A disease-carrying insect that can cause a deadly infection in humans is spreading across the southeastern United States, according to the Centers for Disease Control and Prevention.
In the month of November alone, Triatomine bugs–known more commonly as “kissing bugs”–were discovered in North Carolina, South Carolina, Alabama, Georgia, and Tennessee, bringing the number of affected states to 27 and spanning the entire southern half of the country.
Native to South America, Central America, Mexico, and the southwestern United States, kissing bugs can carry a parasite called Trypanosoma cruzi (T. cruzi) that causes the potentially deadly Chagas disease — described by some researchers as “the new HIV/AIDS of the Americas.”
Infection with Chagas disease often doesn’t produce overt symptoms, especially at first. Less than half of those infected or bitten by a triatomine bug will see a visible skin lesion or a swelling in one of their eyelids. According to the World Health Organization, in the first months after infection Chagas sufferers may experience “fever, headache, enlarged lymph glands, pallor, muscle pain, difficulty in breathing, swelling and abdominal or chest pain,” but others remain asymptomatic.
With a lack of distinctive symptoms, many patients with Chagas disease go undiagnosed (or misdiagnosed) in the acute phase of the illness. Left untreated, the disease gets worse and enters what doctors call the chronic phase. Over time, the T. cruzi parasites nestle into the internal organs of their hosts, leading to swelling of the heart and digestive muscles. At this point, the infection is no longer treatable. As the parasites continue their invasion, they can cause a variety of heart and digestive disorders, as well as pain and discomfort, before ultimately causing sudden death or heart failure.
Chagas is typically spread through the feces of kissing bugs, which got their name because they feed on people’s faces during the night. When a kissing bug bites a human (or other animal), it has to empty its digestive tract to the make room for incoming blood, so it defecates in the bite wound as it feeds. The disease parasite is thus directly introduced into the bloodstream of the victim via the bug’s feces. Chagas can also be spread through blood transfusions or organ transplants from infected donors or from mother to child during pregnancy. In addition, the parasite can be transmitted through foods and juices tainted by the contaminated bug feces.
The CDC estimates that more than 8 million people in South and Central America and over 300,000 people in the United States are infected with Chagas disease. However, the true toll of the disease is difficult to calculate because many carriers don’t know they are infected with the tropical parasitic illness, and many patients are misdiagnosed.
An invasion from within
While it has always been thought that most cases of Chagas disease in the United States were contracted elsewhere, recent research suggests that the disease is being transmitted within our borders with increasing frequency. As Rebecca Kreston explained in Discover Magazine:
The dynamics of the disease are changing, and strong evidence continues to emerge indicating that local infection is occurring among the American population, particularly in the southern states.
Research performed over the past years has consistently shown that the parasite is embedded in the ecology and landscape of the south: its vector, the blood-feeding triatomine insect known as the “kissing bug” for its proclivity to feed near the mouth, resides in a swath of states including Texas, Oklahoma, Louisiana, Mississippi, and Arkansas. Studies of these same bugs show that they not only carry the parasite that causes Chagas disease, but also that they are coming into uncomfortably close contact with humans, with genetic studies indicating bloody feasts of human origin. Most recently, a  study found that many canines in shelters carry T. cruzi, serving as a reservoir that brings the disease into even closer contact with humans.
Other studies have found that an increasing proportion of kissing bugs in the southern United States are carriers of the disease-causing parasite. In August, researchers from Baylor University published a study in the journal Acta Tropica showing that 61.5 percent of Texas kissing bugs now carry the potentially deadly parasite, up from 41.5 percent reported in a 2010 study.
When the same Baylor researchers screened for the disease among Texas blood donors, they discovered that one in every 6,500 people tested positive for the parasite, indicating that the CDC’s estimate of 300,000 cases nationwide may be just a fraction of the true number of infections.
Despite the growing problem of Chagas, most physicians the United States are unfamiliar with the disease, and some who have heard of it mistakenly dismiss the deadly infection as a not-so-serious health concern, even in parts of the country where many people may be living with Chagas symptoms. As a neglected disease, Chagas also lacks the interest of pharmaceutical companies and funding agencies, so surveillance, research, and medical advances remain limited.
According to Kreston, this leaves us extremely vulnerable to the emerging disease:
“What we know now is that … the disease is being acquired domestically and is slowly percolating into the American population from infected bugs within our borders. But a lack of awareness of Chagas, subpar diagnostic tests, and insufficient standardized guidelines are hindering our ability to mount an effective response to the disease and to prevent the continued emergence of this parasite.”
“Without these targeted initiatives,” she warned, “Chagas disease will continue to spread, knowing no borders.”
If you live in the southern United States, there are steps you can take to reduce your risk of contact with the parasite. Triatomine bugs live in cracks and holes in outdoor spaces, so the CDC recommends sealing up any gaps that lead outdoors, especially around windows, walls, roofs and doors. Keeping pets indoors at night and making sure outdoor lights that can attract bugs are a good distance away from the house also helps with prevention.
If you find a Triatomine bug, don’t try to touch or squash it. Instead try to seal it in a container and either freeze it or fill the container with rubbing alcohol. Then take it your local health department for species identification.
You can also contact the CDC’s Division of Parasitic Diseases and Malaria at firstname.lastname@example.org for identification and testing.