Chagas: MSF Fact Sheet

CHAGAS DISEASE

Photo © MSF

Testing children for Chagas in Olopa, Guatemala.

MSF and Chagas disease MSF has been working with patients suffering from Chagas since 1999. MSF currently provides medical care to patients suffering from Chagas in two Bolivian projects, Tarija and Sucre. In Tarija, 20.5% of the population between nine months and 15 years is infected with Chagas.

Between February 2003 and June 2005, MSF tested 4750 children, and 935 of these have already received treatment and are being followed up for two years. In Guatemala, MSF expects to complete

treatment for 200 patients until the end of 2006. MSF has finished two other Chagas projects in Honduras and Nicaragua. In Honduras, MSF successfully treated over 200 patients under 14 years of age and followed them up over two years. In Nicaragua, out of 3500 patients tested, 66 received treatment and follow up. In Mexico, MSF conducted a study that showed a 2.3% prevalence of Chagas in children under 14, and subsequently urged the government to tackle the problem.

MSF FACT SHEET

Chagas is a parasitic disease found on the American continent, where it affects an estimated 16 to 18 million people and claims up to 50,000 lives every year. Dr Carlos Chagas, a Brazilian physician, first described an often fatal condition that damages the victim’s heart, nervous and digestive systems in 1909. Some 100 million people in Latin America are at risk of contracting Chagas today[1]. As a result of increased global travel, cases have also been reported in the US and Europe. Treatments and diagnostic tests for Chagas are inadequate and ill-suited to resource-poor settings, a fact that continues to frustrate medical staff caring for people living with the disease.

[1] http://www.who.int/ctd/chagas/disease.html

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Transmission

A disease of poverty

Chagas is caused by Trypanosoma cruzi, a parasite transmitted to humans by blood-sucking insects known as triatomines. As it bites, the insect carrying the parasite deposits faeces on the person’s skin, and when the person rubs their eyes, mouth or the bite wound, the faeces containing the parasite enters the bloodstream.

Chagas can also be transmitted through blood transfusion, from mother to child during pregnancy, or less commonly, via organ transplants or contaminated food. There is no vaccine against Chagas, and a person can be reinfected after treatment.

The beetles that transmit Chagas live in cracks in the walls and roofs of mud and straw housing, which are common in rural areas and poor urban slums in Latin America. Population movements from rural to urban areas in the 1970s and 80s brought Chagas into cities, and it became an urban infection transmitted through blood transfusions. Blood banks reported Trypanosoma cruzi infection rates ranging from 1.7% in Sao Paulo, Brazil, to 53% in Santa Cruz, Bolivia, where Chagas infection rates far exceeded those of HIV and hepatitis.

Symptoms: a silent killer Chagas infection progresses in stages. During the first acute stage of the disease, which occurs in the immediate aftermath of infection, there are often no apparent symptoms. Children may show some symptoms such as fever, swollen lymph glands, enlarged liver and spleen, or an inflamed bite wound. These symptoms may often be confused with those of other common childhood illnesses, and they pass in a few days.

The indeterminate stage begins between eight to ten weeks after the initial infection and may last for many years. In this stage people do not have symptoms and can carry the parasite for years without knowing it.

About 20-30% of those infected will go on to develop the chronic form of the disease up to ten or twenty years after they first contracted it. By this time, patients will have developed lesions causing irreversible damage to the heart, oesophagus and colon. Heart failure is a common cause of death among young adults - people who should be in the most productive phase of their lives.

Chagas is most common among the poorest and most vulnerable populations. Often unaware of how the disease is caught or what their chances of being cured are, those infected by Trypanosoma cruzi are unlikely to be in a position to fight for their right to be treated. Treatment of the disease has been systematically sidelined by national and regional health authorities.

In turn, Chagas diminishes the productivity of the whole Latin American region. In 2002, the World Health Organization (WHO) reported that economic loss due to early mortality and disability related to Chagas amongst the young adult population was US$8 billion.

The access problem: lack of appropriate diagnostic tests and medicines Chagas is one of the most neglected diseases in the world. Millions of people who were infected ten or twenty years ago still go undetected and untreated.

Diagnosing Chagas is complicated. Doctors usually need to perform two or three blood tests to decide whether a patient is infected. In adults, the disease

R&D efforts begun MSF is one of the founding partners of the Drugs for Neglected Diseases initiative (DNDi), a not-for-profit drug development organization based in Geneva, Switzerland, since 2003. DNDi is currently working on 18 projects, ranging from early discovery screens to phase III clinical trials, and covering sleeping sickness, leishmaniasis and Chagas. DNDi has two Chagas drug projects in pre-clinical development. These efforts will need to be supported and matched by more R&D into Chagas worldwide.

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A family in distress A mother in Tarija has four children under 15. All of them tested positive for Chagas and are currently enrolled in the MSF treatment programme. Yet she has eight children in total.

“What about the other four? They were not tested because they are over 15.

They may have Chagas too, but there is no cure for them. And what about me and my husband? I expect we have Chagas too but there is no cure for us. If we die, who will look after our small children?”

is often not detected or actively diagnosed early on because carriers do not have clear symptoms.

Unfortunately, by the time a patient has developed chronic Chagas, treatment with current drugs is no longer effective. Efforts should therefore be stepped up to develop methods of actively identifying the acute phase of the disease, when patients can truly benefit from available treatment.

It is equally difficult to establish whether a patient has been cured. The only method currently available is to confirm a decrease in the amount of antibodies in the blood.

There are two medicines that can be used to treat Chagas. Nifurtimox, developed by Bayer in 1960, is commercially available for US$48 per treatment course – the equivalent of a Bolivian miner’s monthly salary. Following an agreement negotiated

by WHO, a one-off donation of five million tablets of nifurtimox was made available to Latin America’s Ministries of Health through the Pan American Health Organization (PAHO) in 2004. Benznidazol, first developed by Roche in 1974, is available with delays of up to four months due to constraints in the supply of the drug’s Active Pharmaceutical Ingredient (API). The necessary technology to manufacture benznidazol is being transferred from Roche to a small public laboratory in Brazil. Once functional, this facility will be the sole producer of a drug needed in 21 countries across Latin America.

But the long-term availability of the existing drugs is not guaranteed, and in any case, neither of the two drugs – old and originating from veterinary research – are ideal. First, cure rates are only 6070%, and in chronic cases, they remain under 50%.

Second, the treatment can have severe side-effects

and must be taken under medical supervision. This is a challenge as completing a treatment course takes 30 or 60 days. The drugs cannot be used in adults and there is no formulation adapted for young children - at present, medical staff have to cut tablets to achieve the appropriate dosage and mothers have to mix the crushed pills in juice or breast milk for babies. Third, neither treatment can be prescribed to pregnant women who risk passing the disease to newborns.

The market represented by Chagas patients is insufficient to motivate the private sector to invest in drug development and therapeutic innovations, or even to register existing medicines. But more research and development (R&D) into new molecules is badly needed. An ideal drug candidate would need to be effective for patients in the acute, undetermined and chronic phases of the disease.

Linking treatment and prevention Prevention and blood most Latin not always

programmes, such as vector control transfusion testing, are in place in American countries, even if they are implemented, or effective.

It has been argued that treatment should be available to patients regardless of whether or not vector control activities exist or are functioning.

While MSF began with this notion, it is becoming clear that a treatment-only strategy could backfire.

In Bolivia, for example, where vector control is patchy to say the least, there is a high risk for people to be re-infected. Since treatment is toxic and resource-intensive, treatment efforts are undermined and become unsustainable through weak or ineffective vector control measures. As a

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result of its experiences, MSF now only treats patients when infestation rate is below 3%.

However, this position raises moral and practical dilemmas. Vector control is not always delivering good results, nor is it even possible in the first place. For instance, should infected people in the Amazon Basin – encompassing inaccessible

territories of several South American countries – then not be treated at all? What about areas where vector control is possible, but is not carried out or not completed? Patients might end up seeing their chances of being cured vanish while waiting for the political will and money to be made available in their countries to control the vector.

While there have been efforts to understand Chagas and to control the spread of the vector, too little attention has been paid to treating those who have been contaminated. Through its programmes in Latin America, MSF aims to show that treatment is not only possible, but that it is a humanitarian imperative. While certainly not optimal, MSF’s clinical results demonstrate that existing drugs can be used more widely than previously understood, with manageable side-effects.

Governments of endemic countries will have to recognise their responsibility for public health and commit to taking care of their high-risk population. There is a clear momentum for integrated national Chagas programmes in Latin America, but significant funding is needed from the international community to support the battle against Chagas. National health authorities, donor countries, PAHO and WHO must work out strategies to tackle the disease.

MSF is urging that: ■ The production and availability of nifurtimox and benznidazol, the two existing drugs, be secured.

■ Pediatric versions of the existing drugs be developed.

■ R&D into improving laboratory tests to diagnose all stages of the disease and to monitor treatment and cure be increased.

■ R&D efforts into simple, less toxic, affordable and more efficient treatments for all forms of Chagas disease, and for children and adults alike be stepped up.

Médecins Sans Frontières, Campaign for Access to Essential Medicines Rue de Lausanne 78, CP 116, CH-1211 Geneva 21, Switzerland Telephone: ++41-(0)22-8498 405 Fax: ++41-(0)22-8498 404 Email: access@geneva.msf.org Web: www.accessmed-msf.org

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