Parasite gives a man cancer
In rare case, a patient’s weakened immune system may have let tapeworm spread disease
PETRIFYING PARASITE Dwarf tapeworms (Hymenolepis nana, shown) can become a horrifying problem for people with weakened immune systems. Cells from one man’s tapeworms turned into cancer cells and spread throughout his body.
Courtesy Peter Olson/Natural History Museum, London