Spatial accessibility to health facilities in Sub-Saharan Africa: comparing existing models with survey-based perceived accessibility.

BACKGROUND: Mapping geographical accessibility to health services is essential to improve access to public health in sub-Saharan Africa. Different methods exist to estimate geographical accessibility, but little is known about the ability of these methods to represent the experienced accessibility of the population, and about the added-value of sophisticated and data-demanding methods over simpler ones. Here we compare the most commonly used methods to survey-based perceived accessibility in different geographical settings. METHODS: Modelled accessibility maps are computed for 12 selected sub-Saharan African countries using four methods: Euclidean distance, cost-distance considering walking and motorized speed, and Kernel density. All methods are based on open and large-scale datasets to allow replication. Correlation coefficients are computed between the four modelled accessibility indexes and the perceived accessibility index extracted from Demographic and Health Surveys (DHS), and compared across different socio-geographical contexts (rural and urban, population with or without access to motorized transports, per country). RESULTS: Our analysis suggests that, at medium spatial resolution and using globally-consistent input datasets, the use of sophisticated and data-demanding methods is difficult to justify as their added value over a simple Euclidian distance method is not clear. We also highlight that all modelled accessibilities are better correlated with perceived accessibility in rural than urban contexts and for population who do not have access to motorized transportation. CONCLUSIONS: This paper should guide researchers in the public health domain for knowing strengths and limits of different methods to evaluate disparities in health services accessibility. We suggest that using cost-distance accessibility maps over Euclidean distance is not always relevant, especially when based on low resolution and/or non-exhaustive geographical datasets, which is often the case in low- and middle-income countries.

The impact of COVID-19 on the living and survival conditions of internally displaced persons in Burkina Faso.

In recent years, as in other parts of the Sahel, the threat of terrorism has escalated in Burkina Faso. In 2019, this country hosted the fourth highest number of new conflict-related internal displaced persons (IDPs) in the world. These people have to cope simultaneously with the full spectrum of environmental, social and health-related stresses in the long, medium and short term, respectively. We seek to compare the living conditions of IDPs before and during the lockdown implemented by the authorities (between 27 March and 5 May 2020) to contain the spread of the virus. Interviews were conducted with 106 IDPs in Kongoussi (Central-Northern region). Although no respondent reported having been directly affected by the virus, 84.9% of the IDPs surveyed had no income-generating activities during the lockdown and the remaining 15.1% who continued to work reported that their activities had been greatly scaled-down. For a large majority of them, their living conditions, already described as difficult under 'normal' circumstances (insufficient food, insignificant financial assistance, or difficult access to health care), further deteriorated. In addition, IDPs were unable to leave the camps or regions where they were located to search for better living conditions or to return home. Lastly, 96.2% of respondents believed that the COVID-19 pandemic would have a negative impact on their future. These IDPs, like many in the sub-region and around the world, therefore require urgent assistance from the authorities and humanitarian NGOs, as the slightest new stress is likely to considerably worsen their already vulnerable state.

Neighbourhood-level housing quality indices for health assessment in Dakar, Senegal.

In sub-Saharan African cities, the dearth of accurate and detailed data is a major problem in the study of health and socioeconomic changes driven by rapid urbanization. Data on both health determinants and health outcomes are often lacking or are of poor quality. Proxies associated with socioeconomic differences are needed to compensate the lack of data. One of the most straightforward proxies is housing quality, which is a multidimensional concept including characteristics of both the built and natural environments. In this work, we combined the 2013 census data with remotely sensed land cover and land use data at a very high resolution in order to develop an integrated housing quality-based typology of the neighbourhoods in Dakar, Senegal. Principal component analysis and hierarchical classification were used to derive neighbourhood housing quality indices and four neighbourhood profiles. Paired tests revealed significant variations in the censusderived mortality rates between profile 1, associated with the lowest housing quality, and the three other profiles. These findings demonstrate the importance of housing quality as an important health risk factor. From a public health perspective, it should be a useful contribution for geographically targeted planning health policies, at the neighbourhood spatial level, which is the most appropriate administrative level for interventions.

Desert dust impacts on human health: an alarming worldwide reality and a need for studies in West Africa.

High desert dust concentrations raise concerns about adverse health effects on human populations. Based on a systematic literature review, this paper aims to learn more about the relationship between desert dust and human health in the world and to analyse the place of West Africa as a study area of interest. Papers focussing on the potential relationship between dust and health and showing quantitative analyses, published between January 1999 and September 2011, were identified using the ISI Web of Knowledge database (N = 50). A number of adverse health effects, including respiratory, cardiovascular and cardiopulmonary diseases, are associated with dust. This survey highlights obvious dust impacts on human health independently of the study area, health outcomes and method. Moreover, it reveals an imbalance between the areas most exposed to dust and the areas most studied in terms of health effects. None of these studies has been conducted in West Africa, despite the proximity of the Sahara, which produces about half of the yearly global mineral dust. In view of the alarming results in many parts of the world (Asia, Europe, America), this paper concludes by stressing the importance of carrying out impact studies of Saharan dust in West Africa, where dust events are more frequent and intense than anywhere else.

What do we know about effects of desert dust on air quality and human health in West Africa compared to other regions?

This study aims to compare, on the one hand, the geographical distribution of the desert dust source areas, their contribution to quantities emitted into the atmosphere, the trajectories and the quantities deposited, with on the other hand the areas of research interest focused on the desert dust impacts on air quality and/or human health. Based on a systematic review of the literature using the ISI Web of Knowledge database, we found 231 articles published over the last decade on the desert dust impacts on air quality. Of these, 48% concerned Asian dust and 39% Saharan dust, with the remaining 13% divided between the other dust source areas. However, only one of these studies addressed the worsening air pollution in West Africa, even though it is very close to the Sahara, the greatest contributor to the global dust budget. Moreover, there have been very few studies (41) looking at the direct links between desert dust and human health; in this context too, no interest has been shown in West Africa. Yet this region is also among the areas in which morbidity rates have been noted to be far higher than those found in other regions of the world, and where respiratory infections alone account for more than 20% of the causes of infant mortality. This survey highlights a clear imbalance between those areas most exposed to dust and the most studied areas in terms of dust impacts. Given these findings and the often alarming results published about other regions of the world, we advocate a revival of interest in research on West Africa in order to achieve a better understanding of the desert dust impacts on air quality and health among the populations of this region.