Scientists from the Centers for Disease Control and Prevention have identified a puzzling and unsettling new cancer-like condition in a 41-year-old man, who is believed to have become ill through a common stomach bug.
The case — the first known transmission of cancer cells from a parasite to a human — involves an HIV patient from Colombia who developed multiple, large tumors in various parts of his body. Local doctors biopsied those tumors and found that the cells acted like cancer cells in their destructiveness but were strange in other respects. For one, they were about 10 times smaller than normal human cancer cells. The doctors contacted the CDC for help.
Atis Muehlenbachs, an agency pathologist in the special unit that investigates unexplained mystery illnesses and deaths, wasn’t sure what to make of the cell samples when he and his team received them in 2013. The cells’ growth pattern was cancer-like, they noticed, with overcrowding and a high rate of multiplication. But the cells also fused together, which is rare for human cells.
One early theory, Muehlenbachs said in an interview Wednesday, was that they could be a new type of infectious organism. But after performing dozens of tests, the team discovered the cells contained DNA snippets of a dwarf tapeworm, Hymenolepis nana. That analysis was verified by a researcher and tapeworm expert at the Natural History Museum in London.