Operational aspects of bednet impregnation for community‐based malaria control in Nicaragua, Ecuador, Peru and Colombia

Community intervention projects with pyrethroid (permethrin and lambdacyhalothrin) impregnated bednets and an accompanying community education programme were carried out in 6 malaria endemic areas on the Pacific coast of Nicaragua, Ecuador, Peru and Colombia as well as in the Peruvian Amazon basin. In this paper the operational aspects are analysed: bednet coverage, results of promotional activities for increased bednet use, the sale of low‐cost bednets, techniques and difficulties with impregnation, acceptance of the programme (including washing of impregnated nets), side‐effects, residual concentrations of the chemical in the nets, costs of the impregnation programme and insecticide resistance of the malaria vectors.
We found that the local manufacture of bednets and their sale through village health workers, even in communities with low cash income, is a viable way of increasing bednet coverage; the impregnation of bednets is well accepted if villagers perceive a direct benefit; pretesting of the soaking capacity of different net materials should be done at central level; the instructions for the impregnation procedures of different net materials (cotton and synthetic) should be simple and unambiguous; very cheap thin net materials should be avoided, particularly in the case of lambdacyhalothrin impregnation; educational methods and/or promotion of dark‐colour nets should be further tested in order to decrease the washing frequency of bednets at household level; in areas with early‐biting mosquitoes further studies on the protective efficacy of bednets are necessary; careful monitoring of side‐effects, particularly those of last‐generation pyrethroids, is necessary; and the community‐based impregnation programme is a powerful tool for strengthening community involvement in health actions.     

Use of intermittent presumptive treatment and insecticide treated bed nets by pregnant women in four Kenyan districts

The roll back malaria (RBM) movement promotes the use of insecticide-treated bednets (ITNs) and intermittent presumptive treatment (IPT) of malaria infection as preventive measures against the adverse effects of malaria among pregnant women in Africa. To determine the use of these preventive measures we undertook a community-based survey of recently pregnant women randomly selected from communities in four districts of Kenya in December 2001. Of the 1814 women surveyed, only 5% had slept under an ITN. More than half of the 13% of women using a bednet (treated or untreated) had bought their nets from shops or markets. Women from rural areas used bednets less than urban women (11% vs. 27%; P < 0.001), and 41% of the bednets used by rural women had been obtained free of charge from a research project in Bondo or a nationwide UNICEF donation through antenatal clinics (ANCs). Despite 96% of ANC providers being aware of IPT with sulphadoxine-pyrimethamine (SP), only 5% of women interviewed had received two or more doses of SP as a presumptive treatment. The coverage of pregnant women with at least one dose of IPT with SP was 14%, though a similar percentage also had received at least a single dose as a curative treatment. The coverage of nationally recommended strategies to prevent malaria during pregnancy during 2001 was low across the diverse malaria ecology of Kenya. Rapid expansion of access to these services is required to meet international and national targets by the year 2005. The scaling up of malaria prevention programmes through ANC services should be possible with 74% of women visiting ANCs at least twice in all four districts. Issues of commodity supply and service costs to clients will be the greatest impediments to reaching RBM targets.     

Acceptability and use of insecticide impregnated bednets in northern Ghana

Summary A district-wide study was undertaken in a rural population of northern Ghana to identify factors influencing the acceptance and use of insecticide-impregnated bednets (IIBNs). A series of focus group discussions were conducted during 2 years of implementation of IIBNs to gauge community reactions to the introduction of the nets and a structured questionnaire was administered to approximately 2000 randomly selected individuals. Although the IIBNs were accepted and used because they provided protection from mosquito bites, seasonal factors, patterns of use, and questions of cost were key factors likely to influence the dissemination and effectiveness of bednets. Use of the bednets was highly seasonal. Almost all recipients used their IIBNs in the rainy season (99%), corresponding to the period of high mosquito density and 20% used them in the dry seasons, the period of low mosquito density. Mothers with young children were more likely to wash the bednets frequently (because the children soiled the bednets with faeces and urine), resulting in no protection from the insecticide. Provision of wider bednets, or the provision of plastic sheets with the bednets or possible incorporation of the insecticide in washing soaps could improve protection for young children.
The success of the promotion of IIBNs in malaria control programmes will depend on the cost of the package and the time of year that it is delivered. Financing mechanisms for individual and village groups are discussed. Social research effectively monitored the intervention in this study, and it should be included as an important component of national malaria control programmes.     

Introducing insecticide-treated nets in the Kilombero Valley, Tanzania: the relevance of local knowledge and practice for an information, education and communication (IEC) campaign

Since 1997 the WHO has been recommending an integrative strategy to combat malaria including new medicines, vaccines, improvements of health care systems and insecticide-treated nets (ITNs). After successful controlled trials with ITNs in the past decade, large-scale interventions and research now focus on operational issues of distribution and financing. In developing a social marketing approach in the Kilombero Valley in south-east Tanzania in 1996, a combination of qualitative and quantitative methods was employed to investigate local knowledge and practice relating to malaria. The findings show that the biomedical concept of malaria overlaps with several local illness concepts, one of which is called malaria and refers to mild malaria. Most respondents linked malaria to mosquitoes (76%) and already used mosquito nets (52%). But local understandings of severe malaria differed from the biomedical concept and were not linked to mosquitoes or malaria. A social marketing strategy to promote ITNs was developed on the basis of these findings, which reinforced public health messages and linked them with nets and insecticide. Although we did not directly evaluate the impact of promotional activities, the sharp rise in ownership and use of ITNs by the population (from 10 to > 50%) suggests that they contributed significantly to the success of the programme. Local knowledge and practice is highly relevant for social marketing strategies of ITNs.     

安徽省中华按蚊地区疟疾传播因素的调查

目的了解沿淮和淮河以北中华按蚊分布区疟疾流行因素和特征,为制定相应的防治措施提供依据。方法根据地理分布及疟疾发病情况,选择近年来疟疾发病率较高的怀远县褚集镇、固镇县新马桥镇、墉桥区大店镇、蒙城县立仓镇和涡阳县龙山镇作为疟疾监测点,调查居民疟疾发病情况,疟疾症状及防蚊措施情况,蚊虫密度及叮人率等相关因素。结果调查15个行政村,5 987户,24 433人,有纱门、纱窗690户,蚊帐6 727顶,蚊帐拥有率27.53%;使用蚊帐10 260人,蚊帐使用率为41.99%;经常使用蚊香及杀虫剂灭蚊户分别占68.33%和27.98%。血检疟原虫阳性1 308人(均为间日疟),平均阳性率为9.17%。2005年监测点共发生疟疾1 277例,比2004年同期上升48.48%。通宵帐内中华按蚊平均密度为0.42只/顶.次,平均叮人率为0.22只/人.夜;半通宵帐内人饵诱蚊密度为3.78只/h,叮人率为5.66只/人。疟疾病人发病后及时接受抗疟治疗者仅占3.97%,隔日治疗者占11.53%。结论沿淮和淮河以北中华按蚊分布区的疟疾疫情回升受多种因素影响,疟疾病人得不到及时发现和治疗是主要原因。     

Do insecticide‐treated bednets have an effect on malaria vectors?

The use of insecticide-treated bednets (ITNs) has been widely adopted as an important method for malaria control. Few data exist on effects of ITNs on mosquito biology and ecology, other than the development of insecticide resistance against the insecticides used. There is no hard evidence that the insecticide resistance recorded is the result of insecticidal use on bednets or from agricultural use. Resistance against pyrethroids, the preferred class of insecticides for ITN use, has been recorded from countries in Asia, Africa and South America. Resistance is expressed as reduced excito-repellency and mortality of mosquitoes exposed to insecticide-treated materials. In the absence of resistance, however, most studies on ITN effects report a reduced survival of adult mosquitoes as well as mass killing. Other effects are highly variable, and shifts in time of biting, feeding site and blood hosts have occasionally been reported, but not in proportion to the scale of ITN use. In general, a reduced sporozoite rate is recorded in ITN programmes. Because many of the anticipated behavioural effects caused by insecticidal use will be avoided by the use of untreated nets, studies on the efficacy of untreated nets are required. Examples are presented in which untreated nets provided a reasonable degree of protection against malaria.     

Insecticide-treated bednets reduce mortality and severe morbidity from malaria among children on the Kenyan coast

New tools to prevent malaria morbidity and mortality are needed to improve child survival in sub-Saharan Africa. Insecticide treated bednets (ITBN) have been shown, in one setting (The Gambia, West Africa), to reduce childhood mortality. To assess the impact of ITBN on child survival under different epidemiological and cultural conditions we conducted a community randomized, controlled trial of permethrin treated bednets (0.5 g/m²) among a rural population on the Kenyan Coast. Between 1991 and 1993 continuous community-based demographic surveillance linked to hospital-based in-patient surveillance identified all mortality and severe malaria morbidity events during a 2-year period among a population of over 11 000 children under 5 years of age. In July 1993, 28 randomly selected communities were issued ITBN, instructed in their use and the nets re-impregnated every 6 months. The remaining 28 communities served as contemporaneous controls for the following 2 years, during which continuous demographic and hospital surveillance was maintained until the end of July 1995. The introduction of ITBN led to significant reductions in childhood mortality (PE 33%, CI 7–51%) and severe, life-threatening malaria among children aged 1–59 months (PE 44%, CI 19–62). These findings confirm the value of ITBN in improving child survival and provide the first evidence of their specific role in reducing severe morbidity from malaria.     

Who develops severe malaria? Impact of access to healthcare,socio‐economic and environmental factors on children in Yemen: a case‐control study

Objective To investigate the impact of socio‐economic and environmental factors on developing severe malaria in comparison with mild malaria in Yemen. Method Case‐control study comparing 343 children aged 6 months to 10 years diagnosed with WHO‐defined severe malaria (cases) at the main children’s hospital in Taiz and 445 children with mild malaria (controls) diagnosed in the health centres, which serve the areas where the cases came from. Results In univariate analysis, age <1 year, distance from health centre, delay to treatment and driving time to health centre were associated with progression from mild to severe malaria. In multivariate analysis, distance to nearest health centre >2 km was significantly associated with progression to severe disease. Environmental and vector control factors associated with protection from acquiring malaria (such as sleeping under bednets) were not associated with protection from moving from mild to severe disease. Conclusions Innovative ways to improve access to antimalarial treatment for those living more then 2 km away from health centres such as home management of malaria, especially for infants and young children, should be explored in malaria‐endemic areas of Yemen.     

Socio-cultural determinants of treatment delay for childhood malaria in southern Ghana

We studied socio-cultural determinants of timely appropriate treatment seeking for children under 5 years suspected of having a perceived malaria-related illness. Caretakers of children with suspected malaria were interviewed about illness-related experiences, meanings and behaviour in two endemic villages in southern Ghana. Only 11% of children suspected of having a perceived malaria-related illness received timely appropriate treatment consistent with the Abuja target of treating malaria within 24 h of illness onset; 33% of children received appropriate treatment within 48 h. Reported perceived causes of phlegm predicted timely, appropriate treatment within 24 h of illness onset (P = 0.04) in a multivariate logistic regression model; playing on the ground (P < 0.01) predicted such treatment within 48 h. Two categories of distress, paleness or shortage of blood (P = 0.05) and sweating profusely (P = 0.03), also predicted timely, appropriate treatment within 24 h in a multivariate logistic regression model. Knowing that mosquitoes transmit malaria was not associated with timely, appropriate help seeking for the children, even though such knowledge may promote personal protective measures, especially use of bednets. Patterns of distress and PC were related to timely, appropriate help seeking, but not as expected. Effects on health seeking of illness-related experience and meaning are complex, and explaining their role may strengthen interventions for childhood malaria.     

Promotion of insecticide-treated mosquito nets in Myanmar

A simple health promotion message administered by village midwives raised bednet usage to over 60% in trial hamlets in north Shan State, Myanmar. Treatment of the nets in the study villages produced a reduction in malaria cases. Most villagers were prepared to buy their nets at market prices and were willing to pay for the cost of re-treatment of nets, but very poor, members of the Wa ethnic group required a half-price subsidy for them to afford them. The use of insecticide treated bednets was felt to be appropriate for undeveloped and remote areas of the country where malaria control was difficult.     

Giving bednets "fair" tests in field trials against malaria:a case from Sabah, East Malaysia

Insecticide-impregnated bednets appear to be a potentially cost-effective intervention against endemic malaria in the tropics, but this has yet to be confirmed by field trials. There are two aspects to consider in assessing such trials: (1) the extent to which subjects use nets regularly and properly, and (2) the effectiveness of nets which are truly used regularly and properly in reducing malaria transmission. The second aspect is currently of primary concern, to determine if human-vector relationships for a particular at-risk population are such that bednets can be effective. But to give bednets a "fair" test in this regard requires regular and proper use in the first place. The study described here suggests they did not get a "fair" test in one field trial in Sabah, East Malaysia. The study also strongly suggests that direct observations, rather than post hoc questioning of subjects, may be essential to accurately gauge bednet usage rates. Accurate usage rates are required to determine what proportion of a population needs to use nets to reduce malaria transmission, and to evaluate the effectiveness of promotional programs over time. Direct observations can also yield valuable data on night-time activities that increase malaria risk, such as television viewing that keeps people awake and out of bednets.     

中缅边境两个少数民族居民蚊帐使用情况及其影响因素

目的了解佤族和拉祜族居民蚊帐使用情况及其影响因素,探讨促进蚊帐使用和推广杀虫剂浸泡蚊帐(ITNs)的方法.方法问卷调查,对资料采用EpiInfo 2000进行统计学处理.结果佤族和拉祜族经常或有时使用蚊帐的分别占2.8%和4.8%;而没有蚊帐的分别占67.7%和59.7%;Logistic多因素回归分析结果证实,大部分有蚊帐者不经常使用蚊帐防蚊的原因与当地居民缺乏疟疾预防知识有关.结论两个少数民族中的蚊帐覆盖率和使用率均很低,健康教育、交流沟通和市场营销等是促进蚊帐和ITNs的使用的适当策略.     

Maternal influence on the use of impregnated bednets in the protection of infantile malaria

A cross-sectional survey of 184 mothers or caretakers was undertaken to investigate the effect of socio-behavioral background on decision making in relation to the use of impregnated bednets to prevent malaria for their children in Ratchaburi Province, Thailand. It was found that most mothers had knowledge of the cause, transmission and prevention of malaria. They perceived susceptibility and severity of malaria as a risk to their children, which might even cause death. They also perceived and had positive attitudes toward impregnated bednets as a protection for their children. Three-quaters (76.4%) of them used impregnated bednets regularly to protect their children whereas one-quarter (23.6%) used infrequently and few never used. Bivariate analysis showed that the use of impregnated bednets was significantly related to the factors such as knowledge of malaria prevention, perception of benefits of the use, the receipt of information about the impregnated bednets from malaria workers.     

Review: Intermittent preventive treatment--a new approach to the prevention of malaria in children in areas with seasonal malaria transmission

Intermittent preventive treatment, the administration of a full course of an anti-malarial treatment to a population at risk at specified time points regardless of whether or not they are known to be infected, is now a recommended approach to the prevention of malaria in pregnancy and is being explored as a potential way of preventing malaria in infants. However, in many malaria endemic areas, the main burden of malaria is in older children and increasing use of insecticide treated bednets is likely to increase further the proportion of episodes of malaria that occur in older children. Recently, it has been shown in Senegal and in Mali that intermittent preventive treatment given to older children during the malaria transmission season can be remarkably effective in preventing malaria. This approach to malaria control is likely to be most effective in areas with a high level of malaria transmission concentrated in a short period of the year. However, several issues need to be addressed before intermittent preventive treatment in children can be advocated for use in malaria control programmes. These include: (1) determination of whether intermittent preventive treatment adds to the protection afforded by other control measures such as insecticide-treated bednets; (2) whether an effective and sustainable delivery system can be found; (3) choice of drug to be used; (4) optimum timing of drug administration; (5) the requisite interval between treatments. The potential benefits of intermittent preventive treatment in children are substantial; more research is needed to determine if this is a practical approach to malaria control.     

How local community knowledge about malaria affects insecticide-treated net use in northern Ghana

Large-scale trials of insecticide-treated nets (ITNs) throughout Sub-Saharan Africa demonstrated that they reduce child mortality in malaria endemic communities. These encouraging results have generated interest in ITNs as a viable malaria control strategy in many malaria endemic countries. However, regular use of ITNs under routine or non-project conditions has been beset with several problems. This paper explores how local community knowledge about malaria acts as a barrier to the use of ITNs in three settings. We employed structured formal observation and a range of interviewing techniques which included informal interviews, focus group discussions, semi-structured in-depth interviews, and structured survey interviewing. People recognize the term 'malaria' but have limited biomedical knowledge of the disease, including its aetiology, the role of the vector, and host response. Convulsions and anaemia are rarely linked to malaria. The people acknowledged a role for ITNs in nuisance reduction, but not for malaria prevention.     

广东省流动人口与疟防相关的特点分析

本文通过对流动人口集散频繁的广东省珠江三角洲一带深圳市坪山镇、坑梓镇和中山市三乡镇的３８９６名流动人口的调查，揭示出广东省流动人口的特点：绝大多数是青壮年，１０～４０岁之间占９７．６％，女性占６３．７％，７８．３％的应答者未婚。７４．１％的应答者达不到高中文化程度。家庭人均收入低，月平均为２６元／人，且来源复杂，停留时间短，基本生活条件差。１３．４％的应答者居住在临时工棚，３．６％的应答者无蚊帐，２３．１％的应答者蚊帐有明显破损，８．３％的应答者即使有蚊帐也从来不用。这些特点可以为制订相应的流动人口疟疾管理方案提供依据     

Malaria preventive measures, health care seeking behaviour and malaria burden in different epidemiological settings in Sudan

Objectives  To provide information about preventive measures and treatment seeking behaviour as well as an estimate of the malaria burden in different epidemiological settings for effective monitoring and evaluation of the ongoing efforts.
Methods  Cross-sectional survey carried out in four areas representing different levels of transmission to explore the use of preventive measures, care-seeking behaviour and accessibility in addition to point prevalence was followed by a follow-up phase in which the health workers registered and reported all fever cases including malaria. The relation between the reported malaria incidence, the product of symptomatic/asymptomatic ratio and the prevalence of confirmed malaria cases was used to develop the equation that could predict the true malaria incidence.
Results  Thousand households and 3628 individuals were surveyed. The presence of any net varied between 6.6% and 40%; the percentage of people who reportedly slept under mosquito nets in the previous night varied between 35 and 80. Prompt use of medications ranged between 14 and 48% with a delay of more than 24 h noticed in different areas. The mean number of individuals per household who reported use of anti-malarial drugs in the last 2 weeks ranged between 0.6 (SD = 0.92) and 1.2 (SD = 1.1), with variable cost per treatment and affordability. The prevalence of asymptomatic parasitaemia, fever and confirmed malaria at time of the survey differed by area. The incidence of malaria during the follow-up period was estimated to be 8.5, 178.6, 23.7 and 10.3 episodes per 1000 population in Malakal, Elrank, Elhosh and El Matama, respectively. Based on this, a prediction equation was developed.
Conclusion  We found suboptimal health care seeking behaviour, coverage and use of preventive measures with a high malaria burden. We developed a model for future estimation of malaria episodes.     

Prevalence and correlates of insecticide-treated bednet use among HIV-1-infected adults in Kenya

HIV-1-infected adults are at increased risk for malaria. Insecticide-treated bednets protect individuals from malaria. Little is known about correlates of ownership and use of bednets among HIV-1-infected individuals. We conducted a cross-sectional survey of 388 HIV-1-infected adults recruited from three sites in Kenya (Kilifi, Kisii, and Kisumu) to determine factors associated with ownership and use of optimal bednets. We defined an optimal bednet as an untorn, insecticide-treated bednet. Of 388 participants, 134(34.5%) reported owning an optimal bednet. Of those that owned optimal bednets, most (76.9%) reported using it daily. In a multivariate model, higher socioeconomic status as defined as postsecondary education [OR = 2.8 (95% CI: 1.3–6.4), p = 0.01] and living in a permanent home [OR = 1.7(1.03–2.9), p = 0.04] were significantly associated with optimal bednet ownership. Among individuals who owned bednets, employed individuals were less likely [OR = 0.2(0.04–0.8), p = 0.01] and participants from Kilifi were more likely to use bednets [OR = 2.9 (95% CI 1.04–8.1), p = 0.04] in univariate analysis. Participants from Kilifi had the least education, lowest income, and lowest rate of employment. Our findings suggest that lower socioeconomic status is a barrier to ownership of an optimal bednet. However, consistent use is high once individuals are in possession of an optimal bednet. Increasing access to optimal bednets will lead to high uptake and use.     

Knowledge, attitude and practice on malaria: A study in a tribal belt of Orissa state, India with reference to use of long lasting treated mosquito nets

Local knowledge and practice related to malaria is important for the implementation of culturally appropriate, sustainable and effective interventions. In this context, to know people's knowledge, attitude and practice on malaria and its prevention, a study was carried out in two districts viz., Malkangiri and Koraput of Orissa state in India, the former with ongoing insecticide treated mosquito nets (ITNs) programme and the latter without such programme (non-ITNs). Both qualitative and quantitative methods were used for data collection. The local concepts used for malaria describe only the biomedical symptoms of the disease although a few by meaning in local language reflect people's misconceptions about the cause of malaria. About 63% of the respondents mentioned mosquito bite as the cause for this disease and 65% considered malaria as a serious problem. Qualitative data showed that people from remote villages seek treatment from traditional healers, Disharis. About 64% of the respondents stated that avoiding mosquito bites could prevent malaria. Majority (99%) of the people reported using personal protection measures to avoid mosquito bites. Although, majority of the people were aware of the cause and prevention of malaria (about 70% stated sleeping under mosquito net prevents malaria), a sizable proportion still had misconceptions and hence appropriate communication strategies should be developed and imparted alongside ITNs/LLINs distribution for a behaviour change to adopt such preventive measures. Since, the tribes are habituated to seek treatment from traditional healers; they could be involved in motivating people to use ITNs/LLINs to protect from mosquito bites and malaria.     

Urban malaria: primary caregivers' knowledge,attitudes, practices and predictors of malaria incidence in a cohort of Ugandan children

OBJECTIVES: To assess malaria-related knowledge, attitude and practices (KAP) among primary caregivers, to identify associations between primary caregivers' characteristics and positive KAP towards malaria, and to identify independent predictors of childhood malaria incidence in an urban setting. METHODS: Children aged 6 months to 5 years living in Kampala, Uganda were enrolled as part of a longitudinal study on antimalarial therapy. Primary caregivers of 307 children were interviewed and information was collected on demographics, malaria-related KAP, environmental and household factors. Malaria incidence was measured prospectively using passive surveillance. RESULTS: A total of 90% of respondents reported mosquitoes and/or malaria as the cause of fever. Caregivers reported that if their child had fever, 63% would go to a clinic or hospital as their first action and 97% as their first or second action. Only 38% knew that chloroquine was the recommended first-line treatment for malaria and 29% knew the correct dose. Preventive measures for malaria were reported in 45% of households but only 25% reported using bednets. Higher levels of education for the caregiver were associated with positive malaria-related KAP. Malaria incidence varied widely. The following were independent predictors of malaria incidence: (1). Children aged 24-41 months at enrolment had a higher incidence of malaria. (2). Reported bednet or chemoprophylaxis use reduced the incidence of malaria. (3). A child's place of residence was associated with incidence. (4). Children from households using open water sources had a higher incidence than those using closed sources. CONCLUSION: Primary caregivers were knowledgeable about malaria and used modern health care facilities but knew less about the proper administration of antimalarials and had limited use of preventive measures. Malaria incidence was associated with child's age at enrolment, geography, source of water and the use of preventive measures.