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The
United States is being infected by Chagas, a deadly disease spread by the faeces
of a parasite nicknamed the 'kissing bug'. It bites sleeping victims, ingests
the blood and defecates on them; patients then unknowingly rub the feces into
open membranes.
RT.com reports Chagas
disease is seen as a “silent
killer” by those who study and treat it, as it can often lurk in
people’s bloodstreams for up to two decades before causing their organs to
fail. The initial stage of the tropical illness ‒ the acute phase ‒ is mostly
symptom-free and lasts for the first few weeks or months, according to the US
Centers for Disease Control and Prevention. If a patient does exhibit symptoms,
they can easily be mistaken for another disease.
The
symptoms noted by the patient can include fever, fatigue, body aches, headache,
rash, loss of appetite, diarrhoea, and vomiting. The signs on physical
examination can include mild enlargement of the liver or spleen, swollen
glands, and local swelling (a chagoma) where the parasite entered the body, the
CDC explained.
"People
don't normally feel sick," Melissa Nolan Garcia,
a research associate at Baylor College of Medicine in Houston and the lead
author of two of three recently published studies, explained in a statement, "so they don't seek medical care, but
it ultimately ends up causing heart disease in about 30 percent of those who
are infected."
It
is the second ‒ or chronic‒ phase that is deadly. Patients can develop cardiac
complications, including an enlarged heart (cardiomyopathy), heart failure,
altered heart rate or rhythm, and cardiac arrest (sudden death), as well as
intestinal complications, such as an enlarged esophagus (megaesophagus) or
colon (megacolon) and can lead to difficulties with eating or with passing
stool.
In July, the Centers for Disease Control estimated that 300,000 people in the
US had been infected, and but now it could be closer to 400,000. Medical
research suggests that 40,000 pregnant North American women may be infected
with the disease at any given time, resulting in 2,000 congenital cases through
mother-to-child transmission, according to Fox News Latino. Garcia believes
that the numbers may actually be higher than that, the Examiner reported.
The
Baylor team presented the results of its work on Tuesday at the 63rd Annual
Meeting of the American Society of Tropical Medicine and Hygiene (ASTMH) in New
Orleans. In one of their pilot studies, her team looked at 17 blood donors in
Texas who tested positive for the parasite that causes Chagas disease.
“The
concerning thing is that majority of the patients [I spoke to] are going to physicians,
and the physicians are telling them, ‘No you don’t have the disease’,”
Garcia said, according to Al Jazeera America.
Chagas
disease (American trypanosomiasis) is caused by Trypanosoma cruzi, a protozoan
parasite related to an African version that causes sleeping sickness. It is
endemic to Mexico, Central America, and South America, where an estimated 8
million people have the illness, most of whom do not know they are infected. If
untreated, infection is lifelong and can be life threatening, the CDC noted.
Garcia
spoke to several groups of physicians and cardiologists as part of an
educational campaign to increase physician awareness.
“A
lot of the cardiologists were aware of Chagas disease, but they don’t make the
connection when the patient is sitting in front of them,”
she said.
Dr.
Julie-Ann Crewalk, a pediatrician in Northern Virginia who has dealt with
Chagas, also thinks that the disease is being underdiagnosed.
“It’s
not something that we think of asking right away,”
she told the Atlantic. “I
wouldn’t be surprised if the numbers were higher and we’re just not seeing it.”
The
CDC says that most of the Chagas cases in the US are from people who have
traveled to Latin America, and were infected there. But Garcia told HealthDay
News her research showed that the parasite has arrived in the US, and the
government agency has admitted that triatomine bugs can be found across the
lower half of the country.
"We
are finding new evidence that locally acquired human transmission is occurring
in Texas," she said. "We were surprised to find that 36 percent had evidence
of being a locally acquired case.”
“Additionally,
41 percent of this presumably healthy blood donor population had heart
abnormalities consistent with Chagas cardiac disease,"
Garcia noted. The illness can also be spread through blood and organ donation,
as well as from mother to infant during childbirth.
The
disease is also growing just outside Washington, DC. While the number of people
with Chagas disease in Northern Virginia is small ‒ about two dozen cases,
according to interviews by the Atlantic with local physicians ‒ doctors and
experts there say they wouldn’t be surprised if the numbers were higher
because, along with the lack of routine screening for it, many patients tend to
be undocumented immigrants without health insurance.
Dr.
Rachel Marcus, a cardiologist, believes Northern Virginia could be “ground
zero” for Chagas disease, because of the volume of immigrants from Bolivia,
where the disease is endemic. She told the Atlantic that it’s easy to diagnose
the disease with an electrocardiogram (EKG), but that American doctors don’t
know what they are looking for. “If you were to find that EKG from an area
where Chagas is common, it’s diagnostic,” she said.
Garcia
also agreed with the need to focus on EKGs as a diagnostic tool for the
disease. "Physicians should
consider Chagas when patients have swelling and enlargement of the heart not
caused by high blood pressure, diabetes or other causes, even if they do not
have a history of travel," she said.
The life cycle of Chagas disease, a zoonotic disease that can
be transmitted to humans by blood-sucking triatomine bugs that contain the
protozoan parasite, Trypanosoma cruzi, in their feces (US Centers for Disease
Control and Prevention)
But
even if the deadly disease is diagnosed, there are no viable government-authorized
treatments. The Food and Drug Administration has not yet approved two medicines
‒ nifurtimox and benznidazole ‒ that are currently used to treat the disease
but carry a risk of nerve damage, nausea and weight loss, according to the
ASTMH statement.
The CDC makes the drugs available "when no satisfactory alternative treatment exists," according to the FDA, adding that "subjects are generally willing to accept greater risks from test articles that may treat life-threatening and debilitating illnesses."
The CDC makes the drugs available "when no satisfactory alternative treatment exists," according to the FDA, adding that "subjects are generally willing to accept greater risks from test articles that may treat life-threatening and debilitating illnesses."
