Plasmodium vivax transmission in Africa

Malaria in sub-Saharan Africa has historically been almost exclusively attributed to Plasmodium falciparum (Pf). Current diagnostic and surveillance systems in much of sub-Saharan Africa are not designed to identify or report non-Pf human malaria infections accurately, resulting in a dearth of routine epidemiological data about their significance. The high prevalence of Duffy negativity provided a rationale for excluding the possibility of Plasmodium vivax (Pv) transmission. However, review of varied evidence sources including traveller infections, community prevalence surveys, local clinical case reports, entomological and serological studies contradicts this viewpoint. Here, these data reports are weighted in a unified framework to reflect the strength of evidence of indigenous Pv transmission in terms of diagnostic specificity, size of individual reports and corroboration between evidence sources. Direct evidence was reported from 21 of the 47 malaria-endemic countries studied, while 42 countries were attributed with infections of visiting travellers. Overall, moderate to conclusive evidence of transmission was available from 18 countries, distributed across all parts of the continent. Approximately 86.6 million Duffy positive hosts were at risk of infection in Africa in 2015. Analysis of the mechanisms sustaining Pv transmission across this continent of low frequency of susceptible hosts found that reports of Pv prevalence were consistent with transmission being potentially limited to Duffy positive populations. Finally, reports of apparent Duffy-independent transmission are discussed. While Pv is evidently not a major malaria parasite across most of sub-Saharan Africa, the evidence presented here highlights its widespread low-level endemicity. An increased awareness of Pv as a potential malaria parasite, coupled with policy shifts towards species-specific diagnostics and reporting, will allow a robust assessment of the public health significance of Pv, as well as the other neglected non-Pf parasites, which are currently invisible to most public health authorities in Africa, but which can cause severe clinical illness and require specific control intervention

Olas de calor y salud humana : efectos en la salud de temperaturas extremas y contaminación en España

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Geografía e Historia, leída el 31-03-2022This PhD thesis entitled Extreme heat and human health: The effects of extreme temperatures and pollution on health in Spain examines the impacts of heat waves and air pollution on human mortality. Background. We present this research as a scientific contribution to major societal issues: human impacts on environment, ongoing climate change, population settlements and demographic aging, along with adaptive capacities of our societies, to mention a few. With a clear emphasis on spatial dimensions and a steadfast investment in data collection procedures and statistical methods, we propose a novel perspective on the spatial and temporal geographic, demographic and epidemiological transformations witnessed in Spain during the late 20th and early 21st century. The choice of Spain as a study area is based on the fact that this country as an excellent laboratory in which one could run comprehensive analysis oriented to disentangle complex relationship between changing climate with newly emerging extreme events and human mortality...Esta tesis doctoral titulada Olas de calor y salud humana: Efectos en la salud de temperaturas extremas y contaminación en España examina los impactos de las olas de calor y la contaminación del aire en la mortalidad humana. Introducción. Aportamos con esta tesis una contribución científica a algunos de los problemas sociales más acuciantes: el impacto humano en el medio ambiente, el cambio climático en curso, el asentamiento de la población y el envejecimiento demográfico, junto con las capacidades de adaptación de nuestras sociedades. Con un claro énfasis en la dimensión espacial y en procedimientos de recopilación de datos y métodos estadísticos, proponemos una perspectiva novedosa sobre las transformaciones geográficas, demográficas y epidemiológicas ocurridas en España desde finales del siglo XX. Elegimos España como área de estudio por ser un excelente laboratorio donde se pueden realizar análisis integrales orientados a desentrañar la compleja relación entre elcambio climático, eventos extremos emergentes y la salud y mortalidad humana...Fac. de Geografía e HistoriaTRUEunpu

The Burden of Heat-Related Mortality in Madrid: A Hundred Year Journey

Abstract Background. The association between ambient temperatures and health outcomes was extensively studied in the past decades, especially in the light of exacerbating climate change. Yet long-term studies focusing on the analysis of the changes of mortality answers to extreme heat are rare, particularly in the Mediterranean region. Minimum Mortality, or so-called Optimum temperatures are increasingly used to assess the levels of adaptation to changing temperatures. The warming of the air temperatures in Spain affected the entire national territory since the turn of the XX century. However, the number of studies exploring the evolution of adaptation to heat and relying on multidecadal time-series data in Spain at any administrative level is very limited. To our knowledge, the present research is the first one to leverage daily mortality and temperature data in the city of Madrid since the end of the XIX century until today. Methods. We examined the patterns of adaptation to extreme heat in the city of Madrid in the period from 1890 until 2020 using daily data on air temperature received from the meteorological stations and all-cause mortality from yearly books and civil registers. Using a distributed-lag nonlinear modelling approach we explored the complex heat-mortality relations and estimated the changes in the adaptation metrics by decade. Expected results. Based on the previous research by the authors performed at different spatial levels in Spain for shorter time periods, we expect to see an overall increase in the optimum temperatures over time, along with an increment of the air temperatures, especially in the last decades. We also expect to see a general reduction in the heat-attributable mortality fractions, which would indicate a progressive adaptation to overall warming of air temperatures and intensification of weather extremes. On the other hand, the dose-response relationship is expected to differ between sex- and age-groups, being supposedly the highest for older woman in the beginning of the study period. We expect a spatially different response of mortality to intense heat within the city due to different housing environment and development of urban infrastructures in each area of the city

The burden of heat-related mortality in Madrid: a hundred year journey

Abstract Background. The association between ambient temperatures and health outcomes was extensively studied in the past decades, especially in the light of exacerbating climate change. Yet long-term studies focusing on the analysis of the changes of mortality answers to extreme heat are rare, particularly in the Mediterranean region. Minimum Mortality, or so-called Optimum temperatures are increasingly used to assess the levels of adaptation to changing temperatures. The warming of the air temperatures in Spain affected the entire national territory since the turn of the XX century. However, the number of studies exploring the evolution of adaptation to heat and relying on multidecadal time-series data in Spain at any administrative level is very limited. To our knowledge, the present research is the first one to leverage daily mortality and temperature data in the city of Madrid since the end of the XIX century until today. Methods. We examined the patterns of adaptation to extreme heat in the city of Madrid in the period from 1890 until 2020 using daily data on air temperature received from the meteorological stations and all-cause mortality from yearly books and civil registers. Using a distributed-lag nonlinear modelling approach we explored the complex heat-mortality relations and estimated the changes in the adaptation metrics by decade. Expected results. Based on the previous research by the authors performed at different spatial levels in Spain for shorter time periods, we expect to see an overall increase in the optimum temperatures over time, along with an increment of the air temperatures, especially in the last decades. We also expect to see a general reduction in the heat-attributable mortality fractions, which would indicate a progressive adaptation to overall warming of air temperatures and intensification of weather extremes. On the other hand, the dose-response relationship is expected to differ between sex- and age-groups, being supposedly the highest for older woman in the beginning of the study period. We expect a spatially different response of mortality to intense heat within the city due to different housing environment and development of urban infrastructures in each area of the city

Temporal variation of the temperature-mortality association in Spain: a nationwide analysis

Abstract Background Although adaptation to continuously rising ambient temperatures is an emerging topic and has been widely studied at a global scale, detailed analysis of the joint indicators for long-term adaptation in Spain are scarce. This study aims to explore temporal variations of the minimum mortality temperature and mortality burden from heat and cold between 1979 and 2018. Methods We collected individual all-cause mortality and climate reanalysis data for 4 decades at a daily time step. To estimate the temperature-mortality association for each decade, we fitted a quasi-Poisson time-series regression model using a distributed lag non-linear model with 21 days of lag, controlling for trends and day of the week. We also calculated attributable mortality fractions by age and sex for heat and cold, defined as temperatures above and below the optimum temperature, which corresponds to the minimum mortality in each period. Results We analysed over 14 million deaths registered in Spain between 1979 and 2018. The optimum temperature estimated at a nationwide scale declined from 21 °C in 1979–1988 to 16 °C in 1999–2008, and raised to 18 °C in 2009–2018. The mortality burden from moderate cold showed a 3-fold reduction down to 2.4% in 2009–2018. Since 1988–1999, the mortality risk attributable to moderate (extreme) heat reduced from 0.9% (0.8%) to 0.6% (0.5%). The mortality risk due to heat in women was almost 2 times larger than in men, and did not decrease over time. Conclusion Despite the progressively warmer temperatures in Spain, we observed a persistent flattening of the exposure-response curves, which marked an expansion of the uncertainty range of the optimal temperatures. Adaptation has been produced to some extent in a non-uniform manner with a substantial decrease in cold-related mortality, while for heat it became more apparent in the most recent decade only

Trends in Education-specific Differences in Disability-Free Life Expectancy in Spain, 2008-2017

Background: There is mounting evidence for a recent increase of social disparities in chronic disease prevalence and mortality. However, little is known about how these trends are reflected in combined measures of morbidity, disability and mortality.Method: We use two nationally representative surveys of the Spanish population for the years 2008 to 2017 and standard measures of expected duration of disability and illness to assess time trends and social disparities in mortality, morbidity and expected years lived in disability (DFLE) and with chronic illness (chrDFLE). We provide empirical evidence of shifting trends for these measures. We then decompose these changes into contributions associated with disability, chronic illness and mortality. Finally, we estimate the size of education differentials in DFLE and chrDFLE and evaluate the magnitude and direction of changes of these differentials over time. Results: While the disability based indicator suggests a decrease of expected years without disability for both men and women (expansion of morbidity), the morbidity based indicator shows an increase in time spend free of chronic disease for women but a slight decrease for men. The decrease in time spent without disability was observed for all education groups but is particularly marked for those with low education.Conclusion: We find evidence of an expansion of morbidity in Spain between 2008 and 2017. The bulk of this development is related to increases in time spent with functional limitations over this period. These patterns occur in conjuncture with growing social disparities in time spend with chronic illness or disability.Peer reviewe