Deadly Parasite

Source: Los Angeles Times Website

Parasite is a growing concern for healthcare professionals
One in 3,800 donors in the L.A. area tested positive for Chagas, a deadly
disease that is mainly found in Latin America.

By Rong-Gong Lin II, Times Staff Writer
March 15, 2007


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.

Insect transmission of the parasite in the United States is rare, but
public health and blood bank officials have been concerned about its
increasing prevalence in the blood supply.

In 1996, using an experimental test, the American Red Cross found that one
in 9,850 blood donors in the L.A. area tested positive for the parasite,
Trypanosoma cruzi. Two years later, it was one in every 5,400. By 2006, a
more refined test detected the parasite in one in 3,800 donors. About 10%
to 30% of infected people develop symptoms of chronic disease, experts
say.

By contrast, HIV, which blood banks screen for, shows up in one of every
30,000 donors, said Susan Stramer, executive scientific officer for the
Red Cross.

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.

By late January, the American Red Cross and Phoenix-based Blood Systems,
which collect about 65% of the U.S. blood supply, had started screening
blood for T. cruzi. Other banks, including the Blood Bank of San
Bernardino and Riverside Counties, have no immediate plans for screening
but are monitoring test results from banks that are using the test. In
late February, the CDC reported that the "FDA is expected to recommend
implementation of the test by all blood-collection establishments."

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.

One donor was a native of El Salvador living in Los Angeles, and the other
was born in the U.S. but had traveled to Guadalajara, Mexico, where T.
cruzi is endemic.

Richard Edward Russo, then 73, received the heart from the Salvadoran
native. The Burbank retiree appeared to be recovering nicely last year
when, several weeks after his transplant at St. Vincent Medical Center in
Los Angeles, he developed a fever and a rash. He complained of being tired
and couldn't eat or walk.

About the same time, a 64-year-old man developed similar symptoms after
receiving a transplant at UCLA Medical Center. He had received the heart
from the American tourist.

At both hospitals, doctors submitted the patients to a battery of tests,
concluding separately that they had Chagas.

The CDC sent anti-parasitic medication out from Atlanta. The drug reduced
the parasite in the blood of both men to undetectable levels. But Russo
never got better, his wife, Carolyn, said. He suffered from other
hospital-acquired infections and had pneumonia at least twice.