Brazilian researchers say they have successfully tested a vaccine against schistosomiasis, a disease caused by parasitic worms that afflicts more than 200 million people worldwide.

“This is an unprecedented breakthrough in medicine that involved 30 years of scientific work,” Dr Tania Araujo-Jorge, of the Oswaldo Cruz Institute in Rio de Janeiro, has said.

“We are confident that within three years Brazil will be able to distribute the first vaccine against parasites, and help combat schistosomiasis, a disease that strikes the poorest because it is spread by unsanitary conditions.”

The vaccine against the parasite, which also afflicts cattle, was developed from the reconstruction of a protein found in a species of worm.

The institute said it had successfully tested the vaccine in humans, but that more testing would be required in areas where the parasite is most common, mainly in Africa and South America.

The freshwater parasite can penetrate people’s skin, and children are at especially high risk because they swim and bathe in contaminated water.

Brazil has some 2.5 million cases of schistosomiasis, which initially causes an itchy rash, followed in subsequent weeks by fever, chills, coughing and muscle aches. After a few years, the disease can damage internal organs.

“While the mortality rate is low, schistosomiasis causes incapacity, which makes it a disease that is caused by poverty and one that perpetuates poverty,” Ms Araujo-Jorge said.