The American Red Cross has just launched the use of a new blood test in order to help identify people with “Chagas disease.” Those of you who’ve never even heard of this disease are probably thinking, “So what?” However, this is an important development, as it will help decrease the fatality risk for people with Chagas and reduce the risk of transmission through the blood donation system.
Chagas disease, also referred to as “American trypanosomiasis,” is caused by the parasite “Trypanosoma cruzi” (T. cruzi). Most prevalent in Latin America, this parasite is usually transmitted to humans via the feces of an insect called the “kissing bug” or “triatomine bug.” How do the feces of the bug enter your body? Well, these pests, much like mosquitoes or horse flies, like to feed on human blood. They tend to bite around the facial area — when they do this, they sometimes leave behind traces of feces, which can enter the body through mucous membranes or open wounds, like the bite site itself.
Other methods of infection include eating food containing infected bug feces, receiving infected blood, tissue, or organs, and from an infected mother to child (in the womb). You can’t get it in the same way you would get the flu.
When you’re first infected with Chagas, you go through the “acute phase,” which can last weeks or even months. Symptoms during this time can be very mild and non- specific, including fever, headache, general fatigue, swollen lymph nodes, diarrhea, vomiting, lack of appetite, and muscle aches. You might also notice swelling around the bite site or wherever the parasite entered your body, such as in the eye area.
Even though these symptoms taper off, the infection is still there; this is the “chronic phase” of Chagas. Some people never have any problems once they hit this phase. However, if left undiagnosed and untreated, others (about 30% of Chagas sufferers) can develop some serious complications, years or even decades later. These include problems due to an enlarged esophagus or colon, cardiomyopathy, heart failure, and heart attack.
Even though the condition is still considered rare in the U.S., the number of infected people is on the rise — and that’s not even considering that most people don’t realize they have the disease. In a study on Los Angeles County blood donors, it was discovered that the number of Chagas- infected people had risen from one in 9,850 donors in 1996 to one in 5,400 donors just two years later. This makes it extremely important to detect, especially amongst blood/tissue donors.
As we mentioned back in December, the FDA has already approved a new test, the “ORTHO T. cruzi ELISA Test System,” to look for the antibodies produced by the T. cruzi parasite. The Red Cross has just released results of its own clinical trial on this test.
The organization decided to conduct the study in areas where Chagas disease is believed to be more of a problem: Southern and Northern California and Arizona. Blood donors giving blood in these areas between August 2006 and January 2007 were asked to take part — in all, the Red Cross screened the blood of 148,969 people.
Out of this group, 63 specimens from 61 individuals came up as positive for the parasite that causes Chagas (cases were considered confirmed as positive after retesting). Most of the infected individuals — 79% — were from the Southern California area. However, further testing only confirmed 51% of the 63 samples as being positive for T. cruzi antibodies.
Now that the testing has showed the ORTHO T. cruzi ELISA Test System to be an effective blood-screening tool, the American Red Cross has started to put it into use in its blood, tissue, and organ donations programs. They hope that this test will help protect people receiving blood and tissue donations from Chagas disease.
Blood donation centers not run by the American Red Cross have not been mandated to use the new test, but it’s hoped that they will follow the leader in this health and safety matter. This test is not yet recommended by the FDA for use as a diagnostic tool by doctors and hospitals. However, blood donation centers are expected to follow up with donors infected with the T. cruzi parasite in order to help them get the right advice and treatment.
If caught during the acute phase, Chagas can be successfully treated with drugs to kill the parasite. If it’s not diagnosed until the chronic stage, your options are limited to therapies and treatments, which are meant to help prevent or minimize serious complications associated with the condition.
If you have spent some time in Latin America, especially Mexico, Central America, or South America, or have had a blood transfusion or tissue/organ transplant in California or Arizona, it’s a good idea to see your doctor, especially if you have experienced the symptoms mentioned in this article.