Chagas disease is a parasitic infection of the blood that causes more than 10,000 deaths per year worldwide. The disease is caused by the protozoan Trypanosoma cruzi. It is transmitted to humans by bloodsucking cone-nose bugs (triatomines), nicknamed kissing bugs, because they tend to bite people around the lips when they feed at night.
Chagas disease is most common in Mexico, Central America, and South America. Although there are triatomine bugs in the United States, very few locally transmitted cases of Chagas disease from contact with kissing bugs in the southern U.S. have been documented. Most cases of Chagas disease in the U.S. were obtained in the parts of Latin America where Chagas disease is common. (CDC)
Chagas disease is not likely in Iowa though climate change and global migration increase the possibility of local transmission in the Midwest. Until recently, bloodsucking cone-nose bugs had not been found in Iowa. A single specimen of the eastern blood-sucking conenose (Triatoma sanguisuga) was reported from Lee County, Iowa, in 2017.
Description - What are Kissing Bugs?
Kissing bugs are a specific type of assassin bug (Triatoma sp.) related to bed bugs, boxelder bugs, squash bugs, stink bugs, and about 3,850 other species of true bugs in North America. Like all true bugs (Hemiptera: Heteroptera), they feed with sucking mouthparts. Kissing bugs feed by inserting a needle-like beak into the skin to feed on blood. They are named "kissing bugs" because they often bite people around the mouth at night while they sleep. There is often no pain or irritation from kissing bug bites.
There are several species of assassin bugs in the U.S. in the kissing bug genus. (BugGuide) The eastern bloodsucking conenose bug is 5/8 to 13/16 inches long. Other species of kissing bugs may be up to 1 1/4 inches long. Kissing bugs have a narrow, elongated head and a broad, flat abdomen. They are dark brown to black with orange to red to yellow markings on the outer edges of the abdomen that stick out from under the wings.
Kissing bugs feed on the blood of mammals, birds, reptiles, and other animals. Bites are usually painless and without reaction. However, bites may cause irritation at the bite site or allergic reactions. (UpToDate.com)
In some areas of the world, but not in the upper Midwest, kissing bugs are vectors of Chagas disease. Chagas disease symptoms are highly variable and range from no symptoms to mild ones, such as fever, fatigue, body aches, headache, rash, loss of appetite, diarrhea, and vomiting. More severe symptoms of Chagas disease include enlargement of the liver or spleen, swollen glands, and swelling at the bite site. Recovery is common within a few weeks or months with antiparasitic medication.
Chronic Chagas disease can last for decades, and most people have no symptoms. Approximately 20–30 percent of infected people develop cardiac complications such as an enlarged heart, heart failure, cardiac arrest (sudden death), or gastrointestinal complications. (CDC)
Kissing bugs have a simple life cycle of three stages, egg, nymph, and adult. Nymphs look like small, wingless adults and feed on blood to grow. Adult kissing bugs are good fliers and fly at night to find mates and hosts. Females lay eggs after feeding. The life cycle of the kissing bug may take one to two years.
Kissing bugs obtain the Trypanosome parasite by biting an infected animal or person. The bugs feed at night on a wide variety of vertebrate hosts, including reptiles, amphibians, birds, and mammals. A favored host is the woodrat (Neotoma sp.) though they also feed on raccoons, opossums, livestock, pets, and humans.
Once infected, the bugs pass the parasites in their feces. After feeding, the bugs defecate on the host. The pathogen doesn't enter the body until the person scratches or rubs the bite site and spreads the feces and pathogen into the bite wound, eyes, or mouth.
For more on Chagas disease and its transmission, see this blog from North Carolina State University (where kissing bugs and the woodrat are found).
Iowa does not currently have the right combination of kissing bugs and the preferred mammalian host to present a risk of Chagas transmission in the state. Insecticide application is not warranted for kissing bugs in Iowa.
Many common Iowa insects resemble the kissing bug. Hence the need for careful and accurate diagnosis. The Plant & Insect Diagnostic Clinic is happy to examine any insects of concern either as specimens or digital images. Images of the most common look-a-likes are below. Also see the Texas A&M Extension Entomology site for a look at "non-kissing-bugs."
The most common, non-kissing-bug sample received in Iowa has been the western conifer seed bug. We know this insect well! And it is NOT a kissing bug.
The western conifer seed bug (AKA the “pine seed bug”) has expanded hind tibias identifying it as one of the leaf-footed bugs. The white zig-zag line on the back is a distinctive characteristic of this harmless accidental invader that wanders indoors in the fall after feeding through the summer on sap from pine cones. They are a common accidental household invader, much like the more familiar boxelder bug (only a lot fewer of them). Read more on the Clinic website.