Large-scale delivery of seasonal malaria chemoprevention to children under 10 in Senegal: an economic analysis.

Seasonal Malaria Chemoprevention (SMC) is recommended for children under 5 in the Sahel and sub-Sahel. The burden in older children may justify extending the age range, as has been done effectively in Senegal. We examine costs of door-to-door SMC delivery to children up to 10 years by community health workers (CHWs). We analysed incremental financial and economic costs at district level and below from a health service perspective. We examined project accounts and prospectively collected data from 405 CHWs, 46 health posts, and 4 district headquarters by introducing questionnaires in advance and completing them after each monthly implementation round. Affordability was explored by comparing financial costs of SMC to relevant existing health expenditure levels. Costs were disaggregated by administration month and by health service level. We used linear regression models to identify factors associated with cost variation between health posts. The financial cost to administer SMC to 180 000 children over one malaria season, reaching ∼93% of children with all three intended courses of SMC was $234 549 (constant 2010 USD) or$0.50 per monthly course administered. Excluding research-participation incentives, the financial cost was $0.32 per resident (all ages) in the catchment area, which is 1.2$278 922 or $0.59 per course administered and varied widely between health posts, from$0.38 to $2.74 per course administered. Substantial economies of scale across health posts were found, with the smallest health posts incurring highest average costs per monthly course administered. SMC for children up to 10 is likely to be affordable, particularly where it averts substantial curative care costs. Estimates of likely costs and cost-effectiveness of SMC in other contexts must account for variation in average costs across delivery months and health posts

Large-scale delivery of seasonal malaria chemoprevention to children under 10 in Senegal: an economic analysis

Seasonal Malaria Chemoprevention (SMC) is recommended for children under 5 in the Sahel and sub-Sahel. The burden in older children may justify extending the age range, as has been done effectively in Senegal. We examine costs of door-To-door SMC delivery to children up to 10 years by community health workers (CHWs). We analysed incremental financial and economic costs at district level and below from a health service perspective. We examined project accounts and prospectively collected data from 405 CHWs, 46 health posts, and 4 district headquarters by introducing questionnaires in advance and completing them after each monthly implementation round. Affordability was explored by comparing financial costs of SMC to relevant existing health expenditure levels. Costs were disaggregated by administration month and by health service level. We used linear regression models to identify factors associated with cost variation between health posts. The financial cost to administer SMC to 180 000 children over one malaria season, reaching â 1/493% of children with all three intended courses of SMC was 234 549 (constant 2010 USD) or 0.50 per monthly course administered. Excluding research-participation incentives, the financial cost was 0.32 per resident (all ages) in the catchment area, which is 1.2% of Senegal's general government expenditure on health per capita. Economic costs were 18.7% higher than financial costs at 278 922 or 0.59 per course administered and varied widely between health posts, from 0.38 to 2.74 per course administered. Substantial economies of scale across health posts were found, with the smallest health posts incurring highest average costs per monthly course administered. SMC for children up to 10 is likely to be affordable, particularly where it averts substantial curative care costs. Estimates of likely costs and cost-effectiveness of SMC in other contexts must account for variation in average costs across delivery months and health posts

Effectiveness of Seasonal Malaria Chemoprevention in Children under Ten Years of Age in Senegal: A Stepped-Wedge Cluster-Randomised Trial.

BACKGROUND: Seasonal Malaria Chemoprevention (SMC) with sulfadoxine-pyrimethamine (SP) plus amodiaquine (AQ), given each month during the transmission season, is recommended for children living in areas of the Sahel where malaria transmission is highly seasonal. The recommendation for SMC is currently limited to children under five years of age, but, in many areas of seasonal transmission, the burden in older children may justify extending this age limit. This study was done to determine the effectiveness of SMC in Senegalese children up to ten years of age. METHODS AND FINDINGS: SMC was introduced into three districts over three years in central Senegal using a stepped-wedge cluster-randomised design. A census of the population was undertaken and a surveillance system was established to record all deaths and to record all cases of malaria seen at health facilities. A pharmacovigilance system was put in place to detect adverse drug reactions. Fifty-four health posts were randomised. Nine started implementation of SMC in 2008, 18 in 2009, and a further 18 in 2010, with 9 remaining as controls. In the first year of implementation, SMC was delivered to children aged 3-59 months; the age range was then extended for the latter two years of the study to include children up to 10 years of age. Cluster sample surveys at the end of each transmission season were done to measure coverage of SMC and the prevalence of parasitaemia and anaemia, to monitor molecular markers of drug resistance, and to measure insecticide-treated net (ITN) use. Entomological monitoring and assessment of costs of delivery in each health post and of community attitudes to SMC were also undertaken. About 780,000 treatments were administered over three years. Coverage exceeded 80% each month. Mortality, the primary endpoint, was similar in SMC and control areas (4.6 and 4.5 per 1000 respectively in children under 5 years and 1.3 and 1.2 per 1000 in children 5-9 years of age; the overall mortality rate ratio [SMC: no SMC] was 0.90, 95% CI 0.68-1.2, p = 0.496). A reduction of 60% (95% CI 54%-64%, p < 0.001) in the incidence of malaria cases confirmed by a rapid diagnostic test (RDT) and a reduction of 69% (95% CI 65%-72%, p < 0.001) in the number of treatments for malaria (confirmed and unconfirmed) was observed in children. In areas where SMC was implemented, incidence of confirmed malaria in adults and in children too old to receive SMC was reduced by 26% (95% CI 18%-33%, p < 0.001) and the total number of treatments for malaria (confirmed and unconfirmed) in these older age groups was reduced by 29% (95% CI 21%-35%, p < 0.001). One hundred and twenty-three children were admitted to hospital with a diagnosis of severe malaria, with 64 in control areas and 59 in SMC areas, showing a reduction in the incidence rate of severe disease of 45% (95% CI 5%-68%, p = 0.031). Estimates of the reduction in the prevalence of parasitaemia at the end of the transmission season in SMC areas were 68% (95% CI 35%-85%) p = 0.002 in 2008, 84% (95% CI 58%-94%, p < 0.001) in 2009, and 30% (95% CI -130%-79%, p = 0.56) in 2010. SMC was well tolerated with no serious adverse reactions attributable to SMC drugs. Vomiting was the most commonly reported mild adverse event but was reported in less than 1% of treatments. The average cost of delivery was US$0.50 per child per month, but varied widely depending on the size of the health post. Limitations included the low rate of mortality, which limited our ability to detect an effect on this endpoint. CONCLUSIONS: SMC substantially reduced the incidence of outpatient cases of malaria and of severe malaria in children, but no difference in all-cause mortality was observed. Introduction of SMC was associated with an overall reduction in malaria incidence in untreated age groups. In many areas of Africa with seasonal malaria, there is a substantial burden in older children that could be prevented by SMC. SMC in older children is well tolerated and effective and can contribute to reducing malaria transmission. TRIAL REGISTRATION: ClinicalTrials.gov NCT00712374

Author Correction: Implementation, coverage and equity of large-scale door-to-door delivery of Seasonal Malaria Chemoprevention (SMC) to children under 10 in Senegal.

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Socializing One Health: an innovative strategy to investigate social and behavioral risks of emerging viral threats

In an effort to strengthen global capacity to prevent, detect, and control infectious diseases in animals and people, the United States Agency for International Development’s (USAID) Emerging Pandemic Threats (EPT) PREDICT project funded development of regional, national, and local One Health capacities for early disease detection, rapid response, disease control, and risk reduction. From the outset, the EPT approach was inclusive of social science research methods designed to understand the contexts and behaviors of communities living and working at human-animal-environment interfaces considered high-risk for virus emergence. Using qualitative and quantitative approaches, PREDICT behavioral research aimed to identify and assess a range of socio-cultural behaviors that could be influential in zoonotic disease emergence, amplification, and transmission. This broad approach to behavioral risk characterization enabled us to identify and characterize human activities that could be linked to the transmission dynamics of new and emerging viruses. This paper provides a discussion of implementation of a social science approach within a zoonotic surveillance framework. We conducted in-depth ethnographic interviews and focus groups to better understand the individual- and community-level knowledge, attitudes, and practices that potentially put participants at risk for zoonotic disease transmission from the animals they live and work with, across 6 interface domains. When we asked highly-exposed individuals (ie. bushmeat hunters, wildlife or guano farmers) about the risk they perceived in their occupational activities, most did not perceive it to be risky, whether because it was normalized by years (or generations) of doing such an activity, or due to lack of information about potential risks. Integrating the social sciences allows investigations of the specific human activities that are hypothesized to drive disease emergence, amplification, and transmission, in order to better substantiate behavioral disease drivers, along with the social dimensions of infection and transmission dynamics. Understanding these dynamics is critical to achieving health security--the protection from threats to health-- which requires investments in both collective and individual health security. Involving behavioral sciences into zoonotic disease surveillance allowed us to push toward fuller community integration and engagement and toward dialogue and implementation of recommendations for disease prevention and improved health security

Effects of Ni Additions on the High Temperature Expansion, Melting and Oxidation Behaviors of Cobalt-Based Superalloys

Nickel is often added to cobalt-based superalloys to stabilize their austenitic structure. In this work the effects of Ni on several high temperature properties of a chromium-rich cobalt-based alloy reinforced by high fraction of TaC carbides are investigated. Different thermal analysis techniques are used: differential scanning calorimetry (DSC), thermo-mechanical analysis (TMA) and thermogravimetry (TG). Results show that the progressive addition of nickel did not induce great modifications of microstructure, refractoriness or thermal expansion. However, minor beneficial effects were noted, including reduction of the melting temperature range and slight decrease in thermal expansion coefficient. The most important improvement induced by Ni addition concerns the hot oxidation behavior. In this way, introducing several tens wt % Ni in this type of cobalt-based alloy may be recommended

Influence of the Base Element on the Thermal Properties of Non- Ferrous Chromium-Rich TaC-Containing Alloys Elaborated by Conventional Casting: Part 3: Surface and Cross-Sectional Metallographic Characterization of the Oxidized Alloys

The six alloys the thermal properties of which and the tendency to oxide spallation of which were studied in the first two parts of this work, were here characterized after oxidation for 70 hours at 1250°C. The external chromia scale, and also the CrTaO4 subsurface oxide, formed for all the alloys, almost independently of the Co and Ni proportions in the base element content. But, because of the formation of more CrTaO4 for the nickel-richest alloys probably due to the higher availability of Ta in the matrix and its easier diffusion towards the neighbourhood of the oxidation front, the adherence of chromia was weakened and spallation, suggested by the thermogravimetric curves in the second part of this work, is here really observed and the denuded part of alloys clearly seen. The degradation of the subsurface, which can be in a first time summarized by the development of a carbide-free zone and a {Cr, Ta}-depleted zone, depends on the Co and Ni proportions. The microstructure of the bulk is differently affected by long exposure at elevated temperature. The changes in carbide population characteristics are stronger for the nickel-based alloys than for the cobalt-based ones. Finally, the isothermal oxidation behaviour is best for the nickel-richest alloys but the oxide spallation behaviour and the potential mechanical properties are the best for the cobalt-richest alloys

A study of the dependence on the Co and Ni proportions of the oxidation at elevated temperature of TaC-strengthened {Ni and Co}-based cast superalloys

International audienceCobalt and nickel may play antagonist roles on the microstructures and high temperature properties of cast chromium-rich superalloys containing the same tantalum and carbon molar fractions. Since such alloys may be considered for uses at temperature levels as high as 1200 °C, the whole range of base compositions was explored with six model quaternary alloys with Ni and Co contents varying from 0 to 100% of the remaining elements, the 25 wt%Cr, 0.4 wt%C and 6 wt%Ta being deducted. The interdendritic carbide network of the as-cast microstructures is made of chromium carbides and tantalum carbides for the Ni-richest alloys and of TaC only for the Co-richest ones. {170 h, 1200 °C}-exposure carried out in laboratory air led to important morphology deterioration for the two Ni-richest alloys but limited fragmentation of the TaC in the four Co-richest alloys. At the same time, the most of the alloys more or less well behaved in oxidation, except the two Co-richest alloys for which the too hindered volume diffusion of chromium did not sustain the chromia-forming behavior. Notably the Ni-free cobalt-based alloys suffered from starts of catastrophic oxidation in several surface locations. The quaternary alloy bases allowing taking benefit of the best compromise between hot oxidation resistance and possibly good mechanical behavior at elevated temperature was the model alloys with 14–28 wt%Ni

Influence of the Base Element on the Thermal Properties of Non- Ferrous Chromium-Rich TaC-Containing Alloys Elaborated by Conventional Casting: Part 2: Thermogravimetric and Metallographic Study of the Oxidation Start and of the Oxide Scale Spallation

After a first part devoted to the study of several thermal chemical and mechanical characteristics of the six (xCo-yNi, bal.)-25Cr-0.4C-6Ta alloys, this second part of their study deals with the oxidation behaviour of these alloys in presence of heating or of cooling. The heating and cooling parts of thermogravimetry files of oxidation tests of which the isothermal parts were earlier studied, were analysed by plotting mass variation versus temperature. During heating the oxidation starts and a first mass gain is achieved prior to the isothermal stage. They are slightly influenced by the Co/Ni ratio. During the cooling oxide scale spallation happens for all alloys. For the nickel-richest alloys this phenomenon takes place for a temperature less decreased in comparison to the cobalt-based alloys. The fall in mass due to the loss of oxides by spallation seems a little higher for the nickel-richest alloys than that for the cobalt-richest ones. More than to differences in thermal expansion coefficient, this difference may be linked to the oxidation-induced mass gain achieved prior to spallation start, which is higher for the cobalt-richest alloys than for the nickel-richest ones

Influence of the Base Element on the Thermal Properties of Non- Ferrous Chromium-Rich TaC-Containing Alloys Elaborated by Conventional Casting: Part 1: Thermodynamic Approach, Melting Ranges, as-Cast Microstructures and Thermal Expansion

After preliminary thermodynamic calculations for verifying their refractoriness, six (Ni,Co)-based alloys were synthesized by casting. They contain chromium, carbon and tantalum to achieve interesting chemical and mechanical high temperature properties. Their microstructures in the as-cast state were observed by electron microscopy (SEM) to discover the carbides characteristics. Differential thermal analysis (DTA) was carried out for all of them to assess their melting points notably, for having better knowledge about the level of high temperature at which they can be used potentially. Thereafter thermomechanical analyses (TMA) were run to explore their behaviour in thermal expansion. As shown by the thermodynamic calculations all the alloys are theoretically possible to be shaped by conventional foundry due to liquidus temperatures all below 1400°C. According to these same results, the solidus temperatures of all alloys would stay over 1250°C, this suggesting that all alloys would be able to be used under moderate mechanical stresses at temperatures as high as 1200°C. As suggested by calculations, the as-cast microstructures are all dendritic and the interdendritic spaces are occupied by carbides. According to calculations again, the Ni-richest alloys contain chromium carbides, but tantalum carbides are also present, a presence which was not expected. In contrast the Co-richest versions contain only TaC carbides. The DTA experiments show that the solidus and liquidus temperatures both increase by going from the Ni-richest alloys to the Co-richest ones. The TMA experiments demonstrate that the thermal expansions and thermal contractions are rather continuous, without any irregularities, and the average thermal expansion coefficients, all close to 20 × 10-6K-1, do not systematically depend on the respective proportions of nickel and cobalt. This first part of the whole work will be followed by two other parts dealing with the effect of these Ni and Co proportions on the high temperature oxidation phenomena, for temperature variations and for isothermal conditions respectively