Historically, Chagas disease programmes have focused on prevention of the disease and on vector control. Now, knowing that the majority of those infected by the parasite can be treated, this focus, which excluded treatment, is no longer acceptable. In its ten years of experience in the field, MSF has proved that the diagnosis and treatment of Chagas disease, even in remote rural environments, is viable, necessary and ethically beyond question.
It is time for the governments of endemic countries to fight on all fronts against Chagas disease:
Diagnosis of the sick at the primary care level: Integrating the diagnosis of Chagas disease at the primary care level with available resources. Carrying out routine analysis to find those infected with the parasite, especially in areas where vector transmission is active, in rural zones and zones which receive immigrants from endemic areas.
Reinforcing the supply chains: In order for medicines and diagnostic tests to reach the primary care centres in the remotest zones, strong supply chains are needed. In addition, doctors should ask for the medicines they need.
Treatment for children and, wherever possible, for adults, in the primary care system: Free treatment for children and adults, with monitoring of possible side effects. All children should be treated. Adults should always be assessed to see whether or not it is possible to start treatment. Treating adults with mild heart problems may prevent these from progressing. There is no evidence regarding the effectiveness of the treatment when damage is very advanced. In those over 50 who were probably infected in their childhood or adolescence, the risks and benefits of treatment should be assessed.
Vector control activities: When treating a patient, their house and environment need to be assessed for the presence of the vector, and fumigated if necessary. In addition, systematic fumigations should be carried out in risk areas to control the spread of the insect, and at the same time investment should be made in improving housing.
Determining the prevalence of Chagas: Systemising the collection of data on Chagas disease to establish the number of infected in an area and using this information to calculate the real requirements for medicines and laboratory reagents, to be able to ensure the availability of diagnosis and treatment.
A recent G-Finder study reveals that less than 0.5 per cent of all worldwide Research and Development (R&D) into neglected diseases in 2007 was aimed at Chagas disease.
With the limited resources currently available to treat Chagas disease, medical teams have to deal with many shortfalls and sometimes they don't have any treatment options. New diagnostic tests, better medicines and cure tests urgently need to be developed to deal with this illness.
- Site about Chagas of the Drugs for Neglected Diseases initiative (DNDi)
Currently, MSF uses a rapid diagnostic test to detect cases. Following the recommendations of the World Health Organization (WHO), all positive cases are confirmed with two conventional laboratory serological assays. If there is any discrepancy between the two tests, a third laboratory test must be used to obtain a reliable result.
In environments with limited resources, such as rural areas in Bolivia, where the incidence of the disease is high, the ideal would be to have a highly sensitive and highly specific rapid diagnostic test which would reveal whether the patient was infected or not in a short space of time and would not require specialized laboratories. If a single test is not possible, a combination of two rapid tests could be another option.
There are only two medicines for treating Chagas disease (benznidazole and nifurtimox). The possible side effects from the treatment mean that some patients are unable to complete it and that it is impossible for sufferers to take it without supervision by trained healthcare workers. This all results in restricted access to the treatment, above all in rural areas or where there are no specialised human resources. The problem is particularly serious in adult patients and at the moment, there are still no paediatric versions of the treatment.
The Drugs for Neglected Diseases initiative (DNDi), of which MSF is one of the founding members, is working on a paediatric formula of benznidazole which will probably be available at the end of 2009. DNDi is also working on possible alternative treatments such as posaconazole. Regretfully, these drugs are a long way off from being available on the market, and at low cost, and their effectiveness is still far from being demonstrated.
There is an urgent need to develop new less toxic medicines which require a shorter course of treatment, are effective in the acute and chronic phases of the disease in both adults and children, and are safe for pregnant women.
The current serological methods can take decades to confirm the effectiveness of treatment in adolescents and adults. PCR (polymerase chain reaction) techniques, based on genetic information, have a low sensitivity and specificity for parasites, and they are only available in some research centres. Development of rapid treatment tests which allow for the effectiveness of treatment to be measured and cure to be confirmed in the first two years after treatment for all age groups is essential.
Treatment for Chagas disease does not mean that a person cannot become infected again by a bite from an assassin bug. Vector control strategies, which are fundamental to limit the spread of the disease, depend on detecting the vector and spraying with insecticides. Nevertheless, the assassin bugs have now been found to be resistant to certain products. In addition, to eliminate the insect, spraying must be continuous and housing must be improved.
Furthermore, greater effort must be made to ensure the quality of blood banks to avoid contamination from transfusions or transplants, and to continue to implement prenatal detection control strategies for pregnant women to avoid transmission from mother to child.
The lack of commercial incentives has relegated Chagas disease to be forgotten. In 2007, only $10.1 million dollars were spent on R&D forthis disease. Less than half of this was spent on treatment, vaccines, diagnostic tools and vector control products . In 2006 the WHO Commission for Intellectual Property Rights, Innovation and Health (CIPIH) recognised the failure of current incentives and financing mechanisms for neglected diseases. There is a need to identify new incentives for R&D, including those which de-linkage of the costs of R&D and the final price of health products to obtain better and new diagnostic and treatments.
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