Yazoume Ye

Effect of zinc supplementation on malaria and other causes of morbidity in west African children: randomised double blind placebo controlled trial

Abstract Objective: To study the effects of zinc supplementation on malaria and other causes of morbidity in young children living in an area holoendemic for malaria in west Africa. Design: Randomised, double blind, placebo controlled efficacy trial. Setting: 18 villages in rural northwestern Burkina Faso. Participants: 709 children were enrolled; 685 completed the trial. Intervention: Supplementation with zinc (12.5 mg zinc sulphate) or placebo daily for six days a week for six months. Main outcome measures: The primary outcome was the incidence of symptomatic falciparum malaria. Secondary outcomes were the severity of malaria episodes, prevalence of malaria parasite, mean parasite densities, mean packed cell volume, prevalence of other morbidity, and all cause mortality. Results: The mean number of malaria episodes per child (defined as a temperature ≥37.5°C with ≥5000 parasites/μl) was 1.7, 99.7% due to infection with Plasmodium falciparum. No difference was found between the zinc and placebo groups in the incidence of falciparum malaria (relative risk 0.98, 95% confidence interval 0.86 to 1.11), mean temperature, and mean parasite densities during malaria episodes, nor in malaria parasite rates, mean parasite densities, and mean packed cell volume during cross sectional surveys. Zinc supplementation was significantly associated with a reduced prevalence of diarrhoea (0.87, 0.79 to 0.95). All cause mortality was non-significantly lower in children given zinc compared with those given placebo (5 v 12, P=0.1). Conclusions: Zinc supplementation has no effect on morbidity from falciparum malaria in children in rural west Africa, but it does reduce morbidity associated with diarrhoea. What is already known on this topic Zinc deficiency is common in infants in developing countries Zinc supplementation has been shown to reduce morbidity from infectious disease in such populations, particularly through reductions in morbidity from diarrhoea and respiratory infections Limited evidence exists for zinc supplementation being effective in reducing morbidity from malaria What this study adds Zinc supplementation has no effect on falciparum malaria in children in rural west Africa It is effective in reducing morbidity from diarrhoea and may help to reduce mortality from all causes

The burden of disease profile of residents of Nairobi's slums: Results from a Demographic Surveillance System

BackgroundWith increasing urbanization in sub-Saharan Africa and poor economic performance, the growth of slums is unavoidable. About 71% of urban residents in Kenya live in slums. Slums are characteristically unplanned, underserved by social services, and their residents are largely underemployed and poor. Recent research shows that the urban poor fare worse than their rural counterparts on most health indicators, yet much about the health of the urban poor remains unknown. This study aims to quantify the burden of mortality of the residents in two Nairobi slums, using a Burden of Disease approach and data generated from a Demographic Surveillance System.MethodsData from the Nairobi Urban Health and Demographic Surveillance System (NUHDSS) collected between January 2003 and December 2005 were analysed. Core demographic events in the NUHDSS including deaths are updated three times a year; cause of death is ascertained by verbal autopsy and cause of death is assigned according to the ICD 10 classification. Years of Life Lost due to premature mortality (YLL) were calculated by multiplying deaths in each subcategory of sex, age group and cause of death, by the Global Burden of Disease standard life expectancy at that age.ResultsThe overall mortality burden per capita was 205 YLL/1,000 person years. Children under the age of five years had more than four times the mortality burden of the rest of the population, mostly due to pneumonia and diarrhoeal diseases. Among the population aged five years and above, HIV/AIDS and tuberculosis accounted for about 50% of the mortality burden.ConclusionSlum residents in Nairobi have a high mortality burden from preventable and treatable conditions. It is necessary to focus on these vulnerable populations since their health outcomes are comparable to or even worse than the health outcomes of rural dwellers who are often the focus of most interventions.

Effect of the Affordable Medicines Facility--malaria (AMFm) on the availability, price, and market share of quality-assured artemisinin-based combination therapies in seven countries: a before-and-after analysis of outlet survey data.

BACKGROUND Malaria is one of the greatest causes of mortality worldwide. Use of the most effective treatments for malaria remains inadequate for those in need, and there is concern over the emergence of resistance to these treatments. In 2010, the Global Fund launched the Affordable Medicines Facility--malaria (AMFm), a series of national-scale pilot programmes designed to increase the access and use of quality-assured artemisinin based combination therapies (QAACTs) and reduce that of artemisinin monotherapies for treatment of malaria. AMFm involves manufacturer price negotiations, subsidies on the manufacturer price of each treatment purchased, and supporting interventions such as communications campaigns. We present findings on the effect of AMFm on QAACT price, availability, and market share, 6-15 months after the delivery of subsidised ACTs in Ghana, Kenya, Madagascar, Niger, Nigeria, Uganda, and Tanzania (including Zanzibar). METHODS We did nationally representative baseline and endpoint surveys of public and private sector outlets that stock antimalarial treatments. QAACTs were identified on the basis of the Global Funds quality assurance policy. Changes in availability, price, and market share were assessed against specified success benchmarks for 1 year of AMFm implementation. Key informant interviews and document reviews recorded contextual factors and the implementation process. FINDINGS In all pilots except Niger and Madagascar, there were large increases in QAACT availability (25·8-51·9 percentage points), and market share (15·9-40·3 percentage points), driven mainly by changes in the private for-profit sector. Large falls in median price for QAACTs per adult equivalent dose were seen in the private for-profit sector in six pilots, ranging from US

Monitoring of Health and Demographic Outcomes in Poor Urban Settlements: Evidence from the Nairobi Urban Health and Demographic Surveillance System

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Housing conditions and Plasmodium falciparum infection: protective effect of iron-sheet roofed houses.

4·82. The market share of oral artemisinin monotherapies decreased in Nigeria and Zanzibar, the two pilots where it was more than 5% at baseline. INTERPRETATION Subsidies combined with supporting interventions can be effective in rapidly improving availability, price, and market share of QAACTs, particularly in the private for-profit sector. Decisions about the future of AMFm should also consider the effect on use in vulnerable populations, access to malaria diagnostics, and cost-effectiveness. FUNDING The Global Fund to Fight AIDS, Tuberculosis and Malaria, and the Bill & Melinda Gates Foundation.

Health and demographic surveillance systems: a step towards full civil registration and vital statistics system in sub-Sahara Africa?

The Nairobi Urban Health and Demographic Surveillance System (NUHDSS) was set up in Korogocho and Viwandani slum settlements to provide a platform for investigating linkages between urban poverty, health, and demographic and other socioeconomic outcomes, and to facilitate the evaluation of interventions to improve the wellbeing of the urban poor. Data from the NUHDSS confirm the high level of population mobility in slum settlements, and also demonstrate that slum settlements are long-term homes for many people. Research and intervention programs should take account of the duality of slum residency. Consistent with the trends observed countrywide, the data show substantial improvements in measures of child mortality, while there has been limited decline in fertility in slum settlements. The NUHDSS experience has shown that it is feasible to set up and implement long-term health and demographic surveillance system in urban slum settlements and to generate vital data for guiding policy and actions aimed at improving the wellbeing of the urban poor.

Do migrant children face greater health hazards in slum settlements? Evidence from Nairobi, Kenya

BackgroundIdentification and better understanding of potential risk factors for malaria are important for targeted and cost-effective health interventions. Housing conditions have been suggested as one of the potential risk factors. This study aims to further investigate this risk factor, and is focused on the effect of the type of roof on Plasmodium falciparum infection among children below five years in the North West of Burkina Faso.MethodsIn a cross-sectional study design, 661 children aged six to 60 months were randomly selected from three rural and one semi-urban site at the end of the rainy season (November 2003). The children were screened for fever and tested for Plasmodium falciparum infection. In addition, data on bed net use and house characteristics was collected from the household were each child lived. Using adjusted odds ratios, children living in house roofed with iron-sheet were compared with those in house with mud or grass roof.ResultsOverall P. falciparum infection prevalence was 22.8 % with a significant variation between (Chi-square, p < 0.0001). The prevalence in Cissé (33.3 %) and Goni (30.6 %) were twice times more than in Nouna (15.2 %) and Kodougou (13.2 %). After adjusting for age, sex, use of bed net and housing conditions, children living in houses with mud roofs had significantly higher risk of getting P. falciparum infection compared to those living in iron-sheet roofed houses (Odds Ratio 2.6; 95% Confidence Interval, 1.4–4.7).ConclusionThese results suggest that house characteristics should be taken into consideration when designing health intervention against P. falciparum infection and particular attention should be paid to children living in houses with mud roofs.

Seasonal pattern of pneumonia mortality among under-five children in Nairobi's informal settlements.

BackgroundIn the developed world, information on vital events is routinely collected nationally to inform population and health policies. However, in many low-and middle-income countries, especially those in sub-Saharan Africa (SSA), there is a lack of effective and comprehensive national civil registration and vital statistics system. In the past decades, the number of Health and Demographic Surveillance Systems (HDSSs) has increased throughout SSA. An HDSS monitors births, deaths, causes of death, migration, and other health and socio-economic indicators within a defined population over time. Currently, the International Network for the Continuous Demographic Evaluation of Populations and Their Health (INDEPTH) brings together 38 member research centers which run 44 HDSS sites from 20 countries in Africa, Asia and Oceana. Thirty two of these HDSS sites are in SSA.DiscussionThis paper argues that, in the absence of an adequate national CRVS, HDSSs should be more effectively utilised to generate relevant public health data, and also to create local capacity for longitudinal data collection and management systems in SSA. If HDSSs get strategically located to cover different geographical regions in a country, data from these sites could be used to provide a more complete national picture of the health of the population. They provide useful data that can be extrapolated for national estimates if their regional coverage is well planned. HDSSs are however resource-intensive. Efforts are being put towards getting them linked to local or national policy contexts and to reduce their dependence on external funding. Increasing their number in SSA to cover a critical proportion of the population, especially urban populations, must be carefully planned. Strategic planning is needed at national levels to geographically locate HDSS sites and to support these through national funding mechanisms.SummaryThe paper does not suggest that HDSSs should be seen as a replacement for civil registration systems. Rather, they should serve as a short- to medium-term measure to provide data for health and population planning at regional levels with possible extrapolation to national levels. HDSSs can also provide useful lessons for countries that intend to set up nationally representative sample vital registration systems in the long term.

Micro-epidemiology of Plasmodium falciparum malaria: Is there any difference in transmission risk between neighbouring villages?

Between 60% and 70% of Nairobi City’s population live in congested informal settlements, commonly referred to as slums, without proper access to sanitation, clean water, health care and other social services. Children in such areas are exposed to disproportionately high health hazards. This paper examines the impact of mother and child migration on the survival of more than 10,000 children in two of Nairobi’s informal settlements—Korogocho and Viwandani—between July 2003 and June 2007, using a two-stage semi-parametric proportional hazards (Cox) model that controls for attrition and various factors that affect child survival. Results show that the slum-born have higher mortality than non-slum-born, an indication that delivery in the slums has long-term health consequences for children. Children born in the slums to women who were pregnant at the time of migration have the highest risk of dying. Given the high degree of circular migration, factors predisposing children born in the slums to recent migrant mothers to higher mortality should be better understood and addressed.

Local scale prediction of Plasmodium falciparum malaria transmission in an endemic region using temperature and rainfall

Using longitudinal data from the Nairobi Urban and Demographic Surveillance System (NUHDSS), we examined the seasonal pattern of pneumonia mortality among under-five children living in Nairobis slums. We included 17,787 under-five children resident in the NUHDSS from January 1, 2003 to December 31, 2005 in the analysis. Four hundred thirty-six deaths were observed and cause of death was ascertained by verbal autopsy for 377 of these deaths. Using Poisson regression, we modeled the quarterly mortality risk for pneumonia. The overall person-years (PYs) were 21,804 giving a mortality rate of 20.1 per 1,000 PYs in the study population. Pneumonia was the leading cause of death contributing 25.7% of the total deaths. Pneumonia mortality was highest in the second quarter (risk ratio [RR] = 2.3, confidence interval [CI]: 1.2-4.2 compared with the fourth quarter). The study provides evidence that pneumonia-related mortality among under-fives in Nairobis slums is higher from April to June corresponding to the rainy season and the beginning of the cold season.