'Wellcome' treatment for Schistosome parasite

Professor Karl Hoffmann

01 May 2008

‘Wellcome' treatment for Schistosome parasite
The rivers and lakes of Africa, South America and Asia may be thousands of miles away from the Edward Llwyd Building at Aberystwyth University, but it is here that Karl Hoffmann, Professor of Parasitology at the University's Institute of Biological, Environmental and Rural Science (IBERS), is about to embark on a research project which has the potential to improve the lives of millions of people who are regularly exposed to Schistosome parasitic worms.

An estimated 200 million people are infected by the Schistosome parasite at any given time, with up to 300,000 deaths each year.

Humans are the definitive hosts for the worm. In areas of tropical and sub-tropical Africa, South America and Asia, parasite eggs are released into the environment from infected individuals, hatching on contact with fresh water.

Miracidia released from hatching eggs infect freshwater snails, which act as intermediate hosts, until cercariae, or parasitic larvae to humans, are released. Young cercariae, seeking to find a human definitive host, are highly mobile within water and are stimulated by turbulence, shadows and chemicals found on human skin.

The cercariae attach to humans by suckers, undergo developmental changes while migrating through intact skin to the pulmonary vessels and eventually reach the blood vessels surrounding the liver or bladder. It is at this location that adult worms reach sexual maturity and produce their hundreds-thousands of eggs every day. Many of these eggs are released in human faeces or urine to continue the life cycle, but others stay in the body causing chronic disease. Remarkably, the worms can live in humans for up to 30 years.

Although the parasites can be treated with drugs, they may be building resistance to the treatment that is regularly given, and the implications of this could be devastating, with the real danger of a pandemic that could affect millions.

Professor Hoffmann, who joined the Department at Aberystwyth in September 2007, has recently been awarded a three year research project grant by the Wellcome Trust, the largest medical research charity funding research into human and animal health, which will enable him to work towards creating a vaccine to combat the worms.

It is not known exactly how the larvae penetrate human skin, and the project’s aim is to understand the function of the proteins that are released by the cercariae larvae into the host. Hopefully, this will lead to the creation of a vaccine that will prevent penetration of the skin, thus stopping the worm from completing its life cycle.

Professor Hoffmann, who is originally from Pittsburgh, USA, and a graduate of the Johns Hopkins University Medical School, is very excited at the prospect of building an international team and has already arranged for a Brazilian scientist to join him at Aberystwyth for a year. He hopes also to draw on other expertise from places such as Africa, China and Cambridge, and sees this project, together with others in the Department, as a way of putting Aberystwyth on the map.

“There is excellent work being done here,” he says. “I certainly look forward to the Department becoming a Centre of Excellence for Parasitology in the UK, and also to collaborating with other centres across the world.”

Good news for Aberystwyth, the University and medical science, but very bad news for the Schistosome worms!

* The Institute of Biological, Environmental and Rural Sciences (IBERS http://www.aber.ac.uk/en/ibers/) has been formed following the merger of the Institute of Grassland and Environmental Research (IGER) into Aberystwyth in April 2008. It represents the coming together of the Institute of Grassland and Environmental Research and the University’s Institutes of Biological Sciences and Rural Sciences.
With more than 300 staff and an annual budget of more than £20 million, IBERS will be ideally placed to respond to the challenges of sustainable land use, climate change, and the security of food and water supplies.
IBERS will also provide new opportunities for more than 1,000 undergraduate and research students at Aberystwyth University. The initial investment of more than £50 million over five years will include new research and teaching facilities at both Plas Gogerddan and the University’s Penglais campus.