The Gran Chaco covers an eco-region of 1.3 million km2, extending over Argentina, Bolivia, and Paraguay. Chagas disease is prevalent in this region, with incidences rising since 2001 especially in Argentina, despite major control efforts. Currently, it is believed that 1.5 to 2 million Argentineans carry the disease. Every week, 15 Argentineans die of Chagas disease. Most of the infected live in the provinces of Santiago del Estero, Chaco, Formosa, the areas to the east of Salta and Tucuman, and northern Santa Fe.
Actions taken to address Chagas disease in the region have largely been limited to vector control. Little has been done in providing treatment and healthcare to infected children, adolescents, and young adults. Nevertheless some progress is being made. The implementation of active screening and treatment campaign for children has just started in schools in Argentina and neighbouring countries, and advances have also been made in training doctors to better detect the disease.
Because there is ncurrently no paediatric formula available, administering appropriate dosage to children becomes a challenge. Often tablets are fractioned.
Treatment of adults and children
According to a 1998 WHO/PAHO technical report on treatment guidelines, any infected individual may receive treatment, regardless of age – adults can therefore receive etiological treatment Furthermore, the study clearly demonstrated that adults receiving parasiticide treatment may have lower incidence of cardiopathy. Fortunately, the definition of the indeterminate – or chronic asymptomatic – phase has changed.
In regard to children, doctors and investigators have demonstrated that 9 out of 10 children infected with Chagas disease receiving treatment are completely cured. Furthermore, the experience at the Ricardo Gutiérrez Pediatric hospital in Buenos Aires has shown that if a child begins treatment before the age of one, the likelihood of cure is almost 100%. The cure rate is about 85–90% if we take into account all children treated in the department below the age of 16. Researchers recommend that children born to mothers serologically reactive for Chagas disease receive early diagnostic screening for congenital Chagas disease.
One of the main limitations faced is that the only drug currently available is an adult formulation – 100mg and 120mg tablets. Working with paediatric patients, including infants who weigh less than 4kg, it is very difficult to administer an appropriate dosage that corresponds to their weight and age from a 100mg tablet. This is where the development of a paediatric formulation is badly needed, especially for paediatricians responsible for treating newborns, infants, and children.
Treatment is also prevention
Treating children with Chagas has several advantages: it can avoid the development of cardiac and gastrointestinal diseases later on in their life; treating little girls now can avoid the transmission of Chagas during pregnancy in their adult life, thus avoiding congenital Chagas disease. Furthermore, it allows for a greater number of blood and organ donors.
As Chagas affects a poor region – it does not reach Buenos Aires – there is little economic interest for big pharmas and others who could make a real difference, and so the disease remains neglected. We know that it can be treated and cured – but knowing is not enough...what we need is action.
Field of treatment needs to be reinvented
Sergio Sosa-Estani, Chief of Epidemiological Service at the National Centre for Research in Endemic Diseases of the Ministry of Health (Argentina) says about Chagas: “Research into the disease is so dated and so oriented towards prevention that the field of treatment has to be practically reinvented. The clinical trials for a new compound E1224, a prodrug of ravuconazole, will help to reinvigorate the field. The traditional method of monitoring treatment measures antibodies to T. cruzi. Although useful, this method is not very accurate, and antibodies can persist for years after the parasite has been eradicated. Researchers have developed two standardised polymerase chain reaction tests that detect T. cruzi in blood with qualitative or quantitative results. It can be used to identify infection in individual patients. The quantitative test will help give a better understanding of the course and staging of the disease and response to treatment. Evidence indicates an association between T. cruzi levels, inflammation, and organ damage. That test is in the process of being validated.”
Extract from www.bmj.com/cgi/content/full/339/oct06_1/b4084