The Nobel Prize for physiology or medicine has been split two ways for groundbreaking work on parasitic diseases, BBC News reports.

William C Campbell and Satoshi Omura found a new way of tackling infections caused by roundworm parasites.

Youyou Tu shares the prize for her discovery of a therapy against malaria.

The Nobel committee said the work had changed the lives of hundreds of millions of people affected by these diseases.

The mosquito-borne disease malaria kills more than 450,000 people each year around the world, with billions more at risk of catching the infection.

Parasitic worms affect a third of the world's population and cause a number of illnesses, including river blindness and lymphatic filariasis.

Efforts to eradicate malaria had been failing - older drugs were losing their potency - and the disease was on the rise. Prof Youyou Tu, who in the 1960s had recently graduated from the Pharmacy Department at Beijing Medical University, looked to traditional herbal medicine to find a potential therapy.

She took an extract from the plant called Artemisia annua, or sweet wormwood, and began testing it on malaria parasites. The component, later called artemisinin, was highly effective at killing them, BBC says.