A Colombian man has died after a tapeworm growing in his body developed cancer, spreading to his immune system and causing a tumour.

A study published in the New England Journal of Medicine revealed the 41-year-old man had developed tumours caused by H. nana, the most common tapeworm to infect humans.

The man had gone to doctors in Colombia after experiencing symptoms of a fever, cough and weight loss. He had been diagnosed with HIV 10 years earlier, but was not on any medication.

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A CT scan revealed tumours in his lung and lymph nodes, with further testing revealing the cancer cells.

Researchers determined that the man’s HIV had allowed the tapeworm to go unchecked by his immune system. They said this was the first known report of a man becoming sick from cancer cells developing in a parasite.

He died 72 hours after the discovery.

“We were amazed when we found this new type of disease – tapeworms growing inside a person, essentially getting cancer, that spreads to the person, causing tumors,” said study researcher Dr Atis Muehlenbachs, a staff pathologist at the Centers for Disease Control and Prevention’s Infectious Diseases Pathology Branch (IDPB).

Researchers also recognised this was most likely a rare case, but highlighted the fact that tapeworms and HIV affect millions of people worldwide.