Hundreds of thousands of people in the U.S. could be infected with the deadly disease known as Chagas—and most of them don't know
The vinchuca bug, also known as "the kissing bug," transmits Chagas disease. Image: Helen Coster.
If Maira Gutierrez hadn't donated blood over a decade ago, she probably wouldn't know that she has Chagas, a parasitic disease that may one day stop her heart. The Los Angeles resident felt fine. Only her blood sample, which contained the disease's telltale antibodies, revealed that she was sick. Like many Chagas patients in the United States, Gutierrez probably contracted the disease as a child, when she was living in rural El Salvador. Today she suffers from heart palpitations and undergoes an annual echocardiogram and electrocardiogram to monitor the disease's progress. "It's a relief to know what I have, where it came from, and what it's doing to me," Gutierrez says. "I know that I'm not going to die tomorrow."
Chagas is caused by a parasite called Trypanosoma cruzi (T. cruzi) that remains dormant in peoples' bodies for up to 30 years, until it kills them suddenly by stopping their hearts or rupturing their intestines. It's a silent killer; patients rarely show symptoms or know that they're infected. Worldwide, 18 million people have the disease. Chagas has been a scourge of the developing world for decades—particularly in poor Latin American countries, where a bug called the vinchuca, sometimes known as the kissing bug (because it bites people on their faces while they sleep), transmits the disease. But it's increasingly becoming a U.S. health problem.
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Because of immigration, more and more cases are being reported here: Caryn Bern, a medical epidemiologist in the Division of Parasitic Diseases and Malaria at the Centers for Disease Control and Prevention, estimates that 300,000 immigrants in the United States have Chagas. A disease that originates in rural Latin America is now treated, in many cases, in a cardiologist's office in Los Angeles or an emergency room in New York. In response to this trend, in 2007 cardiologist Sheba Meymandi and the Olive View-UCLA Medical Center opened the U.S.'s first Chagas clinic, in Los Angeles, and have since treated over 100 Chagas patients. (The vast majority of people who have Chagas do not get treated, often because they're asymptomatic or they're undocumented and afraid to seek medical care.) "Forget the Hippocratic oath. Forget being altruistic," Meymandi says. "Congestive heart failure is one of the most expensive diagnoses. If you want to save money in the long term, this should be part of preventative care for Latin American immigrants."
Chagas is a disease of poverty. The vinchuca, which transmits most cases, lives in the walls of mud huts. Humans can only transmit it congenitally—from mother to child—and also through blood transfusions and organ donations. The CDC's Bern says that most Americans with the condition contracted the disease as children in Latin America—and that many are now experiencing late-stage heart problems. "Since blood bank screening started in 2007, 1,400 infected donors have been detected," Bern says. "The majority of infected donors are originally from Latin America, but some are not." Most people who contract Chagas remain asymptomatic; 30 percent will likely develop heart or intestinal disease and die.
The burden of preventing, diagnosing, and ultimately eradicating Chagas falls to the governments of poor Latin American countries, where the disease represents a costly and elusive public health crisis. In landlocked Bolivia, where 60 percent of people live under the poverty line, 1 million people—or almost 10 percent of the population—has Chagas. (Bolivia has the highest rate of infection of any country.) Twenty percent of fertility-age women are infected, and as many as 3,000 infected children are born every year. Other Latin American countries, like Chile and Argentina, have made bigger strides in eradicating the disease, because once people upgrade to homes made of cement, they're no longer exposed to the vinchuca.
Bolivia has been slower to develop. "If we can improve the housing situation, we can reduce Chagas infection," says Dr. Faustino Torrico, who runs a Chagas clinic at the Universidad Mayor de San Simon in Cochabamba, Bolivia. "It's a problem of development. It's not just a coincidence that Bolivia is one of the poorest countries and has the highest prevalence of Chagas."
Public health experts agree that eradicating the vinchuca bug is the first step in stopping Chagas. The vinchuca strikes at night, transmitting the potentially lethal parasite. (Only a small percentage of vinchucas contains the parasite, which is why travelers who are abroad only briefly aren't at risk.) Last year the Bolivian government spent $1 million—a sliver of the country's $422 million health budget—inspecting 44,000 homes for the vinchuca, and fumigating infested homes. "We're trying to stop the spread of a disease that becomes increasingly more expensive to treat, regardless of where the patient lives," says Dr. Justo Chungara, who heads Bolivia's national Chagas program. "But to do that, we need the resources to fumigate more homes and treat more people."
They also need to convince people to get tested and treated, a tough sell because Chagas patients feel fine, and Chagas drugs have painful side effects. A patient might experience a fever, which goes away on its own, before he develops a chronic, asymptomatic stage of the disease. "In general you'll find nothing," says the CDC's Bern. "Unless you know to look for Chagas disease, you won't find it."
Currently, there are only two drugs that fight Chagas disease—benznidazole and nifurtimox—but they cause rashes and gastrointestinal problems. Drug companies in wealthy countries aren't interested in developing and testing Chagas drugs for a simple economic reason: There is no way that considerable investment in research will be recouped in drug sales. Swiss drugmaker Roche manufactured benznidazole until 2006, when it ceased production and transferred the intellectual property to Lafepe, a lab in Brazil. (In countries like Bolivia, benznidazole costs $40 for a two-month supply.) Nifurtimox is manufactured by Bayer and has more frequent side effects; most doctors prescribe it only if their patients can't tolerate benznidazole. But because of delays in manufacturing, benznidazole is currently in short supply. Dr. Torrico, of the Cochabamba, Bolivia Chagas clinic struggles to obtain the drug. "Every day we have 20 new patients," he says."It's not useful to diagnose Chagas if there's no way to treat it."
Another challenge stems from the fact that Chagas patients show minimal symptoms. Doctors simply disagree on how to determine that patients have been cured. With a disease like tuberculosis, patients stop showing symptoms after six months of treatment. But because Chagas patients are asymptomatic to begin with, doctors decide that they've been "cured" based on the number of T. cruzi antibodies that remain in their system. "If you have an infection for 10 years and get treatment, you might need another 10 years post-treatment to be negative," says Dr. Henry Rodriguez, general coordinator for Doctors Without Borders in Bolivia and Paraguay. "It's a risk to take medicine. Probably you will be cured. It's a problem to convince people."
Maira Gutierrez, of Los Angeles, knows this firsthand. After learning that she has Chagas, Gutierrez convinced her mother and brothers to get tested, but her sister won't budge. "She doesn't want to think of herself as someone who has a disease that has no cure, and that she's going to die."