Potentially deadly disease identified in 8 southern states

The brisk chill of autumn swept into the Northwoods this past week, a reminder that winter is not far away and prompting seasonal residents to circle calendar dates for their trips to warmer climates.

This year, the seasonal routine comes with a health advisory, with some researchers sounding the alarm about a little-known but potentially deadly disease known as Chagas. Its presence has been confirmed in at least eight southern and southwestern states.

In a study published this month in Emerging Infectious Diseases, researchers say it is prevalent and dangerous enough to be classified as “endemic,” meaning it is constantly present in a specific population or populated place.

Chagas is caused by a parasite called Trypanosoma cruzi and is transmitted by the triatomine insect, also known as the “kissing bug.” At night, an infected insect feeds on a person, often around the lips or eyes. Its feces, deposited near the bite, contain the parasite. If it enters the wound, infection follows.

The parasite can remain dormant for years, even decades, producing few or no symptoms before suddenly emerging to cause severe cardiac or gastrointestinal disease. Left untreated, Chagas can cause heart failure, arrhythmias, stroke, or sudden death, the American Heart Association reports.

For many years, Chagas was considered a “tropical” illness confined to Central and South America, but now cases have been confirmed in California, Arizona, Texas, Tennessee, Louisiana, Missouri, Mississippi, and Arkansas.

Kissing bugs are present in at least 32 states, primarily in the South and Southwest. By the CDC’s estimate, some 300,000 people from Latin America in the U.S. are already infected. Most people contracted the disease abroad, but a growing number of homegrown cases underscores what researchers call a “robust presence” of the parasite.

Here’s the good news. America’s homes are much more resilient than those of rural Latin America, where the disease is rampant, and residents in areas prone to Chagas can take preventive action: Seal cracks and gaps around homes and cabins; use screens on windows and doors; reduce outdoor lighting that attracts insects; and keep pet sleeping areas indoors when possible.

The study

In the published study, “Chagas Disease, an Endemic Disease in the United States” by Norman L. Beatty of the University of Florida College of Medicine in Gainesville, Florida, and colleagues, the researchers stated that a systematic literature review found 29 confirmed and 47 suspected cases of locally acquired Chagas disease during 2000–2018. 

“Shared risk factors included rural residence, history of hunting or camping, and agricultural or outdoor work,” the study stated. “Those numbers likely greatly underrepresent underlying human infections.” 

Wildlife, captive animals, and companion animals, especially dogs, are commonly infected with T. cruzi parasites across the southern United States, the study observed. Those animals serve as reservoirs that nurture the parasite’s transmission cycle.

Until recently, public health agencies dismissed most U.S. cases as “imported” by immigrants from Latin America, where the World Health Organization estimates that 6 to 7 million people suffer from the disease. However, the new CDC review shows that this is no longer the case.

So far, Texas is the hotspot for the disease. Since 2013, the state’s Department of State Health Services has documented 50 probable and confirmed autochthonous cases, the researchers wrote.

Indeed, the authors asserted, labeling the United States as non-Chagas disease-endemic perpetuates low awareness and underreporting of the disease. They urged that the disease in the U.S. be reclassified as “hypoendemic” — meaning it is present at low but sustained levels — which would allow for broader public awareness campaigns.

“Social and epidemiologic research, which should focus on populations that are disproportionately affected, is lacking,” the researchers wrote. “Recognizing Chagas disease as endemic to the United States would ideally help increase funding agencies’ investment in research toward improved diagnostics and treatment and, perhaps more critically, would support local public health agencies in obtaining resources needed to educate communities, report cases, and prevent new infections.”

Because the disease is mislabeled, the authors contend, physicians rarely consider Chagas in their diagnoses. Veterinarians also underestimate its risks to dogs and other animals, while the media continues to describe it as a foreign disease, detached from American soil.

“The current classification of the United States as nonendemic for Chagas disease has led to critical issues such as low physician and veterinary awareness…which prevents appropriate differential diagnosis and could subsequently contribute to potential underreporting,” they wrote.

Without testing, the disease remains invisible until irreversible damage to the heart or digestive system occurs.

The United States contributes almost a quarter of the world’s scientific research on Chagas disease, the authors wrote, but most of it focuses on pharmacological and diagnostic development and immunology, without sufficient attention to populations that are disproportionately affected.

In other words, the authors contend, we know a great deal about the parasite in a laboratory setting, but not nearly enough about its presence in the communities it threatens.

Chagas has actually been in the U.S for decades, the study reported. 

“The first known autochthonous case of human Chagas disease in the United States occurred in an infant in 1955 in Corpus Christi, Texas, in a home known to be infested with triatomines,” the authors wrote. “However, parasite transmission to humans in the region has occurred since prehistoric times, given, for example, a paleoparasitology study that recovered T. cruzi DNA in a mummified body (dated to 1,150 BP) of a man from western Texas with signs of megacolon.”

During 2013–2023, the review stated, the Texas Department of State Health Services documented 50 probable and confirmed autochthonous cases of Chagas disease, either because the area of vector exposure was known or due to a lack of travel to or previous residence in Chagas disease–endemic areas of Latin America.

Richard Moore is the author of “Dark State” and may be reached at richardd3d.substack.com.