What is the ‘kissing bug’ disease? Texas entomologist explains why it should be considered endemic

AUSTIN (KXAN) — The Centers for Disease Control and Prevention released a report Tuesday raising awareness about the deadly “kissing bug” disease, also known as Chagas. One of the report’s authors, a professor of entomology in Texas, explained why researchers are ringing the alarm on the disease now.

Gabriel Hamer, Ph.D., Texas A&M AgriLife Research entomologist in the Department of Entomology at the Bryan-College Station campus, said Chagas disease is considered a neglected tropical disease, which may be why it’s lesser known by the general population.

“It’s kind of assumed that it occurs elsewhere in Central and South America and is less of a concern here in the U.S.,” Hamer said. “But we recently did publish in the journal ‘Emerging Infectious Diseases’ a perspective article that is kind of just bringing the body of evidence showing that — hey, the kissing bugs have been here a long time, the parasite has been here, infected wildlife have been here… and now we have enough evidence that there’s been locally acquired human cases, and it’s sustained over time, and then that basically meets the definition of endemicity.”

Chagas disease comes from blood-sucking triatomines, commonly known as kissing bugs, that carry the protozoan parasite Trypanosoma cruzi, also known as T. cruzi. That parasite causes the disease.

Hamer was on the team of several researchers from Texas A&M, the University of Florida, and the Texas Department of State Health Services (DSHS) who worked on the article that was published in the CDC’s September volume of Emerging Infectious Diseases, underscoring growing evidence that points to endemic transmission of Chagas.

“The biggest need is awareness, and that is the focus of our publication to share the scientific perspective that Chagas disease is endemic in the U.S.,” Hamer said in a press release issued by Texas A&M. “Too often, medical and veterinary training programs dismiss Chagas as only a tropical disease and irrelevant to public and animal health in the U.S.”

Hamer told KXAN that the United States is not included on the World Health Organization’s list of 21 countries where Chagas is endemic, which is a roadblock in awareness surrounding the potentially deadly disease.

“What happens is we have a lot of medical and veterinary schools where they don’t even have curriculum on Chagas disease,” Hamer explained. “So we have a lot of medical professionals that really are not aware that this is here, and here they are encountering patients, you know, humans or animals that could have Chagas, and it really doesn’t matter where they got exposed — at the end of the day, we want to be able to diagnose and treat people that have it.”

Hamer said the narrative needs to change and believes Chagas should be classified as an endemic disease nationwide, so that more people are aware of the risks, symptoms, treatments, and prevention options before winding up infected with it.

He said Texas is one of the few states that recognizes Chagas as a reportable disease, which means that health authorities investigate human cases to determine how the person got exposed to it. But more than half of the country’s states –32 — have been documented to have the “kissing bugs” that carry Chagas.

Hamer said that the bugs and Chagas disease have historically been more common in the southern portion of the US, but a few northern states, like Delaware, Missouri, Wyoming, and California, have hit new records recently. In Texas, however, researchers and entomologists have known about the bug and disease for a while.

Hamer said that right now, entomologists don’t think anything has changed dramatically in Texas recently when it comes to reported case numbers of Chagas. While investigating all of the human cases of Chagas in Texas since 2013, 50 have been identified in people who did not have a travel history, meaning they got the disease locally, Hamer said.

He added that there isn’t enough evidence or collected data that would help researchers understand why the kissing bugs and their disease are being found in northern states more now. Hamer said the bugs could be migrating because of climate change, or people could be traveling and contracting the disease, and then the disease is getting reported when they get home. There isn’t solid evidence to point to a clear answer, though, which is another reason Hamer said an endemic classification would be beneficial.

“There are hundreds, probably thousands, of Chagas cases all over the U.S., and really hundreds of thousands, or millions, around the world, so people definitely get exposed,” Hamer said. “These kissing bugs exist all the way from the United States down to Argentina, so people could get exposed anywhere throughout the Americas, really, and then travel around the world.”

Hamer said an endemic classification and higher awareness of Chagas disease would also help fund preventative measures, like vector control, and treatment options.

“This is considered a neglected tropical disease, so, therefore it’s difficult to get funding for these kind of systems,” Hamer said. “And we’re hoping that by increasing awareness, recognizing that it’s a concern, not just internationally, but also domestically, that might increase funding opportunity for everybody who might study this system.”

Symptoms

According to the CDC, Chagas disease has two stages; the acute phase and the chronic phase.

Acute phase: This stage happens in the first weeks or months after getting infected. Symptoms are often mild or not there at all and can include:

• Fever
• Feeling tired
• Body aches
• Headache
• Rash
• Loss of appetite
• Diarrhea
• Vomiting
• Eyelid swelling (Romaña’s sign)

Chronic phase: This stage can last many years or even a lifetime. Most people have no symptoms during this time, but about 20-30% of those infected develop serious problems. These include:

• Heart issues, such as an enlarged heart, heart failure, altered heart rate or rhythm, or sudden death.
• Digestive problems, such as an enlarged esophagus or colon, leading to trouble eating or going to the bathroom.

Spread

Chagas disease spreads as follows, according to the CDC:

• The kissing bug bites and sucks blood from infected animals or people. This is how the bug gets the T. cruzi parasites.
• After biting, bugs pass the parasite in their droppings. If these droppings get into someone’s body through a cut in the skin, or near the eyes or mouth, it can lead to infection.
• People might scratch or rub bug feces into a bite wound, their eyes, or mouth without realizing it, which allows the parasite to enter their body.
• A pregnant woman to her baby
• Blood transfusions
• Organ transplants
• Consuming uncooked food contaminated with feces from infected bugs
• Accidental exposure in a lab

The CDC reports that Chagas disease does not spread from person to person like a cold or the flu.

Prevention

The CDC recommends that those traveling to or visiting rural areas that might have Chagas disease be sure to:

• Stay in well-built places (like air-conditioned or screened hotel rooms). This lowers the risk of contact with infected kissing bugs, which often live in poorly built dwellings and are active at night.
• Spray the places where you’re staying with long-lasting insecticides.
• Sleep under bed nets treated with long-lasting insecticide.
• Wear clothing that covers your skin and use bug spray on skin that’s exposed.
• Do not eat salads, raw vegetables, unpeeled fruits, and unpasteurized fruit juices.

There are no vaccines or drugs that can prevent Chagas disease, but there are a few treatment options.

More information about the disease can be found on the CDC’s website or in the perspective article by the team of researchers that included Hamer.