Fungicide Resistance: A Growing Threat to Humans, Animals, and Plants
Fungi are not only a nuisance but can also cause serious diseases in humans, animals, and plants. In fact, fungal infections claim the lives of 1.5 million people every year, and they also pose a threat to food production by attacking crops. To combat these harmful fungi, we have developed chemical agents known as azoles, which are highly effective in killing them.
However, the frequent use of azoles is causing researchers to worry about the development of resistance. Antibiotic resistance is a well-known issue, but fungicide resistance is a topic that has received less attention. The World Health Organization (WHO) has identified the fungus Aspergillus fumigatus as a potential health threat in the future. While this fungus is generally harmless to healthy individuals, it can cause serious infections in people with compromised immune systems. In such cases, azoles are the go-to treatment, making it crucial that they remain effective.
“A. fumigatus that is resistant to azoles is an increasing global problem,” warns Ida Skaar, a senior researcher at the Norwegian Veterinary Institute. With the expected rise in temperature and humidity due to climate change, the problem is only expected to worsen. Therefore, it is essential to gather knowledge about the situation in Norway before it becomes too serious.
Skaar leads a project called NavAzole, which aims to map and understand the development of azole resistance in Norway. This knowledge is crucial for making informed decisions and keeping resistance levels as low as possible. The project takes a One Health perspective, recognizing the interconnectedness of human health, animal health, and the environment. It investigates various application areas of azoles and identifies hotspots for resistance development and spread.
One potential hotspot for resistance development is the use of azole-based pesticides in agriculture. Andrea Ficke, a researcher from the Norwegian Institute of Bioeconomy Research (NIBIO), explains that A. fumigatus is a soil-dwelling fungus that exists in cereal fields. When these fields are sprayed with azole-based fungicides, some of the fungicides end up in the soil and can affect A. fumigatus. Similar to the overuse of antibiotics leading to bacterial resistance, regular exposure to azoles can lead to resistance in A. fumigatus.
The researchers aim to investigate whether resistant A. fumigatus can be found in cereal fields sprayed with azole-based fungicides and whether there is a correlation between resistance development in plant pathogenic fungi and A. fumigatus. Leaf blotch diseases in cereals, such as septoria leaf blotch and septoria nodorum blotch, will be studied as they can cause significant crop losses.
While Ficke has not observed a worrying increase in resistance to fungicides in her 10-12 years of research, both she and Skaar emphasize the importance of preventive measures. Norway has been fortunate to have minimal problems with fungicide resistance in crops, but neighboring countries like Denmark face more serious situations. Therefore, it is crucial to understand the extent of the problem in Norway and implement measures to reduce resistance development.
Integrated pest management (IPM) plays a vital role in reducing unnecessary fungicide use. Just as Norway excels at avoiding unnecessary antibiotic use, equal attention should be given to avoiding unnecessary fungicide use. Once resistance becomes established, it is challenging to eradicate. Therefore, proactive measures are essential.
Fungi develop resistance through genetic variation and random mutations in their DNA. Some individuals may be more tolerant to fungicides, allowing them to survive and reproduce. Over time, the repeated use of the same fungicide selects for increasingly resistant fungi. It is important to avoid one-sided use of fungicides with the same mode of action and to implement IPM strategies in plant production to minimize the need for fungicides.
In conclusion, fungicide resistance is a growing threat to humans, animals, and plants. The frequent use of azoles has raised concerns about the development of resistance, particularly in the fungus A. fumigatus. The NavAzole project in Norway aims to map and understand resistance development to make informed decisions and implement preventive measures. Integrated pest management and responsible fungicide use are crucial in combating resistance and preserving the effectiveness of azoles. By taking a proactive approach, we can mitigate the risks associated with fungicide resistance and protect our health and food production.
