Researchers at the University of Pretoria Institute for Sustainable Malaria Control (UP ISMC) with chemical engineers at the university’s Institute of Applied Materials (IAM) have developed insecticide-impregnated wall linings.   Using wall linings for mosquito control reduces health risks because sprayed insecticides used in the indoor residual spraying (IRS) programme coat dust particles, leading to certain human exposure through contaminated dust on furniture, on floors and in the air. This dust can also contaminate food and water in sprayed homes.  

Impregnated with the insecticides deltamethrin and alpha-cypermethrin the polyethene wall lining is proving successful in protecting homes from mozzies. "Traditionally DDT has been used to combat mosquitos but this is known to have a detrimental effect on our health," advises UP ISMC Director Prof Tiaan de Jager. “Although some toxicity to humans exists with the wall-lining, it’s far less than the current solution.” To limit human contact, linings are installed out of reach of children, and families are instructed not to touch the material.

UP ISMC initiated a six-month pilot study in non-IRS programme communities within malaria hotspot Vhembe, Limpopo to see whether the linings were acceptable to the community. The response has been incredibly positive with researchers deciding to leave the linings in the homes of participants to test long-term efficacy. “These linings have now been in-field for four years," says Prof de Jager.  

The product has been tested further under laboratory conditions. Researchers have found that the linings remain close to 100% effective in killing mosquitoes, even after four years. Specifically, mosquitoes are knocked down within 30 minutes of contact with the lining and die within 24 hours. Importantly, the lining remains well above the World Health Organisation (WHO) recommended minimum effectiveness for internal wall linings. Reports from communities corroborate these results, as community members reported less overall biting and annoyance.  

UP ISMC has commercial and manufacturing partners for further development of this innovative malaria control technology. Working with Huhtamaki to make the light-weight netting and Avima t,o produce and supply the insecticides, the partnerships will see UP ISMC develop and bring the impregnated mesh technology to market.  

Community buy-in

The feedback from community members who participated in the study and have now taken possession of their wall linings. “Those who have moved house have asked if we can move the linings from their original position because it is so effective”, adds Dr Taneshka Kruger, senior project coordinator at the UP ISMC. "Community members have also indicated that if the linings were commercially available and not expensive, they would consider buying and using them."  

Moving ahead

Dr Kruger says the next steps will be: To conduct phase two field trials using test buildings where mosquitoes that die through contact with the lining will be accurately counted To improve how linings are fastened to the walls, and To look at alternative insecticides, especially WHO-approved insecticides.   “The wall linings are going to remain in the huts and the houses for as long as the people want them there and we hope that phase two will start as soon as possible,” closes Prof de Jager.

In the struggle to control malaria, researchers at the University of Pretoria Institute for Sustainable Malaria Control  (UP ISMC) have turned to satellite data to get a heads-up on malaria outbreaks and smartphone apps to control and monitor the disease.  

Technology implemented in the air and on the ground form part of a transdisciplinary solution to the prevalence of malaria in South Africa.  

Satellites to map at-risk areas and predict outbreaks

Up in the air, satellites are being used to predict malaria outbreaks using geographic information systems (GIS) and advanced satellite imaging to identify the environmental factors that allow malaria-spreading mosquitos to breed and thrive.   And armed with this information, outbreaks can be predicted with incredible accuracy. “Using remote sensing as part of an early-warning system for outbreaks, we can forecast malaria occurrences from three to six months in the future,” adds UP ISMC doctorate student Abiodun Morakinyo Adeola. “Our predictions using his model have been correct nine out of 10 times in all five Mpumalanga communities which formed part of the study.” This level of accuracy is on par with the World Health Organisation’s standards. Find out more here.  

Apps to control and monitor malaria

mSpray focusses on malaria control data management for the annual indoor residual spraying (IRS) programme. And was developed at the University of California Berkeley (UCB) with input from researchers at the UP ISMC; specifically Prof Riana Bornman,.  

And the Malaria Buddy app provides information on malaria risk, prevention and symptoms for travellers in malaria endemic areas.  

The indoor residual spraying (IRS) programme is the current preferred method for malaria control in at-risk areas. And, until recently there was no centralised digital database to ensure that spraying was effective, regular and safe. “Previously, the spray workers would go into homes, spray the walls and fill in cards,” says Prof Tiaan de Jager, director of the UP ISMC. “Come the next malaria season, they would go back and spray, but there was no clear database recording what substance was use, where was sprayed or when.”  

mSpray works by allowing spray workers to record information about pesticides sprayed, the number of structures sprayed, concentrations and application procedures - all on their cell phone. This technology reduces the time needed to record or access data and ensures a safer and more effi cient IRS programme.    

Launched in early 2016, Malaria Buddy made in collaboration with Travel With Flair is available for Android and iOS and assists travellers to malaria-endemic areas with information on risk, prevention and symptoms. The UP ISMC team and Travel with Flair are currently designing an updated version to include GPS technology to direct users to the nearest healthcare centre if symptoms are detected.   Prof de Jager is enthusiastic about using mobile technology to combat malaria saying, "We should continue to use cell phone technology as it is much more efficient than manual means to control malaria." 

The University of Pretoria Institute for Sustainable Malaria Control believes that by using a transdisciplinary approach and by focusing on all three parts of malaria; vector, parasite and human health; it's possible to eliminate malaria from South Africa by 2018.  

According to the World health Organisation (WHO) 438,000 people in 2015 died from malaria worldwide with 90% of those deaths occurring in Africa. But progress is being made to decrease this statistic. Comparing deaths from malaria in 2015 to 2000, there was a drop of 48% (839,000 deaths in 2000). "There's been substantial progress towards the World Health Assembly target of reducing the malaria burden by 75% by 2015, but we still have a long way to go,” remarks UP ISMC Director Prof Tiaan de Jager. “Which is why our team have devised a transdisciplinary approach to combat the disease.” 

Indoor residual spraying (IRS), the spraying of the insecticide DDT within traditional homes has added to the reduction of malaria. But it is known to cause environmental problems and damage human health. "Vhembe in Limpopo is a malaria hotspot and is where we carried out our research," adds Prof de Jager. “Despite the use of DDT, malaria remains a constant problem in the area due to ineffective control in neighbouring Zimbabwe. So we need to design an innovative solution to reach our goal to stop Malaria in our borders."  

The solution

The UP ISMC team focus on malaria-related research and has created a transdisciplinary approach of which some place emphasis on the communities in Vhembe, Limpopo  due to its hotspot status. Some of its researchers work within communities to understand their needs and to pilot new technologies and solutions for the challenge of malaria control in South Africa. Although there’s a  broad range of projects at the Institute, three stand out as examples of the transdisciplinary, innovative and inclusive research pioneered by the UP ISMC.  

Insecticidal wall linings

The Institute has developed wall linings impregnated with insecticide, and tested them in Vhembe District, Limpopo. And the communities approved of the intervention and based on laboratory tests remain an effective way to control mosquito numbers and limit transmission of malaria after four years. Read more.  

Apps for malaria control

Another project is using a smartphone app known as mSpray to track and record the details of the IRS programme in the Vhembe area. “The app will help limit the toxic effects of DDT on human populations and reduce the time and effort spent monitoring IRSprogrammes,” adds Prof de Jager. Malaria Buddy is another app developed at the UP ISMC through collaboration with a commercial partner, which provides malaria risk and symptom information for travellers in malaria regions. Read more.  

Understanding the effects of DDT

Another critical project is the research into the effects of DDT and other insecticides on fertility, congenital disabilities and childhood brain development. Researchers studied, amongst other, mothers and their infants to understand how a mother’s exposure to insecticides impacts their child. It is well-known that DDT and similar chemicals can cause health problems, but this research allows a deeper understanding to limit the health impact of IRS. Read more.  

Satellite surveillance to control malaria

Malaria-spreading mosquitoes have a particular set of environmental factors that need to be just right for them to thrive. UP ISMC doctoral student Mr Abiodun Morakinyo Adeola, has combined this knowledge with satellite data to predict malaria outbreaks and to identify most at-risk areas and populations. Read more.

Video: https://youtu.be/L3M04umMzd8  

Infographic: http://www.researchmatters.up.ac.za/cake-gallery/img/uploads/1477719189_294799.png

Research by the University of Pretoria Institute for Sustainable Malaria Control  (UP ISMC) has discovered that conventional methods for controlling malaria (DDT and other common insecticides) leads to endocrine disruption, which means that it interferes with hormones in the human body.  

Worldwide, the use of dichlorodiphenyltrichloroethane, of DDT is controversial. “DDT is known to potentially cause health problems, but the exact effects of indoor residual spraying (IRS) were previously unknown,” explains director of the UP ISMC, Prof Tiaan de Jager. IRS is a programme to spray homes in South African malaria hotspots with insecticides to limit the transmission of the disease.  

An important focus area for the UP ISMC was to understand the developmental effects of constant exposure to insecticides. Its most recent research focused on 750 mothers and babies in Vhembe, Limpopo. The purpose of this study is to understand the effects of DDT exposure on children including birth difficulties, thyroid levels, and neurodevelopment during the first two years of life.    

“There have been reports of poor reproductive health in the Vhembe area, which is why we chose this region and its community for our research," adds Prof de Jager. In other similar research on new mothers and their babies, researchers found that DDT exposure leads to endocrine disruption. "This means DDT chemicals interfere with human hormones. And as a result, individuals experience a decrease in retinol binding protein, limiting vitamin A uptake with an effect on nutritional status," advises Prof de Jager.  

In addition to these effects, research uncovered that high concentrations of environmental DDT impacts semen quality in young men, reducing fertility and leading to congenital disabilities. “Our researchers found that boys whose mothers were exposed to DDT spraying, showed a high rate of defects of the reproductive system,” adds Prof de Jager.  

Another significant finding from yet another study in the area is that DDT and dichlorodiphenyldichloroethylene (DDE, a DDT breakdown product) levels in dust are an accurate measure of insecticide exposure in people who live in IRS areas. This knowledge will make future studies of DDT exposure simpler.   

“We acknowledge that we are still dependent on the use of DDT and other pesticides, but we need to communicate, educate and make people aware of the potential risk,” advises Prof de Jager. “The use of DDT and other insecticides has contributed immensely to controlling malaria in South Africa. And after an alarmingly sharp rise in 2000, the incidence of malaria has significantly decreased due to a more efficient use of DDT and better access to anti-malarial drugs.”  

Advice People living in malaria regions where an IRS programme is used should allow spray workers to do their job. However, we recommend people ensure all food is covered safely or removed, close open water containers, pack clothing away and wait outside while spraying occurs.  Post-spraying, try and ventilate the home. 

Video: https://youtu.be/L3M04umMzd8  

Infographic: http://www.researchmatters.up.ac.za/cake-gallery/img/uploads/1477719189_294799.png