ANDREA SEABROOK, host:
A disease originally from Latin America is now moving into the United States. It's called Chagas. It's carried by an insect known as the kissing bug, and it can lead to gastrointestinal conditions and even heart failure.
Today, at a meeting of the American Association of Blood Banks, a Red Cross official presented evidence that Chagas is spreading northward.
NPR's Brenda Wilson has more.
BRENDA WILSON: People with Chagas disease often show no symptoms for decades. But because the infection can be transmitted through transfusions and organ transplants, blood banks in the U.S. began testing for the disease this year.
Dr. Susan Stramer, the executive scientific officer of the American Red Cross, says 250 cases in blood donors have so far been confirmed.
Dr. SUSAN STRAMER (Executive Scientific Officer, American Red Cross): Until now, we had no idea about the prevalence or the frequency of infected individuals in the United States. So this is the first survey or analysis of how many individuals who live in the United States may be infected and may harbor the parasite.
WILSON: Stramer estimates that about 10,000 people in the U.S. are infected with Chagas. But the numbers of infections are far greater when you consider that the vast majority of the donors who carried the antibodies came from outside the U.S. and are underrepresented as blood donors.
Eradication programs in many countries such as Brazil, Argentina and Chile have cut the number of new cases in Latin America by half. But the parasite isn't standing still. It's been found as far north as Maryland and Northern California.
Dr. STRAMER: They're called reduviid bugs or assassin bugs or kissing bugs. Twenty-seven states harbor this insect. So the insect that supports the parasite is present here in the United States as well as mammals such as possums, skunks. When humans go into rural areas where both the animals are that are infected and the insects, it's possible that humans may be get bitten.
WILSON: At least 20 of the blood donors appear to have acquired the infection in the U.S., and they share certain characteristics.
Dr. STRAMER: We have seen camping, but these are going to be very non-specific. It doesn't mean if you go camping, you're going to get infected. Some of our donors who were infected in the U.S. only are hunters so they may handle what they've hunted. And so if they have contact with the blood after they've killed the animal, that's one potential exposure of. And also because they're outside when they're hunting, they may be exposed to the insects.
WILSON: The insect bites and droppings deposit waste that carries the parasite, which in 10 to 30 percent of the people exposed finds its way to the gut or to heart muscle.
Dr. JAMES MAGUIRE (Director, International Health Division, University of Maryland): I've unfortunately seen many patients who've have chronic Chagas disease.
WILSON: Dr. James Maguire is the director of the International Health Division at the University of Maryland. He worked in a rural area in Bolivia where at one time Chagas had been detected in 45 percent of the people.
He describes it as a disease of the poor, whose mud and stick homes with patched roofs provide a place for the insects to hide. Children bitten that might often don't experience symptoms until decades later as adults.
Dr. MAGUIRE: People become short of breath. They develop edema in the lower extremities. They become weak. And the average survival after the first signs of congestive heart failure without intervention is very short. A couple of years in over half of the people will have died from congestive heart failure.
WILSON: It is treatable if diagnosed before chronic conditions develop.
Mr. RAUL FLORES (Resident, Washington, D.C.): (Through translator) No. I've never heard of it. I didn't know anything about this disease.
WILSON: Raul Flores has never heard of Chagas disease nor had any of the other patients of La Clinica Del Pueblo in Washington, D.C., which serves thousands of Latin American immigrants.
Clinical director Dr. Meredith Josephs says she's seen one patient who'd already been diagnosed by the time she began treating him for congestive heart failure. She says her patients are worried just as much about how they will be perceived.
Dr. MEREDITH JOSEPHS (Medical Director, La Clinica Del Pueblo, Washington, D.C.): I think it would be important to recognize that this parasite is not transmitted from person=to-person contact. So that other persons that do carry this parasite are not putting other people at risk of the disease. I would hate to see for there to be widespread fear with this new information coming out.
WILSON: Some experts say that people who believe they've been exposed to the parasite may want to be tested for Trypanosoma cruzi, the parasite that causes Chagas disease. But neither the World Health Organization nor the Centers of Disease Control and Prevention recommend widespread screening for the disease.
Brenda Wilson, NPR News. Transcript provided by NPR, Copyright NPR.
