Bed bugs are every urbanite's worst nightmare, but from a public health perspective, they're considered rather harmless. Unlike rats or mosquitos, there's no evidence they carry or spread deadly diseases like malaria, yellow fever or dengue. But new research suggests the night-time bloodsucker can transmit the parasite that causes Chagas, a disease endemic to South America.

Chagas disease was thought to be spread only by kissing bugs, another variety of bloodsuckers that typically feed on the faces of sleeping mammals. The disease is caused by a parasite called Trypanosoma cruzi; it's not transmitted by the bite itself but through feces deposited while the kissing bug feeds.

If the parasite can find its way in through the bite would, it can attack the victim's organs and has been specifically implicated in heart complications in humans. Its ill effects often don't appear for 20 years after the infection, making the disease hard to track and treat. The malady kills 50,000 a year, mostly in Central and South America, but doctors have found an increasing number of cases in Texas.

Now, experiments by researchers at the University of Pennsylvania's Perelman School of Medicine and Universidad Peruana Cayetano Heredia in Peru prove that Trypanosoma cruzi can live and travel inside a bedbug, too.

As detailed in a new paper -- published this week in the American Journal of Tropical Medicine and Hygiene -- the research proved bed bugs were able to contract the parasite while feeding on diseased mice, as well as deposit the parasite on healthy mice.

There's no evidence bed bugs are carrying Chagas yet, but if they could, researchers said it could be a disastrous scenario.

"Any time you have an infectious disease and identify a new route of infection, that's something to be concerned about," Rick Tarleton, a Chagas expert at the University of Georgia who wasn't involved in the study, told Newsweek.

"There have always been triatomine bugs and cases of Chagas disease in the U.S., but the kissing bugs we have here don't come into homes frequently like the more dangerous species in South and Central America do," senior study author Michael Z. Levy said in a press release. "I am much more concerned about the role of bed bugs. They are already here -- in our homes, in our beds and in high numbers. What we found has thrown a wrench in the way I think about transmission, and where Chagas disease could emerge next."