A little-known parasite infects 300,000 people in the U.S.

Why isn’t more attention paid to Chagas disease, a potentially lethal infection? Because it’s a disease of poverty.

This story appears in the June 2019 issue of National Geographic magazine.

I grew up believing that my auntie had almost died because she ate an apple in South America.

According to the family stories, the fruit had been contaminated, or maybe an insect had been crawling on it and had bitten Tía Dora. However it had happened, my family understood this: A New York doctor had diagnosed my auntie with Chagas disease. It meant my auntie could die. We didn’t ask questions. English wasn’t our first language. My parents worked in factories. We took care of my auntie as she went in and out of hospitals for decades. When I reached my late 30s, Tía Dora was rushed to the hospital one night. A week later, she died. She was 59 years old, and I thought Chagas was a rare disease. I was wrong.

Named after the Brazilian doctor who discovered the disease in 1909, Chagas is more prevalent today in the United States than the Zika virus. And in the Western Hemisphere, the disease burden of Chagas is almost eight times that of malaria.

Some 10,000 people die each year from Chagas disease. The Centers for Disease Control and Prevention (CDC) estimates that about 300,000 people living in the United States have the disease. Many, like my auntie, grew up in poor communities in South America, Central America, or Mexico. Few know they have Chagas disease because the parasite that causes it, Trypanosoma cruzi, is a cunning microorganism.

It’s transmitted to people by way of a triatomine insect called a kissing bug. In the acute stage, people usually can be cured; unfortunately, less than one percent of infected people are diagnosed or treated. The parasite can live in the body throughout a person’s life without causing symptoms, but 20 to 30 percent of infected people will suffer cardiac damage. Chagas-related heart problems include irregular heartbeats, left ventricular aneurysms, and even heart failure.

Just as frightening is this: T. cruzi can cross the placenta. It’s estimated that as many as 315 babies a year are born with Chagas in the United States. I think of them as the “no-name babies” because health officials don’t know who these children are. Pregnant women are not routinely screened for Chagas in the United States.

In 2014, a few years after my auntie’s death, I traveled to Colombia. At the University of the Andes in Bogotá, biologist Felipe Guhl has been studying the kissing bug disease for more than four decades. There I learned that these insects are homebodies, often living where they don’t have to crawl far to reach prey. That might be a human, a dog, a marsupial, a raccoon—the bugs aren’t picky about which animals they bite. In rural areas of Latin America, they live in the cracks of mud houses during the day and come out at night to feed. The bite, though painless, leaves a small wound. The T. cruzi parasite is in the bugs’ feces and is transmitted when fecal material enters the bite wound.

Guhl says that to eradicate Chagas, you’d have to do away with wildlife—obviously not possible. Also, given the beetle-like bug’s many species, “It’s like a baseball game,” he says. If you get rid of one, “there are other players on the bench.” And the parasite itself is ancient. Guhl and an international team of researchers found T. cruzi in 9,000-year-old mummies from the deserts of Peru and Chile.

Having grown up hearing about Chagas disease and knowing that a dreaded bug could kill me, the last thing I wanted was to see one. And yet I did. Maybe I wanted to face my fears. Maybe I wanted to see the truth of what I only knew as family folklore.

Off I went with Guhl’s research assistant to see their insect colony. The day was chilly, but when the graduate student opened the door to a room the size of a walk-in closet, I stepped into a world both balmy and dimly lit. Think of a mild summer night out in the woods of North Carolina.

The room had shelves filled with glass jars of kissing bugs crawling on filter paper folded accordion style. Several were dark with pretty patterns of amber and black at the edges of their abdomens. Some, like the Rhodnius prolixus, were less than an inch long; others, like the Panstrongylus geniculatus, were longer. Kissing bugs tend to fly when they’re starving. Now they began scrambling up the filter paper toward the cheesecloth covering on the jars. The graduate student smiled at me weakly. “They think we’re going to feed them,” he said. Their dinner? Chicken blood.

Kissing bugs are native to the United States, too. At Texas A&M in College Station, the entomology department has about a hundred specimens, collected years ago. In fact, Texas has the greatest diversity of kissing bug species in the country, and the CDC funded the start of the Texas Chagas Taskforce to raise awareness there.

The CDC, however, estimates 75 or fewer cases of what could be called “homegrown Chagas”—cases where people have been infected by kissing bugs native to the United States.

If we have kissing bugs aplenty in Texas and some 300,000 people in the U.S. infected, why do so few of us know about Chagas? “It’s a disease of poverty,” says Sheba Meymandi, a cardiologist whose team in California’s San Fernando Valley has screened about 9,000 people who were born in Latin America for the disease. Many of the people infected have other issues to worry about: their immigration status, diabetes, and jobs that vanish overnight. Patients come to her when their hearts are failing. Because Chagas isn’t easily transmitted between people, the disease stays largely confined to the Latino community—and that contributes to the lack of knowledge about it.

Through word of mouth in the Washington, D.C., area, I met Janet, a law school graduate from South America who’s married to a U.S. citizen and who asked that we not use her last name to preserve her privacy. Janet had never been screened for Chagas, but her dad was infected and so was her sister. In 2015, pregnant with her second son, she found herself in an emergency room. Her baby, born at 30 weeks, was infected with T. cruzi. While babies infected with this parasite often don’t show any signs of distress, Janet’s premature son weighed less than four pounds and already had scar tissue on his heart. “It was shocking to learn that I could transmit this to my baby,” she told me.

Doctors were able to treat Janet’s son. But the recommended guidelines for newborn screening from the Department of Health and Human Services don’t include congenital Chagas disease, even though there are more estimated cases of the disease than at least 15 other diseases currently listed.

This is particularly devastating because the drug benznidazole can often eliminate the parasite in infected children. In 2017 the Food and Drug Administration approved the drug for use among children. It sounds like good news, and it is, except benznidazole, which was developed in the 1960s and ’70s, can have negative side effects for people with chronic Chagas. The other drug available for Chagas, nifurtimox, also has these limitations. Research funds continue to be scarce for this disease.

I’ve come a long way from thinking that my auntie ate a poisoned apple and contracted an infectious disease. However, the real story—spanning borders and sitting at the intersection of science and social issues like poverty and immigration—has also become more complicated than anything I could have imagined when I was a child.

Daisy Hernández is the author of A Cup of Water Under My Bed: A Memoir and co-editor of Colonize This! Young Women of Color on Today’s Feminism. She is an assistant professor in the creative writing program at Miami University in Ohio, and her book, In Search of the Kissing Bug, is forthcoming from Tin House Books.
Correction: A previous version of this article included an incorrect picture of the triatomine bug. It has been updated with a correct picture.