This study showed that P. falciparum and P. malariae are the most parasites involved in malaria morbidity in North Imbo region. The transmission of P. falciparum was observed year-round. Patients in Murambi are most exposed to malaria infections than those in Rugombo. Further research at large scale including entomological studies is required to better understand the relationship between Entomological Inoculation Rates (EIR) and malaria transmission levels in this setting.

Dengue in Western Uganda: a prospective cohort of children presenting with undifferentiated febrile illness

BackgroundThe spatial distribution and burden of dengue in sub-Saharan Africa remains highly uncertain, despite high levels of ecological suitability. The goal of this study was to describe the epidemiology of dengue among a cohort of febrile children presenting to outpatient facilities located in areas of western Uganda with differing levels of urbanicity and malaria transmission intensity.MethodsEligible children were first screened for malaria using rapid diagnostic tests. Children with a negative malaria result were tested for dengue using a combination NS1/IgM/IgG rapid test (SD Bioline Dengue Duo). Confirmatory testing by RT-PCR was performed in a subset of participants. Antigen-capture ELISA was performed to estimate seroprevalence.ResultsOnly 6 of 1416 (0.42%) children had a positive dengue rapid test, while none of the RT-PCR results were positive. ELISA testing demonstrated reactive IgG antibodies in 28 (2.2%) participants with the highest prevalence seen at the urban site in Mbarara (19 of 392, 4.9%, p < 0.001).ConclusionsOverall, these findings suggest that dengue, while present, is an uncommon cause of non-malarial, pediatric febrile illness in western Uganda. Further investigation into the eocological factors that sustain low-level transmission in urban settings are urgently needed to reduce the risk of epidemics.

A cohort study to identify risk factors for Plasmodium falciparum infection in Burkinabe children: implications for other high burden high impact countries

BackgroundProgress in controlling malaria has stalled in recent years. Today the malaria burden is increasingly concentrated in a few countries, including Burkina Faso, where malaria is not declining. A cohort study was conducted to identify risk factors for malaria infection in children in southwest Burkina Faso, an area with high insecticide-treated net (ITN) coverage and insecticide-resistant vectors.MethodsIncidence of Plasmodium falciparum infection was measured in 252 children aged 5 to 15 years, using active and passive detection, during the 2017 transmission season, following clearance of infection. Demographic, socio-economic, environmental, and entomological risk factors, including use of ITNs and insecticide resistance were monitored.ResultsDuring the six-month follow-up period, the overall incidence of P. falciparum infection was 2.78 episodes per child (95% CI = 2.66–2.91) by microscopy, and 3.11 (95% CI = 2.95–3.28) by polymerase chain reaction (PCR). The entomological inoculation rate (EIR) was 80.4 infective bites per child over the six-month malaria transmission season. At baseline, 80.6% of children were reported as sleeping under an ITN the previous night, although at the last survey, 23.3% of nets were in poor condition and considered no longer protective. No association was found between the rate of P. falciparum infection and either EIR (incidence rate ratio (IRR): 1.00, 95% CI: 1.00–1.00, p = 0.08) or mortality in WHO tube tests when vectors were exposed to 0.05% deltamethrin (IRR: 1.05, 95% CI: 0.73–1.50, p = 0.79). Travel history (IRR: 1.52, 95% CI: 1.45–1.59, p < 0.001) and higher socio-economic status were associated with an increased risk of P. falciparum infection (IRR: 1.05, 95% CI: 1.00–1.11, p = 0.04).ConclusionsIncidence of P. falciparum infection remains overwhelmingly high in the study area. The study findings suggest that because of the exceptionally high levels of malaria transmission in the study area, malaria elimination cannot be achieved solely by mass deployment of ITNs and additional control measures are needed.

Genetic Diversity of Merozoite Surface Protein 2 (MSP2) Plasmodium falciparum Clinical Isolate in Wamena General Hospital

The genetic diversity of typical clinical isolated Plasmodium falciparum in the malaria population varies greatly, especially at the location where malaria disease were recorded at high incidence rate. MSP2 is known as glycoprotein expressed on the surface of merozoites, which is an antigenic protein and has a potential to act as vaccine candidate for malaria. The MSP2 gene has two main allelic groups called FC27 and 3D7/IC. Block 3 from MSP2 gene is the most polymorphic to describe the diversity of parasite populations. The P. falciparum parasite population is often characterized by wide genetic diversity in areas of high transmission intensity. Therefore, the study on P. falciparum diversity is useful to describe the level of malaria transmission. The study of genetic diversity focused on clinical isolated species at Wamena General Hospital was aimed to determine the presence of the MSP2 gene, variety of MSP2 gene allele and the dominant frequency of the MSP2 gene allele. This research has been carried out from March 2018 to February 2019 using a cross sectional approach. The research sample was taken and prepared from Wamena Regional Hospital and followed by the analyzing of DNA isolation, PCR, electrophoresis of the research samples was done at the genetic science laboratory in Jakarta, Indonesia. The samples studied were patients who met the inclusion criteria, namely a single P. falciparum infection with an asexual parasite density &gt;1000 parasites/µl or &gt;3+ (1-10 P/Lp), and were agreed to become respondents by signing an informed consent. A total of 26 clinical isolates of P. falciparum were isolated with the MSP2 gene distribution on the FC27 allele with the highest as many as 25 samples (96.2%), 22 samples (84.6%) of the 3D7 / IC allele while the mixture of the two alleles was 22 samples (84.6%). From a total of 26 samples, there were samples with the male gender category counted for 77.3% and female 41%. The results of the identification of clinical isolated P. falciparum at Wamena Hospital with a total of 26 samples were found in productive age, between 15-34 years with a single allele (95.8%), while 23 cases and mix (both alleles 87.5%) about 21 cases, meanwhile in cases of before-productive age, in which ages were 12 and 14 years of age with a single allele 100% (FC27) 2 cases and 50% (3D7/IC) found to be 1 case, The mixture of the two alleles is 50% was only 1 case and there was no sample at non-productive age observed. Key words: Malaria; MSP-2; P. falciparum; Wamena

English

West Africa is one of the regions in Africa with the highest levels of malaria transmission a descriptive study was carried out to inventorise the medicinal plants traditionally used against malaria by traditional therapists in five malaria endemic areas of the Segou region, in Mali. Sixty-five traditional therapists were randomly selected to be part of the study. Questions were posed using semi-structured interviews, which solicited information on species used, plant organs used, as well as methods of preparation and routes of administration of decoctions. Results indicate that 69 species distributed over 27 families are used to treat malaria. The most represented families are Fabaceae (24.63%), Combretaceae (13.04%), Rubiaceae (7.24%) and Meliaceae (5.79%). The most cited species are Argemone mexicana (CF=0.78), Combretum micranthum (CF=0.84), Conocarpus biocarpa (CF=0.70), Gardenia sokotensis (CF=0.75) and Mitragyna inermis (CF=0.81). The recipe mostly involves leaves (82.43%), with the decoctions mainly taken orally. Key words: Antimalarial plants, ethnobotanical survey, Segou, Mali.