Chagas

        

Chagas disease is parasitic disease found on the American continent, where it affects an estimated 16 - 18 million people and claims up to 50 000 lives a year. Treatments and diagnostic tests for Chagas are inadequate and ill-suited for resource-poor settings. 

New drugs are needed to treat both the acute and chronic forms of the disease, as are safer and more effective drugs adapted to patient needs for instance drugs specifically formulated for children.

 

Chagas is caused by the parasite, Trypanosoma cruzi, which is transmitted to humans by blood-sucking insects widely known as the "kissing bugs". It can also be transmitted through blood transfusions and from mother to child during pregnancy. There is no vaccine against Chagas and a person can be reinfected after treatment.

The symptoms of the acute stage of the disease, which may include fever, swollen lymph glands, enlarged liver and spleen, or an inflamed bite wound, are sometimes seen in children. But quite often, at this stage of the disease, there are no apparent symptoms and people can carry the parasite for years without knowing it. 

About 20-30% of those infected develop the chronic form of the disease in ten or twenty years later. The lesions that develop in this phase cause irreversible damage to the heart, oesophagus and colon. Patients gradually become more ill, and heart failure is a common cause of death among them.

 

Existing medical tools far from ideal

Diagnosis of Chagas requires several blood tests and in adults the disease is often not actively diagnosed in the early stages because carriers tend to be asymptomatic. By the time a patient has developed chronic Chagas, treatment with current drugs is no longer effective

There are two medicines that can be used to treat Chagas. The first, nifurtimox is primarly used in the acute and early stages of the disease only. It is available commercially for US$48 which is approximately one month's salary for a miner in Bolivia where the disease is rife. The other medication, Benznidazole, requires 60 days treatment in acute infections and is only effective in 50% of cases.

Neither medicine eliminates the parasite in the blood during the chronic phase of the disease. And the drugs are ineffective against some strains of the parasite. Finally many patients don’t finish the treatment because of its side-effects, and because the treatment lasts 30 to 60 days and needs to be taken under medical supervision

As things are, the millions of people infected ten or twenty years ago, the adults who go untested for want of a suitable drug, and all those who have reached or will reach the chronic phase of the disease are left to suffer and die in neglect.

What needs to be done

National health authorities, donor countries, PAHO and WHO must assume their responsibilities in approaching Chagas disease from a public health point of view. They need to shift from vector control and costly case management of chronic phase patients with serious cardiac symptoms to a comprehensive public health approach. MSF has set the following goals:
• The production and availability of the two existing drugs must be secured.
• R&D into improving early diagnostic tools effective at all stages of the diseases must be increased.
• More R&D for easy-to-use, less toxic, affordable and more efficient medicines to treat patients in all stages of the disease is needed.

Read MSF's Chagas Fact Sheet