Latest News Archive

Please select Category, Year, and then Month to display items
Previous Archive
05 September 2022 | Story Andrè Damons | Photo Andrè Damons
Prof Abdon Atangana
Prof Abdon Atangana, Professor of Applied Mathematics in the Institute for Groundwater Studies (IGS) and a highly cited mathematician for the years 2019-2021, says existing mathematical models are used to first fit collected data and then predict future events. It is for this reason he introduced a new concept that can be used to test whether the spread will have one or several waves.

With a new outbreak of the Ebola Virus Disease (EVD) reported this year in Democratic Republic of the Congo (DRC) – the 14th EVD outbreak in the country – researchers at the University of the Free State (UFS) introduced a new concept that can be used to test whether the spread will have one or several waves. They believe the focus should be to identify the source or the hosts of this virus for it to be a complete eradication. 

According to the Centers for Disease Control and Prevention (CDC), the Ministry of Health in the Democratic Republic of the Congo (DRC) declared an outbreak of Ebola in Mbandaka health zone, Equateur Province on April 23, 2022. EVD, formerly known as Ebola haemorrhagic fever, is a severe, often fatal illness affecting humans and other primates. The virus is transmitted to people from wild animals (such as fruit bats, porcupines and non-human primates) and then spreads in the human population through direct contact with the blood, secretions, organs or other bodily fluids of infected people, and with surfaces and materials (e.g. bedding, clothing) contaminated with these fluids, according to the World Health Organisation (WHO).
 
Prof Abdon Atangana, Professor of Applied Mathematics in the Institute for Groundwater Studies (IGS), says existing mathematical models are used to first fit collected data and then predict future events. Predictions help lawmakers to take decisions that will help protect their citizens and their environments. The outbreaks of COVID-19 and other infectious diseases have exposed the weakness of these models as they failed to predict the number of waves and in several instances; they failed to predict accurately day-to-day new infections, daily deaths and recoveries.

Solving the challenges of the current models

In the case of COVID-19 in South Africa, it is predicted that the country had far more infections than what was recorded, which is due to challenges faced by the medical facilities, poverty, inequality, and other factors. With Ebola in the DRC, data recorded are not far from reality due to the nature of the virus and its symptoms. However, the predictions show although some measures have been put in place in DRC and other places where the Ebola virus spread, they will still face some challenges in the future, as the virus will continue to spread but may have less impact. 

“To solve the challenges with the current models, we suggested a new methodology. We suggested that each class should be divided into two subclasses (Detected and undetected) and we also suggested that rates of infection, recovery, death and vaccination classes should be a function of time not constant as suggested previously. These rates are obtained from what we called daily indicator functions. For example, an infection rate should be obtained from recorded data with the addition of an uncertain function that represents non-recorded data (Here more work is still to be done to get a better approximation).

“I introduced a new concept called strength number that can be used to test whether the spread will have one or several waves. The strength number is an accelerative force that helps to provide speed changes, thus if this number is less than zero we have deceleration, meaning there will be a decline in the number of infections. If the number is positive, we have acceleration, meaning we will have an increase in numbers. If the number is zero, the current situation will remain the same,” according to Prof Atangana. 

To provide better prediction, he continues, reliable data are first fitted with the suggested mathematical model. This helps them to know if their mathematical model is replicating the dynamic process of the spread. The next step is to predict future events, to do this, we create three sub-daily indicator functions (minimum, actual, and maximum). These will lead to three systems, the first system represents the worst-case scenario, the second is the actual scenario, and the last is a best-case scenario.

Virus will continue to spread but with less impact

Using this method, Prof Atangana, a highly cited mathematician for the years 2019-2021, says he and Dr Seda Igret Araz, postdoctoral student, were able to predict that, although some measures have been put in place in DRC and other places where the Ebola virus spreads, they will still face some challenges in the future as the virus will continue to spread but may have less impact. 

To properly achieve the conversion from observed facts into mathematical formulations and to address these limitations, he had to ask fundamental questions such as what is the rate of infection, what is the strength of the infection, what are the crossover patterns presented by the spread, how can day-to-day new infected numbers be predicted and what differential operator should be used to model a dynamic process followed by the spread?

This approach was tested for several infectious diseases where we present the case of Ebola in Congo and Covid-19 in South Africa.  

News Archive

Research into veld fires in grassland can now help with scientifically-grounded evidence
2015-04-10

While cattle and game farmers are rejoicing in the recent rains which large areas of the country received in the past growing season, an expert from the University of the Free State’s Department of Animal, Wildlife, and Grassland Sciences, says that much of the highly inflammable material now available could lead to large-scale veld fires this coming winter.

Prof Hennie Snyman, professor and  researcher in the Department of Animal, Wildlife, and Grassland Sciences, warns that cattle and game farmers should be aware, in good time, of this problem which is about to rear its head. He proposes that farmers must burn firebreaks as a precaution.

At present, Prof Snyman focuses his research on the impact of fire and burning on the functioning of the grassland ecosystem, especially in the drier grassland regions.

He says the impact of fire on the functioning of ecosystems in the ‘sour’ grassland areas of Southern Africa (which includes Kwazulu-Natal, Limpopo, Mpumalanga, the Eastern Cape, and the Harrismith environs) is already well established, but less information  is available for ‘sweet’ semi-arid grassland areas. According to Prof Snyman, there is no reason to burn grassland in this semi-arid area. Grazing by animals can be effectively used because of the high quality material without having to burn it off. In the sourer pasturage, fire may well form part of the functioning of the grassland ecosystem in view of the fact that a quality problem might develop after which the grass must rejuvenate by letting it burn.

Prof Snyman, who has already been busy with the research for ten years, says quantified data on the impact of fire on the soil and plants were not available previously for the semi-arid grassland areas. Fires start frequently because of lightning, carelessness, freak accidents, or damaged power lines, and farmers must be recompensed for this damage.

The shortage of proper research on the impact of fires on soil and plants has led to burnt areas not being withdrawn from grazing for long enough. The lack of information has also led to farmers, who have lost grazing to fires, not being compensated fairly or even being over-compensated.

“When above-and below-ground plant production, together with efficient water usage, is taken into account, burnt grassland requires at least two full growing seasons to recover completely.”       

Prof Snyman says farmers frequently make the mistake of allowing animals to graze on burnt grassland as soon as it begins to sprout, causing considerable damage to the plants.

“Plant roots are more sensitive to fire than the above-ground plant material. This is the reason why seasonal above-ground production losses from fire in the first growing season after the fire can amount to half of the unburnt veld. The ecosystem must first recover completely in order to be productive and sustainable again for the long term. The faster burnt veld is grazed again, the longer the ecosystem takes to recover completely, lengthening the problem with fodder shortages further.  

Prof Snyman feels that fire as a management tool in semi-arid grassland is questionable if there is no specific purpose for it, as it can increase ecological and financial risk management in the short term.

Prof Snyman says more research is needed to quantify the impact of runaway fires on both grassland plant productivity and soil properties in terms of different seasonal climatic variations.

“The current information may already serve as valuable guidelines regarding claims arising from unforeseen fires, which often amount to thousands of rand, and are sometimes based on unscientific evidence.”

Prof Snyman’s research findings have been used successfully as guidelines for compensation aspects in several court cases.

 

We use cookies to make interactions with our websites and services easy and meaningful. To better understand how they are used, read more about the UFS cookie policy. By continuing to use this site you are giving us your consent to do this.

Accept