Satellites to aid in the fight against Malaria

The earth is continually orbited and observed by a multitude of satellites. Popular films portray them as watching our every move and sniffing out arch villains from on high. Reality is however far less sinister, as many of these satellites are actually employed in much more humanitarian pursuits. Images obtained via these satellites can for example provide public health experts with a powerful tool for monitoring and predicting the prevalence of some vector borne diseases, particularly in the developing world.

This field is known as tele-epidemiology. Tele-epidemiology involves the study of human and animal diseases that are transmitted by vectors, which are closely linked to climate and the environment, by using space technology. It combines different types of data that includes physical factors such as temperature and humidity, health data and socioeconomic data (that is typically gathered by more traditional means) with remote sensing data – in other words data gathered by scanning the earth by satellite or high-flying aircraft – such as climatological, environmental and land use data. This allows researchers to analyse the relationships that exist between the climate, the environment and animal and human health in a given area and to determine whether there are links between the infectious diseases and the environment in which they develop. The goal of the process is to provide public health professionals with tools such as risk maps and forecasting models that will allow them to monitor and anticipate epidemics and put mechanisms such as early warning systems and prevention programmes in place.

One such vector borne disease that is particularly relevant to South Africa and its neighbouring countries is malaria. Malaria is a complex parasitic disease that is found mostly in tropical areas and transmitted by mosquitoes of the genus Anopheles. According to the record of the World Health Organization (WHO), 207 million malaria cases and 627 000 deaths were reported worldwide during 2012. Ninety per cent of these deaths occurred in sub-Saharan Africa and 77% of the victims were children younger than five years. More than 10% of the South African population live in the country’s three malaria-endemic provinces, namely Limpopo, Mpumalanga and KwaZulu-Natal.

The vectors of malaria (Anopheles mosquitoes) thrive in warm, moist environments and it is feared that the projected levels of global warming may enable parasite carrying mosquitoes to spread over more provinces of South Africa and in the process expose more people to the disease. A good climate-modelling system for malaria is therefore an important tool for providing early warning on possible malaria outbreaks and for studying the potential impacts of future climate change on the disease. Such a system will also give decision makers the time necessary to deploy intervention methods to help prevent large-scale spread of the disease.

Since the tele-epidemiology concept could be a lever to address the malaria epidemics in southern Africa, a bilateral discussion was initiated between the University of Pretoria Centre for Sustainable Malaria Control (UP CSMC) and the French National Centre for Space Studies (CNES) to explore the potential of a joint research programme using remote sensing to help prevent the spread of malaria. This discussion culminated in a workshop co-hosted by the UP CSMC and the French Embassy on 29 and 30 June 2015. The workshop was attended by scientists from various French research institutions such as CNES, the IRD’s UMR Espace pour le Développement (ESPACE-DEV), the Laboratoire d’Aérologie of the Midi-Pyrénées Observatoire, as well as South African partners such as the South African National Space Agency (SANSA) and the Medical Research Council (MRC). The Manager of the Limpopo Province Malaria Control Programme and delegates from the National Department of Health and the World Health Organisation (WHO) also contributed to the discussions. Other delegates included representatives from the universities of Zimbabwe, Mozambique and Reunion, as well as the Pasteur Institute of Madagascar. The objectives of the workshop were to draw the key players of the planned programme together in order to identify suitable partners for collaboration, to define the boundaries of the research programme and to explore funding opportunities. The proposed collaborative programme is currently known as the ‘Remote sensing for malaria control in Africa’ programme, or ReSMaCA.

It is envisioned that research activities between the UP CSMC and their French partners will focus on the expansion of predictive malaria-risk maps to investigate the impacts of climate variability and changes on the occurrence and intensity of malaria epidemics. Some of these research partners already have similar programmes in place in other African countries.

CNES for example has applied a tele-epidemiological conceptual approach to monitor Rift Valley fever (RVF) in Senegal. RVF is a viral disease found essentially in Africa and is – like malaria – spread by mosquitoes. The disease causes very serious economic losses in livestock in the Sahelian region of Senegal annually and could potentially also infect humans. The work done on the project to date has linked the abundance of RVF vectors to the dynamics of ponds in the area, including their associated vegetation cover and turbidity degree. Turbidity is a measure of the degree to which the water loses its transparency owing to the presence of suspended particulates. The more total suspended solids in the water, the murkier it seems and the higher the turbidity. The ponds’ dynamics in turn, is associated with the spatio-temporal variability of rainfall events. One of the project’s successes to date include a brand-new index for the detection of small and temporary ponds. The index was set up using high-spatial SPOT-5 satellite images and the coupling of in-situ measurements and remote-sensing derived products in order to model dynamic zones potentially occupied by mosquitoes (ZPOM). This combines mechanisms linking rainfall variability, the dynamics of ponds and the density of aggressive vectors.

ESPACE-DEV in turn has a malaria project in the Comoros that aims to characterise the spatio-temporal dynamics of malaria, as well as the ecological and social patterns of the disease. Some of the objectives of the project are to build environmental knowledge through remote sensing; to build a spatial database (geo-catalogue) that will be usable by the Ministry of Health; to identify inequalities in the health system by conducting surveys; to determine the possible impact of control actions; and to model the occurrence of malaria in the Comoros statistically. Similarly, the Pasteur Institute of Madagascar’s malaria project on Madagascar uses remote sensing data to map the persistent abnormal malaria situation on the island. The data they have accumulated to date have enabled them to develop – in collaboration with US AID and ESPACE-DEV – a web based Malaria Early Warning System using mobile phones to collect real-time data from the field.

The lessons learnt by UP’s potential partners in projects like the ones mentioned above that have been underway for a while, could prove immensely valuable in making the proposed ReSMaCA programme a success as well.

In addition to the many international partners that will potentially collaborate on the programme, the UP CSMC will also collaborate with various partners at UP such as the Unit for Geo-information and Mapping (UGM) of the Department of Geography, Geo-informatics and Meteorology (GGM). The Unit hosts a variety of geospatial datasets and (as representative of UP) also has a Distribution of Spatial Information Agreement with the City of Tshwane. The Department’s Laboratory for Atmospheric Studies (LAS), which was launched with support from Eskom and Sasol earlier this year, was also suggested as a collaborative partner for the programme, as the atmospheric modelling undertaken by the Laboratory could provide more detail on the spatial (and temporal) distribution of climates related to malaria outbreaks, while climatic models generated at LAS could serve as an early warning instrument to assist in malaria risk management, for example in relation to weather prediction, seasonal outlooks and climate change projections.

Prof Tiaan de Jager, Director of the UP CSMC, says that innovative methods, available technologies and a creative approach can assist the University of Pretoria to address some of the serious cross-border issues that currently threaten the malaria elimination targets set by the South African government. As a Collaborating Centre of the Medical Research Council (MRC), the UP CSMC is excited about the new partnership with the French institutions and looking forward to combat malaria, using space technologies.

Prof Tiaan de Jager

July 13, 2015

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Researchers

Professor Tiaan de Jager

Professor Tiaan de Jager is serving his second term as Dean of the Faculty of Health Sciences at the University of Pretoria (UP). He is a professor in Environmental Health at UP’s School of Health Systems and Public Health (SHSPH) and holds an Extraordinary Professorship in the section Andrology at the University’s Department of Urology, School of Medicine.

Prof De Jager, who completed his undergraduate studies at Free State University, says his research interest was piqued in 1993 when he became a medical natural scientist at UP’s Department of Urology in the Faculty of Health Sciences and its academic partner Steve Biko Academic Hospital. His research career officially kicked off when he enrolled for a PhD in Reproductive Biology at UP in 1995.

He is doing research at the University because it is a leading research institution that is not only graduating the leaders of tomorrow but has as its vision the creation of new knowledge with the aim of making a difference locally and globally. Prof De Jager says he is proud to be part of this visionary institution and fortunate to be able to lead and conduct research within this framework. “We focus our activities and contribution to making an impact on society above all else,” he says. “It is important to me that we graduate students who are not only good at their jobs and well educated, but who also understand that they have a responsibility to be life-changers and that they need to impact society and contribute positively to change in Africa.”

The attainment of the 2030 Agenda for Sustainable Development Goals (SDGs) is a common thread throughout Prof De Jager’s research, which places a specific focus on SDG 3 (Good Health and Well-being). “My primary research focus is on male reproductive health, specifically related to environmental health and toxicology,” he explains. “I investigate the effects of environmental endocrine-disrupting chemicals (EDCs), including insecticides used for malaria vector control, such as dichlorodiphenyltrichloroethane (DDT), on male reproductive health.”
The link between male reproductive health and malaria control has resulted in several international research projects that deal with the impact of malaria and associated malaria control on communities where the disease is prevalent, including South Africa, Botswana, Zimbabwe, Mozambique and Malawi. These novel research concepts are fed into safer malaria control strategies, which include drug discovery solutions; policy and regulatory framework intervention; prevention with public health partners; and education and awareness raising.

Prof De Jager is the Director of the UP Institute for Sustainable Malaria Control (UP ISMC), which is a prime example of cross-faculty research. This transdisciplinary institute involves all nine UP faculties as well as the Gordon Institute of Business Science school. The UP ISMC coordinates and promotes collaborative research on safer, more sustainable malaria control and management strategies, generates new knowledge and supports new activities pertaining to safe malaria control in Africa.

“Our interactions and collaborations, however, are not limited to the confines of UP, but includes partners from all spheres,” Prof De Jager says. “This includes communities, government, private industry, and international partners based at research institutions, higher education institutions and science councils.”

As Director of the UP ISMC, Prof De Jager’s main agenda is researching and coordinating efforts to bring about sustained control, eventually leading to the elimination of malaria, starting in South Africa and extending to neighbouring countries like Botswana, Mozambique, Zimbabwe and Malawi.

“Communities affected by malaria need to take responsibility for the control of mosquito vectors and the prevention of bites, while healthcare providers need to take responsibility for early-warning systems and treatment to alert communities to the presence of possible outbreaks,” says Prof De Jager.
Vector control efficacy and malaria treatment services rely on the commitment of and buy-in from provincial and national governments, as poor communities are unable to carry the costs themselves.

In South Africa, malaria is most prevalent in the Vhembe District in Limpopo. Here, malaria control policies rely on indoor residual spraying, using chemicals such as DDT and pyrethroids to control mosquito vectors. “Based on the evidence of the danger that DDT poses to both human (Bornman et al. 2018) and natural ecosystems, we have started developing and exploring alternative methods of control,” Prof De Jager explains. “In the Vhembe District, we have tested indoor polyethylene wall linings impregnated with long-lasting insecticides, with great success (Kruger et al. 2015), and in Botswana and Zimbabwe, we have field-tested the efficacy of microbial larvicides to control mosquito larvae (Mpofu et al. 2016). Both these methods have the potential to be effective if local communities are supported by municipal and provincial agencies based on sound research methodologies.”

The institute has seen several highlights over the past few years, one of the most recent being a breakthrough in 2020 amid the challenges brought on by the COVID-19 pandemic. “We had a breakthrough relating to drug discovery, where we were trying to find compounds to block the parasite interaction,” Prof De Jager explains. “Our research group, under the lead of Prof Lyn-Marie Birkholtz along with local and international partners, focused their research on the parasite and found specific drug compounds that can be effectively used as part of an intervention. This is a major breakthrough in terms of our malaria research.”

Other highlights span a longer period; a few noteworthy examples include the UP ISMC being designated as one of three South African Medical Research Council-collaborating centres for malaria research in the country; the UP ISMC being host to the DSI/NRF SARChI Chair on Sustainable Malaria Control (Prof Birkholtz); and the institute being named winner of the Communication for Outreach and Creating Awareness of SET and Innovation Award at the 2017/2018 NSTF-South32 Awards.

Some of Prof De Jager’s personal research highlights include successfully graduating several postgraduate students. Also, many of his students have won awards at the annual Faculty Research Day where their research projects were presented. His appointment as an expert peer reviewer of the World Health Organisation’s (WHO) ‘Global assessment of the state of the science of endocrine disruptors’ document was another highlight, as was his appointment by the National Minister of Health to the South African Malaria Elimination Committee.

Over the past 18 months, Prof De Jager says he has dedicated his time to further developing and growing the UP ISMC, with the long-term aim of malaria control and elimination. Various experts and role players from UP and government are currently involved. “The UP ISMC is developing safer alternatives for malaria control, including chemical product design/development, which includes WHO Phase II and III Field Trials on new patents for malaria vector control [Prof Walter Focke, Chemical Engineering], health impact/toxicology/health risk [Prof Riana Bornman, SHSPH, who Prof De Jager credits as his research mentor] and integrated vector management/decision tools and policy [Dr Clifford Mutero, SHSPH and Duke University].

“To take this into the future, and using opportunities created by big data sciences, we have introduced an initiative using remote sensing for malaria control (ReSMaCA) in collaboration with the French and South African national space agencies (CNES and SANSA), and national, regional and other international researchers. This approach takes climate change into account when developing early-warning systems for malaria. The programme will focus on environmental and climate issues, and will include vector and parasite control strategies, with a strong focus on cross-border malaria transmission. With funding from the German Research Foundation, we are also working on assessing the controlled release of volatile mosquito repellents from nanostructured polymers to reduce infectious tropical diseases including malaria. These initiatives focus on innovative approaches to malaria elimination in the African region and will involve researchers from developing countries facilitating capacity building and contributing towards the development of the African continent.”

Prof De Jager adds that an international project on malaria insecticides and reproductive health, funded by the Canadian Institutes of Health Research, laid the foundation for projects in Chiapas in Mexico, Quebec City, Canada, and later in Limpopo, further driving his special interest in malaria-related research.

His research agenda will continue to focus on questions related to the SDGs, particularly on EDCs, malaria control and the environment. “My passion is to continue being a life-changer through my contribution to research, making a difference in society and battling for a better life for our vulnerable, poor communities.”

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