Chagas disease, a condition transmitted by the “kissing bug,” is now classified as endemic in the United States, according to a recent announcement from the Centers for Disease Control and Prevention (CDC).
While Chagas disease has long been considered endemic in Latin America—where about 8 million people are believed to be infected—the CDC’s recognition of its presence in the U.S. is expected to improve medical education and help doctors identify cases more effectively.
Estimates suggest that approximately 45,000 people in Los Angeles County are infected with Chagas disease, out of more than 300,000 across the country. Fewer than 2% of those affected are aware they carry the parasite.
“Most people living with Chagas disease are unaware of their diagnosis, often until it’s too late to have effective treatment,” says , chief of infectious diseases at UCLA Health.
The insect responsible for transmitting Chagas disease is known by several names: conenose bug, barber bug, or vinchuca in Spanish. It bites humans on the face and then defecates near the wound, depositing the T. cruzi parasite on the skin. Scratching the bite can introduce the parasite into the bloodstream.
explains , a professor of clinical microbiology at the .
Many individuals with Chagas disease do not show symptoms during either its acute or chronic phases. The acute phase lasts about two months; some may develop severe eyelid swelling—a sign described as “almost a hallmark of acute Chagas infection” by Dr. Yang—as well as fever, fatigue, body aches, headache, loss of appetite, diarrhea and vomiting. These symptoms often resemble other illnesses.
During its chronic phase—which can last a lifetime—about one in five people develop serious heart or digestive complications such as an enlarged heart or colon, heart failure or cardiac arrest.
Left untreated, Chagas disease “kills the heart very slowly,” Dr. Yang says.
At UCLA Health, patients presenting with heart-related symptoms who are diagnosed with heart disease receive blood tests for Chagas disease, according to , an infectious diseases physician and researcher working with transplant patients.
Some manage their condition with medication for heart failure; others require a transplant. “Patients with Chagas disease as cause of end stage heart failure generally do very well after heart transplantation,” Dr. Schaenman says. “And they can live a full and high-functioning life after the transplant.”
However, transplantation may reactivate Chagas disease in those previously infected; these patients are monitored closely and treated with anti-parasite medication if necessary.
Anti-parasite drugs only work during acute infection or recurrence after transplant—not once antibodies indicate past exposure. “Unfortunately, if you’re antibody positive…there’s no medication that’s effective to treat it at that point in time,” Dr. Schaenman says. Still, awareness helps monitor potential symptoms and risks.
Testing is recommended for individuals from Mexico or Central/South America—or those who have traveled there—who develop heart issues. Sleeping under nets is advised when visiting rural areas in Latin America due to risk from kissing bugs.
In Los Angeles County specifically, kissing bugs have not typically carried T. cruzi based on current testing results; however insects found in Texas have tested positive for carrying this parasite.
“The kissing bugs in the endemic area — Latin America — almost all of them carry the parasite,” Dr. Yang says.
“With global warming, there’s concern among scientists that the borders for where endemic infections occur are shifting northward,” Dr. Schaenman adds.
Kissing bugs prefer homes made from mud or adobe but will also inhabit cracks where pets or rodents reside—and tend to prefer biting humans over animals when given a choice.
Other transmission routes include congenital transmission (from mother to fetus), organ transplants and blood transfusions—blood donations have been screened for Chagas since 2007 per CDC guidelines—and through eating uncooked food contaminated by T. cruzi parasites.
UCLA Health continues research and provides care related to infectious diseases like Chagas.
