New drug candidates show promise for cure for Chagas disease

A team of researchers from Canada has developed a class of compounds which may help eradicate a neglected tropical disease that is currently hard to kill in its chronic form. The research was published ahead of print in Antimicrobial Agents and Chemotherapy.

Chagas disease or American trypanosomiasis, caused by Trypanosoma cruzi, affects about 18 million people living mostly in Latin America. The parasite is transmitted to humans by blood-sucking reduviid bugs, also known as kissing bugs due to their predilection for feeding on the faces of their victims. In the United States, Chagas disease is considered one of the neglected parasitic infections, a group of five parasitic diseases that have been targeted by CDC for public health action.

"While historically infection was largely confined to poor and rural populations in Central and South America, it has been emerging in the U.S., Canada, Europe, Japan, and Australia, due to immigration, and nonvectorial transmission is becoming a public health threat," says Deborah Nicoll-Griffith of the Merck Frosst Centre for Therapeutic Research in Kirkland, Quebec, a researcher on the study. One 2005 estimate put the number of people infected within the U.S. at 300,000 (1/1000).

There are two phases of Chagas disease: the acute phase and the chronic phase. Both phases can be symptom free or life threatening. Left untreated the disease can lead to cardiac and digestive disorders, as the parasite burrows into the heart, esophagus and colon tissue where it causes damage over time.

The current standard of care, the drug benznidazole, has significant activity against the parasite during the acute phase, but is less effective once the disease becomes chronic.

Efforts to find new drugs focus on disrupting an enzyme, cruzipain, which the parasite uses for digestion, to produce other cellular machinery, to evade the host's immune system, and to invade heart and gastrointestinal tissues.

Chagas disease

Chagas disease is an illness spread by insects. It is common in South and Central America.

Chagas disease is caused by a parasite. It is common in Latin America but not in the United States. Infected blood-sucking bugs, sometimes called kissing bugs, spread it. When the bug bites you, usually on your face, it leaves behind infected waste. You can get the infection if you rub it in your eyes or nose, the bite wound or a cut. The disease can also spread through contaminated food, a blood transfusion, a donated organ or from mother to baby during pregnancy.

If you notice symptoms, they might include

Fever
Flu-like symptoms
A rash
A swollen eyelid

These early symptoms usually go away. However, if you don't treat the infection, it stays in your body. Later, it can cause serious intestinal and heart problems.