An orange yeast species, Rhodotorula taiwanensis, isolated several years ago from a sidewalk in Baltimore, may be the basis for environmental traps that can reduce the transmission of malaria.
This discovery, made by researchers at the Bloomberg School of Public Health at Johns Hopkins University, was published in the journal Proceedings of the National Academy of Sciences. The yeast, due to its smell and sticky properties, attracts and can even hold Anopheles gambiae mosquitoes—the main carrier of malaria in Africa. Malaria remains one of the leading causes of death in the world, resulting in over 600,000 fatal cases in 2024, according to the World Health Organization.
R. taiwanensis, in addition to Maryland, is found in soil and on plants in many regions of the world, including on the surface of sugarcane and rice leaves, stems of wormwood, and on blueberries. This species is also found in starter cultures for traditional alcohol production in India and Korean soy sauce.
Mosquito attraction and trap
Research has shown that of the seven tested yeast species, only the R. taiwanensis 200S strain, isolated by Casadevall’s laboratory in 2023 during a study of Baltimore fungi, demonstrated the ability to attract female A. gambiae mosquitoes. The yeast’s scent consists mainly of the organic compounds acetone and 3-methyl-1-butanol, creating a simple but distinctive aroma.
Experiments confirmed that the yeast’s attractiveness works largely through the insects’ sense of smell, particularly through a class of insect olfactory sensors known as odorant receptors. In addition to attraction, researchers noted that both male and female Anopheles mosquitoes often get stuck in the sticky biofilms formed by R. taiwanensis, which resemble quicksand.
Perspectives on malaria control
According to study co-author Conor McMeniman, an assistant professor in the Department of Molecular Microbiology and Immunology at the Bloomberg School, “Our findings suggest that these common yeast may be the basis for safe and inexpensive mosquito control strategies”. Co-author Arturo Casadevall, a Bloomberg distinguished professor and chair of the Department of Molecular Microbiology and Immunology, added that “Rhodotorula yeast are common components of fungal populations—or ‘mycobiomes’—found on insects and are widely present in the environment”.
Researchers are now considering the possibility of developing Rhodotorula-based traps to combat malaria, using the aromatic and sticky properties of these yeast. Currently, an assessment of the attractiveness of R. taiwanensis to other species of malaria mosquitoes, as well as to nuisance mosquitoes in the US, is underway.
Source: Phys.org