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14 August 2024 | Story Martinette Brits | Photo Supplied
Dr Luther van der Mescht
Dr Luther van der Mescht, Senior Lecturer in the Department of Zoology and Entomology.

Ticks that feed on South Africa’s cattle are developing resistance to the only effective pesticides, making them increasingly difficult to control. If this issue is not addressed, the spread of these parasites and their resistance to pesticides could significantly impact farmers' incomes and food security.

According to a study by Dr Luther van der Mescht, Senior Lecturer in the Department of Zoology and Entomology, many tick populations in South Africa are resistant to at least two of the three main types of acaricides (chemical classes) used in the country.

Dr Van der Mescht notes that with around 12 million cattle in South Africa, these ticks not only lower meat and milk production but also carry pathogens that can cause potentially fatal diseases. He estimates that the economic losses from tick-borne diseases and the use of acaricides could reach up to R670 million annually in the cattle industry alone.

He adds that South Africa's agricultural sector is unique due to its dual farming system, which includes both subsistence and commercial farmers, amplifying the impact of ticks. “The country is also home to a wide variety of tick species that transmit numerous pathogens across a diverse range of habitats and climates in which cattle are farmed. Consequently, the effects of ticks and tick-borne diseases in South Africa may be more severe compared to those in developed countries.”

Dr Van der Mescht highlights that ticks are developing resistance primarily due to poor farm management practices, such as underdosing, overdosing, and excessive use of acaricides. “Additionally, insufficient government support in educating farmers and managing resistance exacerbates the problem.”

Managing acaricide resistance

Dr Van der Mescht explains that while ticks will inevitably develop resistance to acaricides, this usually happens much slower if pesticides are used strategically. To slow the development of resistance, several measures can be implemented: 

• Minimise the number of acaricide treatments.
• Assess tick diversity and acaricide resistance at the farm level and monitor it regularly. The study found that acaricide resistance was highly variable across South Africa, likely due to different farm management practices; hence it should be assessed at the farm level.
• Quarantine animals when transferring them to a new farm, ensuring they are free of ticks before releasing them.
• Rotate acaricides from different chemical classes, with a gap of at least two years between applications.

• Government veterinary services should raise awareness about acaricide resistance and provide support, particularly to under-resourced farmers. Establishing acaricide resistance testing laboratories would help monitor resistance and offer guidance to farmers.

Expert in parasitology

Dr Van der Mescht is particularly fascinated by the fact that most animals on earth follow a parasitic way of life. He graduated with a PhD in Conservation Ecology from the Department of Conservation Ecology and Entomology at Stellenbosch University in 2015, focusing on rodent parasites.

Career highlights include receiving the Wilhelm Neitz Memorial Scholarship in Parasitology from the Parasitological Society of Southern Africa (PARSA) for study abroad, and the Blaustein Centre for Scientific Cooperation Postdoctoral Fellowship in 2016 from Ben-Gurion University of the Negev, Israel, to conduct research on the experimental evolution of host specialisation. He also received the Claude Leon Foundation Postdoctoral Fellowship in 2019 to study the cat flea at Stellenbosch University’s Department of Botany and Zoology.

With over four years of experience in the industry at a contract research organisation, he has conducted more than 40 clinical studies for international pharmaceutical companies and published over 50 peer-reviewed scientific articles.

Making research visible, impactful, and relevant to society

Dr Van der Mescht recently published an article for The Conversation and participated in interviews with eNCA, Newzroom Afrika, and Cape Talk to discuss his research. “This effort aligns with the Vision 130 strategy of being a regionally engaged university and supports one of the key pillars of research development at the University of the Free State (UFS), which is to make our research visible, impactful, and relevant to society.”

He also highlighted the significance of popular science, noting that it helps scientists communicate their research to a broader audience, build their professional reputation, enhance their funding opportunities, and improve their research outcomes.

News Archive

NRF grants of millions for Kovsie professors
2013-05-20

 

Prof Martin Ntwaeaborwa (left) and Prof Bennie Viljoen
20 May 2013


Two professors received research grants from the National Research Foundation (NRF). The money will be used for the purchase of equipment to add more value to their research and take the university further in specific research fields.

Prof Martin Ntwaeaborwa from the Department of Physics has received a R10 million award, following a successful application to the National Nanotechnology Equipment Programme (NNEP) of the NRF for a high-resolution field emission scanning electron microscope (SEM) with integrated cathodoluminescence (CL) and energy dispersive X-ray spectrometers (EDS).

Prof Bennie Viljoen from the Department of Microbial, Biochemical and Food Biotechnology has also been awarded R1,171 million, following a successful application to the Research Infrastructure Support Programme (RISP) for the purchase of a LECO CHN628 Series Elemental Analyser with a Sulphur add-on module.

Prof Ntwaeaborwa says the SEM-CL-EDS’ state-of-the art equipment combines three different techniques in one and it is capable of analysing a variety of materials ranging from bulk to individual nanoparticles. This combination is the first of its kind in Africa. This equipment is specifically designed for nanotechnology and can analyse particles as small as 5nm in diameter, a scale which the old tungsten SEM at the Centre of Microscopy cannot achieve.

The equipment will be used to simultaneously analyse the shapes and sizes of submicron particles, chemical composition and cathodoluminescence properties of materials. The SEM-CL-EDS is a multi-user facility and it will be used for multi- and interdisciplinary research involving physics, chemistry, materials science, life sciences and geological sciences. It will be housed at the Centre of Microscopy.
“I have no doubt that this equipment is going to give our university a great leap forward in research in the fields of electron microscopy and cathodoluminescence,” Prof Ntwaeaborwa said.

Prof Viljoen says the analyser is used to determine nitrogen, carbon/nitrogen, and carbon/hydrogen/nitrogen in organic matrices. The instrument utilises a combustion technique and provides a result within 4,5 minutes for all the elements being determined. In addition to the above, the machine also offers a sulphur add-on module which provides sulphur analysis for any element combination. The CHN 628 S module is specifically designed to determine the sulphur content in a wide variety of organic materials such as coal and fuel oils, as well as some inorganic materials such as soil, cement and limestone.

The necessity of environmental protection has stimulated the development of various methods, allowing the determination of different pollutants in the natural environment, including methods for determining inorganic nitrogen ions, carbon and sulphur. Many of the methods used so far have proven insufficiently sensitive, selective or inaccurate. The availability of the LECO analyser in a research programme on environmental pollution/ food security will facilitate accurate and rapid quantification of these elements. Ions in water, waste water, air, food products and other complex matrix samples have become a major problem and studies are showing that these pollutants are likely to cause severe declines in native plant communities and eventually food security.

“With the addition of the analyser, we will be able to identify these polluted areas, including air, water and land pollution, in an attempt to enhance food security,” Viljoen said. “Excess levels of nitrogen and phosphorous wreaking havoc on human health and food security, will be investigated.”

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