The Centers for Disease Control and Prevention (CDC) scientists have found that cancer cells that originate in a common tapeworm could take root in people who have weakened immune systems, and could cause cancer-like tumors.

It is the first ever known case of a person becoming ill due to cancer cells that arose in a parasite, Hymenolepis nana in this case, the dwarf tapeworm.

The report, published in the November 5 issue of the New England Journal of Medicine, has raised concern that other similar cases, if they occur, could be misdiagnosed as human cancer, mainly in developing countries where this tapeworm and immune-system-suppressing illnesses like HIV are common.

Lead author of the study, Atis Muehlenbachs, MD, PhD, staff pathologist in CDC’s Infectious Diseases Pathology Branch (IDPB), said, that they were surprised when they discovered this new type of disease, wherein tapeworms grow inside a person essentially getting cancer that spreads to the person, and cause tumors.

Muehlenbachs added, “We think this type of event is rare. However, this tapeworm is found worldwide and millions of people globally suffer from conditions like HIV that weaken their immune system. So there may be more cases that are unrecognized”. Muehlenbachs mentioned that it was definitely an area that deserves further research.

H. nana infects around 75 million people at any given time, which has made it the most common tapeworm infection in human beings. The tapeworm enters into people when they consume food infected with mouse droppings or insects or by ingesting feces from a person who is infected. Children are the easiest target of it. In most of the people no symptoms are seen. However, the tapeworm thrives among the ones, who have weak immune systems, including the ones who have HIV or are taking steroids.