Hundreds of thousands of people in the United States have been infected with the potentially fatal kissing bug disease, but U.S. health care workers’ lack of awareness often prevents successful diagnosis and treatment, according to a report released this week.
The dearth of federally licensed drugs to combat the disease also limits patients' access to treatment, according to findings presented at the annual meeting of the American Society of Tropical Medicine and Hygiene (ASTMH) on Thursday.
“This is a real health concern in the United States that deserves much more attention, research and funding for patient care and education,” said Dr. Jennifer Manne-Goehler, a clinical fellow at Harvard Medical School and Beth Israel Deaconess Medical Center in Boston who was the lead author of the study.
More than 300,000 people in the U.S. have kissing bug, or Chagas, disease, endemic to Mexico, Central America and South America — where there 8 million people have been infected, according to the Centers for Disease Control and Prevention (CDC).
At the onset, symptoms of the disease — caused by a parasite, Trypanosoma cruzi, which is spread through the feces of kissing bugs — can include fever, fatigue, body aches, rash, diarrhea and vomiting, according to the CDC (PDF). After the initial acute stage, most people enter a prolonged asymptomatic state, during which few parasites are found in the blood, the CDC says. Regardless of symptoms, the disease can be transmitted to others. People are often unaware they have been infected and can know for sure only if they complete blood tests.
Over time, the disease can cause heart failure and intestinal complications.
An ASTMH press statement released Tuesday called the disease a “stealthy parasitic infection,” often spread via blood-sucking kissing bugs, which “feed on people’s faces during the night.” Transmission can also occur through blood transfusions or organ donations from infected people, according to the CDC. During pregnancy, mothers can transmit the disease to their babies.
The Food and Drug Administration has not yet approved two medicines — nifurtimox and benznidazole — that are currently used to treat the disease but carry a risk of nerve damage, nausea and weight loss, according to the ASTMH statement.
The CDC makes the drugs available "when no satisfactory alternative treatment exists," according to the FDA, adding that "subjects are generally willing to accept greater risks from test articles that may treat life-threatening and debilitating illnesses."
Manne-Goehler’s study used data collected from the American Association of Blood Banks and the CDC. From 2007 to 2013, 1,908 blood donors tested positive for Chagas disease, but only 422 doses of medications have been administered by the CDC.
“This highlights an enormous treatment gap,” Manne-Goehler said in the ASTMH statement.
The infection rate in the U.S. is much higher than previously thought, the ASTMH reported, and the effects can be deadly.
“The disease can be fatal if not treated,” said Melissa Nolan Garcia, a research associate at Baylor College of Medicine in Houston and co-author of a separate study on Chagas disease in Texas published in the American Journal of Tropical Medicine and Hygiene on Tuesday.
“You are normally asymptomatic until disease has progressed at which time treatment is not helpful. We call this the silent disease,” Garcia said.
“The concerning thing is that majority of the patients [I spoke to] are going to physicians, and the physicians are telling them, ‘No you don’t have the disease,’ she said.
Garcia spoke to several groups of physicians and cardiologists as part of an educational campaign to increase physician awareness.
“A lot of the cardiologists were aware of Chagas disease, but they don’t make the connection when the patient is sitting in front of them,” she said.