Do Malaria Vector control Measures Impact Disease-Related Behaviour and Knowledge? Evidence from a Large-scale Larviciding Intervention in Tanzania.

Recent efforts of accelerated malaria control towards the long-term goal of elimination had significant impacts in reducing malaria transmission. While these efforts need to be sustained over time, a scenario of low transmission could bring about changes in individual disease risk perception, hindering adherence to protective measures, and affecting disease-related knowledge. The goal of this study was to investigate the potential impact of a successful malaria vector control intervention on bed net usage and malaria-related knowledge. Dar es Salaam's Urban Malaria Control Program was launched in 2004 with the aim of developing a sustainable larviciding intervention. Larviciding was scaled-up using a stepped-wedge design. Cross-sectional and longitudinal data were collected using a randomized cluster sampling design (2004--2008). Prevalence ratios (PR) for the effect of the larviciding intervention on bed net usage (N = 64,537) and household heads' knowledge of malaria symptoms and transmission (N = 11,254) were obtained from random effects regression models.\ud The probability that individuals targeted by larviciding had used a bed net was reduced by 5% as compared to those in non-intervention areas (PR = 0.95; 95% credible intervals (CrI): 0.94-0.97) and the magnitude of this effect increased with time. Larviciding also led to a decline in household heads' knowledge of malaria symptoms (PR = 0.88; 95% CrI: 0.83-0.92) but no evidence of effect on knowledge of malaria transmission was found. Successful control interventions could bring about further challenges to sustaining gains in reducing malaria transmission if not accompanied by strategies to avoid changes in individual knowledge and behaviour. This study points to two major research gaps. First, there is an urgent need to gather more evidence on the extent to which countries that have achieved significant decline in malaria transmission are also observing changes in individual behaviour and knowledge. Second, multidisciplinary assessments that combine quantitative and qualitative data, utilizing theories of health behaviour and theories of knowledge, are needed to optimize efforts of national malaria control programmes, and ultimately contribute to sustained reduction in malaria transmission

The Effect of Malaria on Settlement and Land Use: Evidence from the Brazilian Amazon

We estimate the effect of malaria on settlement and land use patterns in the Brazilian Amazon, where potential settlers were randomly assigned to plots in a newly opened settlement area. The random assignment allows us to estimate the risk of malaria on each plot based only on its characteristics. Using survey data, we find that a high malaria risk significantly reduces the probability that a plot is inhabited. Using satellite images, we find that a high malaria risk does not reduce forest clearance or crop coverage on a plot. Non-resident farming substitutes for physical inhabitation when malaria risk is high.malaria, settlement, land use, Brazil, Amazon

Public Acceptance and Willingness-to-Pay for a Future Dengue Vaccine: A Community-Based Survey in Bandung, Indonesia

Background: All four serotypes of dengue virus are endemic in Indonesia, where the population at risk for infection exceeds 200 million people. Despite continuous control efforts that were initiated more than four decades ago, Indonesia still suffers from multi-annual cycles of dengue outbreak and dengue remains as a major public health problem. Dengue vaccines have been viewed as a promising solution for controlling dengue in Indonesia, but thus far its potential acceptability has not been assessed. Methodology/Principal Findings We conducted a household survey in the city of Bandung, Indonesia by administering a questionnaire to examine (i) acceptance of a hypothetical pediatric dengue vaccine; (ii) participant's willingness-to-pay (WTP) for the vaccine, had it not been provided for free; and (iii) whether people think vector control would be unnecessary if the vaccine was available. A proportional odds model and an interval regression model were employed to identify determinants of acceptance and WTP, respectively. We demonstrated that out of 500 heads of household being interviewed, 94.2% would agree to vaccinate their children with the vaccine. Of all participants, 94.6% were willing to pay for the vaccine with a median WTP of US$1.94. In addition, 7.2% stated that vector control would not be necessary had there been a dengue vaccination program. Conclusions/Significance: Our results suggest that future dengue vaccines can have a very high uptake even when delivered through the private market. This, however, can be influenced by vaccine characteristics and price. In addition, reduction in community vector control efforts may be observed following vaccine introduction but its potential impact in the transmission of dengue and other vector-borne diseases requires further study

Cost-effectiveness of larviciding for urban malaria control in Tanzania

Background: Larviciding for malaria control can contribute to an Integrated Vector Management (IVM) approach. This intervention is currently supported in settings where breeding habitats are ‘few, fixed, and findable’, such as urban areas of sub-Saharan Africa, but the knowledge base regarding the cost-effectiveness of larviciding is non-existent. Methods: Programme costs and effectiveness data were collected from the Dar es Salaam Urban Malaria Control Programme in Tanzania. Cost-effectiveness ratios (CER) were estimated from the provider and societal perspectives for standard indicators using different malaria transmission scenarios. Results: CER for microbial larviciding were highly dependent on the assumed baseline malaria incidence rates. Using the societal perspective, net CER were estimated (in 2012 US dollars) at $43 (95$15-181) per disability-adjusted life year averted (DALY) when malaria incidence was 902 infections per 1,000 individuals, increasing to $545 (95$337-1,558) per DALY at an incidence of 122 per 1,000. Larviciding was shown to be cost-effective in Tanzania for incidences as low as 40 infections per 1,000 people per year. Conclusion: This is believed to be the first study to estimate the cost-effectiveness of larviciding for urban malaria control in sub-Saharan Africa. The results support the use of larviciding as a cost-effective intervention in urban areas and managers of national malaria control programme should consider this intervention as part of an IVM approach. Electronic supplementary material The online version of this article (doi:10.1186/1475-2875-13-477) contains supplementary material, which is available to authorized users

Factors affecting providers’ delivery of intermittent preventive treatment for malaria in pregnancy: a five-country analysis of national service provision assessment surveys

Background: Intermittent preventive treatment in pregnancy (IPTp) delivered during antenatal care (ANC) visits has been shown to be a highly efficacious and cost-effective intervention. Given the high rates of ANC attendance in sub-Saharan Africa, the current low IPTp coverage represents considerable missed opportunities. The objective of this study was to explore factors affecting provider’s delivery of IPTp during ANC consultations. Methods: Data from five nationally representative service provision assessment surveys informed the statistical analyses (Kenya, Namibia, Rwanda, Tanzania, and Uganda; 2006-2010). Poisson regression models with robust/clustered standard errors were used to estimate the effect of different determinants on IPTp delivery from 4,971 observed ANC consultations. Results: The five major modifiable determinants of IPTp delivery were: 1) user-fees for ANC medicines (relative risk (RR) = 0.76; 95% confidence intervals (95% CI): 0.62-0.93); 2) facilities having IPTp guidelines (RR = 1.12; 95% CI: 1.01-1.24); 3) facilities having implemented IPTp as part of their routine ANC services offering (RR = 4.18; 95% CI: 1.75-10.01); 4) stock-outs of sulphadoxine-pyrimethamine (RR = 0.40; 95% CI: 0.27-0.60); and, 5) providers having received IPTp training (RR = 1.21; 95% CI: 1.09-1.35). Using the population-attributable fraction, it was estimated that addressing these barriers jointly could lead to a 31% increase in delivery of this intervention during ANC consultations. Of these four potentially modifiable determinants, training of providers for IPTp had the largest potential impact. Conclusions: If proved to be cost-effective, dispensing IPTp training to ANC providers should be prioritized. Multifaceted approaches targeted in areas of low coverage and/or type of facilities least likely to provide this intervention should be implemented if the Roll Back Malaria target of 100% IPTp coverage by 2015 is to be attained. Electronic supplementary material The online version of this article (doi:10.1186/1475-2875-13-440) contains supplementary material, which is available to authorized users

Agricultural settlement and soil quality in the Brazilian Amazon

This paper discusses the implications of poor or non-existent information on soil quality, at the proper scale, during the planning and implementation of settlement projects in the Brazilian Amazon. Based on data from the Machadinho settlement project, Rondônia, we show that most settlers had no knowledge about the agricultural capability of the area, did not receive technical information, could not afford agricultural inputs, planted inadequate crops in the early years of occupation, and did not manage to stay in their plot for a long period of time. Satellite images indicated that patches of land with good soil quality were not necessarily the first to be utilized. Inadequately planned settlements face many challenges (poor soil being one of them) and are likely to result in land turnover, conversion of land into pasture, land concentration among wealthier persons, invasion of areas by poorer people, and deforestation, defying the main purpose of agrarian reform

Dehiscence of detached internal limiting membrane in eyes with myopic traction maculopathy with spontaneous resolution

Background: Idjwi, an island of approximately 220,000 people, is located in eastern DRC and functions semi-autonomously under the governance of two kings (mwamis). At more than 8 live births per woman, Idjwi has one of the highest total fertility rates (TFRs) in the world. Rapid population growth has led to widespread environmental degradation and food insecurity. Meanwhile family planning services are largely unavailable.Methods: At the invitation of local leaders, we conducted a representative survey of 2,078 households in accordance with MEASURE DHS protocols, and performed ethnographic interviews and focus groups with key informants and vulnerable subpopulations. Modelling proximate determinates of fertility, we evaluated how the introduction of contraceptives and/or extended periods of breastfeeding could reduce the TFR.Results: Over half of all women reported an unmet need for spacing or limiting births, and nearly 70% named a specific modern method of contraception they would prefer to use; pills (25.4%) and injectables (26.5%) were most desired. We predicted that an increased length of breastfeeding (from 10 to 21 months) or an increase in contraceptive prevalence (from 1% to 30%), or a combination of both could reduce TFR on Idjwi to 6, the average desired number of children. Increasing contraceptive prevalence to 15% could reduce unmet need for contraception by 8%.Conclusions: To meet women’s need and desire for fertility control, we recommend adding family planning services at health centers with NGO support, pursuing a community health worker program, promoting extended breastfeeding, and implementing programs to end sexual- and gender-based violence toward women

Challenges for malaria elimination in Brazil

Brazil currently contributes 42 % of all malaria cases reported in the Latin America and the Caribbean, a region where major progress towards malaria elimination has been achieved in recent years. In 2014, malaria burden in Brazil (143,910 microscopically confirmed cases and 41 malaria-related deaths) has reached its lowest levels in 35 years, Plasmodium falciparum is highly focal, and the geographic boundary of transmission has considerably shrunk. Transmission in Brazil remains entrenched in the Amazon Basin, which accounts for 99.5 % of the country’s malaria burden. This paper reviews major lessons learned from past and current malaria control policies in Brazil. A comprehensive discussion of the scientific and logistic challenges that may impact malaria elimination efforts in the country is presented in light of the launching of the Plan for Elimination of Malaria in Brazil in November 2015. Challenges for malaria elimination addressed include the high prevalence of symptomless and submicroscopic infections, emerging anti-malarial drug resistance in P. falciparum and Plasmodium vivax and the lack of safe anti-relapse drugs, the largely neglected burden of malaria in pregnancy, the need for better vector control strategies where Anopheles mosquitoes present a highly variable biting behaviour, human movement, the need for effective surveillance and tools to identify foci of infection in areas with low transmission, and the effects of environmental changes and climatic variability in transmission. Control actions launched in Brazil and results to come are likely to influence control programs in other countries in the Americas

Urban agriculture and Anopheles habitats in Dar es Salaam, Tanzania.

A cross-sectional survey of agricultural areas, combined with routinely monitored mosquito larval information, was conducted in urban Dar es Salaam, Tanzania, to investigate how agricultural and geographical features may influence the presence of Anopheles larvae. Data were integrated into a geographical information systems framework, and predictors of the presence of Anopheles larvae in farming areas were assessed using multivariate logistic regression with independent random effects. It was found that more than 5% of the study area (total size 16.8 km2) was used for farming in backyard gardens and larger open spaces. The proportion of habitats containing Anopheles larvae was 1.7 times higher in agricultural areas compared to other areas (95% confidence interval = 1.56-1.92). Significant geographic predictors of the presence of Anopheles larvae in gardens included location in lowland areas, proximity to river, and relatively impermeable soils. Agriculture-related predictors comprised specific seedbed types, mid-sized gardens, irrigation by wells, as well as cultivation of sugar cane or leafy vegetables. Negative predictors included small garden size, irrigation by tap water, rainfed production and cultivation of leguminous crops or fruit trees. Although there was an increased chance of finding Anopheles larvae in agricultural sites, it was found that breeding sites originated by urban agriculture account for less than a fifth of all breeding sites of malaria vectors in Dar es Salaam. It is suggested that strategies comprising an integrated malaria control effort in malaria-endemic African cities include participatory involvement of farmers by planting shade trees near larval habitats

Prevalence and correlates of childhood anemia in the MINA-Brazil birth cohort study

OBJECTIVE: To describe the prevalence and predictors of childhood anemia in an Amazonian population-based birth cohort study. METHODS: We estimated the prevalence of maternal anemia at delivery (hemoglobin [Hb] concentration < 110 g/L) in women participating in the MINA-Brazil birth cohort study and in their children examined at 1 and 2 years (Hb < 110 g/L) and at 5 years of age (Hb < 115 g/L). We measured ferritin, soluble transferrin receptor, and C-reactive protein concentrations in mothers at delivery and in their 1- and 2-year old children to estimate the prevalence of iron deficiency and its contribution to anemia, while adjusting for potential confounders by multiple Poisson regression analysis (adjusted relative risk [RRa]). RESULTS: The prevalence 95% confidence interval (CI) of maternal anemia, iron deficiency, and iron-deficiency anemia at delivery were 17.3% (14.0–21.0%), 42.6% (38.0–47.2%), and 8.7% (6.3–11.6)%, respectively (n = 462). At age 1 year (n = 646), 42.2% (38.7–45.8%) of the study children were anemic, 38.4% (34.6–42.3%) were iron-deficient, and 26.3 (23.0–29.9) had iron-deficiency anemia. Prevalence had decreased to 12.8% (10.6–15.2%), 18.1% (15.5–21.1%), and 4.1% (2.8–5.7%), respectively, at 2 years (n = 761); at 5 years of age, 5.2% (3.6–7.2%) children were anemic (n = 655). Iron deficiency (RRa = 2.19; 95%CI: 1.84–2.60) and consumption of ultraprocessed foods (UPF) (RRa = 1.56; 95%CI: 1.14–2.13) were significant contributors to anemia at 1 year, after adjusting for maternal schooling. At 2 years, anemia was significantly associated with maternal anemia at delivery (RRa: 1.67; 95%CI: 1.17–2.39), malaria since birth (2.25; 1.30–3.87), and iron deficiency (2.15; 1.47–3.15), after adjusting for child ’s age and household’s wealth index. CONCLUSIONS: Anemia continues to be highly prevalent during pregnancy and early childhood in the Amazon. Public health policies should address iron deficiency, UPF intake, maternal anemia, and malaria in order to prevent and treat anemia in Amazonian children