Chagas disease, a deadly infection caused by ‘kissing bugs’, may have taken root in the US, researchers say
A deadly, little-known parasitic infection known as Chagas disease, once considered a threat only abroad, may be endemic in the United States, researchers claim in a new study.
Chagas disease is often called a silent killer because it can go unnoticed for years, even decades, before life-threatening complications develop. It is caused by a parasite transmitted by a group of blood-sucking insects known as kissing bugs, due to their tendency to bite people around the mouth.
The disease typically unfolds in two phases: an immediate acute phase and a chronic phase that often occurs much later. During the acute phase, infected people often have no complaints. If this is the case, the complaints are usually mild and non-specific, such as headache, fever and muscle pain. During the chronic phase, which typically occurs 10 to 30 years after the initial infection, the parasites can begin to cause serious damage to the heart and digestive tract. About a third of patients develop serious heart disease as a result. Another 10% suffer from digestive or neurological problems, according to the World Health Organization.
More than 7 million people worldwide are estimated to be infected with Chagas and the disease causes 10,000 deaths annually, the WHO says. Most cases are found in Central and South America, where kissing bugs are common. In 2016, researchers estimated that about 300,000 people in the US were dealing with chronic Chagas cases, but almost all of them contracted the disease in another country before coming here.
In an article published this month, a group of experts argue that we should consider the disease a serious health threat, even for those who never leave the country. They identify eight states (California, Arizona, Texas, Tennessee, Louisiana, Missouri, Mississippi and Arkansas) with confirmed Chagas cases in humans caused by local transmission. This is sufficient reason to consider the disease endemic – that is, always present – in the US, they argue.
“Recognizing the endemicity of Chagas disease in the United States is critical to achieving global health goals,” the authors write in the study.
Most states do not track Chagas cases, so the true number of infections in the country is not known, but researchers say there is evidence to suggest the disease is much more common than previously thought. The Texas State Health Department cataloged 51 locally transmitted cases of Chagas between 2013 and 2023. The state also tracked more than 400 cases in dogs during the same period. Infected dogs have been found in 22 other states and Washington, DC
Gabriel Hamer, an entomologist at Texas A&M, told the Los Angeles Times that the known cases of Chagas likely represent “just the tip of the iceberg” of the disease’s actual spread.
Species of kissing insects known to spread Chagas have been found in 32 states, including every state in the southern half of the US.
What you need to know
Fortunately, Chagas can be cured with antiparasitic medications if caught early. However, treatments become less effective the longer a person is infected.
“If we screen for it and detect it early, most patients could be cured,” Dr. Salvador Hernandez, a cardiologist, told NewsNation. “The problem is that it doesn’t, and people end up dying or needing terribly expensive care, including organ transplants and surgeries.”
Once Chagas becomes chronic, it cannot be cured with medications, but according to the Mayo Clinic, medications can help delay the onset of the most serious complications. In some cases, infected people may need a pacemaker, heart surgery, or even a heart replacement.
Trypanosoma cruzi, the cause of Chagas disease, which is transmitted by triatomid insects. (Ed Reschke/Getty Images)
Identifying Chagas early is critical. Most of the symptoms that occur in the acute phase, if they occur at all, are common and easily attributable to typical viruses such as flu or the common cold. They include fever, fatigue, body aches, headache, diarrhea and vomiting. However, there is one telltale symptom, known as Romaña’s sign: a swelling of the eyelid that sometimes occurs when the parasite enters the body through the eye. Signs of chronic Chagas include heart problems and digestive problems.
Dogs are also often asymptomatic in the acute phase, although they sometimes show swollen lymph nodes, pale gums and stomach problems. During the chronic phase, dogs may exhibit heart problems, lethargy, and abdominal distension.
In their study, the researchers say that categorizing Chagas as endemic will significantly improve our ability to “address this neglected disease, which, as has been shown, has never been exclusively tropical.”
