David A. Larsen

Coverage of intermittent preventive treatment and insecticide-treated nets for the control of malaria during pregnancy in sub-Saharan Africa: a synthesis and meta-analysis of national survey data 2009-11.

BACKGROUND Pregnant women in malaria-endemic countries in sub-Saharan Africa are especially vulnerable to malaria. Recommended prevention strategies include intermittent preventive treatment with two doses of sulfadoxine-pyrimethamine and the use of insecticide-treated nets. However, progress with implementation has been slow and the Roll Back Malaria Partnership target of 80% coverage of both interventions by 2010 has not been met. We aimed to review the coverage of intermittent preventive treatment, insecticide-treated nets, and antenatal care for pregnant women in sub-Saharan Africa and to explore associations between coverage and individual and country-level factors, including the role of funding for malaria prevention. METHODS We used data from nationally representative household surveys from 2009-11 to estimate coverage of intermittent preventive treatment, use of insecticide-treated nets, and attendance at antenatal clinics by pregnant women in sub-Saharan Africa. Using demographic data for births and published data for malaria exposure, we also estimated the number of malaria-exposed births (livebirths and stillbirths combined) for 2010 by country. We used meta-regression analysis to investigate the factors associated with coverage of intermittent preventive treatment and use of insecticide-treated nets. RESULTS Of the 21·4 million estimated malaria-exposed births across 27 countries in 2010, an estimated 4·6 million (21·5%, 95% CI 19·3-23·7) were born to mothers who received intermittent preventive treatment. Insecticide-treated nets were used during pregnancy for 10·5 million of 26·9 million births across 37 countries (38·8%, 34·6-43·0). Antenatal care was attended at least once by 16·3 of 20·8 million women in 2010 (78·3%, 75·2-81·4; n=26 countries) and at least twice by 14·7 of 19·6 million women (75·1%, 72·9-77·3; n=22 countries). For the countries with previous estimates for 2007, coverage of intermittent preventive treatment increased from 13·1% (11·9-14·3) to 21·2% (18·9-23·5; n=14 countries) and use of insecticide-treated nets increased from 17·9% (15·1-20·7) to 41·6% (37·2-46·0; n=24 countries) in 2010. A fall in coverage by more than 10% was seen in two of 24 countries for intermittent preventive treatment and in three of 30 countries for insecticide-treated nets. High disbursement of funds for malaria control and a long time interval since adoption of the relevant policy were associated with the highest coverage of intermittent preventive treatment. High disbursement of funds for malaria control and high total fertility rate were associated with the greatest use of insecticide-treated nets, whereas a high per-head gross domestic product (GDP) was associated with less use of nets than was a lower GDP. Coverage of intermittent preventive treatment showed greater inequity overall than use of insecticide-treated nets, with richer, educated, and urban women more likely to receive preventive treatment than their poorer, uneducated, rural counterparts. INTERPRETATION Although coverage of intermittent preventive treatment and use of insecticide-treated nets by pregnant women has increased in most countries, coverage remains far below international targets, despite fairly high rates of attendance at antenatal clinics. The effect of the implementation of WHOs 2012 policy update for intermittent preventive treatment, which aims to simplify the message and align preventive treatment with the focused antenatal care schedule, should be assessed to find out whether it leads to improvements in coverage. FUNDING Bill & Melinda Gates Foundation.

Population-Wide Malaria Testing and Treatment with Rapid Diagnostic Tests and Artemether-Lumefantrine in Southern Zambia: A Community Randomized Step-Wedge Control Trial Design

Reducing the human reservoir of malaria parasites is critical for elimination. We conducted a community randomized controlled trial in Southern Province, Zambia to assess the impact of three rounds of a mass test and treatment (MTAT) intervention on malaria prevalence and health facility outpatient case incidence using random effects logistic regression and negative binomial regression, respectively. Following the intervention, children in the intervention group had lower odds of a malaria infection than individuals in the control group (adjusted odds ratio = 0.47, 95% confidence interval [CI] = 0.24–0.90). Malaria outpatient case incidence decreased 17% in the intervention group relative to the control group (incidence rate ratio = 0.83, 95% CI = 0.68–1.01). Although a single year of MTAT reduced malaria prevalence and incidence, the impact of the intervention was insufficient to reduce transmission to a level approaching elimination where a strategy of aggressive case investigations could be used. Mass drug administration, more sensitive diagnostics, and gametocidal drugs may potentially improve interventions targeting the human reservoir of malaria parasites.

Community Coverage with Insecticide-Treated Mosquito Nets and Observed Associations with All-Cause Child Mortality and Malaria Parasite Infections

Randomized trials and mathematical modeling suggest that insecticide-treated mosquito nets (ITNs) provide community-level protection to both those using ITNs and those without individual access. Using nationally representative household survey datasets from 17 African countries, we examined whether community ITN coverage is associated with malaria infections in children < 5 years old and all-cause child mortality (ACCM) among children < 5 years old in households with one or more ITNs versus without any type of mosquito net (treated or untreated). Increasing ITN coverage (> 50%) was protective against malaria infections and ACCM for children in households with an ITN, although this protection was not conferred to children in households without ITNs in these data. Children in households with ITNs were protected against malaria infections and ACCM with ITN coverage > 30%, but this protection was not significant with ITN coverage < 30%. Results suggest that ITNs are more effective with higher ITN coverage.

An individual-level meta-analysis assessing the impact of community-level sanitation access on child stunting, anemia, and diarrhea: Evidence from DHS and MICS surveys

Background A lack of access to sanitation is an important risk factor child health, facilitating fecal-oral transmission of pathogens including soil-transmitted helminthes and various causes of diarrheal disease. We conducted a meta-analysis of cross-sectional surveys to determine the impact that community-level sanitation access has on child health for children with and without household sanitation access. Methodology/Principal findings Using 301 two-stage demographic health surveys and multiple indicator cluster surveys conducted between 1990 and 2015 we calculated the sanitation access in the community as the proportion of households in the sampled cluster that had household access to any type of sanitation facility. We then conducted exact matching of children based on various predictors of living in a community with high access to sanitation. Using logistic regression with the matched group as a random intercept we examined the association between the child health outcomes of stunted growth, any anemia, moderate or severe anemia, and diarrhea in the previous two weeks and the exposure of living in a community with varying degrees of community-level sanitation access. For children with household-level sanitation access, living in a community with 100% sanitation access was associated with lowered odds of stunting (adjusted odds ratio [AOR] = 0.97, 95%; confidence interval (CI) = 0.94–1.00; n = 14,153 matched groups, 1,175,167 children), any anemia (AOR = 0.73; 95% CI = 0.67–0.78; n = 5,319 matched groups, 299,033 children), moderate or severe anemia (AOR = 0.72, 95% CI = 0.68–0.77; n = 5,319 matched groups, 299,033 children) and diarrhea (AOR = 0.94; 95% CI = 0.91–0.97); n = 16,379 matched groups, 1,603,731 children) compared to living in a community with < 30% sanitation access. For children without household-level sanitation access, living in communities with 0% sanitation access was associated with higher odds of stunting (AOR = 1.04, 95% CI = 1.02–1.06; n = 14,153 matched groups, 1,175,167 children), any anemia (AOR = 1.05, 95% CI = 1.00–1.09; n = 5,319 matched groups, 299,033 children), moderate or severe anemia (AOR = 1.04, 95% CI = 1.00–1.09; n = 5,319 matched groups, 299,033 children) but not diarrhea (AOR = 1.00, 95% CI = 0.98–1.02; n = 16,379 matched groups, 1,603,731 children) compared to children without household-level sanitation access living in communities with 1–30% sanitation access. Conclusions/Significance Community-level sanitation access is associated with improved child health outcomes independent of household-level sanitation access. The proportion of children living in communities with 100% sanitation access throughout the world is appallingly low. Ensuring sanitation access to all by 2030 will greatly improve child health.

Targeting indoor residual spraying for malaria using epidemiological data: a case study of the Zambia experience

BackgroundIn Zambia and other sub-Saharan African countries affected by ongoing malaria transmission, indoor residual spraying (IRS) for malaria prevention has typically been implemented over large areas, e.g., district-wide, and targeted to peri-urban areas. However, there is a recent shift in some countries, including Zambia, towards the adoption of a more strategic and targeted IRS approach, in coordination with increased emphasis on universal coverage of long-lasting insecticidal nets (LLINs) and effective insecticide resistance management. A true targeted approach would deliver IRS to sub-district areas identified as high-risk, with the goal of maximizing the prevention of malaria cases and deaths.ResultsTogether with the Government of the Republic of Zambia, a new methodology was developed applying geographic information systems and satellite imagery to support a targeted IRS campaign during the 2014 spray season using health management information system data.Discussion/ConclusionThis case study focuses on the developed methodology while also highlighting the significant research gaps which must be filled to guide countries on the most effective strategy for IRS targeting in the context of universal LLIN coverage and evolving insecticide resistance.

Household Dengue Prevention Interventions, Expenditures, and Barriers to Aedes aegypti Control in Machala, Ecuador

The Aedes aegypti mosquito is an efficient vector for the transmission of Zika, chikungunya, and dengue viruses, causing major epidemics and a significant social and economic burden throughout the tropics and subtropics. The primary means of preventing these diseases is household-level mosquito control. However, relatively little is known about the economic burden of Ae. aegypti control in resource-limited communities. We surveyed residents from 40 households in a high-risk community at the urban periphery in the city of Machala, Ecuador, on dengue perceptions, vector control interventions, household expenditures, and factors influencing purchasing decisions. The results of this study show that households spend a monthly median of US

Location, location, location: environmental factors better predict malaria-positive individuals during reactive case detection than index case demographics in Southern Province, Zambia

2.00, or 1.90% (range: 0.00%, 9.21%) of their family income on Ae. aegypti control interventions. Households reported employing, on average, five different mosquito control and dengue prevention interventions, including aerosols, liquid sprays, repellents, mosquito coils, and unimpregnated bed nets. We found that effectiveness and cost were the most important factors that influence people’s decisions to purchase a mosquito control product. Our findings will inform the development and deployment of new Ae. aegypti control interventions by the public health and private sectors, and add to prior studies that have focused on the economic burden of dengue-like illness.

Neighborhood trauma due to violence: a multilevel analysis

BackgroundDecreasing malaria transmission leads to increasing heterogeneity with increased risk in both hot spots (locations) and hot pops (certain demographics). In Southern Province, Zambia, reactive case detection has formed a part of malaria surveillance and elimination efforts since 2011. Various factors may be associated with finding malaria infections during case investigations, including the demographics of the incident case and environmental characteristics of the location of the incident case.MethodsCommunity health worker registries were used to determine what factors were associated with finding a malaria infection during reactive case detection.ResultsLocation was a more powerful predictor of finding malaria infections during case investigations than the demographics of the incident case. After accounting for environmental characteristics, no demographics around the incident case were associated with finding malaria infections during case investigations. Various time-invariant measures of the environment, such as median enhanced vegetation index, the topographic position index, the convergence index, and the topographical wetness index, were all associated as expected with increased probability of finding a malaria infection during case investigations.ConclusionsThese results suggest that targeting the locations highly at risk of malaria transmission is of importance in elimination settings.

A qualitative study of perceptions of a mass test and treat campaign in Southern Zambia and potential barriers to effectiveness

Abstract:In Syracuse, New York the social determinants of trauma from neighborhood violence are rooted in historical processes, including urban renewal, the Rockefeller drug laws, and de-industrialization. These contributed to destabilizing Syracuse communities of color, resulting in disproportionate incarceration, family disruption, and economic devastation. Community violence, clustering in densely populated neighborhoods, creates unmanageable stress for the families who live in them. A map of gunshots and gun fatalities (2009 to 2014) illustrates the continuing onslaught of bullets being fired, often in close proximity to elementary schools. A community survey indicated that over half of respondents personally knew more than 10 murder victims. Half the respondents scored positive on the Civilian PTSD Checklist; there thus is a great deal of unaddressed traumatic stress in the community. This analysis, conducted to prepare for planning future interventions to reduce the community trauma and violence, is part of an ongoing university-community collaboration.

Assessing the Impact of Leveraging Traditional Leadership on Access to Sanitation in Rural Zambia

BackgroundA mass test and treat campaign (MTAT) using rapid diagnostic tests (RDTs) and artemether-lumefantrine (AL) was conducted in Southern Zambia in 2012 and 2013 to reduce the parasite reservoir and progress towards malaria elimination. Through this intervention, community health workers (CHWs) tested all household members with rapid diagnostic tests (RDTs) and provided treatment to those that tested positive.MethodsA qualitative study was undertaken to understand CHW and community perceptions regarding the MTAT campaign. A total of eight focus groups and 33 in-depth and key informant interviews were conducted with CHWs, community members and health centre staff that participated in the MTAT.ResultsInterviews and focus groups with CHWs and community members revealed that increased knowledge of malaria prevention, the ability to reach people who live far from health centres, and the ability of the MTAT campaign to reduce the malaria burden were the greatest perceived benefits of the campaign. Conversely, the primary potential barriers to effectiveness included refusals to be tested, limited adherence to drug regimens, and inadequate commodity supply. Study respondents generally agreed that MTAT services were scalable outside of the study area but would require greater involvement from district and provincial medical staff.ConclusionsThese findings highlight the importance of increased community sensitization as part of mass treatment campaigns for improving campaign coverage and acceptance. Further, they suggest that communication channels between the Ministry of Health, National Malaria Control Centre and Medical Stores Limited may need to be improved so as to ensure there is consistent supply and management of commodities. Continued capacity building of CHWs and health facility supervisors is critical for a more effective programme and sustained progress towards malaria elimination.