Compounds discovered for treatment of neglected chagas disease

A new class of compounds has been developed that could help to completely eradicate Chagas disease. This tropical disease is hard to treat in its chronic form and affects around 18 million people living in areas throughout Latin America. However, Canadian researchers have developed new drugs that could help to lessen the impact of the disease.

Chagas disease, also known as American trypanosomiasis, is caused by a parasite called Trypanosoma cruzi. This parasite is transmitted via reduviid bugs that suck blood. The disease is considered to be one of the most neglected infections within the US, however the Centers for Disease Control and Prevention (CDC) has now targeted it for public health action.

Historically, chagas disease was generally confined to poorer areas throughout South and Central America, according to Deborah Nicoll-Griffith from the Merck Frosst Centre for Therapeutic Research in Quebec. However, due to immigration it has become a more widespread problem, affecting areas of Europe, the US, Canada, Australia and Japan. This spread of the disease, continued Ms Nicoll-Griffith, means that it is now a huge threat to public health.

Chagas disease has two phases, the acute phase and the chronic phase. Both of these phases can present no symptoms and can be equally life threatening. If the disease receives no treatment, it can develop into digestive and heart conditions, caused by the parasite burrowing into organs and causing increasing levels of damage.

Currently the drug benznidazole is used as treatment, which offers effective action against the parasite during the acute phase. However, once the disease reaches the chronic phase, the drug is less effective. The development of new drug treatments against the disease have focused on the disruption of the enzyme cruzipain. This enzyme is used by the parasite to escape the host's immune system, to aid its digestion, to produce cellular machinery and to burrow into gastrointestinal and cardiovascular tissues.

Researchers identified two reversible cysteine protease inhibitor compounds, which work by jamming the enzyme. The compounds were tested on mice and were found to have a higher cure rate of chagas disease while it is in the acute phase when compared to current treatments. However, further development is still needed before the compounds can be used to treat humans.