The ongoing bedbug epidemic has been a pain—if not full-on pestilence—for those infested and for those in constant terror of becoming so. The biting bugs are not known to carry infectious diseases like other bloodsuckers, such as ticks or mosquitoes. But the chemicals used to beat back these tiny insects seem to be making some of the bite-plagued sick.

At least 111 people in seven states reported becoming ill after coming in contact with an area treated for bedbugs (Cimex lectularius) between 2003 and 2010, according to a new report published online Friday by the U.S. Centers for Disease Control and Prevention (CDC).

The most common symptoms were neurological effects—dizziness and headaches—shortness of breath, and gastrointestinal complaints such as nausea and vomiting. One 65-year-old North Carolina woman, who had multiple underlying conditions, died after excessive insecticide use at home, including direct application to her hair and skin, in an effort to get rid of bedbugs.

The chemicals implicated in most of the reactions were pyrethrins (natural compounds) and pyrethroids (synthetic compounds based on pyrethrins), which are both frequent insecticide ingredients. With increased use, however, some populations of bedbugs have developed a resistance to pyrethroids, which is bad for itchy humans, who might be inclined to spray more and more of the chemicals if they don't seem to be working.

The states that participated in the illness identification program were California, Florida, Michigan, New York (where more than half the cases were reported), North Carolina, Texas and Washington. Nearly three quarters of the illnesses were from 2008, 2009 and 2010.

Most case reports came through poison control centers, which means that there are probably plenty of other instances of illness that go unreported and that have occurred in other states. It also means, though, that it is difficult to make definitive links between the bedbug treatments and the symptoms, without having more clinical knowledge of the individuals' other health issues and their environment. So the CDC cautiously calls the link between most of the illnesses and treatments "possible," with some 16 percent of cases being "probable" or "definite."

Many of the reactions were likely due to people either using too much insecticide or not washing their linens after applying the poison. The modest number of reported illnesses overall "does not suggest a large public health burden," the CDC noted. But people would be wise to use other, non-chemical control methods, such as keeping mattresses and box springs in bug-resistant covers, laundering or discarding infested items, and using temperature treatments (which can kill bugs with extreme heat or cold) provided by some extermination companies, the agency suggested. And it's usually a good idea to seek professional help—and to stick to the instructions on chemicals, which will tell you it's a bad idea to put the stuff directly on your sheets, or, obviously, your skin.