Tackling an Invisible Invader

This op-ed was first published in UCLA Today Online.

By Claire Panosian Dunavan

TEN YEARS AGO, in our hospital's cardiology ward, I met a man with severe heart failure. A day laborer from Mexico, he was eligible for a new heart, but first we needed to learn what was wrong with his old one. The usual suspects — clogged coronaries, leaky valves, alcohol-induced muscle damage — had already been ruled out.

A week later, we had the answer. The patient tested positive for Chagas disease, a South American parasitic scourge principally acquired from blood-sucking bugs. At last we could tell the weary man why his heart was a stretched-out balloon, his lungs chronically waterlogged. Over decades, a tiny invader had slowly destroyed his body's vital pump.

But no amount of earnest talk convinced him to consider a transplant. In his soul, he was already "muerto," he said. Before long, he would be dead in body as well.

Chagas disease is no stranger to the United States. At least 100,000 infected persons from the parasite's native haunts — the southernmost tip of Latin America through Mexico — reside in our cities and towns. Most have no knowledge of their hidden invader.

In Los Angeles, which probably has more Chagas patients than any other city in the nation, as many as 1-in-2,000 to 1-in-10,000 blood donors have been exposed to the parasite. Roughly one-quarter of those donors remain capable of transmitting it.

Sometimes their organs are also contagious. This lesson was brought home last year when two Southern California patients developed acute (and ultimately fatal) Chagas disease after receiving infected heart transplants.

The good news? In December 2006, the Food and Drug Administration licensed a new test to screen donated blood for the disease. That should reveal the true scope of infection in regions like ours and safeguard future blood and organ recipients from one more deadly threat.

Other consequences of blood testing are less clear. What will happen, for example, to the many previously undiagnosed carriers that screening will reveal, including outwardly healthy people who rolled up their sleeves to donate blood before a family member's operation?

Because only 10% to 30% of Chagas patients develop heart complications over a lifetime, many newly identified carriers will need a yearly electrocardiogram and medical checkup.

However, other victims could require far more: from antiparasitic drugs, cardiac pacemakers and specialized gastrointestinal procedures to — on rare occasions — heart transplant evaluation.

In Los Angeles, what makes the most sense is to house this multifaceted medical expertise under one roof. A local center of excellence could not only diagnose and treat patients with Chagas disease, but also focus on other imported infections unfamiliar to most area physicians.

Ten years ago, help came too late for my patient. I still remember looking into his eyes and watching the final flickers of hope fade. With earlier diagnosis and skillful care, however, we have much to offer his fellow sufferers.

There's also a moral principle at stake: Licensing a blood test to protect the uninfected should not give us the license to ignore those who are.

(Dunavan, a clinical professor of medicine and infectious diseases, is co-founder of UCLA's Program in Global Health.)