Assassin bugs are the vector of the Chagas parasite

Centers for Disease Control and Prevention

[BUENOS AIRES] Argentinean scientists have found a new way of diagnosing and treating chronic Chagas heart disease.

The research was published this month (June) in the Journal of Clinical and Experimental Immunology.

Chagas disease is caused by the parasite Trypanosoma cruzi, which is  transmitted to humans by blood-sucking insects of the subfamily Triatominae — sometimes called assassin bugs.

After initial infection, most people enter a chronic stage of the disease — lasting several months or years — where they experience no symptoms. During this time, the parasite invades the body's organs, especially causing damage to the heart.

There are drugs to treat this early chronic stage, but the parasite also causes a process similar to autoimmunity — a condition where antibodies produced by the patient's own immune system against the parasite begin to attack the body's own tissues — against which the drugs are not effective.

Project leader Mariano Levin, from the Institute of Genetic Engineering and Molecular Biology Research in Argentina, explains that these antibodies attack the heart, altering cardiac rhythms and, in some cases, causing death.

Using fragments of a surface heart muscle protein — the target of the damaging antibodies — the team was able to design a diagnostic test to detect the presence of the antibodies.

The test involves taking blood from a patient and mixing it with heart muscle protein fragments and a fluorescent marker. If there are any antibodies present in the blood, they will bind to the fragment and marker and make it fluoresce.

The team also showed that the damaging antibodies can be mopped up using the same heart muscle protein fragments, representing a possible new treatment.

They hope in the future that these heart fragments could be used to filter the antibodies from the blood, using a method similar to haemodialysis — a method used to clean the blood of patients with kidney disease.

Although patients will be still infected with the Chagas parasite, the treatment would help improve their heart condition, say the researchers.

A similar method has already been tested on 200 patients with heart disease in Europe, says Levin, and the next step will be to finalise a treatment protocol to test it in patients with Chagas disease.

Chagas disease is mainly found in Latin America and, according to the World Health Organization, affects 16–18 million people, with 300,000 new cases each year.


Link to abstract in Clinical and Experimental Immunology

Reference: Clinical and Experimental Immunology 148, 440 (2007)