Research@NWU March 2025

From grasses to exotic trees: research project uncovers what causes allergic reactions

asal congestion, sneezing, coughing, rashes and swelling, and even asthma and allergic rhinitis ...

Allergies can seriously affect people's quality of life. Researchers from the NWU are on a mission to not only understand which plants and trees are through their pollen impacting the health of local communities, but also to empower people to effectively manage their allergies.

The research stems from the nationwide initiative called the South African Pollen Monitoring Network (SAPNET, managed by Lung Institute/UCT), which seeks to understand pollen production patterns and reduce exposure to allergy-causing pollens.

The research team comprises Prof Frank Neumann, an aerobiologist and palynologist* and professor in Geology and Soil Science at the Faculty of Natural and Agricultural Sciences; Dr Dorra Gharbi, an aerobiologist, co-principal investigator of the research project and NWU affiliate; and Keneilwe Podile, project administrator and MSc student.

Their participation in the project has already led to one published paper on the subject with another currently under review.

Set to conclude in July this year but with the hope of an extension, the project consists of counting, identifying and monitoring pollen through spore traps, as well as conducting free skin prick tests at the Potchefstroom and Vanderbijlpark campuses together with allergologists, nurses and many student helpers.

These tests, funded by Grand Challenge Canada and the South African Medical Research Council (SAMRC), will continue at the two campuses and are also being expanded to the surrounding communities. The first free skin prick tests for 2025 were done in Sharpeville in January.

The tests have revealed some valuable insights into the types of pollen that affect the various communities.

And the culprits are ...

Exotic trees and grasses are the main culprits causing allergies in the NWU's communities, with one of the worst being ragweed – an invasive weed – also known as Ambrosia, a North American weed.

"Ragweed is causing a problem in the Potchefstroom area especially," explains Prof Neumann. He says ragweed counts reach moderate levels in Potchefstroom but are much higher than in the rest of South Africa. Ragweed is highly allergenic and high occurrences of pollen are prevalent around the Potchefstroom sampling site.

"In the Vanderbijlpark area, which is one of South Africa's most polluted regions, these airborne pollen from alien plants contribute significantly to allergic diseases in the area, along with fungal spores," says Dr Gharbi.

So far, the team has analysed the results of skin prick tests on 138 participants in the Vanderbijlpark area to determine what causes their allergic reactions. More than three quarters of the participants tested positive for at least one aeroallergen.

Grass pollen was the biggest culprit, with Bermuda grass affecting 41,5% of the participants. Ryegrass, maize pollen and a mix of other grasses are also ranked high on the list. Problematic trees included olive, plane and oak.

Additionally, fungal spores such as Alternaria and Cladosporium, which also thrive in polluted environments, triggered reactions in a smaller but still sizeable portion of the participants.

*Palynology is the study of pollen grains and other spores especially as found in archaeological or geological deposits.

*Aerobiology is the study of airborne biological particles, e.g. pollen and spores, and their movement and impact on human health, animal and plant health.

Impactful research will continue after project completion

The researchers say they plan to expand their work by conducting similar tests in diverse communities, particularly in highly polluted townships.

"Allergy awareness campaigns, better urban planning and improved air quality regulations could help mitigate this growing problem," Prof Neumann says.

"The SAMRC and other institutions may play a crucial role in addressing these issues through policy changes and further research."

The NWU researchers hope to make significant contributions in the study of allergies as climate change continues to reshape environments and communities must contend with the consequences of an increasingly allergenic world.

For more information or to participate in the study, contact Keneilwe.

Click here to learn more about the research project.

Watch the video of the skin prick tests for pollen and fungal spores on the Potchefstroom Campus.

From left are Prof Frank Neumann, Dr Dorra Gharbi and Keneilwe Podile.