Man gets cancer from parasite

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A new scientific study has suggested that tapeworms could start parasitism which could later on cause cancer in the body of a man.

A case based on a 41-year-old man in Colombia shows that the guy came to doctor complaining of fever, cough, fatigue and weight loss that had lasted several months. Scans revealed tumors in his lungs, liver, adrenal glands, lymph nodes and other spots in his body. The disease looked like cancer, but it puzzled doctors: the small cells in the growths weren’t human cancer cells.

DNA analysis revealed a shock: The cancer cells came from dwarf tapeworms (Hymenolepiasis nana), pathologist Atis Muehlenbachs of the US Centers for Disease Control and Prevention and colleagues report in the Nov 5 New England Journal of Medicine. Contagious cancers affect dogs, Tasmanian devils and clams, but this is the first time researchers have found a parasite giving a person cancer.

HIV infection had weakened the man’s immune system so that tapeworm stem cells could grow unchecked, the researchers speculate. Mutations then turned the stem cells into cancer. The case raises concerns that people with weakened immune systems may be in danger of contracting similar tapeworm cancers. ‘This is a rare disease,’ Muehlenbachs says, but ‘we don’t know how rare.’