The impact of insecticide-treated bednets on malaria and anaemia in pregnancy in Kassena-Nankana district, Ghana: a randomized controlled trial

Interventions for malaria prevention in pregnancy; factors influencing uptake and their effect on pregnancy outcomes among post-natal women in a tertiary facility in the Volta Region of Ghana

Objectives

Malaria in pregnancy is associated with adverse pregnancy outcomes including maternal anaemia and low birthweight. Uptake of preventive interventions is sub-optimal in sub-Saharan Africa including Ghana. Understanding local-level factors that influence uptake of these interventions can enhance control. The study assessed uptake of intermittent preventive treatment of malaria during pregnancy using sulphadoxine-pyrimethamine (IPTp-SP) and insecticide-treated net (ITN) use, their determinants and effects on pregnancy outcomes.

Methods

A cross-sectional study involving 349 post-partum women was conducted from 25 August 2022 to 9 October 2022 at the Ho Teaching Hospital. A structured questionnaire was used to collect data on participant socio-demographics, ITN use, number of doses of sulphadoxine-pyrimethamine received, knowledge of malaria in pregnancy, haemoglobin levels and birth weight among others. Summary statistics were reported as frequencies, percentages and means. Associations between exposure and outcome variables were assessed using logistic regression methods and odds ratios reported with 95% confidence intervals. Statistical significance was concluded at p < 0.05.

Results

More than 80% (291) of respondents received ⩾3 doses of intermittent preventive treatment using sulphadoxine-pyrimethamine and 64.8% (226) slept under ITNs the night before the survey. Age >25 years, employment, good knowledge of malaria in pregnancy, parity ⩾2 and initiating antenatal care visits in the first trimester facilitated the uptake of these interventions. Receiving ⩾3 doses of sulphadoxine-pyrimethamine was associated with having normal-weight babies (adjusted odds ratio 2.80, 95% CI: 1.07, 7.34; p = 0.036) while ITN use was associated with having term babies (adjusted odds ratio 2.72, 95% CI: 1.24, 5.90; p = 0.013) and normal maternal haemoglobin concentration at term (adjusted odds ratio 1.57, 95% CI: 1.01, 2.47; p = 0.044).

Conclusions

The interventions were beneficial against low birthweight and preterm births which predispose to neonatal deaths and poor cognitive function in children. Malaria in pregnancy health campaigns should be intensified, especially among younger-aged primigravidae, to increase their knowledge of the condition as a way to further improve uptake of these preventive interventions.

Preterm Delivery and Neonatal Deaths among Anaemic Pregnant Women in the Bolgatanga Metropolis of Ghana

Preterm deliveries and neonatal deaths as functions of anaemia in pregnancy are of major public health interest. However, data on the prevalence of preterm deliveries and their association with mortality in anaemic pregnant women in the study area are scanty. Thus, the study sought to investigate the prevalence of preterm delivery and neonatal deaths among anaemic pregnant women in the Bolgatanga Regional Hospital in the Upper East Region of Ghana during the past five years. A retrospective study design was adopted, and data were gathered between March and May 2016. Records of women who were anaemic during any trimester of their pregnancy and delivered in the hospital within the last five years were included in the study. In all, two hundred (200) cases were reviewed. Data on the sociodemographic characteristics, health status, and birth outcome of participants were captured, and analyses were conducted using SPSS version 21 while considering significant differences at p < 0.05. The study revealed that more than half of the anaemic women (52.5%, n = 105) had preterm deliveries, while neonatal mortality was 8.5% (n = 17). The proportion of mothers who received dietary or medical intervention for the treatment of anaemia and the number of attendances to antenatal clinics were comparable between preterm and normal-term mothers (p > 0.05). Mothers with preterm deliveries had a higher risk of neonatal mortality (AOR = 13.66, 95% CI = 1.65-113.30, and p=0.015). This study has shown that anaemia in pregnancy increases the risk of preterm delivery and neonatal death. It is recommended that extra care be given to pregnant women with anaemia, while further studies are conducted with a larger sample size to substantiate the claims made in this study.

Trends of malaria infection in pregnancy in Ghana over the past two decades: a review

Background

There has been a global decline in malaria transmission over the past decade. However, not much is known of the impact of this observation on the burden of malaria infection in pregnancy in endemic regions including Ghana. A narrative review was undertaken to help describe trends in malaria infection in pregnancy in Ghana. Among others, such information is important in showing any progress made in malaria in pregnancy control.

Methods

To describe trends in pregnancy-associated malaria infection in Ghana, a search and review of literature reporting data on the prevalence of asymptomatic Plasmodium falciparum infection in pregnancy was conducted.

Results

Thirty-six (36) studies, conducted over 1994–2019, were included in the review. In the northern savannah zone with largely seasonal malaria transmission, prevalence appeared to reduce from about 50–60% in 1994–2010 to 13–26% by 2019. In the middle transitional/forest zone, where transmission is perennial with peaks in the rainy season, prevalence apparently reduced from 60% in the late 1990 s to about 5–20% by 2018. In the coastal savannah area, there was apparent reduction from 28 to 35% in 2003–2010 to 5–11% by 2018–2019. The burden of malaria infection in pregnancy continues to be highest among teenagers and younger-aged pregnant women and paucigravidae.

Conclusions

There appears to be a decline in asymptomatic parasite prevalence in pregnancy in Ghana though this has not been uniform across the different transmission zones. The greatest declines were noticeably in urban settings. Submicroscopic parasitaemia remains a challenge for control efforts. Further studies are needed to evaluate the impact of the reduced parasite prevalence on maternal anaemia and low birthweight and to assess the local burden of submicroscopic parasitaemia in relation to pregnancy outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-04031-3.

Varying levels of protection against Plasmodium falciparium infection were conferred on non-users of long lasting insecticidal nets (LLINS) sleeping in rooms where different number of LLINS were hung in hyper endemic state of West Africa

The use of Long Lasting Insecticidal Nets (LLINs) has greatly reduced the health and economic impact posed by malaria. This study evaluated the residual effect of LLINs on malaria parasite infections among non-LLIN users sleeping in rooms where nets were hung. This study was carried out at Federal University of Agriculture Abeokuta, Ogun State, Nigeria. A total of 259 students were systematically recruited into this study and were classified into two groups of LLINs users and non-users. The LLIN users were further classified according to the proportion of net usage and this includes; < 50%, exactly 50% and > 50% respectively. Finger prick blood samples were collected from the participants and microscopically analysed for the presence of parasites. Demographic characteristics were also recorded. A general prevalence of 40.5% positivity for malaria was recorded among the study population. A significantly high prevalence (p < 0.05) of malaria was recorded among non-users of LLINs compared to users (AOR 4.66, 95%CI 1.27-17.06). A significantly low prevalence of malaria parasite infection was recorded among non-users of LLINs occupying rooms where LLINs was hung compared with non-users from rooms where LLIN were not used. Furthermore, a reduction in prevalence of malaria and parasite densities was observed among non-users of LLINs (occupying rooms where LLINs was hung) as the proportion of LLIN usage increased in such rooms (p < 0.05). This study showed that some level of protection may be conferred on non-users of LLINs staying in rooms where LLINs are hung.

Anaemia at antenatal care initiation and associated factors among pregnant women in West Gonja District, Ghana: a cross-sectional study

INTRODUCTION

Anaemia in pregnancy remains a critical public health concern in many African settings; but its determinants are not clear. The purpose of this study was to assess anaemia at antenatal care initiation and associated factors among pregnant women in a local district of Ghana.

METHODS

A facility-based cross-sectional survey was conducted. A total of 378 pregnant women attending antenatal care at two health facilities were surveyed. Data on haemoglobin level, helminths and malaria infection status at first antenatal care registration were extracted from antenatal records booklets of each pregnant women. Questionnaires were then used to collect data on socio-demographic and dietary variables. Binary and multivariate logistic regression analyses were done to assess factors associated with anaemia.

RESULTS

The prevalence of anaemia was 56%, with mild anaemia being the highest form (31.0%). Anaemia prevalence was highest (73.2%) among respondents aged 15-19 years. Factors that significantly independently reduced the odds of anaemia in pregnancy after controlling for potential confounders were early (within first trimester) antenatal care initiation (AOR=5.01; 95% CI =1.41-17.76; p=0.013) and consumption of egg three or more times in a week (AOR=0.30; 95% CI=0.15-0.81; P=0.014).

CONCLUSION

Health facility and community-based preconception and conception care interventions must not only aim to educate women and community members about the importance of early ANC initiation, balanced diet, protein and iron-rich foods sources that may reduce anaemia, but must also engage community leaders and men to address food taboos and cultural prohibitions that negatively affect pregnant woman.

Descriptive epidemiology of anaemia among pregnant women initiating antenatal care in rural Northern Ghana

Background

Anaemia in pregnancy is associated with adverse obstetric outcomes. When detected early in pregnancy, it can be treated; however, information on its prevalence and associated factors is limited in rural Ghana.

Aim

The aim of this study was to determine the prevalence and maternal factors associated with anaemia in pregnancy at first antenatal care (ANC) visits.

Setting

The study was conducted in the Navrongo War Memorial Hospital, a secondary referral facility in the Kassena-Nankana district in rural northern Ghana.

Methods

A retrospective analysis of antenatal clinic records of pregnant women collected from January to December 2014. All pregnant women initiating antenatal clinic, who had initial haemoglobin (Hb) levels measured, were included in the study. Logistic regression analyses were carried out to determine factors associated with anaemia at the initiation of ANC.

Results

We analysed data from 506 women with median Hb of 11.1 g/dL (IQR 7.31–13.8). The median gestational age at booking was 14 weeks (5–36 weeks). The prevalence of anaemia was 42.7%, with 95% confidence interval (CI) [38.4–47.1], and was high among teenage mothers (52% [34.9–67.8]), mothers who booked in the third trimester (55% [33.6–74.7]) and grand multiparous women (58% [30.7–81.6]). Factors associated with anaemia included grand multiparity (odds ratio [OR] = 1.94 with 95% CI [1.58–2.46]), booking during the third trimester (OR = 2.06 [1.78–2.21]) and mother who were underweight compared to those with normal weight (OR = 3.17 [1.19–8.32]).

Conclusion

Burden of anaemia in pregnancy is still high in rural northern Ghana. We advocate further strengthening of the primary health care system to improve early access to ANC delivery.

Keywords

anaemia in pregnancy; booking visit; maternal and child health; Navrongo; rural; Ghana.

Health outcomes related to the provision of free, tangible goods: A systematic review

BACKGROUND

Free provision of tangible goods that may improve health is one approach to addressing discrepancies in health outcomes related to income, yet it is unclear whether providing goods for free improves health. We systematically reviewed the literature that reported the association between the free provision of tangible goods and health outcomes.

METHODS

A search was performed for relevant literature in all languages from 1995-May 2017. Eligible studies were observational and experimental which had at least one tangible item provided for free and had at least one quantitative measure of health. Studies were excluded if the intervention was primarily a service and the free good was relatively unimportant; if the good was a medication; or if the data in a study was duplicated in another study. Covidence screening software was used to manage articles for two levels of screening. Data was extracted using an adaption of the Cochrane data collection template. Health outcomes, those that affect the quality or duration of life, are the outcomes of interest. The study was registered with PROSPERO (CRD42017069463).

FINDINGS

The initial search identified 3370 articles and 59 were included in the final set with a range of 20 to 252 246 participants. The risk of bias assessment revealed that overall, the studies were of medium to high quality. Among the studies included in this review, 80 health outcomes were statistically significant favouring the intervention, 19 health outcomes were statistically significant favouring the control, 141 health outcomes were not significant and significance was unknown for 28 health outcomes.

INTERPRETATION

The results of this systematic review provide evidence that free goods can improve health outcomes in certain circumstances, although there were important gaps and limitations in the existing literature.

Impact of the use and efficacy of long lasting insecticidal net on malaria infection during the first trimester of pregnancy - a pre-conceptional cohort study in southern Benin

Background

Malaria in pregnancy is prevalent in Sub-Saharan Africa. The first trimester of pregnancy is a critical period and the best preventive measure is Long Lasting Insecticidal Nets (LLIN). Unfortunately, few studies have been conducted which focuses on the usage and efficacy of LLIN on malaria prevention during the first trimester.

Methods

We assessed the use and effectiveness of LLIN in early pregnancy in Benin and its impact on malaria infection risk. We followed-up a cohort of 240 pregnant women from pre-conception to the end of the first trimester of pregnancy in Southern Benin. Parasitological, maternal and LLIN data were actively collected before, at the beginning and end of the first trimester of pregnancy. A Cox regression model was used to determine the relationship between the time to onset of the first malaria infection and the use, physical integrity, and bio-efficacy of the LLIN, adjusted for relevant covariables.

Results

The good use, good physical integrity and biological efficacy of LLIN were associated with a decreased risk of occurrence of the first malaria infection in early pregnancy (HRa = 0.38; (0.18–0.80); p < 0.001; HRa = 0.59; (0.29–1.19); p < 0.07; HRa = 0.97; (0.94–1.00); p < 0.04 respectively), after adjustment for other covariates. Primi/secundigravidity and malaria infection before pregnancy were associated with a risk of earlier onset of malaria infection.

Conclusion

The classically used LLIN’s indicators of possession and use may not be sufficient to characterize the true protection of pregnant women in the first trimester of pregnancy. Indicators of physical integrity and bio-efficacy should be integrated with those indicators in evaluation studies.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-5595-2) contains supplementary material, which is available to authorized users.

Anaemia in pregnancy and associated factors: a cross sectional study of antenatal attendants at the Sunyani Municipal Hospital, Ghana

BACKGROUND

Anaemia in pregnancy is an important health issue resulting in high maternal morbidity and mortality. The purpose of the current study was to identify factors associated with anaemia among pregnant women receiving antenatal care at the Sunyani Municipal Hospital in Ghana.

METHODS

A cross-sectional study involving pregnant women seeking antenatal care at the Sunyani Municipal Hospital was conducted between May and June, 2015. It involved the collection of data on socio demographic and obstetric variables, medical interventions and malaria infection, consumption of iron containing foods and supplements using a case record form and a structured questionnaire. Also, data on haemoglobin concentrations at first and current antenatal visit were collected. Bivariate and multivariate statistical analysis were done to determine factors associated with anaemia.

RESULTS

Out of the 316 participants, 129 (40.8%) were found to be anaemic (Hb <11.0 g/dl) at the time of their first ANC visit (mean Hb: 11.21 g/dl, range 6.8-15.1 g/dl). Seventy-nine (61.2%) of them had mild anemia (Hb 9.0-10.9 g/dl), 48 (37.2%) had moderate anemia (Hb 7.0-8.9 g/dl) whilst 2 (1.6%) had severe anemia (Hb <7.0 g/dl). During their most recent ANC visit, the prevalence of anaemia was found to be similar to that of the first visit with 131 (41.5%) of them being anaemic [mean Hb: 11.24 g/dl, range 8.10-14.5 g/dl]. The haemoglobin levels however improved significantly during the most recent visit compared to the first with none of the women being severely anaemic (Hb <7.0 g/dl). The prevalence of moderate anaemia reduced from 37.2% (CI 28.9-46.2) during the first visit to 19.1% (12.7-26.9) during the most recent visit, a reduction of 48.7%. Malaria infection, frequency at which one consumed fish/snails and gestational age at first ANC visit were the main factors found to be associated with anaemia among the pregnant women.

CONCLUSIONS

Malaria infection, fish/snails intake and gestational age at first ANC visit were significantly associated with anaemia. Addressing these factors can reduce the incidence of anaemia in pregnancy.

Seroprevalence of Antibodies against Plasmodium falciparum Sporozoite Antigens as Predictive Disease Transmission Markers in an Area of Ghana with Seasonal Malaria Transmission

Introduction

As an increasing number of malaria-endemic countries approach the disease elimination phase, sustenance of control efforts and effective monitoring are necessary to ensure success. Mathematical models that estimate anti-parasite antibody seroconversion rates are gaining relevance as more sensitive transmission intensity estimation tools. Models however estimate yearly seroconversion and seroreversion rates and usually predict long term changes in transmission, occurring years before the time of sampling. Another challenge is the identification of appropriate antigen targets since specific antibody levels must directly reflect changes in transmission patterns. We therefore investigated the potential of antibodies to sporozoite and blood stage antigens for detecting short term differences in malaria transmission in two communities in Northern Ghana with marked, seasonal transmission.

Methods

Cross-sectional surveys were conducted during the rainy and dry seasons in two communities, one in close proximity to an irrigation dam and the other at least 20 Km away from the dam. Antibodies against the sporozoite-specific antigens circumsporozoite protein (CSP) and Cell traversal for ookinetes and sporozoites (CelTOS) and the classical blood stage antigen apical membrane antigen 1 (AMA1) were measured by indirect ELISA. Antibody levels and seroprevalence were compared between surveys and between study communities. Antibody seroprevalence data were fitted to a modified reversible catalytic model to estimate the seroconversion and seroreversion rates.

Results

Changes in sporozoite-specific antibody levels and seroprevalence directly reflected differences in parasite prevalence between the rainy and dry seasons and hence the extent of malaria transmission. Seroconversion rate estimates from modelled seroprevalence data did not however support the above observation.

Conclusions

The data confirms the potential utility of sporozoite-specific antigens as useful markers for monitoring short term/seasonal changes in malaria transmission. It may however be essential to update models to allow for assessment of seasonal changes in malaria transmission, which usually occur within four to six months.

Design of a Phase III cluster randomized trial to assess the efficacy and safety of a malaria transmission blocking vaccine

Vaccines interrupting Plasmodium falciparum malaria transmission targeting sexual, sporogonic, or mosquito-stage antigens (SSM-VIMT) are currently under development to reduce malaria transmission. An international group of malaria experts was established to evaluate the feasibility and optimal design of a Phase III cluster randomized trial (CRT) that could support regulatory review and approval of an SSM-VIMT. The consensus design is a CRT with a sentinel population randomly selected from defined inner and buffer zones in each cluster, a cluster size sufficient to assess true vaccine efficacy in the inner zone, and inclusion of ongoing assessment of vaccine impact stratified by distance of residence from the cluster edge. Trials should be conducted first in areas of moderate transmission, where SSM-VIMT impact should be greatest. Sample size estimates suggest that such a trial is feasible, and within the range of previously supported trials of malaria interventions, although substantial issues to implementation exist.

Treatment and prevention of malaria in pregnancy: opportunities and challenges

Control of malaria in pregnancy through prevention or treatment may save lives of mothers and babies. Selection of drugs for treatment of infected pregnant women, or for prevention in exposed populations is problematic owing to resistance to established drugs and lack of pregnancy-specific safety and pharmacological data for new drugs. Encouragingly, a number of new drugs and combinations of drugs hold promise for effective treatment, but adequate data on their safety in pregnancy is currently lacking. Our principal challenges are to decide which drugs to develop for use in malaria treatment and prevention in pregnancy and to develop mechanisms to rapidly and comprehensively evaluate their safety. Prevention of pregnancy malaria by vaccination may also become possible, but targets must be closely defined, and strategies developed to test candidates against meaningful end points.

Malaria in pregnancy

Pregnant women have a higher risk of malaria compared to non-pregnant women. This review provides an update on knowledge acquired since 2000 on P. falciparum and P.vivax infections in pregnancy. Maternal risk factors for malaria in pregnancy (MiP) include low maternal age, low parity, and low gestational age. The main effects of MIP include maternal anaemia, low birth weight (LBW), preterm delivery and increased infant and maternal mortality.

P. falciparum infected erythrocytes sequester in the placenta by expressing surface antigens, mainly variant surface antigen (VAR2CSA), that bind to specific receptors, mainly chondroitin sulphate A. In stable transmission settings, the higher malaria risk in primigravidae can be explained by the non-recognition of these surface antigens by the immune system. Recently, placental sequestration has been described also for P.vivax infections. The mechanism of preterm delivery and intrauterine growth retardation is not completely understood, but fever (preterm delivery), anaemia, and high cytokines levels have been implicated.

Clinical suspicion of MiP should be confirmed by parasitological diagnosis. The sensitivity of microscopy, with placenta histology as the gold standard, is 60% and 45% for peripheral and placental falciparum infections in African women, respectively. Compared to microscopy, RDTs have a lower sensitivity though when the quality of microscopy is low RDTs may be more reliable. Insecticide treated nets (ITN) and intermittent preventive treatment in pregnancy (IPTp) are recommended for the prevention of MiP in stable transmission settings. ITNs have been shown to reduce malaria infection and adverse pregnancy outcomes by 28–47%. Although resistance is a concern, SP has been shown to be equivalent to MQ and AQ for IPTp. For the treatment of uncomplicated malaria during the first trimester, quinine plus clindamycin for 7 days is the first line treatment and artesunate plus clindamycin for 7 days is indicated if this treatment fails; in the 2^nd and 3^rd trimester first line treatment is an artemisinin-based combination therapy (ACT) known to be effective in the region or artesunate and clindamycin for 7 days or quinine and clindamycin. For severe malaria, in the second and third trimester parenteral artesunate is preferred over quinine. In the first trimester, both artesunate and quinine (parenteral) may be considered as options. Nevertheless, treatment should not be delayed and should be started immediately with the most readily available drug.

Behavioral change communications on malaria prevention in Ghana

The purpose of this study is to assess the various communications strategies designed to promote insecticide-treated nets (ITN) use among pregnant women and children. This study is an exploratory study into the communications activities by institutions involved in malaria prevention in Ghana. In-depth interviews were conducted and the data were analyzed. We found that most of the interventions are aimed at encouraging the target markets to acquire ITNs, although most messages on malaria prevention are not integrated. Several challenges were noted, including financial constraints, lack of human resources, cultural barriers, negative publicity, and negative perceptions on malaria.

Malaria in pregnancy: the difficulties in measuring birthweight

Recommendations for interventions to control malaria in pregnancy are often based on studies using birthweight as the primary endpoint. Differences in birthweight may be attributable partly to methodological difficulties. We performed a structured search of the literature using ‘malaria’, ‘pregnancy’ and ‘birth weight’ as search terms. Of the clinical trials reporting birthweight, only 33% (14/43) gave information about the timing of the measurement and details on the scales used. Seventy seven per cent explained how gestational age was estimated. We propose a standardised method for the measurement and reporting of birthweight in future studies.

School-based participatory health education for malaria control in Ghana: engaging children as health messengers

Background

School children have been increasingly recognized as health messengers for malaria control. However, little evidence is available. The objective of this study was to determine the impact of school-based malaria education intervention on school children and community adults.

Methods

This study was conducted in the Dangme-East district of the Greater Accra Region, Ghana, between 2007 and 2008. Trained schoolteachers designed participatory health education activities and led school children to disseminate messages related to malaria control to their communities. Three schools and their respective communities were chosen for the study and assigned to an intervention group (one school) and a control group (two schools). Questionnaire-based interviews and parasitological surveys were conducted before and after the intervention, with the intervention group (105 children, 250 community adults) and the control group (81 children, 133 community adults). Chi-square and Fisher's Exact tests were used to analyse differences in knowledge, practices, and parasite prevalence between pre- and post-intervention.

Results

After the intervention, the misperception that malaria has multiple causes was significantly improved, both among children and community adults. Moreover, the community adults who treated a bed net with insecticide in the past six months, increased from 21.5% to 50.0% (p < 0.001). Parasite prevalence in school children decreased from 30.9% to 10.3% (p = 0.003). These positive changes were observed only in the intervention group.

Conclusions

This study suggests that the participatory health education intervention contributed to the decreased malaria prevalence among children. It had a positive impact not only on school children, but also on community adults, through the improvement of knowledge and practices. This strategy can be applied as a complementary approach to existing malaria control strategies in West African countries where school health management systems have been strengthened.

Risk factors associated with congenital malaria in Enugu, South Eastern Nigeria

There is paucity of data on the risk factors associated with congenital malaria in Nigeria. This study assessed the risk factors for congenital malaria in a population of neonates delivered at the University of Nigeria Teaching Hospital, Enugu, South Eastern Nigeria. It was a prospective cross-sectional study of neonates who were delivered in the institution from 2 April 2003 to 15 April 2004 as well as their mothers. Thick and thin blood films were made from maternal, baby and cord blood as well as the placenta for each mother/baby pair to determine malaria parasite density counts and for species identification. The maternal samples were obtained as soon as labour was confirmed while the cord and baby's blood as well as placental smears were taken within 1 h of delivery. Data analysis was by means of descriptive and inferential statistics as well as univariate and multivariate logistic regression at the 95% confidence level using the statistical software SPSS for Windows Version 10. A total of 658 mother/baby pairs were recruited into the study within the 13-month period. Out of this number, 625 mother/baby pairs completed the study and their data were subsequently analysed. A total of 356 (56.96%) mothers and 203 (32.48%) babies were smear positive for Plasmodium falciparum. On univariate logistic regression with presence or absence of the congenital malaria as the dependent variable, six out of the 13 putative risk factors tested were statistically significant. These were low compared with higher socioeconomic classes (OR = 1.41, 95% CI = 1.18 - 1.69, p = 0.00); low compared with normal birth weight (OR = 2.14, 95% CI = 1.39 - 3.30, p = 0.001); positive placental malaria parasitaemia (OR = 6.29, 95% CI, 4.73 - 8.37, p = 0.000), positive maternal blood malaria parasitaemia (OR = 5.04, 95% CI = 3.74 - 6.78, p = 0.000), positive cord blood malaria parasitaemia (OR = 26.87, 95% = 15.79 - 45.74, p = 0.000) and parity of 0 - 1 compared with other parities (OR = 1.31, 95% CI = 1.11 - 1.55, p = 0.002). On multivariate logistic regression, three of the six factors that were significant on univariate logistic regression remained significant. These were: positive placental malaria parasitaemia (OR = 2.55, 95% CI = 1.45 - 4.47, p = 0.001); positive cord malaria parasitaemia (OR = 18.90, 95% CI = 10.68 - 33.46, p = 0.000 and parity of 0 - 1 compared with other parities (OR = 1.66, 95% CI = 1.09 - 2.52, p = 0.02). It was concluded that the risk factors for congenital malaria identified in this study emphasise the need for effective preventive and curative treatment of malaria not only during pregnancy but also during delivery in malaria endemic areas. Additionally, congenital malaria should now rank high among the list of differential diagnosis of fever in the newborn in such endemic areas.

Evaluation of cluster-randomized trials on maternal and child health research in developing countries

OBJECTIVE

To summarize and evaluate all publications including cluster-randomized trials used for maternal and child health research in developing countries during the last 10 years.

METHODS

All cluster-randomized trials published between 1998 and 2008 were reviewed, and those that met our criteria for inclusion were evaluated further. The criteria for inclusion were that the trial should have been conducted in maternal and child health care in a developing country and that the conclusions should have been made on an individual level. Methods of accounting for clustering in design and analysis were evaluated in the eligible trials.

RESULTS

Thirty-five eligible trials were identified. The majority of them were conducted in Asia, used community as randomization unit, and had less than 10,000 participants. To minimize confounding, 23 of the 35 trials had stratified, blocked, or paired the clusters before they were randomized, while 17 had adjusted for confounding in the analysis. Ten of the 35 trials did not account for clustering in sample size calculations, and seven did not account for the cluster-randomized design in the analysis. The number of cluster-randomized trials increased over time, and the trials generally improved in quality.

CONCLUSIONS

Shortcomings exist in the sample-size calculations and in the analysis of cluster-randomized trials conducted during maternal and child health research in developing countries. Even though there has been improvement over time, further progress in the way that researchers utilize and analyse cluster-randomized trials in this field is needed.

The epidemiology of malaria among pregnant women attending antenatal clinics in an area with intense and highly seasonal malaria transmission in northern Ghana

OBJECTIVE

To describe the factors associated with malaria infection and anaemia in pregnancy in northern Ghana.

METHOD

We studied 3642 pregnant women of all gravidities and gestational age of 18-32 weeks who attended an antenatal clinic in the Kassena-Nankana district of Ghana between June 2004 and July 2006. Blood samples were examined for haemoglobin concentrations and parasitaemia, and we obtained socio-demographic data, an obstetric history, information on their past and current state of health and bed net use.

RESULTS

The overall prevalence of malaria parasitaemia during pregnancy was 47%. Older age [adjusted odds ratio (AOR) 0.65, 95% CI 0.54-0.78], multigravidity (AOR 0.51, 95% CI 0.42-0.61) and third trimester of pregnancy (AOR 0.85, 95% CI 0.73-0.99) were associated with a decreased risk of parasitaemia. Enrollment during the rainy or post-rainy season was associated with an increased risk of parasitaemia (AOR 2.59, 95% CI 2.20-3.04 and AOR 3.12, 95% CI, 2.60-3.74 respectively). Malaria infection was associated with an increased risk of anaemia among young women. The prevalences of anaemia (Hb<11.0 g/dl) and severe anaemia (Hb<7.0 g/dl) during pregnancy were 72% and 2% respectively. The risk of anaemia was lower in older women (AOR 0.79, 95% CI, 0.64-0.97), multigravidae (AOR 0.67, 95% CI 0.55-0.83) and in educated women (AOR 0.81, 0.68-0.98).

CONCLUSION

The prevalence of malaria parasitaemia and anaemia among pregnant women in Kassena-Nankana district is high with marked seasonal variation. Targeting of interventions to the high transmission season and to paucigravidae may be appropriate in this setting.

Malaria in Women and Children

After reading this chapter and answering the discussion questions that follow, you should be able to

Explain the global burden of malaria, discuss its clinical manifestations, and appraise its health impact on women and children.

Analyze the mechanisms and consequences of malaria and HIV co-infection and discuss current treatment, control and prevention strategies.

Describe the challenges posed by vector resistance to insecticides, parasite resistance to antimalarials, climate change, wars/conflicts, and HIV/AIDS to malaria control and prevention efforts.

Evaluate social, cultural, and economic limitations of community-based programs for malaria control and prevention.

A randomized, controlled trial of intermittent preventive treatment with sulfadoxine-pyrimethamine, amodiaquine, or the combination in pregnant women in Ghana

BACKGROUND

The use of sulfadoxine-pyrimethamine (SP) for intermittent preventive treatment in pregnancy (IPTp) is threatened by the spread of resistance to SP. Therefore, we studied the efficacy, safety, and tolerance of amodiaquine (AQ) or the combination of AQ and SP (SPAQ) as possible alternative treatments.

METHODS

The study was performed in Ghana from June 2004 through February 2007. Women were individually randomized to receive IPTp with SP (n=1328), AQ (n= 986), or SPAQ (n=1328). Incidences of anemia, peripheral anemia, and placental parasitemia at delivery were assessed for paucigravidae, as were the birth weights of their infants. Delivery outcomes and the incidence of adverse events were investigated for all women.

RESULTS

The prevalences of anemia (as defined by a hemoglobin concentration of <11.0 g/dL) at delivery were comparable between the SP and AQ groups and between the SP and SPAQ groups. Similarly, there was no significant difference between the SP and AQ groups or between the SP and SPAQ groups with regard to the incidences of low birth weight (LBW). Women who received AQ or SPAQ were more likely to report adverse events than were those who received SP.

CONCLUSION

The effects of IPTp with AQ or SPAQ on maternal anemia and LBW were comparable to the effects of IPTp with SP; however, IPTp regimens that contain AQ are unlikely to be useful as an alternative to IPTp with SP in Ghana, because of a high frequency of associated adverse events.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT00146783 .

Risk factors for moderate to severe anemia among children in Benin and Mali: insights from a multilevel analysis

BACKGROUND

Anemia currently affects 2 billion people throughout the world. Although the immediate causes of anemia among children are known (including malnutrition and infections), the importance of contextual determinants and their relationships with individual effects have rarely been explored.

OBJECTIVE

To identify anemia risk factors at the individual, household, and community levels among Beninese and Malian children, using simple and multilevel regression methods.

METHODS

An analysis was undertaken of nationally representative data collected in 2001 in Benin (n = 2,284) and Mali (n = 2,826) by the Demographic and Health Surveys. Sixteen potential risk factors for anemia were considered at the individual, household, and community levels. Comparative analyses were carried out using simple and multilevel logistic regression models.

RESULTS

Simple and multilevel logistic regression analyses yielded broadly similar results. Risk factors for moderate to severe anemia included incomplete immunization, stunted growth, recent infection, absence of bednet, low household living standard, rural residency (Mali), low maternal education, and low community development index (Benin). In addition, multilevel analysis indicated a clustering level of anemia in communities (intraclass correlation) of 14% and 19% in Benin and Mali, respectively.

CONCLUSIONS

Risk factors for child anemia appeared at all three levels (individual, household and community). Community-level clustering seemed to be low. Therefore, interventions to address anemia need not be village- or region-specific. Identifying a successful and replicable program is now a priority in child survival endeavors. It is likely that such a program would include a focus on improving immunization coverage, increased bednet usage, and reduced protein-energy malnutrition.

Maternal anaemia as an indicator for monitoring malaria control in pregnancy in sub-Saharan Africa

DESIGN

Malarial anaemia is a major problem in many developing countries and often occurs more frequently in first pregnancies, as primigravidae are more susceptible to Plasmodium falciparum malaria and are at excess risk of malarial anaemia.

OBJECTIVE AND METHODS

To analyse the excess risk of anaemia in primigravidae as a potential indicator of malaria control and exposure in pregnant women living in sub-Saharan Africa. The sensitivity, specificity and predictive values for anaemia in first compared with later pregnancies are calculated for 27 studies from malarious and 7 studies from nonmalarious areas.

SETTING

Surveys of pregnancy anaemia reported for highly malarious and nonmalarious areas.

RESULTS

In malarious areas, the weighted odds ratio for excess anaemia (haemoglobin [Hb] <11 g/dl) in primigravidae compared with multigravidae for all studies was 1.34 (95% CI 1.14-1.58). At an Hb cutoff below 8 g/dl, the weighted odds ratio was 1.79 (95% CI 1.52-2.10). In nonmalarious areas, there was no increased risk of anaemia in primigravidae with Hb below 11 g/dl (OR 0.80; 95% CI 0.63-1.90) or below 8 g/dl (OR 0.82, 95% CI 0.51-1.28).

CONCLUSIONS

In view of the consistency of results across highly malarious areas compared with nonmalarious areas, maternal anaemia has the potential to be used for surveillance of malaria control in pregnancy. Based on the analysis, an anaemia nomogram is developed for use as a surveillance indicator in malarious areas in sub-Saharan Africa.

Insecticide-treated nets for the prevention of malaria in pregnancy: a systematic review of randomised controlled trials

BACKGROUND

Protection from malaria with insecticide-treated bednets (ITNs) during pregnancy is widely advocated, but evidence of benefit has been inconsistent. We undertook a systematic review of randomised trials.

METHODS AND FINDINGS

Three cluster-randomised and two individually randomised trials met the inclusion criteria; four from Africa (n = 6,418) and one from Thailand (n = 223). In Africa, ITNs compared to no nets increased mean birth weight by 55 g (95% confidence interval [CI] 21-88), reduced low birth weight by 23% (relative risk [RR] 0.77, 95% CI 0.61-0.98), and reduced miscarriages/stillbirths by 33% (RR 0.67, 0.47-0.97) in the first few pregnancies. Placental parasitaemia was reduced by 23% in all gravidae (RR 0.77, 0.66-0.90). The effects were apparent in the cluster-randomised trials and the one individually randomised trial in Africa. The trial in Thailand, which randomised individuals to ITNs or untreated nets, showed reductions in anaemia and fetal loss in all gravidae, but not reductions in clinical malaria or low birth weight.

CONCLUSIONS

ITNs used throughout pregnancy or from mid-pregnancy onwards have a beneficial impact on pregnancy outcome in malaria-endemic Africa in the first few pregnancies. The potential impact of ITNs in pregnant women and their newborns in malaria regions outside Africa requires further research.

Reducing the burden of malaria in pregnancy by preventive strategies

Malaria is one of the most common and preventable causes of adverse birth outcomes. In Africa, important progress has been made in the past decade with the introduction of a preventive strategy for malaria in pregnancy consisting of intermittent preventive treatment in pregnancy (IPTp) and insecticide-treated nets, yet their coverage is still unacceptably low and malaria continues to demand a huge toll on pregnant women and their newborn babies. Increasing the frequency of dosing of IPTp with sulfadoxine-pyrimethamine might provide temporary respite, but increasing resistance to sulfadoxine-pyrimethamine makes research into safe, efficacious, and affordable alternatives for IPTp one of the highest priorities for the control of malaria in pregnancy. A number of promising alternatives are, or will soon be, available that need to be evaluated as IPTp after their safety and pharmacokinetics in pregnancy have first been assessed in parasitaemic women. Little is known about appropriate control strategies in Asia and Latin America for Plasmodium falciparum and Plasmodium vivax malaria in pregnancy, which in most countries rely on responsive case management approaches. The role of case management based on proactive screening for malaria infection of women attending antenatal care or preventive approaches with insecticide-treated nets or IPTp are urgently needed. To achieve these objectives, multicentre and multidisciplinary approaches are required across the range of malaria transmission settings that include assessment of immunological effect of successful preventions, the perceptions and acceptability of different preventive approaches, and their cost-effectiveness.

Insecticide-treated nets

Insecticide-treated nets (ITNs) are the most powerful malaria control tool to be developed since the advent of indoor residual spraying (IRS) and chloroquine in the 1940s, and as such they have been an important component of global and national malaria control policies since the mid-1990s. Yet a decade later, coverage is still unacceptably low: only 3% of African children are currently sleeping under an ITN, and only about 20% are sleeping under any kind of net. This review charts the scientific, policy and programmatic progress of ITNs over the last 10 years. Available evidence for the range of programmatic delivery mechanisms used at country level is presented alongside the key policy debates that together have contributed to the evolution of ITN delivery strategies over the past decade. There is now global consensus around a strategic framework for scaling up ITN usage in Africa, which recognizes a role for both the public sector (targeting vulnerable groups to promote equity) and the private sector (sustainable supply). So, while progress with increasing coverage to date has been slow, there is now global support for the rapid scale-up of ITNs among vulnerable groups by integrating ITN delivery with maternal and child health programmes (and immunization in particular), at the same time working with the private sector in a complementary and supportive manner to ensure that coverage can be maintained for future generations of African children.

The effect of malaria transmission intensity on neonatal mortality in endemic areas

Estimates of the impact of Plasmodium falciparum infections during pregnancy on neonatal mortality have not taken into account how this varies with the level of malaria endemicity and thus do not indicate the possible effects of malaria control strategies that reduce transmission. We now review the relevant literature, and propose a mathematical model for the association between P. falciparum transmission and neonatal death. The excess risk of neonatal mortality in malaria-endemic areas appears to be insensitive to the intensity of P. falciparum transmission over a wide range of endemicity. Moderate reductions in the overall level of malaria transmission in endemic areas are therefore unlikely to significantly reduce neonatal mortality. The magnitude of the excess risk is very uncertain because existing estimates are heavily dependent on the questionable assumption that the effects are mediated by birth weight. Accurate prediction of the impact of malaria control measures targeted at pregnant women requires direct estimates of malaria-attributable neonatal mortality rates.

Insecticide-treated nets for preventing malaria in pregnancy

BACKGROUND

Malaria in pregnancy is associated with adverse consequences for mother and fetus. Protection with insecticide-treated nets (ITNs) during pregnancy is widely advocated, but evidence of their benefit has been inconsistent.

OBJECTIVES

To compare the impact of ITNs with no nets or untreated nets on preventing malaria in pregnancy.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group Specialized Register (January 2006), CENTRAL (The Cochrane Library 2005, Issue 4), MEDLINE (1966 to January 2006), EMBASE (1974 to January 2006), LILACS (1982 to January 2006), and reference lists. We also contacted researchers working in the field.

SELECTION CRITERIA

Individual and cluster randomized controlled trials of ITNs in pregnant women.

DATA COLLECTION AND ANALYSIS

Three authors independently assessed trials for methodological quality and extracted data. Data were combined using the generic inverse variance method.

MAIN RESULTS

Six randomized controlled trials were identified, five of which met the inclusion criteria: four trials from sub-Saharan Africa compared ITNs with no nets, and one trial from Asia compared ITNs with untreated nets. Two trials randomized individual women and three trials randomized communities. In Africa, ITNs, compared with no nets, reduced placental malaria in all pregnancies (relative risk (RR) 0.79, 95% confidence interval (CI) 0.63 to 0.98). They also reduced low birthweight (RR 0.77, 95% CI 0.61 to 0.98) and stillbirths/abortions in the first to fourth pregnancy (RR 0.67, 95% CI 0.47 to 0.97), but not in women with more than four previous pregnancies. For anaemia and clinical malaria, results tended to favour ITNs, but the effects were not significant. In Thailand, one trial randomizing individuals to ITNs or untreated nets showed a significant reduction in anaemia and stillbirths/abortions in all pregnancies but not for clinical malaria or low birthweight.

AUTHORS' CONCLUSIONS

ITNs have a beneficial impact on pregnancy outcome in malaria-endemic regions of Africa when used by communities or by individual women. No further trials of ITNs in pregnancy are required in sub-Saharan Africa. Further evaluation of the potential impact of ITNs is required in areas with less intense and Plasmodium vivax transmission in Asia and Latin America.

Malaria in the pregnant woman

Women become more susceptible to Plasmodium falciparum malaria during pregnancy, and the risk of disease and death is high for both the mother and her fetus. In low transmission areas, women of all parities are at risk for severe syndromes like cerebral malaria, and maternal and fetal mortality are high. In high transmission areas, where women are most susceptible during their first pregnancies, severe syndromes like cerebral malaria are uncommon, but severe maternal anemia and low birth weight are frequent sequelae and account for an enormous loss of life. P. falciparum-infected red cells sequester in the intervillous space of the placenta, where they adhere to chondroitin sulfate A but not to receptors like CD36 that commonly support adhesion of parasites infecting nonpregnant hosts. Poor pregnancy outcomes due to malaria are related to the macrophage-rich infiltrates and pro-inflammatory cytokines such as tumor necrosis factor-alpha that accumulate in the intervillous space. Women who acquire antibodies against chrondroitin sulfate A (CSA)-binding parasites are less likely to have placental malaria, and are more likely to deliver healthy babies. In areas of stable transmission, women acquire antibodies against CSA-binding parasites over successive pregnancies, explaining the high susceptibility to malaria during first pregnancy, and suggesting that a vaccine to prevent pregnancy malaria should target placental parasites. Prevention and treatment of malaria are essential components of antenatal care in endemic areas, but require special considerations during pregnancy. Recrudescence after drug treatment is more common during pregnancy, and the spread of drug-resistant parasites has eroded the usefulness of the few drugs known to be safe for the woman and her fetus. Determining the safety and effectiveness of newer antimalarials in pregnant women is an urgent priority. A vaccine that prevents pregnancy malaria due to P. falciparum could be delivered before first pregnancy, and would have an enormous impact on mother-child health in tropical areas.

Prevention of anaemia in pregnancy using insecticide-treated bednets and sulfadoxine-pyrimethamine in a highly malarious area of Kenya: a randomized controlled trial

To compare the effects of intermittent treatment with sulfadoxine-pyrimethamine (SP) given during the second and third trimester of pregnancy, the use of insecticide-treated nets (ITN), or the combination of both on haemoglobin (Hb) levels during pregnancy, a randomized, placebo-controlled intervention trial was conducted in a malaria-endemic area of western Kenya from July 1997 to September 1999. Primigravidae and secundigravidae were enrolled into the study and randomized into 4 intervention groups: (i) ITNs and SP, (ii) ITNs and placebo SP, (iii) SP alone, and (iv) placebo SP. All groups were offered case management and iron and folic acid supplementation. Seven hundred and fifty-two women were followed until delivery (53.2% were primigravidae and 46.8% secundigravidae). Among primigravidae in all the groups there was a significant improvement in Hb levels at delivery (107.6 g/L) compared with recruitment (101.9 g/L) (P < 0.006) with the greatest improvement in the combination ITNs + SP group. The protective efficacy of ITNs + SP on anaemia was 55.8% (95% CI 30.6-71.8), of SP alone 50.9% (95% CI 22.2-69.0), and of ITNs 41.6% (95% CI 9.8-62.3). Among secundigravidae, Hb levels were slightly lower at delivery compared with recruitment (P = 0.03). It was concluded that malaria is a major cause of anaemia in primigravidae but that other causes play a more significant role in secundigravidae, and that intermittent treatment with SP or use of ITNs benefits primigravidae more than secundigravidae.

Cost-effectiveness of malaria control interventions when malaria mortality is low: insecticide-treated nets versus in-house residual spraying in India

Malaria is one of the leading causes of morbidity and mortality in the developing world and a major public health problem in India. Disillusioned by in-house residual spraying (IRS), and increasingly aware that insecticide-treated nets (ITNs) have proved to be effective in reducing malaria mortality and morbidity in various epidemiological settings, policy-makers in India are keen to identify which is the more cost-effective malaria control intervention. A community randomised controlled trial was set up in Surat to compare the effectiveness and efficiency of IRS and ITNs. Both control strategies were shown to be effective in preventing malaria over the base-case scenario of early diagnosis and prompt treatment. The mean costs per case averted for ITNs was statistically significantly lower (Rs. 1848, 1567-2209; US$ 52) than IRS (Rs. 3121, 2386-4177, US$ 87). The incremental cost-effectiveness ratio for ITNs over IRS was Rs. 799 (US$ 22). The conclusions were robust to changes in assumptions. This study expands the scope of recent comparative economic evaluations of ITNs and IRS, since it was carried out in a low mortality malaria endemic area.

Insecticide-treated bed nets and curtains for preventing malaria

BACKGROUND

Malaria is an important cause of illness and death in many parts of the world, especially in sub-Saharan Africa. There has been a renewed emphasis on preventive measures at community and individual levels. Insecticide-treated nets (ITNs) are the most prominent malaria preventive measure for large-scale deployment in highly endemic areas.

OBJECTIVES

To assess the impact of insecticide-treated bed nets or curtains on mortality, malarial illness (life-threatening and mild), malaria parasitaemia, anaemia, and spleen rates.

SEARCH STRATEGY

I searched the Cochrane Infectious Diseases Group trials register (January 2003), CENTRAL (The Cochrane Library, Issue 1, 2003), MEDLINE (1966 to October 2003), EMBASE (1974 to November 2002), LILACS (1982 to January 2003), and reference lists of reviews, books, and trials. I handsearched journals, contacted researchers, funding agencies, and net and insecticide manufacturers.

SELECTION CRITERIA

Individual and cluster randomized controlled trials of insecticide-treated bed nets or curtains compared to nets without insecticide or no nets. Trials including only pregnant women were excluded.

DATA COLLECTION AND ANALYSIS

The reviewer and two independent assessors reviewed trials for inclusion. The reviewer assessed trial methodological quality and extracted and analysed data.

MAIN RESULTS

Fourteen cluster randomized and eight individually randomized controlled trials met the inclusion criteria. Five trials measured child mortality: ITNs provided 17% protective efficacy (PE) compared to no nets (relative rate 0.83, 95% confidence interval (CI) 0.76 to 0.90), and 23% PE compared to untreated nets (relative rate 0.77, 95% CI 0.63 to 0.95). About 5.5 lives (95% CI 3.39 to 7.67) can be saved each year for every 1000 children protected with ITNs. In areas with stable malaria, ITNs reduced the incidence of uncomplicated malarial episodes in areas of stable malaria by 50% compared to no nets, and 39% compared to untreated nets; and in areas of unstable malaria: by 62% for compared to no nets and 43% compared to untreated nets for Plasmodium falciparum episodes, and by 52% compared to no nets and 11% compared to untreated nets for P. vivax episodes. When compared to no nets and in areas of stable malaria, ITNs also had an impact on severe malaria (45% PE, 95% CI 20 to 63), parasite prevalence (13% PE), high parasitaemia (29% PE), splenomegaly (30% PE), and their use improved the average haemoglobin level in children by 1.7% packed cell volume.

REVIEWERS' CONCLUSIONS

ITNs are highly effective in reducing childhood mortality and morbidity from malaria. Widespread access to ITNs is currently being advocated by Roll Back Malaria, but universal deployment will require major financial, technical, and operational inputs.

Seasonal profiles of malaria infection, anaemia, and bednet use among age groups and communities in northern Ghana

We conducted all-age point prevalence surveys to profile the severity and seasonality of malaria and anaemia in Kassena-Nankana District of northern Ghana. Random cross-sectional surveys were timed to coincide with the end of low (May 2001) and high (November 2001) malaria transmission seasons and to yield information as to the potential value of haemoglobin (Hb) levels and parasitaemia as markers of malaria morbidity and/or malaria vaccine effect. Parasitaemia was found in 22% (515 of 2286) screened in May (dry-low transmission), and in 61% of the general population (1026 of 1676) screened in November (wet-high transmission). Malaria prevalence in May ranged from 4% (infants <6 months and adults 50-60 years) to 54% (children 5-10 years). Age-specific malaria prevalence in November ranged from 38% (adults 50-60 years) to 82% (children 5-10 years). Differences between low- and high-transmission periods in the prevalence of severe anaemia (SA) among young children (6-24 months) were unexpectedly comparable (low, 3.9%vs. high, 5.4%; P = 0.52) and greatly reduced from levels measured in this same community and age group in November 2000 (12.5%) and November 1996 (22.0%). Despite the lower frequency of anaemia/SA in young children surveyed in 2001, it was still clear that this condition was strongly associated with parasitaemia and that children under 5 years of age experienced a significant drop in their mean Hb levels by the end of the high transmission season. Prevalence of parasitaemia was significantly lower (P < 0.01) among infants and young children (<2 years) whose parents reported the use of bednets. There was a significantly lower risk of parasitaemia among infants [odds ratio (OR) 6-8] and young children (OR 3-4) living in the central, more urbanized sector of the study area.

Importance and prevention of malaria in pregnancy

Malaria in pregnancy is one of the most important preventable causes of low birthweight deliveries worldwide. It is also a major cause of severe maternal anaemia contributing to maternal mortality. It is estimated that 40% of the world's pregnant women are exposed to malaria infection during pregnancy. The clinical features of Plasmodium falciparum malaria in pregnancy depend to a large extent on the immune status of the woman, which in turn is determined by her previous exposure to malaria. In pregnant women with little or no pre-existing immunity, such as women from non-endemic areas or travellers to malarious areas, infection is associated with high risks of severe disease with maternal and perinatal mortality. Women are at particular risk of cerebral malaria, hypoglycaemia, pulmonary oedema and severe haemolytic anaemia. Fetal and perinatal loss has been documented to be as high as 60-70% in non-immune women with malaria. Adults who are long-term residents of areas of moderate or high malaria transmission, including large parts of sub-Saharan Africa, usually have a high level of immunity to malaria. Infection is frequently asymptomatic and severe disease is uncommon. During pregnancy this immunity to malaria is altered. Infection is still frequently asymptomatic, so may go unsuspected and undetected, but is associated with placental parasitization. Malaria in pregnancy is a common cause of severe maternal anaemia and low birthweight babies, these complications being more common in primigravidae than multigravidae. Preventative strategies include regular chemoprophylaxis, intermittent preventative treatment with antimalarials and insecticide-treated bednets.

Malaria prevention strategies

Acute and severe consequences of pregnancy-associated malaria (PAM), such as materno-fetal death or cerebral malaria, seem limited to unstable malaria areas. In areas of stable endemicity, the main consequences are maternal anaemia and low birth weight (LBW) babies, particularly in primigravidae. Placental malaria seems more frequent and its consequences more severe in HIV-infected women. Since 1964, several chemoprophylaxis controlled trials have been undertaken, mainly in Tropical Africa where malaria is stable. Most showed an increase in mean birth weight in the prophylaxis group, especially among primigravidae. Similar findings were made with anaemia. Prophylaxis seems less effective in the case of HIV-malaria co-infection, which may require an increase in the number of doses. At present, intermittent treatment with sulfadoxine-pyrimethamine given twice or thrice during pregnancy in antenatal clinics seems the best policy for preventing PAM. Such effective prophylaxis should be integrated with other antenatal clinic services. Recently identified molecular receptors involved in cytoadherence of parasitized erythrocytes to placenta could yield new therapeutic or vaccine approaches, specifically targeted to pregnant women.

Free bednets to pregnant women through antenatal clinics in Kenya: a cheap, simple and equitable approach to delivery

Kenya's National Malaria Strategy states that insecticide-treated nets (ITNs) would be considered as a free service to pregnant women assuming sufficient financial commitment from donors. In 2001, United Nation's Children's Fund (UNICEF) and the Government of Kenya brokered support to procure and distribute nets and K-O TABs (deltamethrin) to 70 000 pregnant women in 35 districts throughout Kenya around Africa Malaria Day. This intervention represented the single largest operational distribution of ITN services in Kenya to date, and this study evaluates its success, limitations and costs. The tracking process from the central level through to antenatal clinic (ANC) facilities suggests that of the 70 000 nets procured, 37 206 nets (53%) had been distributed to pregnant women throughout the country within 12 weeks. One-fifth of the nets procured (14 117) had gone out to individuals other than pregnant women, most of these at the request of the district teams, with only 2870 nets estimated to have gone astray at the ANC facilities. At 12 weeks, the remaining 18 677 nets were still in storage awaiting distribution, with more than two-thirds having reached the district, and nearly half already being held at ANC facilities. The cost of getting a net and K-O TAB to an ANC facility ready for distribution to a pregnant woman was US$ 3.81. Accounting for the 14 117 nets that had gone to other users, the cost for an ITN received by a pregnant woman was US$ 5.26. Delivering ITNs free to pregnant women through ANCs uses an existing system (with positive spin-offs of low delivery cost and simple logistics), is equitable (as it not only targets those who can afford it) and can have the added benefits of strengthening ANC service, delivery and use.

Insecticide-treated bednets and curtains for preventing malaria

BACKGROUND

Malaria is an important cause of illness and death in many parts of the world, especially in Africa. There has been a renewed emphasis on preventive measures, both at community and at individual level. Insecticide treated bednets and curtains are a promising preventive measure.

OBJECTIVES

The objective of this review was to assess the effects of insecticide-treated bednets or curtains in preventing malaria

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group trials register, Medline, Embase and the reference lists of articles. We handsearched journals, contacted researchers, funding agencies and net and insecticide manufacturers.

SELECTION CRITERIA

Randomized and quasi-randomized trials of insecticide-treated bednets or curtains with a sufficient dose of a suitable insecticide compared with nets without insecticide or no nets at all. Studies including pregnant women were excluded.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed and data extracted by the reviewer. Trial inclusions/exclusions were reviewed by two independent individuals.

MAIN RESULTS

Of 65 identified studies, 18 were included. Of these, 11 were randomized by cluster rather than individually. Mortality in children under five was measured in four trials. When impregnated nets were compared with plain nets or no nets, the summary relative risk was 0. 83. This translates to an estimate of protective efficacy of 17%. For treated nets compared with untreated nets, the relative risk of child mortality was 0.77. About six lives can be saved each year for every 1000 children protected with insecticide-treated nets. Insecticide-treated nets also reduced the incidence of mild malarial episodes by 48% (controls=no nets) and 34% (controls=untreated nets).

REVIEWER'S CONCLUSIONS

Insecticide-treated nets appear to be effective in reducing childhood mortality and morbidity from malaria. Widespread access to insecticide-treated nets will require major financial, technical and operational inputs.