Chagas, a disease caused by a parasite transmitted via the Triatoma bug (aka, the kissing bug), is claiming thousands of lives in Central and South America. Some experts are even calling it the “new HIV/AIDS of the Americas”. But is this comparison accurate, and how big a threat is the disease to the US?
Chagas is not a new disease. It’s named after Carlos Chagas (circa 1909), a Brazilian doctor who discovered that Triatoma carry a potentially lethal parasite called Trypanosoma cruzi. After several of his patients developed a strange infection that he couldn’t identify, Chagas set out to investigate how humans come in contact with the pathogen and its effects on the body of its host. He probably didn’t realize at the time that his work was groundbreaking in the history of epidemiology (Chagas later went on to identify the parasitic fungal genus Pneumocystis, another major discovery).
Kissing bugs, named because they bite the face and lips of humans (they’re also called assassin bugs), live in tropical climates near warm-blooded vertebrates to gain easy access to their blood. They stay hidden for much of the day, living in concealed places such as the cracks in a piece of wood and thatched roofs, and usually strike their victims as they sleep. The bugs defecate as they feed, allowing the parasite they carry to infect a new host.
According to the Centers for Disease Control and Prevention (CDC), the early stage of Chagas occurs immediately after infection and may have mild or no symptoms at all. Symptoms generally include fever, malaise, and a swelling of one eye. If left untreated, the infection can continue for years, often with no further symptoms, and over time it damages the heart, intestines and esophagus. There are two known treatments for the disease but they only work when administered in the early stages of infection. Once organ tissue has been damaged, it’s usually too late.
According to an editorial in the online journal PLoS, about 10 million people are currently living with Chagas, making it one of the most common neglected tropical diseases in Latin America and the Caribbean. It kills roughly 20,000 people worldwide every year. Lead author Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston, warns that the disease is spreading globally and there may be between 300,000 and 1 million cases in the US.
While the infection is triggered by contact with a kissing bug, the disease appears to spread most rapidly via blood transfusions, organ transplants, and from mother to child during pregnancy – hence the comparison with HIV/AIDS.
There are, however, major differences between Chagas and HIV/AIDS, including that the parasite is not transmitted via sexual contact. And unlike HIV, which evaded detection in the blood supply for years, Chagas can be identified through blood screening and eliminated before it spreads. The problem is that screening requirements differ from country to country, and too often screening procedures are poorly administered or simply ignored.
Also unlike HIV/AIDS-at least in the early days of the disease-we know proven ways to prevent Chagas infection. Insect nets that prevent kissing bugs from biting humans are effective. Proper screening of the blood supply and reporting the disease are critical steps, as well as screening for the disease during pregnancy.
Is the disease a threat to the US? That depends on where you live. Texans, in particular, may have cause for concern because blood-donation screening is not mandatory in the state and physicians are not required to report the disease’s occurrence to health authorities, according to Wired.
What we do know is that Chagas is a major problem throughout Central and South America, and will continue to be until measures are taken to prevent its transmission. Unfortunately, those measures require adequate funding, and the countries most afflicted by the disease are also among the poorest. And since people can remain infected for up to 30 years before succumbing, we may have only started to see the true extent of the damage.