Health experts are calling on the United States to reclassify Chagas disease as endemic after new evidence suggests the parasitic illness may be more widespread than previously recognized.
An estimated 280,000 people in the US are living with Chagas disease, according to the Centers for Disease Control and Prevention (CDC). While the disease is officially endemic in 21 countries across the Americas, the US has long been considered outside that category. But a report published this month in the CDC’s Emerging Infectious Diseases journal argues that growing evidence challenges the “nonendemic” label.
The disease, caused by the parasite Trypanosoma cruzi, is primarily transmitted by triatomine insects, more commonly known as “kissing bugs.” These insects, which feed on blood, are capable of spreading the parasite after biting humans and leaving infected feces near the wound. Experts note that kissing bugs have been identified in at least 32 US states, and confirmed locally acquired infections have occurred in eight, including California, Texas, Arizona, and Louisiana.
“Labeling the United States as non–Chagas disease–endemic perpetuates low awareness and underreporting,” the authors wrote, warning that the lack of recognition may hinder surveillance, diagnosis, and treatment. Although the report acknowledged that existing data are insufficient to prove an increase in the insect’s population, it stressed that encounters between humans and kissing bugs are being reported more frequently.
Silent but dangerous illness
Often dubbed a “silent killer,” Chagas disease can remain dormant in the body for years after infection. Many people never show symptoms, but in its acute phase the disease may cause swelling at the infection site, fever, rash, and body aches. While these symptoms can subside, untreated infections may progress to a chronic stage.
The CDC estimates that 20–30% of infected individuals eventually develop severe complications, including heart failure, irregular heartbeat, or digestive problems caused by enlargement of the esophagus or colon. In some cases, the disease can be fatal.
No vaccine available
Currently, there is no vaccine or preventive drug for Chagas disease. Public health authorities recommend preventive measures such as using insecticide-treated bed nets, applying repellents, spraying insecticides inside homes, and avoiding sleeping in mud or thatch houses, where kissing bugs thrive. The disease can also be transmitted through contaminated food, organ transplants, or blood transfusions, though screening programs in many countries have reduced those risks.
Growing public health concern
Experts say that underreporting, lack of awareness, and limited diagnostic testing mean many cases in the US go undetected. As the presence of kissing bugs becomes more widely recognized, scientists warn that the country may need to strengthen surveillance and research efforts.
With both the US and Latin America facing the burden of the disease, the report concludes that rethinking the US’s classification could lead to improved monitoring and better protection for vulnerable communities.
