When a single cure is offered for multiple conditions it’s usually a scam, like a snake oil salesmen who promises a single cure for all ills. However, evidence that one chemical can treat three neglected tropical diseases has been published in Nature, a much more reliable source than a fast-talking salesman on the back of a wagon or a late night infomercial.

Sleeping sickness, leishmaniasis, and Chagas disease are all parasitic diseases neglected by medical researchers because they afflict some of the poorest people on Earth. With those affected unable to afford treatments, pharmaceutical companies have shown little interest in bringing treatments to market.

Dr Frantisek Supek of the Genomics Institute of the Novartis Research Foundation has found a possible solution – a class of drugs that hit all three diseases, reducing the costs compared to the development required for three unrelated treatments.

"We found that these parasites harbor a common weakness,” Supek said in a statement. “We hope to exploit this weakness to discover and develop a single class of drugs for all three diseases."

Collectively the three diseases cause more than 50,000 deaths a year, and infect millions. Each is caused by single-celled organisms called kinetoplastids, although the species responsible are different.

Leishmaniasis is spread by sand fly bites and infects more than a million people in tropical and subtropical countries, a minority having the more serious visceral form that infects the spleen or liver.

Sleeping sickness is not a general inability to wake up, specifically referring to African trypanosomiasis, spread by the tsetse fly. Death from it is preceded by years of confusion, personality changes and slurred speech.

Chagas disease is restricted to the western hemisphere where it affects 8 million people exposed to the feces of triatomine bugs.

Treatments exist for each, but they are expensive, unreliable and have serious side effects, and little effort has been put into finding improvements. Remarkably, the best treatment for trypanosomiasis, eflornithine, is only available at all because it is also used to prevent unwanted facial hair in women. The existence of a substantial industry producing eflornithine for cosmetic reasons has lowered the cost of production to the point where the manufacturer donates additional supplies to aid agencies. It has saved tens of thousands of lives, but would have been unaffordable without the economies of scale the dual use provides.

After testing more than 3 million chemicals, Supek’s team identified one, GNF6702, that kills all three kinetoplastids but does not damage cultured mammalian cells.

"We were able to detect the [trypanosomiasis] parasite in the brain using an imaging system that detects the presence of genetically modified light-emitting parasites,” said co-author Dr Elmarie Myburgh of the University of York. "We then tested the chemical developed by Novartis using our imaging method which showed that it can get into the brain and kill the parasites."

After modifying GNG6702 to increase its effectiveness, and demonstrating its harmlessness in mice, the authors are conducting toxicity tests they hope will lead to clinical trials.