How did man die of cancer from a parasitic worm?

A man has died of cancer from a parasitic worm - in a case that initially baffled experts.

The 41-year-old Colombian patient had HIV, and his weakened immune system allowed the cancer to flourish.

Scientists were amazed when a molecular test revealed high levels of tapeworm DNA.

Dr Peter Olson was one of the specialists at the Natural History Museum in London who helped to identify the parasite.

He said it was a unique case.