Tapeworms Can Give Us Cancer, CDC Says

Dwarf Tapeworm eggs (Hymenolepis nana)
Dwarf Tapeworm eggs. Photo: Carolina Biological/Visuals Unlimited/Corbis

Aside from causing diarrhea, weakness, and sometimes deadly malnutrition, tapeworms can also apparently give us cancer.

Scientists from the Centers for Disease Control and Prevention recently took on the case of a 41-year-old Colombian man with multiple tumors throughout his body. “Pretty much by accident,” NPR says, researchers discovered that the tumors were not made of human DNA. No, the cells had come from a dwarf tapeworm. This was a big, horrible surprise. “This is a very unusual, very unique illness,” Atis Muehlenbachs, a CDC pathologist, told the Washington Post. NPR talked to one Colombian doctor who says “if another doctor called him up for advice on a similar case, he wouldn’t know what to say.”

The Colombian patient also had HIV, which prevented his immune system from fighting against the spawning tapeworm cells. He ended up dying 72 hours after researchers had finally figured out why he was sick. 

Despite a few rare exceptions, cancer has never been considered a transmittable disease, but now there’s cause for alarm for the estimated 75 million people, mainly in developing nations, who are currently infected with dwarf tapeworms.