Recently, the U.S. Food and Drug Administration (FDA) gave its stamp of approval to a new screening test that could detect the parasite that causes “Chagas disease.” This means that people who need blood transfusions or organ/tissue transplants can be protected from one more dangerous disease.
Chagas disease, which gets its name from the doctor who discovered it in the 1900s, is more common in Latin America than anywhere else in the world. However, it has traveled here, carried over by infected people and transmitted through the blood.
The disease is caused by a parasite, “Trypanosoma Cruzi” (T. cruzi), which enters a person’s bloodstream from contact with the feces of a bug (which is known as the “kissing bug” or “triatomine bug”) that’s common in Mexico, Central America, and South America. An infected person can transmit the parasite to other people through blood contact, meaning by donating blood or organs.
That’s why scientists have been working so hard on developing a blood test to detect Chagas. The disease is not extremely common in the U.S., but the number of infected people here is on the rise, mainly due to the flow of people between countries (especially from Mexico to the U.S.).
A major problem with Chagas disease is that the preliminary stages (the “acute phase”) can be almost unnoticeable. For weeks or months after infection, a person might not have any signs of it occurring. Alternatively, he/she might only experience seemingly generic symptoms, like headache, fatigue, fever, aches, rash, diarrhea, swollen glands, and lack of appetite. If a doctor knows what to look for fairly soon after infection, he/she might find some swelling in the spot on the body where the parasite entered and/or that the liver and spleen have become slightly enlarged.
These symptoms do tend to disappear without any treatment so many people don’t seek medical attention. However, even though there are no longer any symptoms, the infection is still there and it can be transmitted to other people through a blood transfer.
In the “chronic phase,” some people never experience any more health problems, even though the parasite remains in their body, but others can develop some serious complications. Chagas disease can bring on issues with the digestive system, including enlarged colon or esophagus, which can mean difficulty eating food or going to the bathroom. Moreover, the infection can cause severe or even fatal heart problems, such as heart failure, cardiomyopathy, heart rate irregularities, or cardiac arrest.
As it’s not a common health problem, this disease is difficult to diagnose. Once it’s discovered that you have Chagas, your doctor will prescribe some kind of treatment to kill the parasite and will also take steps to treat any of your symptoms or complications.
As you can see, because of its lack of symptoms, or the generality of them, Chagas disease can slip under the radar. This characteristic is what made it the target of scientists. Specifically, when it comes to donating blood and/organs, we need to be able to detect the presence of the infection, so that it’s not spread to others. Until now, we didn’t have such a test; not one approved by the FDA, anyway.
However, Ortho-Clinical Diagnostics has come up with a test, the “ORTHO T. cruzi ELISA Test System,” which has been proven to zero in on antibodies produced by the T. cruzi parasite. In several studies, the test was found to be 99% accurate in detecting infected blood. For the moment, the FDA has approved this exceedingly accurate test for use in screening blood, organ, cell, and tissue donors, but it has yet to be approved for use as a diagnostic tool. We’ll keep you updated.