Climatic variable selection using random forests regression for malaria transmission modelling in Mpumalanga Province, South Africa.

Master of Science in Environmental science. University of KwaZulu-Natal, Durban 2015.Malaria is one of the wold’s most prevalent vector borne diseases with sub-Saharan Africa bearing the highest burden of reported cases. Climate is one of the major determinant factors of malaria transmission as it influences the spatial and temporal pattern of transmission. It is therefore important to be able to understand the relationship between climatic variables and malaria transmission because an understanding of the interactions between them at a local level is an important part in potential outbreaks, targeting vector control strategies, and developing malaria early warning systems. This study covered the Ehlanzeni district of Mpumalanga province in South Africa. It was aimed at determining the climatic variable importance of temperature, lag temperature, rainfall, lag rainfall, humidity, altitude and NDVI in relation to malaria transmission. The random forest algorithm was used to relate the climatic variables extracted from remote sensing imagery and malaria case data collected from health facilities in order to establish individual measures of variable importance and to develop a spatial and temporal prediction models. In this study altitude appeared to be the most responsible variable for malaria transmission because it was most frequently selected as one of the top variables with the highest variable importance followed by NDVI and temperature. The combination of climatic variables that produced the highest coefficient of determination values was altitude, NDVI, and temperature. This suggests that these 3 variables have high predictive capabilities and as a result they should be selected for spatial and temporal modelling of malaria. Furthermore, it was expected that the predictive models generated by the random forest algorithm could be used as an operational malaria early warning system using forecast climatic variable identified in this study in order to assist in containing any potential reoccurrence of malaria after elimination

A study protocol to determine heat-related health impacts among primary chsoolchildren in South Africa

Abstract:Climate models predict that the global average temperature of Earth will rise in the future. Studies show that high classroom temperatures can affect the ability of the student to learn and function. It is important to understand the impact that heat will have on the health, wellbeing, and academic performance of learners, as they spend a significant amount of time in classrooms compared to any other environment. A follow-up panel study among 20 public primary schools in the Gauteng province (South Africa) will be carried out, in which Grade 4 learners will be selected to complete an hourly heat-health symptom questionnaire. A Cambridge Neuropsychological Test Automated Battery (CANTAB) test will be used to determine their memory and attention span. A nursing practitioner will measure body weight, height, and temperature. Lascar data loggers will beusedtomeasureindoorclassroomtemperature. Schoolprincipalswillcompleteaquestionnaireon existing school coping mechanisms and policies in place that help deal with hot weather conditions. This is the first study to quantitatively assess the effects of heat on learners’ health, well-being and school performance in South Africa. The outcomes of this study will enable policymakers and public officials to develop appropriate school heat adaptation and mitigation measures and will assist in channeling their resources where it is most needed

Gathering the evidence and identifying opportunities for future research in climate, heat and health in South Africa : the role of the South African Medical Research Council

Abstract: Background. A changing climate is likely to have widespread and varying impacts on ecosystems and human health. South Africa (SA) is particularly vulnerable to the impacts of climate change, given the projected increases in temperature, and changes in the amount and patterns of rainfall. Moreover, SA’s vulnerability is exacerbated by extreme inequality and poverty. To prepare for the impacts of climate change and to ensure timeous adaptation, a perspective is given on essential heat and health research in the country. Objectives. To gather studies conducted by the South African Medical Research Council (SAMRC)’s Environment and Health Research Unit (EHRU) to illustrate the range of possible research key areas in the climate, heat and health domain and to present future research priorities. Methods. Studies conducted by the SAMRC’s EHRU were gathered and used to illustrate the range of possible research key areas in the climate, heat and health domain. Using national and international published and grey literature, and tapping into institutional research experiences, an overview of research findings to date and future research priorities were developed. Results. Heat and health-related research has focussed on key settings, for example, schools, homes and outdoor work places, and vulnerable groups such as infants and children, the elderly and people with pre-existing diseases. The need to address basic needs and services provision was emphasised as an important priority. Conclusions. High and low temperatures in SA are already associated with mortality annually; these impacts are likely to increase with a changing climate. Critical cross-sectoral research will aid in understanding and preparing for temperature extremes in SA

Lagged association between climate variables and hospital admissions for pneumonia admissions in South Africa

Pneumonia is a leading cause of hospitalization in South Africa. Climate change could potentially affect its incidence via changes in meteorological conditions. We investigated the delayed effects of temperature and relative humidity on pneumonia hospital admissions at two large public hospitals in Limpopo province, South Africa. Using 4062 pneumonia hospital admission records from 2007 to 2015, a time-varying distributed lag non-linear model was used to estimate temperature-lag and relative humidity-lag pneumonia relationships. Mean temperature, relative humidity and diurnal temperature range were all significantly associated with pneumonia admissions. Cumulatively across the 21-day period, higher mean daily temperature (30 °C relative to 21 °C) was most strongly associated with a decreased rate of hospital admissions (relative rate ratios (RR): 0.34, 95% confidence interval (CI): 0.14–0.82), whereas results were suggestive of lower mean daily temperature (12 °C relative to 21 °C) being associated with an increased rate of admissions (RR: 1.27, 95%CI: 0.75–2.16). Higher relative humidity (>80%) was associated with fewer hospital admissions while low relative humidity (<30%) was associated with increased admissions. A proportion of pneumonia admissions were attributable to changes in meteorological variables, and our results indicate that even small shifts in their distributions (e.g., due to climate change) could lead to substantial changes in their burden. These findings can inform a better understanding of the health implications of climate change and the burden of hospital admissions for pneumonia now and in the future

An analysis of past and future heatwaves based on a heat‑associated mortality threshold : towards a heat health warning system

Additional file 1. Full names of codes used for districts.Additional file 2. Heatwave characteristics from 2014 - 2019 as defined using threshold of 12.8 oC and duration of two days or more.Additional file 3. Heatwave characteristics for period 2020 – 2039 using data simulated from RCP 4.5 projections.Additional file 4. Heatwave characteristics for period 2020 – 2039 using data simulated from RCP 8.5 projections.Heatwaves can have severe impacts on human health extending from illness to mortality. These health effects are related to not only the physical phenomenon of heat itself but other characteristics such as frequency, intensity, and duration of heatwaves. Therefore, understanding heatwave characteristics is a crucial step in the development of heat-health warning systems (HHWS) that could prevent or reduce negative heat-related health outcomes. However, there are no South African studies that have quantified heatwaves with a threshold that incorporated a temperature metric based on a health outcome. To fill this gap, this study aimed to assess the spatial and temporal distribution and frequency of past (2014 – 2019) and future (period 2020 – 2039) heatwaves across South Africa. Heatwaves were defined using a threshold for diurnal temperature range (DTR) that was found to have measurable impacts on mortality. In the current climate, inland provinces experienced fewer heatwaves of longer duration and greater intensity compared to coastal provinces that experienced heatwaves of lower intensity. The highest frequency of heatwaves occurred during the austral summer accounting for a total of 150 events out of 270 from 2014 to 2019. The heatwave definition applied in this study also identified severe heatwaves across the country during late 2015 to early 2016 which was during the strongest El Niño event ever recorded to date. Record-breaking global temperatures were reported during this period; the North West province in South Africa was the worst affected experiencing heatwaves ranging from 12 to 77 days. Future climate analysis showed increasing trends in heatwave events with the greatest increases (80%—87%) expected to occur during summer months. The number of heatwaves occurring in cooler seasons is expected to increase with more events projected from the winter months of July and August, onwards. The findings of this study show that the identification of provinces and towns that experience intense, long-lasting heatwaves is crucial to inform development and implementation of targeted heat-health adaptation strategies. These findings could also guide authorities to prioritise vulnerable population groups such as the elderly and children living in high-risk areas likely to be affected by heatwaves.The South African Medical Research Council.https://ehjournal.biomedcentral.comam2023Geography, Geoinformatics and Meteorolog

Exploring Meteorological Conditions and Human Health Impacts during Two Dust Storm Events in Northern Cape Province, South Africa: Findings and Lessons Learnt

Dust storms are meteorological hazards associated with several adverse health impacts including eye irritations, respiratory and cardiovascular disorders, and vehicular road accidents due to poor visibility. This study investigated relations between admissions from a large, public hospital that serves people living in Northern Cape and Free State provinces, South Africa during 2011 to 2017, and meteorological variables (temperature and air quality) during two dust storms, one in October 2014 (spring) and the second in January 2016 (summer), identified from the media as no repository of such events exists for South Africa. Distributed nonlinear lag analysis and wavelet transform analysis were applied to explore the relationships between hospital admissions for respiratory and cardiovascular diseases, eye irritation, and motor vehicle accidents; maximum temperature, and two air quality ‘proxy measures,’ aerosol optical depth and Ångström exponent, were used as ground-based air quality data were unavailable. Eye irritation was the most common dust-related hospital admission after both dust storm events. No statistically significant changes in admissions of interest occurred at the time of the two dust storm events, using either of the statistical methods. Several lessons were learnt. For this type of study, ground-based air quality and local wind data are required; alternative statistical methods of analysis should be considered; and a central dust storm repository would help analyze more than two events. Future studies in South Africa are needed to develop a baseline for comparison of future dust storm events and their impacts on human health

Socio-economic, infrastructural and health-related risk factors associated with adverse heat-health effects reportedly experienced during hot weather in South Africa

Abstract: Introduction: poor urban communities are likely to bear the brunt of climate change impacts on health and well-being. The City of Johannesburg, South Africa, is predicted to experience an average increase in ambient temperature of 4°C by 2100. Focusing on the urban environment, this study aimed to determine socio-economic, infrastructural and health-related risk factors for heat-related adverse health effects. Methods: this was a crosssectional study. Data of interest were collected using a pretested and validated questionnaire administered to parents of children attending schools participating in a school heat study. Information related to demographic, socio-economic and household-level determinants of health, which has an impact on the individual prevalence of adverse heat-health effects associated with hot weather, was collected for 136 households and 580 individuals. Results: sweating (n = 208 individuals; 35%), headache and nausea (n = 111; 19%) and weakness, fatigue and dizziness (n = 87; 15%) were the most common heat-health effects reportedly experienced by individuals (n = 580) during hot weather. Individuals who suffered from hypertension (OR = 2.32, 95% CI: 1.34 - 4.05, p = 0.003) and individuals older than 60 years (OR = 1.81, 95% CI: 1.27-1.99, p < 0.001) compared to other age groups were more likely to experience 'any heat-health effects'. Living in government-sponsored detached housing and in houses with asbestos roofs were associated with an increase in reported experience of 'any heat-health effects' compared to living in other housing types. Conclusion: heathealth awareness campaigns should target people suffering from pre-existing diseases and the elderly, as these groups are especially vulnerable to heat. Focus should also be given to appropriate roofing and insulation in government-sponsored housing since summertime temperatures are projected to increase

Dwelling characteristics influence indoor temperature and may pose health threats in LMICs

BACKGROUND: Shelter and safe housing is a basic human need that brings about a sense of ownership, selfsufficiency, and citizenship. Millions of people around the world live in inadequate dwellings in unhealthy areas, such as urban slums. These dwellings may experience indoor temperatures that impact inhabitants’ health. Indoor dwelling temperatures vary depending on many factors including geographic location, such as inland versus coastal. In an era of climate change, understanding how dwelling characteristics influence indoor temperature is important, especially in low- and middle-income countries, to protect health. OBJECTIVE: To assess indoor temperature in low-cost dwellings located in a coastal setting in relation to dwelling characteristics. METHODS: Indoor temperature and relative humidity loggers were installed from 1 June 2017 to 15 May 2018 in 50 dwellings in two settlements in a coastal town on the east coast of South Africa. Ambient outdoor temperature data were obtained from the national weather service, indoor temperature data were converted into apparent temperature, and heat index calculations were made to consider possible heat-health risks. A household questionnaire and dwelling observation assessment were administered. A mixed-effects linear regression model was constructed to consider the impact of dwelling characteristics on indoor apparent temperature. FINDINGS: Among 17 dwellings with all data sets, indoor temperatures were consistently higher than, and well correlated (r = 0.92) with outdoor temperatures. Average differences in indoor and outdoor temperatures were about 4°C, with statistically significant differences in percentage difference of indoor/outdoor between seasons (p < 0.001). Heat indices for indoor temperatures were exceeded mostly in summer, thereby posing possible health risks. Dwellings with cement floors were statistically significantly cooler than any other floor type across all seasons. CONCLUSIONS: Low-cost dwellings experienced temperatures indoors higher than outdoor temperatures in part due to floor type. These results help inform interventions that consider housing and human health (n = 289).The South African Medical Research Council (SAMRC), the Nelson Mandela University (NMU) and the National Research Foundation (South Africa).https://www.annalsofglobalhealth.orgpm2020Geography, Geoinformatics and Meteorolog

Bibliometric trends of South African environmental health articles between 1998 and 2015: Making local research visible and retrievable

Background. South Africa (SA) has to grapple with multiple burdens of disease for which environmental factors have a role to play in both causation and prevention. This article describes a bibliometric review of environmental health indexed literature for SA over an 18-year period.Objectives. To provide an overview of the nature of SA-based published environmental health indexed research and to identify search challenges, frequently researched topics, and gaps and opportunities for future research.Methods. The Web of Science, PubMed and Science Direct were used to search for original, peer-reviewed and review articles with the inclusion criteria ‘environmental health’ and ‘South Africa’ available online and published between 1998 and 2015, inclusively.Results. A total of 230 journal articles were included in the bibliometric analysis. The highest number of articles (n=54) was published in 2015. The majority of the first authors were affiliated with SA institutions (n=160, 69.5%). For the articles where funding was explicitly declared (n=148), the three most frequently occurring agencies that funded the published research were the National Research Foundation in SA (n=17), the South African Medical Research Council (n=13) and the Water Research Commission (n=9). There was little inter-annual/environmental health category variation over time owing to the relatively small sample size. The largest number of retrieved journal articles was in the area of environmental pollution control (n=76), followed by environmental health lifestyle and behaviour-related topics (n=42) and then water monitoring (n=26).Conclusions. Despite the research needed to solve large environmental health challenges in SA, environmental health was only used as a keyword in title, author keywords or abstract for 230 SA-based studies over an 18-year period. This makes it extremely difficult for environmental health research to be located and used to inform the profession as well as the research agenda. Several issues that environmental health practitioners are typically tasked to implement and monitor are not indexed as environmental health topics. The need for authors to use ‘environmental health’ as a keyword is emphasised, particularly if research is to inform decision-making and policy support, as well as guide future research in the country