TORONTO – They’re parasites that feed on people’s faces in the still of the night. And while the infection they spread typically occurs in Latin America, cases of Chagas disease are now popping up in the United States.
Chagas – dubbed the “kissing bug” disease – is a parasitic infection. Triatomine bugs, which transmit the infection, bite especially around the mouth.
Humans who are infected can spread Chagas via blood transfusions, organ transplants or from mother to child. It can lead to heart disease and even death, scientists are warning.
It’s traditionally a tropical disease in South America, Central America and Mexico but U.S. researchers say Chagas has now made its way into Texas and other states. They’re calling it an “emerging” U.S. public health threat.
“We were astonished to not only find such a high rate of individuals testing positive for Chagas in their blood, but also high rates of heart disease that appear to be Chagas-related,” Melissa Nolan Garcia, an epidemiologist at the Baylor College of Medicine, said.
Garcia and her Houston colleagues have been studying Chagas disease in the U.S. state, but they warn that because the bug is so stealthy, they’re pretty sure many cases go undiagnosed. Last week, she presented her findings and heeded warnings to fellow health officials at an annual American Society of Tropical Medicine meeting.
“We’ve been working with physicians around the state to increase awareness and diagnosis of this important emerging infectious disease,” she said.
What is Chagas disease?
Chagas disease – or American trypanosomiasis – is spread through blood-sucking bugs called “kissing bugs” because they feed on people’s faces at night. The researchers say it affects seven to eight million people worldwide.
The bugs hide in cracks in poorly-constructed homes. After they bite, they deposit feces to close the bite. And once its victims touch the bite, they accidentally rub the infected feces into their wound.
What are the symptoms?
Sometimes symptoms don’t turn up until one or two weeks after the initial bite, but they can last for about two months, according to the government of Canada’s travel information about the bug.
“The symptoms are usually mild or do not occur at all, but in rare cases can cause death,” the agency warns on its website.
Acute symptoms range from: swelling around the infected bite, fever, headache, swollen lymph nodes, muscle pain and difficulty breathing.
Chronic conditions are those that show up a decade or more after the initial infection. In those cases, the symptoms can be life-threatening heart conditions.
But if it’s caught early on, it can be treated.
How prevalent is it in the U.S. and Canada?
In routine testing of Texas blood donors, Garcia’s team found that one in every 6,500 blood donors tested positive for exposure to the parasite that causes Chagas disease. That’s 50 times higher than the Centers for Disease Control and Prevention’s estimate of about one in 300,000.
“We think of Chagas disease as a silent killer,” Garcia said. “People don’t normally feel sick so they don’t seek medical care, but it ultimately ends up causing heart disease in about 30 per cent of those who are infected,” she warned.
In a separate study, Garcia followed 17 Houston families who were infected. Forty-one per cent of them had signs of heart disease stemming from their infection. They had swollen, weakened heart muscles and an irregular heart rhythm because of the parasite burrowing into heart tissue.
Most of the families lived in rural areas or spent lots of time outdoors. One was a hunter while another half dozen travelled outside of the U.S. extensively.
The risk of contracting Chagas disease within Canadian borders is low, experts say. Ottawa’s travel information about the parasite suggests that travel may be the culprit, but even then, the odds are low.
“It’s what we call a neglected tropical disease,” according to Canadian microbiologist Jason Tetro.
He says it’s been around for centuries, primarily in South America. It’s akin to Lyme disease, West Nile virus, malaria, Dengue fever or chikungunya.
While Chagas has migrated north into the U.S., he’s not worried about Canadians’ safety.
“We have good shelters, we have windows screened off and our climate is helping us. We’re a long way from seeing it become endemic in the U.S.,” he said.