This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
The kissing bug may have the most misleadingly cute name in entomology. It bites, rather than smooches, its victims around the mouth or face. But far worse than the bite itself is what may find its way into it: wriggling worm-like parasitic protists called Trypanosoma cruzi that teem in the feces of these bugs, which they deposit without regard for their victims directly onto their face. The parasites may get rubbed into the wound by a sleeper scratching either bite or bug, and eventually burrow into victims' hearts. There they riddle the tissue for decades, feeding on blood or lymph and triggering a cascade of events that may cause fatal heart disease decades later in about a third of victims.
The infection is generally treatable with drugs that come with a distasteful array of side effects if the disease is caught in its early stages when most victims are unaware they are infected. But once symptoms emerge, the disease becomes increasingly difficult or impossible to reverse. In other words, kissing bugs might more aptly be named something like bloody filthy death bugs. They are kind of cute-looking, though.
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"Triatoma dimidiata-adult" by Felipe Guhl - PLoS Neglected Tropical Diseases May 2008Image page. Licensed under CC BY 2.5 via Wikimedia Commons.
See how their little bug eyes stick out of the side of their head? I would not be saying that, of course, if I had to fend them off by the hundreds each night as many people in South America do.
Until now, Americans were thought to be safe from the pernicious parasite and its persistent host unless they travelled to Latin America, where the disease is common. Now, scientists are coming to the uneasy realization that some Americans -- at least in hot spots like southeast Texas -- may be more vulnerable to infection right here at home than previously suspected. And not just from kissing bugs, but perhaps also from a hitherto unsuspected source: bed bugs.
Here's a video of Trypanosoma cruzi in all its squeam-inducing glory, freshly culled from bed bug feces.
Scientists just demonstrated the Chagas parasite can be transmitted between bedbugs and mice via the fecal-wound route, raising the disturbing possibility they could do the same thing to humans. Until now, bed bugs were known to be a horrifying scourge, but they were at least thought to be a non-disease-transmitting horrifying scourge.
Today Scientific American online news published an article I wrote that surveys and examines the new evidence.
One particularly disturbing aspect I did not have room to discuss in my article is what happens when Americans without a history of travel to Latin Americago to their doctors with positive test results in hand. Many U.S. doctors have been trained to believe that it's impossible to acquire T. cruzi from kissing bugs in the United States.
In a study conducted by Melissa Nolan Garcia, a research associate at the National School of Tropical Medicine at the Baylor College of Medicine, only a quarter of the physicians whose patients approached them with a letter indicating a positive T. cruzi test result from a blood bank went so far as to do an electrocardiogram to check for heart abnormalities. In the case of one patient who was enrolled in their study a year ago, his physician told him, "'There's no way you have this,” she said. “'You've never travelled to an endemic country. You've never been to Latin or South America. This is a false positive.'”
Yet when she saw him again a year after his initial visit his heart disease had advanced so rapidly that he now needed a pacemaker. “I had to tell him he's no longer a candidate for [anti-parasite] treatment,” she said. “Ultimately he'll likely die from this disease.”
To read more, check out my article here.