The Kissing Bug

by Daisy Hernandez

  Dr. Madigan believed the disease was on the rise in Texas for a simple reason: “we are developing more land.” Starting in the late nineties, Texas had more than a million acres of open land turned over for development, and between 2010 and 2017, it had added more housing than any other state—close to a million units. In 2018, Apple announced it was building a $1 billion campus in the Austin area on a former ranch that measures about seven thousand acres.

  Dr. Madigan looked at the state’s housing boom from the kissing bug’s perspective. In Texas, these insects feed on mammals like wood rats. The housing boom was disrupting that ecological process, and more housing translates into more families with pet dogs. To the kissing bug, those dogs are no different from wood rats, Dr. Madigan said. The dogs are dinner. “It’s like having baby wood rats in your backyard,” he told me.

  And what about climate change? Was it affecting kissing bugs?

  Insects that carry disease are usually sensitive to temperature shifts. Warmer temperatures can change how often a mosquito bites a person, and kissing bugs tend to feed more frequently during warmer times of the year. That said, scientists have pointed out that it is hard to isolate climate change as the single cause for the spread of vector-borne diseases. There are too many other factors to consider including housing conditions, access to healthcare, and land development. Also while insects carrying pathogens might appear in a new area when it becomes warmer, they could die off in another area that grows too hot.

  A few studies on the possible effects of climate change on the kissing bug disease have turned up varying results. In Chile, one group of researchers mapped the risk of the parasite being transmitted from one common triatomine species called T. infestans and found that climate change could increase the risk of transmission in certain parts of the country. Argentinian researchers looked at five species of kissing bugs in Venezuela and found that higher temperatures would make certain regions of that country less friendly to the insects, though their model did not consider the risk for transmission of the parasite.

  In 2013, researchers from the University of Texas-Pan American and the University of Texas at Austin teamed up with colleagues from Mexico’s Universidad Nacional Autónoma and focused on predicting how climate change might alter the fate of two species of the kissing bugs common in Texas: T. sanguisuga and T. gerstaeckeri. One model showed the insects moving as far north as Michigan and New York.

  …

  In 2015, the CDC granted Texas researchers a half-million-dollar federal grant, spread out over five years, to raise awareness among health care providers about the kissing bug disease. It was part of an initiative to tackle a handful of what the CDC labeled “neglected parasitic infections.” Dr. Susan Montgomery, who leads the epidemiology team at the CDC’s parasitic diseases branch and is a leading expert on the kissing bug disease in the United States, told me, “We consider them neglected because there’s relatively little attention that’s been devoted to their surveillance or prevention or treatment in the US.”

  The list of neglected parasitic infections includes the kissing bug disease and also toxoplasmosis—the disease that made news when Martin Shkreli hiked the price on a drug used to treat it. Also on the list: toxocariasis, a disease caused by dog and cat roundworms, and most common among poor Black people in the US. Every year, the disease blinds at least seventy people, most of them children.

  How did a half-million-dollar federal grant for the kissing bug disease end up in Texas? Dr. Cropper from the Lackland Air Force Base told me it was, in part, because he brought the opportunity to the attention of Paula Stigler Granados, a professor in public health, who at the time was teaching at the University of Texas’s regional campus in San Antonio. Professor Stigler Granados applied for the five-year grant, received it, and created the Texas Chagas Task Force, connecting veterinarians, health professionals, and entomologists across the state. Its members produced a guide to kissing bugs in Texas and a video for health care providers, and when the CDC funding fell short after a few years, Professor Stigler Granados applied for local grants and got them.

  Another CDC grant was awarded to Morven Edwards, a pediatric infectious disease specialist in Texas, who created educational materials about the congenital form of the kissing bug disease and who gave grand rounds, or medical lectures, about it.

  There was only one problem with the federal government sending money for the kissing bug disease to Texas: it is not where most infected people live. A year after the grants were announced, a study led by Jennifer Manne-Goehler, a clinical fellow at Harvard Medical School, estimated that California has about seventy thousand people with the kissing bug disease—all of whom, like Tía Dora, are immigrants from Latin America. This number of people surpasses that in every other state in the country, including Texas, which has only about half the number of infections.

  Dr. Montgomery at the CDC couldn’t answer my questions about funding. She did explain that there had been an application process and a review of those applications, and I realized that the agency had not proactively directed the money toward Texas as much as it had reacted to applications from the state. Dr. Montgomery also insisted that these measures had made a difference across the country in raising awareness of the disease.

  “When blood screening started in 2007 in the United States, we would get calls from health care providers whose patients showed up in their office with a letter from the blood bank saying: ’You tested positive for Chagas disease,’” Dr. Montgomery said. “Now, this year, most of the inquiries are from providers whose patient is an immigrant from Latin America.”

  …

  No one I spoke to thought Americans had to worry about an outbreak of the kissing bug disease from insects native to the United States. The CDC has recorded fewer than a hundred such infections. Even if these bugs managed to colonize a suburban home, pesticides are usually easy to find at local stores and often affordable. Also, a worried person can contact local health officials, perhaps sooner than one seventy-four-year-old woman did in rural Louisiana a year after Hurricane Katrina. She had more than fifty bites from kissing bugs, and streaks of fecal matter from the insects could be seen on the walls of her house. After a fumigation, twenty dead kissing bugs were collected. While more than half the insects carried T. cruzi, and the woman herself tested positive, this remains a rare case.

  A more common scenario is what occurred in Arizona between 2017 and 2018. Researchers screened more than a hundred women and men in Tuscon and Bisbee who reported bites from local kissing bugs, and while they found that some people had allergic reactions to the bites, not a single person turned up infected with T. cruzi.

  IF TÍA HAD KNOWN

  If I had told my auntie that I planned to gaze, in person, upon the parasite T. cruzi, she would have startled and asked, “Is it really possible to look at it?” She would have grimaced, pulled her shoulders up to her ears, as if the news offended her. She would have turned into a journalist: Where will you see it? With whom? Is it safe? Are you sure it’s safe?

  Tía Dora would have asked all this from the sofa in her living room, her feet tucked under her as if she were a schoolgirl and not a woman in her late fifties. Though I knew it was the disease that made her look tiny and delicate, I sometimes blamed the furniture in her apartment. The entertainment center spanned a wall of the living room and a television set crowded another wall, and after Tío Papeles died, Tía Dora placed a dining table into that same room. Sometimes weighing only eighty pounds, my auntie looked like she lived in a dollhouse stuffed with too much furniture.

  She was not a timid woman though. It was one trait that we shared. We were both driven. She had wanted to become a schoolteacher in the United States and had barreled her way through bureaucracy and college courses in English do that. And me? I wanted to know what had killed her and what had terrified me, and so one afternoon, I called a complete stranger who had spent a lifetime studying the parasite T. cruzi and asked if he would answer a few que
stions and if I could see the parasites he had worked with. He said yes. I only had to make my way to Iowa.

  …

  Dr. Louis Kirchhoff was waiting for me at the airport in Cedar Rapids. He immediately reminded me of the older editors at the New York Times, where I reported for a year during my twenties. He had a carefully trimmed white beard and carried a small notebook and several pens in his shirt pocket. He looked like a reporter ready to find a good story.

  I had tracked his work for more than a year. Often, Dr. Kirchhoff’s name popped up in articles about testing people for the kissing bug disease. In the mid-eighties, having finished medical school and a four-year fellowship at the National Institutes of Health, he took a position as an assistant professor at the University of Iowa and began, as he told me, “pushing around strands of DNA” from T. cruzi.

  Three decades later, discussing the prospect of this trip, he had told me, “It’ll be fun. You’ll like the parasite.”

  …

  Confession: initially, I found it easier to look at photographs of Trypanosoma cruzi than the kissing bugs. The insects felt familiar and horrifying while the single-celled parasite—magnified and photographed—struck me as something I would find in an Octavia Butler science fiction novel, which is to say that T. cruzi is a shape-shifter. In the belly of a kissing bug, it looks like a tadpole with a pointed face and is called an epimastigote. When the parasite moves into the insect’s lower intestines, it takes on the appearance of an eel with a Mohawk—a trypomastigote. In that form, the parasite leaves the kissing bug by way of the insect’s feces, and when it has the fortune to land upon a human body, particularly near a person’s eyes, mouth, or nose, it invades.

  Its shape-shifting is not done. Once T. cruzi makes it into the human body, it penetrates cells, and after a few hours, it turns into what can be described as a lavender coin: an oval shape, the tail almost gone, and, often in stained slides, with a lavender hue. In this stage, the parasite is now an amastigote and begins to multiply. This can happen in the tissue of the human heart. The lavender coin becomes two, then four, and so on, and after several cycles, the parasites shape-shift again, this time back into eels with Mohawks. They vibrate. They thrash. They overwhelm the cell they inhabit, killing it in the process, and the parasites begin hunting again—finding another cell, sneaking in, and transforming again into coins. If this cycle is repeated often enough in the heart, cells gradually die off, and scar tissue forms. Over the course of decades, the heart loses strength. It is hard to pump blood with scar tissue.

  The parasite is technically a trypanosome. From the Greek, trypanon means a borer, one that punctures wood or plant material by rotating. Soma means body. An organism that drills into the body. The term trypanosome was actually coined in 1843 when a scientist first found the parasite in frogs.

  …

  During lunch near Iowa City, Dr. Kirchhoff explained, over his margarita pizza, that T. cruzi has a special pouch of DNA minicircles called a kinetoplast. “It’s loaded with DNA,” he said, adding that the RNA messages transcribed from the DNA undergo a lot of editing, which raises many questions. “Why do they have a complicated system for editing messages? We don’t do that, and we’re more complicated.”

  He told me that once the parasite makes its way into the human body, it has a lot to consider. “Here’s the problem. From the parasite’s perspective, as soon as they get in, they get attacked by the immune system.” Millions of years ago, though, the parasite figured out a way around this issue: it exits the bloodstream. “What T. cruzi does is get into the cells and multiply, and they don’t have to deal with attacks.”

  In other words, the parasite finds a sanctuary in the human body, where it can reproduce safely. I thought this was cunning, but Dr. Kirchhoff did not approve of that word, arguing that it has a negative connotation. “They’re very smart,” he said between bites of pizza, and technically T. cruzi is not targeting humans. It takes up residence in a great number of mammal species. Again, from the parasite’s perspective, humans just happen to be another mammal.

  Dr. Kirchhoff spent years trying to figure out how to test people for evidence of T. cruzi infection. Along with his collaborator Keiko Otsu, he recombined distinct segments of the parasite’s DNA to create hybrid coding sequences. They inserted these hybrids into benign laboratory strains of E. coli. These bacteria functioned like factories, churning out billions of the hybrid recombinant proteins derived from T. cruzi. After much testing, Dr. Kirchhoff and Otsu figured out which of these hybrid recombinant proteins would work best in testing people for the kissing bug disease.

  He licensed the proteins to Abbott Diagnostics, and by 2016, the FDA had approved three tests for screening blood donors across the country, including two that primarily use Dr. Kirchhoff’s hybrid recombinant proteins. If a blood donor is infected with T. cruzi, some of the donor’s antibodies will recognize these recombinant proteins and grab on to them. “These bound antibodies can then be detected,” Dr. Kirchhoff noted, and this leads to a positive test result.

  …

  The day clouded over as Dr. Kirchhoff and I walked across the University of Iowa campus toward the Eckstein Medical Research Building. It was here that he had worked for so many years with T. cruzi’s DNA. While Dr. Kirchhoff was no longer conducting new research, he kept batches of the parasite on hand to meet federal regulations for the screening test and borrowed lab space from a generous colleague in the building.

  The laboratory had steel-gray counters, rows of sterilized flasks, and lots of binders stuffed with papers. Dr. Kirchhoff hauled what looked like a Styrofoam cooler from off the top of a metal shelf and carried it into a room with two biosafety cabinets and a table with two microscopes. He pulled a flask from the cooler and held it to the light. It looked like it had a shot of bourbon in it. The liquid was a suspension of bovine liver powder and salts, and I could see dots floating in it: T. cruzi—millions, alive.

  Dr. Kirchhoff rocked the flask so the liquid spread. “They think they’re in the gut of an insect,” he said. In other words, the parasites didn’t know they were in a flask. They thought they were inside a kissing bug.

  These parasites, Dr. Kirchhoff told me, belonged to the Tulahuén strain, which has been widely studied by scientists conducting research into T. cruzi. It was isolated from a person who lived in Tulahuén, Chile, during the 1940s, and it had been maintained in liquid culture all these decades. In other words, I was in a room with the descendants of parasites that had been isolated from someone in South America before Tía Dora was born.

  I noticed a flask in the cooler labeled “LOL.” “What does that stand for?”

  “Lots of life,” he said, matter-of-fact.

  He put the flask under the microscope, adjusted the lenses, and after a few seconds, he declared, “This is the best. It’s just loaded with parasites.”

  I laughed to avoid feeling the fear in my gut, and I peered into the microscope. At first, I saw a blurry piece of white paper. When my eyes adjusted, I noticed clumps of tangled black hair floating into view. Besides the thin, tangled hair strands, pencil marks stained the screen, as if a child had drawn the number one sideways, vertically, and diagonally. The more I looked at the field visible through the microscope, the more the flask of parasites reminded me of a cell phone, its screen cracked and scratched. Where were the parasites? “I can’t see it,” I finally said.

  Dr. Kirchhoff adjusted the microscope. When I still couldn’t make out the parasite, he patiently pulled out his iPhone, took a photo of the flask, then zoomed in. “There,” he said, satisfied. “You can see them now.”

  I squinted at the photograph. “Wait. The scratches are the parasites?” I asked, dumbfounded.

  Dr. Kirchhoff examined the photograph on his phone. He had studied this parasite for much of his professional life. They were apparently as familiar to him as his own fingernails, and I had just told him the object of his obsession looked like a scratched cell phone screen. “I guess you
could say that,” he said hesitantly.

  I returned to the microscope. I focused my eyes on one area of the flask, and this time I could see that the scratch on the glass was thrashing. Its tail, or flagellum, enabled the parasite to move. I focused on a second scratch, another parasite. This one floated, the movement so incredibly slight, it would be easy to miss. I watched as a third parasite joined a tangle of fine black hair. My vision shifted, and I could see that the clump of fine hair was not a clump at all, but rather a bundle of parasites, their tails vibrating.

  …

  Another confession: I did not think of Tía Dora when I saw the parasites. I watched them thrash and thought: They’re alive. They are tinier than a strand of human hair, and they are alive. Later, I wondered how I could have been taken, even for a few seconds, by a shape-shifting parasite that can kill the human heart and that had killed my auntie.

  IN SEARCH OF OTHER FAMILIES

  FALTA

  Tía Dora would have approved of my new life in Ohio, and specifically my apartment. She would have liked the hardwood floors, the built-in bookshelves, and the elm tree outside the living room window. She would have loved the park around the corner, the coffee and quiche sold on the main street, and the shopkeeper who imported gloves knitted in Peru. She would have admired the historic gas lamps on the sidewalk, then told my mother on the phone that the apartment was “del high class.”

  She would have adored the college campus where I was teaching, swelled with pride when I told her the school had opened in the early nineteenth century, taken pictures with me next to the redbrick buildings. She would have raised both eyebrows when I told her that civil rights activists trained college students here in 1964 to register Black voters in Mississippi. She would have murmured, “Tiene su historia,” which would have been her polite Colombian way of acknowledging that key historical events had taken place, but she never wanted to be involved in anything political.