Progress made to weaken a deadly disease

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EXCITING DISCOVERY: Scientists in the UK have made a significant discovery that could pave the way for the development of a new drug treatment for one of the world’s most lethal diseases. – LPS photo

LONDON: Schistosomiasis is a chronic and debilitating illness caused by blood flukes and kills 300,000 people each year – a death toll second only to malaria among parasitic diseases – and leaves more than 200 million chronically ill.

In terms of the impact on people’s lives this disease exceeds tuberculosis, malaria and is level with Aids in terms of disease burden.

It has a major impact on what they can do.

They cannot go to school, they cannot work and they are in constant pain.

People become infected when larval forms of the parasite – released by freshwater snails – penetrate their skin during contact with infested water.

In the body, the larvae develop into adult schistosomes.

Adult worms live in the blood vessels where the females release eggs.

Some of the eggs are passed from the body in the faeces or urine to continue the parasite lifecycle.

Others become trapped in body tissues, causing an immune reaction and progressive damage to organs.

Schistosomiasis is prevalent in tropical and subtropical areas, especially in poor communities without access to safe drinking water and adequate sanitation.

Of the 207 million people with the disease, 85 per cent live in Africa.

There are two main forms of schistosomiasis – intestinal and urogenital – caused by five main species of blood fluke.

To combat its effects, scientists from Aberystwyth University in Wales have produced a paper, recently published in the magazine Nature Communications.

Professor Karl Hoffmann from the university’s Institute of Biological, Environmental & Rural Sciences outlines how they have identified a specific DNA modification of the parasitic flatworm Schistosoma mansoni that gives rise to schistosomiasis.

Professor Hoffmann said: “This discovery – in the way in which schistosome genes may be modified – is incredibly exciting as it simultaneously opens up a new approach for schistosomiasis control but also provides evidence that illustrates an important functional role for this specific modification in the development of a parasitic worm species.”

The research has been funded by the UK’s Wellcome Trust and the Sandler Centre for Basic Research in Parasitic Diseases of the United States.

Professor Hoffmann and colleagues show for the first time that the genomic DNA of the blood fluke Schistosoma mansoni is methylated, and go on to identify the protein (a DNA methyltransferase) that is likely to mediate this process.

DNA methylation – the attachment of a methyl group to one of four nucleobases that make up an organism’s DNA – is considered to be one of the most important genome modifications in nature and is involved in developmental biology, gene expression regulation and phenotypic diversity. — LPS