A group of scientists have called for the potentially dangerous Chagas “kissing bug†disease to be considered endemic to the United States as more animals and humans are becoming infected, including in Missouri.
The scientists, from research institutions in Texas and Florida, made their case published in the September issue of the peer-reviewed Emerging Infectious Diseases journal published monthly by the U.S. Centers for Disease Control and Prevention.
Chagas disease is caused by the microscopic parasite Trypanosoma cruzi, which makes its way into humans via triatomine insects, several species of which are common across 32 southern states, according to the article.
The blood-sucking insects are known as kissing bugs because they tend to make their way into homes and bite humans on their faces while they are sleeping.
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What actually transmits the parasite is the bug’s poop, which can get wiped into the person’s eyes, mouth or a wound. The parasite can also be spread from pregnant women to their fetus or through blood transfusions and organ transplants.
At first, Chagas disease often goes unnoticed or has mild symptoms such nausea, diarrhea or body aches. If a bite or the parasite gets near the eye, the eyelid may swell.
But serious complications can emerge years later. In about 20% to 30% of cases, , the parasite becomes active and causes serious heart and digestive system issues. Early treatment can be lifesaving.
Locally-acquired infections among humans have been identified in eight states, including Missouri, the journal authors found. As many as 76 confirmed and suspected cases were reported between 2000 and 2018 in those eight states. But because Chagas disease is not required to be reported to the CDC, the true prevalence is unknown.
In Texas, where human cases have required to be reported to state health officials since in 2013, the Texas Department of State Health Services has documented 50 probable and confirmed locally-acquired Chagas infections through 2023.
About 8 million people across the world, including 280,000 in the United States, have Chagas disease, often without knowing it, . It is considered endemic in 21 countries across Mexico, Central America and South America, according to the World Health Organization.
The Texas and Florida scientists argue that cases of Chagas disease in the U.S. are likely much higher than reported.
Classifying the disease as endemic – which means it is constantly present in a geographic area – would raise its profile, the journal authors agued.
The change “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,†they stated.
There is no standardized surveillance of triatomine bugs in the U.S., but they “are increasingly recognized because of frequent encounters with humans†in and around homes, the journal article states. In addition, dogs have increasingly been diagnosed with Chagas disease, and it affects them much the same way it does humans.
Infected dogs have been found in 23 states, including Missouri, according to the article. In Texas, where canine Chagas disease has been most studied, researchers have found nearly 31 new infections per 100 dogs a year at several large dog kennels.
Missouri is also among 17 states where infections among wildlife have been documented, including woodrats, opossums, skunks and raccoons.
While humans are not likely infected from animals such as dogs and rodents, they can host the parasite, spreading it to the biting bugs.
Because blood donations in the U.S. are screened for Chagas disease, cases are often discovered this way, explained , an infectious disease expert at Washington University School of Medicine.
That’s how at the end of 2017, a 53-year-old Missouri woman discovered she had Chagas disease. A case study by the Missouri Department of Health and Senior Services revealed she had no travel history that would have placed her at significant risk and never had a blood transfusion or organ transplant.
Hers is the only locally-acquired human case in Missouri that has been documented. Other cases that have been identified were acquired in other countries.
The woman recalled no symptoms, but tests revealed an irregular heartbeat and thickening of a heart ventricle. The women took a 60-day course of an antiparasitic medication to prevent further damage.
Budge, the said U.S. residents are still more protected than those in southern countries, where the bugs tend to hide in thatched roofs or the cracks in adobe walls during the day and come out to feed at night.
“We have sealed off or drywalled walls, we have windows with screens on them. Our homes are not as ideal a place for these bugs to live as some of the more tropical area of Central and South America or even in Mexico,†he said.
The bugs are easy to spot. Adult bugs range in size from a penny to a quarter and can fly. They have distinctive orange, red or yellow markings on the sides of their abdomen, a distinctive cone-shaped head and six long legs.
“It’s not that we don’t have the bugs, it’s just that the opportunity for the bugs to intermingle with us while we’re sleeping is much lower in most places in the United States,†Budge said.
Budge, the infectious disease expert, said he agrees with authors’ call for more awareness about how U.S. residents can be infected locally, even if it’s unlikely.
“We don’t want someone to show up with signs or symptoms of something that could be Chagas disease and then say, ‘Well, we’re not going to consider that as a potential cause because it doesn’t exist here,’†he said.
“That would be misinformation. It’s rare, but it can happen here.â€
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