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10 December 2018 | Story Leonie Bolleurs | Photo Leonie Bolleurs
One step closer to treat HIV/Aids
Nthabiseng Mokoena is working on an article based on her research about drug development in infection models, which will be published under the Research Chair in Pathogenic Yeasts.

South Africa has the biggest and most high-profile HIV epidemic in the world, with an estimated seven million people living with HIV in 2015. In the same year, there were 380 000 new infections while 180 000 South Africans died from AIDS-related illnesses. 

Invasive fungal infection, common in certain groups of patients with immune deficits, is a serious driver of global mortality in the context of the global HIV pandemic. 

“Despite a major scientific effort to find new cures and vaccines for HIV, hundreds of thousands of HIV-infected individuals continue to die on a yearly basis from secondary fungal infection. Intensive research needs to be done to help reduce the unacceptably high mortality rate due to the infection in South Africa,” said Nthabiseng Mokoena.

Mokoena is a master’s student of Prof Carlien Pohl-Albertyn, who is heading the Research Chair in Pathogenic Yeasts in the Department of Microbial, Biochemical and Food Biotechnology at the University of the Free State (UFS). 

She received her master’s degree at the December graduations of the UFS. Her thesis is titled: Caenorhabditis elegans as a model for Candida albicans-Pseudomonas aeruginosa co-infection and infection induced prostaglandin production.

Research Chair in Pathogenic Yeasts

Earlier this year, the National Research Foundation approved the Research Chair in Pathogenic Yeasts. One of the projects of the group of scientists in this chair include a study of the interaction between the yeast, Candida albicans and the bacterium, Pseudomonas aeruginosa in different hosts, using a variety of infection models.

In her research, Mokoena studied the response of infectious pathogens such as yeasts and bacteria, using a nematode (little roundworm) as an infection model to mimic the host environment. Nematodes have a number of traits similar to humans. It is thus a good alternative for humans as infection models, as it is unethical to use the latter.

Nematodes have a number of advantages, including its low cost and fast reproduction and growth. 

Mokoena monitored the survival of the nematodes to see how infectious the pathogens are, especially in combination with each other. 

Role of infection model for drug development

When these two pathogens were studied in a lab (in vitro), it was found that they can inhibit each other, but after studying them in the infection model (in vivo), Mokoena showed that these pathogens are more destructive together. 

This finding has a huge impact for the pharmaceutical industry, as it can provide information on how drugs need to be designed in order to fight infectious diseases where multiple organisms cause co-infections.

Many pathogens are resistant to drugs. Through this model, drugs can be tested in a space similar to the human body. Seeing how pathogens react to drugs within a space similar to the human body, can contribute to drug development. 

Not only are drugs developed more effectively through this model, it is also less expensive. 

It is the first time that the combination of the yeast, Candida albicans and the bacterium, Pseudomonas aeruginosa, is being experimented on in this model. 

News Archive

Fight against Ebola virus requires more research
2014-10-22

 

Dr Abdon Atangana
Photo: Ifa Tshishonge
Dr Abdon Atangana, a postdoctoral researcher in the Institute for Groundwater Studies at the University of the Free State (UFS), wrote an article related to the Ebola virus: Modelling the Ebola haemorrhagic fever with the beta-derivative: Deathly infection disease in West African countries.

“The filoviruses belong to a virus family named filoviridae. This virus can cause unembellished haemorrhagic fever in humans and nonhuman monkeys. In literature, only two members of this virus family have been mentioned, namely the Marburg virus and the Ebola virus. However, so far only five species of the Ebola virus have been identified, including:  Ivory Coast, Sudan, Zaire, Reston and Bundibugyo.

“Among these families, the Ebola virus is the only member of the Zaire Ebola virus species and also the most dangerous, being responsible for the largest number of outbreaks.

“Ebola is an unusual, but fatal virus that causes bleeding inside and outside the body. As the virus spreads through the body, it damages the immune system and organs. Ultimately, it causes the blood-clotting levels in cells to drop. This leads to severe, uncontrollable bleeding.

Since all physical problems can be modelled via mathematical equation, Dr Atangana aimed in his research (the paper was published in BioMed Research International with impact factor 2.701) to analyse the spread of this deadly disease using mathematical equations. We shall propose a model underpinning the spread of this disease in a given Sub-Saharan African country,” he said.

The mathematical equations are used to predict the future behaviour of the disease, especially the spread of the disease among the targeted population. These mathematical equations are called differential equation and are only using the concept of rate of change over time.

However, there is several definitions for derivative, and the choice of the derivative used for such a model is very important, because the more accurate the model, the better results will be obtained.  The classical derivative describes the change of rate, but it is an approximation of the real velocity of the object under study. The beta derivative is the modification of the classical derivative that takes into account the time scale and also has a new parameter that can be considered as the fractional order.  

“I have used the beta derivative to model the spread of the fatal disease called Ebola, which has killed many people in the West African countries, including Nigeria, Sierra Leone, Guinea and Liberia, since December 2013,” he said.

The constructed mathematical equations were called Atangana’s Beta Ebola System of Equations (ABESE). “We did the investigation of the stable endemic points and presented the Eigen-Values using the Jacobian method. The homotopy decomposition method was used to solve the resulted system of equations. The convergence of the method was presented and some numerical simulations were done for different values of beta.

“The simulations showed that our model is more realistic for all betas less than 0.5.  The model revealed that, if there were no recovery precaution for a given population in a West African country, the entire population of that country would all die in a very short period of time, even if the total number of the infected population is very small.  In simple terms, the prediction revealed a fast spread of the virus among the targeted population. These results can be used to educate and inform people about the rapid spread of the deadly disease,” he said.

The spread of Ebola among people only occurs through direct contact with the blood or body fluids of a person after symptoms have developed. Body fluid that may contain the Ebola virus includes saliva, mucus, vomit, faeces, sweat, tears, breast milk, urine and semen. Entry points include the nose, mouth, eyes, open wounds, cuts and abrasions. Note should be taken that contact with objects contaminated by the virus, particularly needles and syringes, may also transmit the infection.

“Based on the predictions in this paper, we are calling on more research regarding this disease; in particular, we are calling on researchers to pay attention to finding an efficient cure or more effective prevention, to reduce the risk of contamination,” Dr Atangana said.


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