19 research outputs found

    Knowledge, attitudes and practices of malaria control among communities from the health district of Forécariah in the Republic of Guinea, West Africa.

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    BACKGROUND & OBJECTIVES: Malaria is the leading cause of death in children under 5-yr of age in the Republic of Guinea. This study aimed at investigating the knowledge, attitudes and practices of malaria control in urban and rural communities in Guinea in order to better target future health interventions. METHODS: A cross-sectional survey of 200 randomly selected households was conducted in an urban site and in three rural villages within the health district of Forιcariah using two semi-structured questionnaires. RESULTS: Only 18.5% of the respondents were aware of the role of mosquitoes in the transmission of malaria in both urban and rural households. Mosquito nets were identified as a malaria prevention method by 11.5% of the participants and only 8.5% of the respondents mentioned stagnant water as a potential mosquito breeding site. Households' heads were more aware of mosquito control methods, with 56 and 42% of the respondents recognizing that bednets or insecticidal coils can protect from mosquitoes, respectively. Despite the limited knowledge of malaria transmission and prevention, 55% of the households owned at least one long-lasting insecticide-treated net (LLIN) and 79% of the net-owning households slept under a net/LLIN the night before the survey. INTERPRETATION & CONCLUSION: In order to maximize the benefits of malaria control strategies, health education should be implemented, building on the higher awareness of mosquito control methods and stressing the role of vectors in transmitting the disease

    Seasonal Malaria Chemoprevention in Guinea in 2020: coverage survey results

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    In 2020 SMC was implemented in 17 out of 33 prefectures, which include 50% of the population outside the city of Conakry. The COVID-19 pandemic, and the presidential elections in Guinea, could potentially have affected SMC campaigns in 2020, it was therefore important to evaluate coverage of SMC given these challenges and the increased area of implementation. The survey took place from 20 Dec 2020 to 4 Jan 2021. All children aged 3 months to 7 years were included in order to determine coverage in the target age group (aged at least 3months at the time of treatment, and aged not more than 59 months at cycle 1) and to determine the proportion of children above the recommended age limit who received treatment. Caregivers were asked about the process of SMC administration, to recall which months their child had received SMC treatments, and about adherence and reasons for any missed doses. Dates of treatments were recorded from the SMC card, and SMC registers were checked to verify SMC treatments for children who did not have a card for inspection during the survey, and for subset of children with cards. In addition, all persons who slept in the household the night before the survey were listed, all bednets owned by the household were also listed and inspected, and for each person, the net they slept under, if any, was noted. A total of 2,447 children eligible to receive 4 treatments were surveyed in 90 clusters. A total of 1374/1521 of households agreed to participate, a response rate of 90.3%. 465 children too old to be eligible for SMC, were also surveyed. Use of LLINs was assessed for a total of 7,028 household members. Cycle 1 took place in July, cycle 2 in August, cycle 3 in September and cycle 4 in October. The median interval between treatments, based on dates recorded on SMC cards, was 33 days between cycle 1 and cycle 2, and 32 days between cycle 2 and 3, and 32 days between cycles 3 and 4. Children aged 3 to 59 months at the time of cycle 1 were eligible to receive SMC four times, and should receive all of these treatments to maximise their protection. Overall, the percentage of eligible children who received SMC was 78.2% in cycle 1, 79.9% in cycle2, 77.4% in cycle3, and 77.2% in cycle 4. Children who did not receive SMC in cycle 1 tended not to receive SMC in later cycles. A total of 17.6% of children did not receive any SMC treatment in 2020, and 70.8% of eligible children received four monthly treatments. SMC was equitable with similar coverage in boys and girls and according to caregiver wealth based on ranking according to household assets. In 99.5% of treated children, the first dose was directly observed, either administered by the CHW (87.4%) or by the caregiver in the presence of the CHW (12.2%). In a small number of cases, (0.5% of children) the blister pack was left with the caregiver to administer later, not observed by the CHW. Reported adherence to the unsupervised doses of amodiaquine was very high. Of eligible children treated at cycle 4, caregivers reported that 96.8% received all three daily doses. Public information campaigns appeared successful, 93.6% of households were aware of SMC and 92.1% said they knew in advance the date of the last campaign. Caregivers were asked if they understood key aspects of SMC, they scored 66% overall on a 10-point questionnaire. Most caregivers (77%) knew that SMC is used to prevent malaria and most (76%) knew that there are 2 tablets to be taken on the first day and one on each of the next two days (85%). However there was a widespread view that SMC drugs could be used for treatment if there was someone unwell in the household (only 36% of caregivers gave the correct response, that SMC drugs should not be used in this way), and only 63% of caregivers appreciated the importance of completing the 3-day course of treatment. In the 2018 SMC survey, 30.2% of children slept under a LLIN the night before the survey. In the 2019 survey, following a mass distribution campaign, this increased to 86% of children. In the 2020 survey, this had fallen to 66% of children under 5 slept who under an LLIN the night before the survey. Children above the age of 5 were less likely to use an LLIN than children under 5. This drop in LLIN use above the age of 5 was more marked in some areas than others. The percentage of the 5-9 age group that slept under an LLIN was only 54%. Of 1,377 households surveyed, 73.5% had at least one LLIN and 23.4% had one LLIN for every 2 persons. This compares with 89.8% had at least one LLIN and 36.8% had one LLIN for every 2 persons in the household, in 2019. Access to a LLIN, the percentage of the population who could sleep under a LLIN if there were two people per net, was 25.4% in 2018. This increased to 68.2% in 2019, and decreased 52.3% to the current survey. 61% of household members slept under an LLIN. High SMC coverage has been maintained in 2020 despite the challenges of delivery during the COVID-19 pandemic

    Seasonal Malaria Chemoprevention Coverage in Guinea in 2019

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    SMC involves the administration of a treatment course of sulfadoxine-pyrimethamine plus amodiaquine once a month to children aged 3–59 months during the high risk period each year to prevent malaria. SMC over 4 months of the year was introduced in Guinea in 2015 in 6 prefectures, scaling up to 13 prefectures by 2018. The present survey was conducted at the end of the 2019 transmission season to determine SMC coverage and use of LLINs, following national distribution of LLINs in 2019. During the survey, the feasibility of using SMC registers to validate caregiver report of SMC treatments, was investigated. Of children eligible for four SMC treatments, 88% had received an SMC card, and 68% had a card available for inspection in the survey. There was 83% agreement between caregiver report of the number of treatments and the number indicated on the record card. In 55 clusters where SMC registers were available, an attempt was made to find entries in the SMC register for the children in the survey who did not have an SMC card, this was possible for 339/580 (58%) children, and for these children there was 79% agreement with the caregivers’ report. Allowing for the fact that most children who did not receive any SMC treatments will not be listed in the register, it appears that a high proportion of children who received SMC but did not have a card at the survey, were located in registers. We recommend that registers be used in futures surveys to cross-check SMC status. Overall, 81% of children received SMC at cycle 1, 79% at cycle 2, 78% at cycle 3 and 49% at cycle 4. In 97% of treated children, the first dose was directly observed (administered by the CHW, 96.9%, or, in a small number, by the caregiver in the presence of the CHW, 0.4%). A small number of children (0.1%) received the first dose from the caregiver later, not observed by the CHW; the reason given was that the child was away at the time the CHW visited. And for 2.6% of children, although the caregiver received the blister pack, the first dose was not administered. Reported adherence to the unsupervised doses of amodiaquine was very high. Of eligible children treated at cycle 4, caregivers reported that 96.1% received all three daily doses. Caregivers were asked if the child swallowed all the medicine, spat out some medicine, or vomitted all the medicine. Most responded the child swallowed the medicine without vomitting. Of those who were treated, a total of 93.9% of children were reported to have received and swallowed the 3 daily doses without vomitting. In a similar survey in 2018, 30.2% of children slept under a net the night before the survey. In this 2019 survey, 86% (95%CI 79%,90%) of children slept under an LLIN the night before the survey. Of 1038 households surveyed, 89.8% had at least one LLIN but only 36.8% had one LLIN for every 2 persons. This compares with 39.7% had at least one LLIN and 13.1% had one LLIN for every 2 persons in the household, in 2018. Access to a LLIN (the percentage of the population who could sleep under a LLIN if there were two people per net) was 25.4% in 2018. This has increased to 68.2% in the current survey. There was a notable dip in bednet use in children 5-14 years of age, 67% slept under an LLIN the night before the survey compared to 85% of 0-4year-olds and 81% of 15-19-year-olds. This is of concern, children who stop receiving SMC at age 5 need to be protected with an effective net, and specific efforts need to be made to ensure high levels of LLIN use in this age group. In some areas where SMC is currently being implemented, more than 4 cycles of SMC are needed to provide protection throughout the high risk period. Given the success of the current programme and high levels of coverage being achieved each month, extensions to SMC should be considered, the most urgent priority is to provide 5 cycles in some of the current areas, and to expand the number of prefectures where SMC is implemented

    Seasonal Malaria Chemoprevention Coverage Survey Guinea, 2018

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    The 2018 SMC coverage survey in Guinea was conducted by the University Gamal Abdel Nasser, Conakry and the London School of Hygiene & Tropical Medicine, in collaboration with the National Malaria Control Programme and Catholic Relief Services, Guine

    An open dataset of Plasmodium falciparum genome variation in 7,000 worldwide samples.

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    MalariaGEN is a data-sharing network that enables groups around the world to work together on the genomic epidemiology of malaria. Here we describe a new release of curated genome variation data on 7,000 Plasmodium falciparum samples from MalariaGEN partner studies in 28 malaria-endemic countries. High-quality genotype calls on 3 million single nucleotide polymorphisms (SNPs) and short indels were produced using a standardised analysis pipeline. Copy number variants associated with drug resistance and structural variants that cause failure of rapid diagnostic tests were also analysed.  Almost all samples showed genetic evidence of resistance to at least one antimalarial drug, and some samples from Southeast Asia carried markers of resistance to six commonly-used drugs. Genes expressed during the mosquito stage of the parasite life-cycle are prominent among loci that show strong geographic differentiation. By continuing to enlarge this open data resource we aim to facilitate research into the evolutionary processes affecting malaria control and to accelerate development of the surveillance toolkit required for malaria elimination

    Pf7: an open dataset of Plasmodium falciparum genome variation in 20,000 worldwide samples

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    We describe the MalariaGEN Pf7 data resource, the seventh release of Plasmodium falciparum genome variation data from the MalariaGEN network.  It comprises over 20,000 samples from 82 partner studies in 33 countries, including several malaria endemic regions that were previously underrepresented.  For the first time we include dried blood spot samples that were sequenced after selective whole genome amplification, necessitating new methods to genotype copy number variations.  We identify a large number of newly emerging crt mutations in parts of Southeast Asia, and show examples of heterogeneities in patterns of drug resistance within Africa and within the Indian subcontinent.  We describe the profile of variations in the C-terminal of the csp gene and relate this to the sequence used in the RTS,S and R21 malaria vaccines.  Pf7 provides high-quality data on genotype calls for 6 million SNPs and short indels, analysis of large deletions that cause failure of rapid diagnostic tests, and systematic characterisation of six major drug resistance loci, all of which can be freely downloaded from the MalariaGEN website

    Développement de biomarqueurs pour la surveillance précoce de la neurotoxicité du méthylmercure chez le rat

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    Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.L'objectif de cette étude était de développer des biomarqueurs de la neurotoxicité précoce du MeHg chez le rat adulte, en utilisant les lymphocytes et plaquettes du sang circulant comme substituts de neurones centraux. Pour ce faire, nous avons d'abord évalué la captation de la choline, de la dopamine (DA), de la sérotonine (5-HT), la liaison aux récepteurs muscarinergiques (mChRs) et dopaminergic Ds dans les synaptosomes du cortex cérébral, du striatum, de l'hypothalamus, de l'hippocampe, du tronc cérébral et du cervelet, après exposition in vitro à différentes concentrations de chlomre de MeHg (0, l, 2.5 et 5 µM). Dans ces conditions, la captation de la 5-HT était mesurée au niveau des plaquettes. De même, la captation de la DA et la liaison aux récepteurs mCKRs et Dz étaient évaluées au niveau des lymphocytes du sang circulant. Enfin, les résultats in vitro étaient validés en évaluant les voies cholinergiques et monoaminergiques dans les mêmes régions du cerveau et au niveau des plaquettes et lymphocytes chez des rats mâles adultes gavés au chlorure de MeHg (0, 2, 4 et 6 mg/kg pendant 10 jours consécutifs)

    Population genetic structure of Plasmodium falciparum across a region of diverse endemicity in West Africa.

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    BACKGROUND: Malaria parasite population genetic structure varies among areas of differing endemicity, but this has not been systematically studied across Plasmodium falciparum populations in Africa where most infections occur. METHODS: Ten polymorphic P. falciparum microsatellite loci were genotyped in 268 infections from eight locations in four West African countries (Republic of Guinea, Guinea Bissau, The Gambia and Senegal), spanning a highly endemic forested region in the south to a low endemic Sahelian region in the north. Analysis was performed on proportions of mixed genotype infections, genotypic diversity among isolates, multilocus standardized index of association, and inter-population differentiation. RESULTS: Each location had similar levels of pairwise genotypic diversity among isolates, although there were many more mixed parasite genotype infections in the south. Apart from a few isolates that were virtually identical, the multilocus index of association was not significant in any population. Genetic differentiation between populations was low (most pairwise F(ST) values < 0.03), and an overall test for isolation by distance was not significant. CONCLUSIONS: Although proportions of mixed genotype infections varied with endemicity as expected, population genetic structure was similar across the diverse sites. Very substantial reduction in transmission would be needed to cause fragmented or epidemic sub-structure in this region

    Breakdown in the process of incipient speciation in Anopheles gambiae.

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    Understanding genetic causes and effects of speciation in sympatric populations of sexually reproducing eukaryotes is challenging, controversial, and of practical importance for controlling rapidly evolving pests and pathogens. The major African malaria vector mosquito Anopheles gambiae sensu stricto (s.s.) is considered to contain two incipient species with strong reproductive isolation, hybrids between the M and S molecular forms being very rare. Following recent observations of higher proportions of hybrid forms at a few sites in West Africa, we conducted new surveys of 12 sites in four contiguous countries (The Gambia, Senegal, Guinea-Bissau, and Republic of Guinea). Identification and genotyping of 3499 A. gambiae s.s. revealed high frequencies of M/S hybrid forms at each site, ranging from 5 to 42%, and a large spectrum of inbreeding coefficient values from 0.11 to 0.76, spanning most of the range expected between the alternative extremes of panmixia and assortative mating. Year-round sampling over 2 years at one of the sites in The Gambia showed that M/S hybrid forms had similar relative frequencies throughout periods of marked seasonal variation in mosquito breeding and abundance. Genome-wide scans with an Affymetrix high-density single-nucleotide polymorphism (SNP) microarray enabled replicate comparisons of pools of different molecular forms, in three separate populations. These showed strong differentiation between M and S forms only in the pericentromeric region of the X chromosome that contains the molecular form-specific marker locus, with only a few other loci showing minor differences. In the X chromosome, the M/S hybrid forms were more differentiated from M than from S forms, supporting a hypothesis of asymmetric introgression and backcrossing
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