Dr. Meredith Mahoney, a zoologist for the Illinois State Museum, made a discovery in her Springfield home that could be a bellwether not only to global climate change but to a deadly disease making its way into the Midwest.
Perhaps the actual discovery should be attributed not to Mahoney but to her cat, Darcie.
"She was playing with something in my living room, and I've discovered it's best to find out what she's playing with. It was a bug," Mahoney said.
What Darcie was batting about was a triatominae, which is better known as a kissing bug.
The insect is a scourge in Latin America. It clamps onto people's faces while they sleep and sucks their blood. Worse yet, it is the vector for a parasite that causes Chagas disease.
While the ailment can be mild, causing swelling and fever, it also can be long lasting and lead to congestive heart failure in infected humans and dogs.
Little did the cat – or the insect – know, but Mahoney's institution was working with a researcher at Saint Louis University tracking the northly migration of kissing bugs.
Ellen Santos, an epidemiologist at SLU, published an article this month in Entomology Today tracking the presence of kissing bugs in Illinois and Missouri. She said there has been at least one case of a Missouri resident believed to have been infected with Chagas disease in their local community.
Kissing bugs are black or dark brown, with red, orange or yellow stripes around the edge of their bodies. They can be up to an inch long.
Typically, U.S. physicians only find the disease among those who have immigrated from or visited Central or South America. Part of the reason for this is because kissing bugs thrive in warm climates.
But global warming may mean that the bugs are migrating farther north. Santos said the purpose of her study is to establish a baseline to track migration of the insect species as the planet continues to warm.
Already, the presence of kissing bugs in places like Sangamon and Champaign counties indicates that the creatures' range is much farther north than previously thought.
Dr. Becky Smith, a veterinarian and epidemiologist at the University of Illinois College of Veterinary Medicine in Champaign-Urbana said global warming is a reasonable hypothesis for why insects not previously found in central Illinois are becoming more common.
"Vectors (disease carriers) are now more common and in our area. And I am concerned. I mostly work with ticks and we know that there are species of ticks that didn't used to be able to survive winters in Illinois that we have this far north. But now they are in Champaign County," she said. "There are mosquitoes that are surviving the winter, and now apparently these kissing bugs that can spread Chagas disease are also surviving the winters here."
In decades past, kissing bugs were occasionally found in northern Illinois, Smith said. Today, there appear to be established populations in central Illinois.
In Illinois, the mammals most likely to be infected with Chagas disease are racoons, she said.
Animals are more likely to be infected than humans because they sometimes eat bugs, Santos said.
But Smith added there are other factors that make canines more vulnerable,
"I think dogs are more vulnerable than humans in the U. S. because dogs are more likely to be exposed to the outside," she said. "Kissing bugs like to feed at night and they tend to not be able to get into our houses. But if the dog lives outside or lives in a kennel, then the kissing bugs might find a potential host for biting."
There is no vaccine or other preventive treatment for Chagas disease in dogs or humans, Smith said.
"Unfortunately, there's not much good treatment after infection," she said. "The treatment of Chagas disease in dogs is not very strong yet. And for prevention, it's all about vector control," she said. "Kissing bugs really like wooded areas, brush piles and wood piles. So, cleaning those up is one of the pieces of advice that people give. They are active at night and attracted to light – if you have a light outside your house, they may be attracted to it. So, you want to turn off those outdoor lights and clean up the brush and wood pile."
Dr. Vidya Sundareshan, a professor of infectious disease at Southern Illinois University School of Medicine in Springfield, said the primary concern for the spread of Chagas disease in the United States has been through blood transfusions and organ transplants from infected donors who contracted the disease in Central or South America.
She added that in Latin America, "It's most common in more rural areas where there are houses made of mud or straw. In those kinds of houses, the bugs hide and at nighttime they come out and then they bite people. After the blood meal, the bugs actually defecate and in their gut is the parasite Trypanosoma cruzii. ... The people that they bite will scratch and they can put it in their eye or other places."
Initial symptoms of infection can include diarrhea, nausea and labored breathing, she said. Sundareshan added there are some antiparasitic medications that can be used to treat infected patients.
But sometimes the disease is not detected early enough and permanent heart damage can result. She said area residents should not be unduly alarmed but there is reason for concern.
"Yes, when you're seeing these (insects), they're telling us something. So, we want to be careful and definitely track (their population migration.) So, surveillance is very, very, very important."
Scott Reeder, a staff writer for Illinois Times, can be reached at [email protected].
