A drug that can treat schistosomiasis has been taken off the market

Earlier this year, American doctors looking for a drug to treat schistosomiasis - also known as bilharzia - a parasitic disease which causes severe liver damage, found that the drug's US manufacturer had stopped production as it was losing money, even though the disease is thought to affect over 200 million people worldwide.

On further investigation, researchers from the Baylor College of Medicine found that many effective drugs used to treat tropical diseases were no longer being made, the reason given, they were not economically viable.

Yet many countries are still reliant on drugs which are no longer manufactured. Bithionol is widely used to combat damage caused by liver flukes, but it has not been produced since 1979.

Tax incentives

In the US, remaining stocks of such drugs have been passed to the government 's Centers for Disease Control to be distributed on an as-needed basis.

The researchers are now recommending government support and tax incentives to encourage US companies to produce such drugs.

However, they say that drugs produced in the US to treat animals may have a wider use.

One drug used to treat heart worms in dogs is also effective against river blindness in humans.