Use Of Insecticide-treated Bed Nets Research Articles

Evaluating indoor residual spray for reducing malaria infection prevalence in Eritrea: Results from a community randomized control trial

This paper examines the relationship between indoor residual spray (IRS) and malaria parasite infection in Gash Barka Zone, Eritrea, an area with near universal coverage of insecticide treated bednets (ITN) and already low malaria parasite prevalence. A community randomized control trial was conducted in 2009. Malaria parasite infection prevalence was 0.5% [95% confidence interval (CI): 0.37–0.78%], with no significant difference detected between treatment and control areas. ITN possession remains high, with over 70% of households reporting ITN ownership [95% CI: 68.4–72.9]. ITN use among individuals within ITN-owning households was just under half [46.7% (95% CI: 45.4–48.0)]. Slight differences in ITN possession and use were detected between treatment and control areas. There was no significant difference in malaria parasite infection prevalence among individuals in households with ≥1 ITN compared to those in households without ITNs, nor among individuals reporting ITN use. Among individuals in ITN-owning households, sleeping under an ITN offered no statistically significant protection from malaria parasite infection. Community participation in environmental and larval habitat management activities was low: 17.9% (95% CI: 16.0–19.7). It is likely that IRS, larval habitat management and ITN distribution alone may be insufficient to interrupt transmission without corresponding high ITN use, sustained IRS application in areas where infections are clustered, and promptly seeking laboratory diagnosis and treatment of all fevers. Eritrea is ready for elimination, irrespective of inconclusive impact evaluation results.

Community trial of insecticide-treated bed net use promotion in southern Ghana: the Net Use Intervention study

Insecticide-treated nets (ITNs) reduce malaria transmission and related morbidity and child mortality; however, incorrect and inconsistent use limits their protective factors. This community trial titled the Net Use Intervention study sought to bridge the gap between ITN ownership and use in southern (coastal) Ghana and to determine the best mix of communication tools to affect behavior of ITN owners to consistent use while maintaining optimal internal and external validity. This two-group, non-randomized experiment evaluated a multichannel, multisector intervention process over the course of 8weeks. A longitudinal cohort was scientifically sampled from six intervention and six control communities for both baseline and posttest surveys. The posttest survey showed no change in knowledge of ITNs in the intervention or control. In terms of use the previous night, there was a strong and statistically significant intervention effect (OR = 1.67; p < .05) within the intervention communities. The overall increase in ITN coverage was approximately one person per night per every two households. The promotion efforts succeeded well beyond the planners' expectations, not only promoting usage but also dramatically increasing demand for new ITNs.

Malaria in South Sudan 4: treatment of uncomplicated P. falciparum malaria.

The study was carried out among 334 pregnant and newly delivered women seen at Juba Teaching Hospital in 2009. The objective was to assess the coverage of insecticide-treated bed-nets (ITN) and Intermittent Preventive Therapy (IPT) among these women and the factors associated with their use. Overall 87% of the women used ITN and 61% used IPT. ITN use was positively associated with buying nets, indoor spraying of insecticide and higher household income. IPT use was positively associated with more frequent antenatal clinic visits, indoor spraying and buying ITN.

Effects of transmission reduction by insecticide-treated bed nets (ITNs) on parasite genetics population structure: I. The genetic diversity of Plasmodium falciparum parasites by microsatellite markers in western Kenya

BackgroundInsecticide-treated bed nets (ITNs) reduce malaria transmission and are an important prevention tool. However, there are still information gaps on how the reduction in malaria transmission by ITNs affects parasite genetics population structure. This study examined the relationship between transmission reduction from ITN use and the population genetic diversity of Plasmodium falciparum in an area of high ITN coverage in western Kenya.MethodsParasite genetic diversity was assessed by scoring eight single copy neutral multilocus microsatellite (MS) markers in samples collected from P. falciparum-infected children (< five years) before introduction of ITNs (1996, baseline, n = 69) and five years after intervention (2001, follow-up, n = 74).ResultsThere were no significant changes in overall high mixed infections and unbiased expected heterozygosity between baseline (%MA = 94% and He = 0.75) and follow up (%MA = 95% and He = 0.79) years. However, locus specific analysis detected significant differences for some individual loci between the two time points. Pfg377 loci, a gametocyte-specific MS marker showed significant increase in mixed infections and He in the follow up survey (%MA = 53% and He = 0.57) compared to the baseline (%MA = 30% and He = 0.29). An opposite trend was observed in the erythrocyte binding protein (EBP) MS marker. There was moderate genetic differentiation at the Pfg377 and TAA60 loci (FST = 0.117 and 0.137 respectively) between the baseline and post-ITN parasite populations. Further analysis revealed linkage disequilibrium (LD) of the microsatellites in the baseline (14 significant pair-wise tests and ISA = 0.016) that was broken in the follow up parasite population (6 significant pairs and ISA = 0.0003). The locus specific change in He, the moderate population differentiation and break in LD between the baseline and follow up years suggest an underlying change in population sub-structure despite the stability in the overall genetic diversity and multiple infection levels.ConclusionsThe results from this study suggest that although P. falciparum population maintained an overall stability in genetic diversity after five years of high ITN coverage, there was significant locus specific change associated with gametocytes, marking these for further investigation.

"Before we used to get sick all the time": perceptions of malaria and use of long-lasting insecticide-treated bed nets (LLINs) in a rural Kenyan community

BackgroundMalaria is a leading global cause of preventable morbidity and mortality, especially in sub-Saharan Africa, despite recent advances in treatment and prevention technologies. Scale-up and wide distribution of long-lasting insecticide-treated nets (LLINs) could rapidly decrease malarial disease in endemic areas, if used properly and continuously. Studies have shown that effective use of LLINs depends, in part, upon understanding causal factors associated with malaria. This study examined malaria beliefs, attitudes, and practices toward LLINs assessed during a large-scale integrated prevention campaign (IPC) in rural Kenya.MethodsQualitative interviews were conducted with 34 IPC participants who received LLINs as part of a comprehensive prevention package of goods and services. One month after distribution, interviewers asked these individuals about their attitudes and beliefs regarding malaria, and about their use of LLINs.ResultsVirtually all participants noted that mosquitoes were involved in causing malaria, though a substantial proportion of participants (47 percent) also mentioned an incorrect cause in addition to mosquitoes. For example, participants commonly noted that the weather (rain, cold) or consumption of bad food and water caused malaria. Regardless, most participants used the LLINs they were given and most mentioned positive benefits from their use, namely reductions in malarial illness and in the costs associated with its diagnosis and treatment.ConclusionsAttitudes toward LLINs were positive in this rural community in Western Kenya, and respondents noted benefits with LLIN use. With improved understanding and clarification of the direct (mosquitoes) and indirect (e.g., standing water) causes of malaria, it is likely that LLIN use can be sustained, offering effective household-level protection against malaria.

Analysis of Anopheles arabiensis Blood Feeding Behavior in Southern Zambia during the Two Years after Introduction of Insecticide-Treated Bed Nets

Anopheles arabiensis mosquitoes are the primary vector responsible for Plasmodium falciparum transmission in Macha, Zambia. Because insecticide-treated bed nets (ITNs) have the potential to alter host feeding behavior, the extent of the zoophilic and exophagic tendencies of the vector was evaluated during the two rainy seasons after ITN introduction. Centers for Disease Control light traps, paired indoor/outdoor human landing catches, and outdoor cattle-baited collections were used to assess potential changes in host preference. Results support the hypothesis that An. arabiensis mosquitoes in Macha remain highly anthropophilic despite high ITN use. Anopheles arabiensis mosquitoes in Macha appear to be relatively exophagic and have been caught biting outdoors immediately after sunset and before sunrise, potentially circumventing some of the protective effects of ITNs.

Centers for Disease Control Light Traps for Monitoring Anopheles arabiensis Human Biting Rates in an Area with Low Vector Density and High Insecticide-Treated Bed Net Use

Human landing catches (HLCs) are currently the preferred method to determine vector human biting rates (HBRs), which are key determinants of entomologic inoculation rates and important measures for assessing the impact of vector control efforts. Although HLCs are the most direct means of establishing HBRs, they are labor-intensive, and their use is facing increasing ethical concerns. The relationship between Centers for Disease Control (CDC) light traps and HLC collections was evaluated in Macha, Zambia during the 2007-2008 and 2008-2009 rainy seasons. A CDC light trap captured on average 1.91 (95% confidence interval = 1.16-2.28) times as many An. arabiensis per night as an indoor HLC. Additionally, nets treated with deltamethrin did not affect the numbers of An. arabiensis collected. Our results suggest that in regions where use of vector control interventions is high and vector densities are low, CDC light traps can be used to monitor An. arabiensis HBRs.

Availability and utilization of malaria prevention strategies in pregnancy in eastern India

BackgroundMalaria in pregnancy in India, as elsewhere, is responsible for maternal anemia and adverse pregnancy outcomes such as low birth weight and preterm birth.It is not known whether prevention and treatment strategies for malaria in pregnancy (case management, insecticide-treated bednets, intermittent preventive therapy) are widely utilized in India.MethodsThis cross-sectional study was conducted during 2006-2008 in two states of India, Jharkhand and Chhattisgarh, at 7 facilities representing a range of rural and urban populations and areas of more versus less stable malaria transmission. 280 antenatal visits (40/site) were observed by study personnel coupled with exit interviews of pregnant women to assess emphasis upon, availability and utilization of malaria prevention practices by health workers and pregnant women. The facilities were assessed for the availability of antimalarials, lab supplies and bednets.ResultsAll participating facilities were equipped to perform malaria blood smears; none used rapid diagnostic tests. Chloroquine, endorsed for chemoprophylaxis during pregnancy by the government at the time of the study, was stocked regularly at all facilities although the quantity stocked varied. Availability of alternative antimalarials for use in pregnancy was less consistent. In Jharkhand, no health worker recommended bednet use during the antenatal visit yet over 90% of pregnant women had bednets in their household. In Chhattisgarh, bednets were available at all facilities but only 14.4% of health workers recommended their use. 40% of the pregnant women interviewed had bednets in their household. Only 1.4% of all households owned an insecticide-treated bednet; yet 40% of all women reported their households had been sprayed with insecticide. Antimalarial chemoprophylaxis with chloroquine was prescribed in only 2 (0.7%) and intermittent preventive therapy prescribed in only one (0.4%) of the 280 observed visits.ConclusionsA disconnect remains between routine antenatal practices in India and known strategies to prevent and treat malaria in pregnancy. Prevention strategies, in particular the use of insecticide-treated bednets, are underutilized. Gaps highlighted by this study combined with recent estimates of the prevalence of malaria during pregnancy in these areas should be used to revise governmental policy and target increased educational efforts among health care workers and pregnant women.

TRUST IN HEALTH PROVIDERS AS A CATALYST FOR MALARIA PREVENTION: HETEROGENEOUS IMPACTS OF HEALTH EDUCATION IN RURAL GHANA

Although knowledge about effectiveness of insecticide-treated bed nets (ITNs) is fairly widespread in Ghana, their use remains far from universal. We test and validate the hypothesis that health education of hospitals and health centers in rural Ghana is more effective for groups that display relatively high trust to health providers. We estimate heterogeneous impacts of health education on ITN and/or bed net use and on fever as a crude proxy for malaria in the Brong Ahafo and Upper East regions in Ghana, with help of propensity-adjusted regression. The degree of trust in health providers appears to be a key factor in determining the effectiveness of health education in both regions. The effect is not ruled out by controlling for general trust. There are indications of nonlinear effects. The Kassena-Nankana seems to be an exception to this rule—despite low trust in health providers, health education is highly effective for this ethnic group.

Effect of incentives on insecticide-treated bed net use in sub-Saharan Africa: a cluster randomized trial in Madagascar

BackgroundInsecticide-treated bed nets (ITNs) have been shown to reduce morbidity and mortality due to malaria in sub-Saharan Africa. Strategies using incentives to increase ITN use could be more efficient than traditional distribution campaigns. To date, behavioural incentives have been studied mostly in developed countries. No study has yet looked at the effect of incentives on the use of ITNs. Reported here are the results of a cluster randomized controlled trial testing household-level incentives for ITN use following a free ITN distribution campaign in Madagascar.MethodsThe study took place from July 2007 until February 2008. Twenty-one villages were randomized to either intervention or control clusters. Households in both clusters received a coupon redeemable for one ITN. After one month, intervention households received a bonus for ITN use, determined by visual confirmation of a mounted ITN. Data were collected at baseline, one month and six months. Both unadjusted and adjusted results, using cluster specific methods, are presented.ResultsAt baseline, 8.5% of households owned an ITN and 6% were observed to have a net mounted over a bed in the household. At one month, there were no differences in ownership between the intervention and control groups (99.5% vs. 99.4%), but net use was substantially higher in the intervention group (99% vs. 78%), with an adjusted risk ratio of 1.24 (95% CI: 1.10 to 1.40; p < 0.001). After six months, net ownership had decreased in the intervention compared to the control group (96.7% vs. 99.7%), with an adjusted risk ratio of 0.97 (p < 0.01). There was no difference between the groups in terms of ITN use at six months; however, intervention households were more likely to use a net that they owned (96% vs. 90%; p < 0.001).ConclusionsHousehold-level incentives have the potential to significantly increase the use of ITNs in target households in the immediate-term, but, over time, the use of ITNs is similar to households that did not receive incentives. Providing incentives for behaviour change is a promising tool that can complement traditional ITN distribution programmes and improve the effectiveness of ITN programmes in protecting vulnerable populations, especially in the short-term.

Awareness and use of insecticide-treated bed nets among children attending outpatient clinic at UNTH, Enugu - the need for an effective mobilization process.

The promotion of insecticide-treated net (ITN) can be a key approach towards the reduction of morbidity and mortality from malaria. To determine the proportion of mothers using insecticide treated nets for their children and reasons for nonuse. Prospective hospital-based study. Consecutive mothers attending the children's out patient clinic of UNTH, Ituku-Ozalla, Enugu, whose children presented with fever without localizing focus were interviewed with the aid of an open-ended structured questionnaire. Awareness of ITN was found in 184 (80%) of the 230 mothers interviewed, while only 48 (26.1%) use it for their children. There was statistically significant difference in terms of ITN awareness between the highly educated mothers and those with lower educational qualification (p = 0.000) but, in terms of ITN usage, there was no significant difference between the two groups (p = 0.40). Socio economic class did not influence the use of ITN (p = 0.153). A greater number; 56 (41.2%) have no reason for non-use. Reasons for nonuse include use of windows and door nets 22 (16.2%) and not convenient to spread 18 (13.2%). There was a high awareness of ITN, which did not influence usage.

Effect of training on the use of long-lasting insecticide-treated bed nets on the burden of malaria among vulnerable groups, south-west Ethiopia: baseline results of a cluster randomized trial

BackgroundIn Ethiopia, the utilization of long-lasting insecticide-treated bed nets (LLITN) is hampered by behavioural factors such as low awareness and negative attitude of the community. The aim of this study was to present the design and baseline results of a cluster randomized trial on the effect of training of household heads on the use of LLITN.MethodsThis baseline survey was undertaken from February to March, 2009 as part of a randomized cluster trial. A total of 11 intervention and 11 control Gots (villages) were included in the Gilgel Gibe Field Research Centre, south-west Ethiopia. House to house visit was done in 4135 households to collect information about the use of LLITN and socio-demographic variables. For the diagnosis of malaria and anaemia, blood samples were collected from 2410 under-five children and 242 pregnant women.ResultsOne fourth of the households in the intervention and control Gots had functional LLITN. Only 30% of the observed LLITN in the intervention and 28% in the control Gots were hanged properly. Adults were more likely to utilize LLITN than under-five children in the control and intervention Gots. The prevalence of malaria in under-five children in the intervention and control Gots was 10.5% and 8.3% respectively. The intervention and control Gots had no significant difference concerning the prevalence of malaria in under-five children, [OR = 1.28, (95%CI: 0.97, 1.69)]. Eight (6.1%) pregnant women in the intervention and eight (7.2%) in the control Gots were positive for malaria (P = 0.9). Children in the intervention Gots were less likely to have anaemia than children in the control Gots, [OR = 0.75, (95%CI: 0.62, 0.85)].ConclusionThe availability and utilization of LLITN was low in the study area. The prevalence of malaria and anaemia was high. Intervention strategies of malaria should focus on high risk population and vulnerable groups.

Use of insecticide treated bed nets among pregnant women in Kilifi District, Kenya

Malaria is one of the most serious public health problems in Kenya. Pregnant women are among the groups with the highest risk of malaria. Use of insecticide treated bed nets (ITNs) is a cost-effective method of controlling malaria. Despite this, there is low utilisation of ITNs among pregnant women in Kilifi district which is an endemic malaria zone. To determine knowledge, attitude and practice on the use of ITNs in the prevention of malaria among pregnant women in Kilifi district. A descriptive cross-sectional study. The district hospital and the five health centres in Kilifi district Two hundred and twenty pregnant women attending antenatal clinics (ANC) between October and December 2007. Knowledge on malaria illness and ITNs was high with majority of pregnant women having adequate level of knowledge (86.9%). There was significant association between level of education and adequate knowledge (P-value = 0.010). Good attitude on ITNs use was low. There was no association between good attitude and any of the socio-demographic variables. The majority of pregnant women attending ANC owned ITNs (75.4%). ITNs usage was high (70.5%). There was significant association between religion and good practice (p-value = 0.050). Although adequate level of knowledge on malaria and protective role of ITNs was high, there was no association between knowledge with practice and attitude. Before any malaria preventive intervention is implemented in an area, different socio-cultural factors must be considered when behavioural interventions for malaria control are designed and implemented. Targeted health education should be disseminated to the community to remove stigma and misconceptions associated with ITNs. Community concerns and fears should be addressed.

Malaria parasitaemia and household use of insecticide treated bed nets: A cross-sectional survey of under-fives in Jos, Nigeria

Background: In spite of enormous investments in Malaria control programme, malaria is still a major cause of morbidity and mortality among under-fives. Objective: The objective of this study was to determine malaria parasitaemia in under-fives and to relate it to household use of Insecticide Treated Bed Nets (ITBNs) in Jos - a malaria endemic setting. Methodology: A cross-sectional study was carried out in a selected settlement in Jos North Local Government Area (LGA) in September 2007 towards the end of the rainy season. All households with children less than 5 years of age in the selected settlement were listed and then 150 of the households were selected using systematic sampling technique. In each selected household one under five was selected and where there were more than one under five only one was selected by balloting. The selected 150 under-fives were then studied using thumb prick blood smear to determine the presence of malaria parasite in their peripheral blood and a semi structured interviewer administered questionnaire to obtain information on household use of ITBNs in the community. Result: Malaria parasitaemia was found in 57 (38.0%) of the children and the highest age specific prevalence of 46.4% was among the 36-47 months age group. The females were more (46.6%) infected than their male counterparts (29.9%) p=0.035. Eighty three (55.3%) mothers owned ITBNs but only 61(40.7%) used them for their children. Children who slept under ITBNs were less likely to have malaria parasites in their blood compared with those who did not (p=0.000..). Mothers’ age and education were among other factors that positively influenced the use of ITBNs. Conclusion: Malaria parasitaemia is high in this community and sleeping under ITBN has been found to significantly reduce the prevalence of parasitaemia in the children studied. It is therefore recommended that the ITBNs campaign should be intensified so that the ITBN use can cover all the under-fives. Key words : Malaria; Insecticide; bed nets; under-fives,

Modeling the effects of integrating larval habitat source reduction and insecticide treated nets for malaria control.

Integrated vector management for malaria control has received a lot of recent interest. Attacking multiple points in the transmission cycle is hoped to act synergistically and improve upon current single-tool interventions based on the use of insecticide-treated bed nets (ITNs). In the present study, we theoretically examined the application of larval habitat source reduction with ITNs in reducing malaria transmission. We selected this type of environmental management to complement ITNs because of a potential secondary mode of action that both control strategies share. In addition to increasing vector mortality, ITNs reduce the rate at which female mosquitoes locate human hosts for blood feeding, thereby extending their gonotrophic cycle. Similarly, while reducing adult vector emergence and abundance, source reduction of larval habitats may prolong the cycle duration by extending delays in locating oviposition sites. We found, however, that source reduction of larval habitats only operates through this secondary mode of action when habitat density is below a critical threshold. Hence, we illustrate how this strategy becomes increasingly effective when larval habitats are limited. We also demonstrate that habitat source reduction is better suited to human populations of higher density and in the presence of insecticide resistance or when the insecticidal properties of ITNs are depleted.

Burden of malaria in pregnancy in Jharkhand State, India

BackgroundPast studies in India included only symptomatic pregnant women and thus may have overestimated the proportion of women with malaria. Given the large population at risk, a cross sectional study was conducted in order to better define the burden of malaria in pregnancy in Jharkhand, a malaria-endemic state in central-east India.MethodsCross-sectional surveys at antenatal clinics and delivery units were performed over a 12-month period at two district hospitals in urban and semi-urban areas, and a rural mission hospital. Malaria was diagnosed by Giemsa-stained blood smear and/or rapid diagnostic test using peripheral or placental blood.Results2,386 pregnant women were enrolled at the antenatal clinics and 718 at the delivery units. 1.8% (43/2382) of the antenatal clinic cohort had a positive diagnostic test for malaria (53.5% Plasmodium falciparum, 37.2% Plasmodium vivax, and 9.3% mixed infections). Peripheral parasitaemia was more common in pregnant women attending antenatal clinics in rural sites (adjusted relative risk [aRR] 4.31, 95%CI 1.84-10.11) and in those who were younger than 20 years (aRR 2.68, 95%CI 1.03-6.98). Among delivery unit participants, 1.7% (12/717) had peripheral parasitaemia and 2.4% (17/712) had placental parasitaemia. Women attending delivery units were more likely to be parasitaemic if they were in their first or second pregnancy (aRR 3.17, 95%CI 1.32-7.61), had fever in the last week (aRR 5.34, 95%CI 2.89-9.90), or had rural residence (aRR 3.10, 95%CI 1.66-5.79). Malaria control measures including indoor residual spraying (IRS) and untreated bed nets were common, whereas insecticide-treated bed nets (ITN) and malaria chemoprophylaxis were rarely used.ConclusionThe prevalence of malaria among pregnant women was relatively low. However, given the large at-risk population in this malaria-endemic region of India, there is a need to enhance ITN availability and use for prevention of malaria in pregnancy, and to improve case management of symptomatic pregnant women.

Patterns of Household Insecticide Use and Pyrethroid Resistance inAnopheles Gambiae Sensu Stricto(Diptera: Culicidae) within the Accra Metropolis of Ghana

Insecticide resistance due to mutations in the knockdown resistance (kdr) gene in Anopheles gambiae populations has been reported in some West African countries, despite the absence of large-scale mosquito control in this sub-region. Agricultural and/or household use of insecticides has been implicated in the development of resistance in An. gambiae. However, such studies had not been carried out in Ghana, where large-scale use of insecticide-treated bed nets is a major component of the Roll Back Malaria programme. There is therefore a need to establish baseline information on patterns of insecticide use and vector susceptibility levels in Ghana. A questionnaire survey of 171 households with 800 inhabitants was conducted to obtain information on knowledge, attitude and perception of respondents on household insecticide use in the Accra metropolis. Also, adult An. gambiae were tested for resistance to permethrin and deltamethrin using WHO adult mosquito test kits. The polymerase chain reaction (PCR) was us...

Effect of two different house screening interventions on exposure to malaria vectors and on anaemia in children in The Gambia: a randomised controlled trial

House screening should protect people against malaria. We assessed whether two types of house screening--full screening of windows, doors, and closing eaves, or installation of screened ceilings--could reduce house entry of malaria vectors and frequency of anaemia in children in an area of seasonal malaria transmission. During 2006 and 2007, 500 occupied houses in and near Farafenni town in The Gambia, an area with low use of insecticide-treated bednets, were randomly assigned to receive full screening, screened ceilings, or no screening (control). Randomisation was done by computer-generated list, in permuted blocks of five houses in the ratio 2:2:1. Screening was not treated with insecticide. Exposure to mosquitoes indoors was assessed by fortnightly light trap collections during the transmission season. Primary endpoints included the number of female Anopheles gambiae sensu lato mosquitoes collected per trap per night. Secondary endpoints included frequency of anaemia (haemoglobin concentration <80 g/L) and parasitaemia at the end of the transmission season in children (aged 6 months to 10 years) who were living in the study houses. Analysis was by modified intention to treat (ITT), including all randomised houses for which there were some outcome data and all children from those houses who were sampled for haemoglobin and parasitaemia. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN51184253. 462 houses were included in the modified ITT analysis (full screening, n=188; screened ceilings, n=178; control, n=96). The mean number of A gambiae caught in houses without screening was 37.5 per trap per night (95% CI 31.6-43.3), compared with 15.2 (12.9-17.4) in houses with full screening (ratio of means 0.41, 95% CI 0.31-0.54; p<0.0001) and 19.1 (16.1-22.1) in houses with screened ceilings (ratio 0.53, 0.40-0.70; p<0.0001). 755 children completed the study, of whom 731 had complete clinical and covariate data and were used in the analysis of clinical outcomes. 30 (19%) of 158 children from control houses had anaemia, compared with 38 (12%) of 309 from houses with full screening (adjusted odds ratio [OR] 0.53, 95% CI 0.29-0.97; p=0.04), and 31 (12%) of 264 from houses with screened ceilings (OR 0.51, 0.27-0.96; p=0.04). Frequency of parasitaemia did not differ between intervention and control groups. House screening substantially reduced the number of mosquitoes inside houses and could contribute to prevention of anaemia in children. Medical Research Council.

Status of insecticide susceptibility in Anopheles gambiae s.l. from malaria surveillance sites in The Gambia

BackgroundVector control is an effective way of reducing malaria transmission. The main vector control methods include the use of insecticide-treated bed nets and indoor residual spraying (IRS). Both interventions rely on the continuing susceptibility of Anopheles to a limited number of insecticides. However, insecticide resistance, in particular pyrethroid-DDT cross-resistance, is a challenge facing malaria vector control in Africa because pyrethroids represent the only class of insecticides approved for treating bed nets and DDT is commonly used for IRS. Here baseline data are presented on the insecticide susceptibility levels of malaria vectors prior to The Gambian indoor residual spraying intervention programme.MethodsAnopheles larvae were collected from six malaria surveillance sites (Brikama, Essau, Farafenni, Mansakonko, Kuntaur and Basse) established by the National Malaria Control Programme and the UK Medical Research Council Laboratories in The Gambia. The mosquitoes were reared to adulthood and identified using morphological keys and a species-specific polymerase chain reaction assay. Two- to three-day old adult female mosquitoes were tested for susceptibility to permethrin, deltamethrin and DDT using standard WHO protocols, insecticide susceptibility test kits and treated papers.ResultsAll Anopheles mosquitoes tested belonged to the Anopheles gambiae complex. Anopheles arabiensis was predominant (54.1%), followed by An. gambiae s.s. (26.1%) and Anopheles melas (19.8%). Anopheles gambiae s.s. and An. arabiensis were found at all six sites. Anopheles melas was recorded only at Brikama. Mosquitoes from two of the six sites (Brikama and Basse) were fully susceptible to all three insecticides tested. However, DDT resistance was found in An. gambiae from Essau where the 24 hours post-exposure mortality was <80% but 88% for permethrin and 92% for deltamethrin.ConclusionThis current survey of insecticide resistance in Anopheles provides baseline information for monitoring resistance in The Gambia and highlights the need for routine resistance surveillance as an integral part of the proposed nation wide IRS intervention using DDT.

Initial treatment of severe malaria in children is inadequate - a study from a referral hospital in Cameroon

Background . Severe malaria, caused by Plasmodium falciparum, is potentially fatal, with a case mortality rate of 15 - 20%, despite treatment. Aim . To document epidemiological and clinical features, including initial treatment, of severe malaria in children referred to a general paediatric unit in Cameroon. Methods . A prospective cross-sectional study investigating characteristics of children admitted for severe malaria, confirmed with a positive thick blood smear. Results . A total of 309 (29.2%) children were identified out of 1 060 admissions, of whom 52% were males and 48% females, and mean age 46.3 (1 - 180) months. Most children were aged artesunate + amodiaquine (18%), and artesunate + mefloquine (6%). Only 16% of the mothers said they had used insecticidetreated bed nets (ITNs). Conclusion . In most cases, there is a delay before consultation, with most children initially self-medicated at home. Initial consultations are at primary local health facilities where less effective drugs are prescribed at inadequate dosages. Recommended ACTs were also often prescribed at inadequate dosages. Education in the use of ITNs, home treatment of simple malaria, and appropriate use of ACTs should be promoted.