New tool in the fight against tropical diseases

Scientists have developed a novel tool that exploits baker's yeast to speed up the development of new drugs to fight multiple tropical diseases, including malaria, schistosomiasis and African sleeping sickness.

The unique screening method uses yeasts that have been genetically engineered to express parasite and human proteins to identify chemical compounds that target disease-causing parasites but do not affect their human hosts.

Parasitic diseases affect millions of people annually, often in the most deprived parts of the world. Every year, malaria alone infects over 200 million people, killing an estimated 655,000 individuals, mostly under the age of five.

Unfortunately, our ability to treat malaria, which is caused by Plasmodium parasites, has been compromised by the emergence of parasites that are resistant to the most commonly-used drugs. There is also a pressing need for new treatments targeting other parasitic diseases, which have historically been neglected.

Currently, drug-screening methods for these diseases use live, whole parasites. However, this method has several limitations. First, it may be extremely difficult or impossible to grow the parasite, or at least one of its life cycle stages, outside of an animal host.

For example, the parasite Plasmodium vivax, responsible for the majority of cases of malaria in South America and South-East Asia, cannot be continuously cultivated in laboratory conditions. Second, the current methods give no insight into how the compound interacts with the parasite or the toxicity of the compound to humans.