Chagas disease: Sleep tight and don’t let the bedbugs bite.
Researchers have found that bedbugs can spread Chagas disease among mice. And since the Trypanosoma cruzi parasitic protozoan affects many mammals – including both mice and men –, it’s not impossible that bedbugs could spread the disease among humans as well, according to University of Pennsylvania epidemiologist Michael Levy. “We've shown that the bedbug can acquire and transmit the parasite. Our next step is to determine whether they are, or will become, an important player in the epidemiology of Chagas disease,” Levy said.
A study published in the American Journal of Tropical Medicine and Hygiene shows that bedbugs can not only become infected after feeding on diseased mice but also pass on the parasite to other mice. Scientists from University of Pennsylvania and the Universidad Peruana Cayetano Heredia in Peru allowed 2,000 bedbugs to feed on the infected mice. The results are best summed up by study co-author Renzo Salazar, who claimed he had “never seen so many parasites in an insect. I expected a scenario with very low infection, but we found many parasites-they really replicate well in the gut of the bedbugs” Afterward, the bugs feasted on uninfected mice, of which 9 out 12 developed an infection.
To paraphrase Val Kilmer in Kiss Kiss Bang Bang, Chagas disease pulls the trigger but it may take 20 years for the bullet to hit. In other words, an infected individual can literally drop dead from cardiac arrest one or two decades after infection. According to Hitchcock, though, this is not suspense but surprise because people don’t know they have Chagas disease – nay, they don’t even know what Chagas is. This is to Levy what makes this disease a “silent epidemic,” especially in South and Central America and Mexico. Transmission in the United States is negligible, though – cases are few and far between, usually imported by travelers returning from Latin America.
It is estimated that Chagas infects 6-8 million and kills 50,000 every year around the world, but one reason that the U.S. sees few cases is that the kissing bugs that spread this disease are not able to reach humans who live in well-made buildings. Kissing bugs are night feeders that attack the face, around the lips or eyes, or other uncovered areas. However it’s not their bite but their waste that spreads Chagas disease; their feces can enter wounds when the person scratches or enter the body through the eyes or mouth. Levy and his fellow researchers found that many bedbugs tend to defecate soon after feeding.
Additionally, bedbugs feed on humans in larger numbers than kissing bugs, and are harder to find and kill. “Just for example let’s say you have bedbugs in a bed, and an infant in that bed with a pacifier, which comes into contact with [insect feces] and goes into the mouth,” Chagas disease expert at the University of Georgia Rick Tarleton – who wasn’t involved in the study – said. “That’s a potential transmission.” Moreover, populations of bedbugs have increased lately in the U.S. “it would be a disaster (if bedbugs could spread the disease),” Levy said. “If Chagas starts to spread, we wouldn't know it, due to the slow nature of the disease.”