A little-known but potentially deadly parasite from Latin America has become one of the latest threats to the blood and organ supplies in the United States, especially in Los Angeles, where many donors have traveled to affected countries, health officials say.
Last year, two heart transplant patients at different Los Angeles hospitals contracted the parasitic disease, called Chagas, causing health authorities to issue a national bulletin. Within months, both patients subsequently died, although not directly from Chagas, according to the U.S. Centers for Disease Control and Prevention.
The parasite, which is generally passed to humans from a blood-sucking insect that looks like a striped cockroach, can feed over years on tissues of the heart and gastrointestinal tract. After decades, tissues can be eroded so much that the organs fail.
If caught early, strong anti-protozoal drugs such as nifurtimox can bring the parasite to undetectable levels or, in some cases, eliminate it entirely.
If the parasite is given the chance to multiply over years or decades, however, those infected may have to be treated with heart-regulating drugs or get a pacemaker or heart transplant.
The U.S. Food and Drug Administration approved a test suitable for widespread screening in December. Blood banks have now begun systematically checking their supplies for the Chagas parasite.
No organ donors in the United States are now being screened for the parasite, although the organ procurement agency that covers much of Southern California plans to begin testing some donors in mid-April. At first, the screening will be focused on people who have lived in or traveled to rural parts of Latin America, said Thomas Mone, chief executive of the agency, OneLegacy.
In Latin America, about 10 million to 12 million people are believed to be infected with the Chagas parasite. As many as 1 million of them are expected to die from the disease unless there are advances in treatment, according to Dr. James Maguire, a University of Maryland expert on the disease.
“Chagas is very, very prevalent in South and Central America,” said Marek Nowicki, a USC blood-disease expert who studied the effect of Chagas on the Southern California organ supply with the National Institute of Transplantation.
“The number of [immigrant] Latinos in Southern California, Texas and other parts of the United States are growing, but especially in L.A., a large proportion of organ donors are Latino,” Nowicki said. “They’re basically bringing with them the disease prevalence in the area they used to live.”
The problem is not limited to immigrants. Tourists, too, can be carriers. The heart transplant cases in Los Angeles last year illustrate the problem.
As a result of the cases, the CDC last summer warned doctors that the prevalence of infection might be higher than previously thought, especially in areas like Los Angeles County.
Chagas is a clear reminder that “diseases don’t have geographic borders anymore,” said Dr. Suman Radhakrishna, an infectious diseases expert in Los Angeles who helped treat Russo. Doctors need to be “cognizant that diseases happening elsewhere in the world can happen in our backyard too.”
Diseases like Chagas and cysticercosis have emerged as an issue for some opponents of illegal immigration, who argue that exotic diseases are often spread by illegal immigrants.
“Curbing illegal entry will diminish the problem of exposure to such diseases because legal immigrants are medically screened to protect the U.S. public,” said Jack Martin, special projects director for the Federation for American Immigration Reform, an immigration control group..
Public health officials say the migration of diseases has always been an issue—and is especially so today, in an increasingly mobile world with a global economy. Many urge caution, not alarm.