Mexican and US scientists are working on developing a vaccine to stop Chagas disease which is expected to be available within the next three years.
Involved in the research, reported in Investigación y Desarrollo are the Baylor College of Medicine, the Center for Research and Advanced Studies, Autonomous University of Yucatán, the Birmex Laboratory and the Sabin Vaccine Institute; with funding from the Carlos Slim Health Institute.
So far, the drug that has shown the best results against Chagas disease is benznidazole. However, when administered in newly infected people it has a 60% effectiveness at stopping the progression of the disease and often has side effects that make patients leave the treatment, says Dr Maria Elena Bottazzi from Baylor College of Medicine in Houston, Texas, who led the therapeutic vaccine project.
The new investigational vaccine has demonstrated better tolerance, efficiency and can be used in conjunction with benznidazole, she added.
Chagas disease mainly affects lower income populations in rural areas. It is caused by the parasite Trypanosoma cruzi and is transmitted by a blood transfusion or by the bite of Triatoma infestans, also know as the 'kissing bug'.
If the condition is not detected during the first two months, or temporal phase, it passes to a chronic phase, in which the parasites move through the bloodstream into the heart and the digestive system tissues, which will gradually be undermined.
The symptoms of the disease can range from dizziness and digestive problems, to abdominal pain, palpitations and difficulty with swallowing; over time cardiac failure will occur owing to deformation of the myocardium, and in severe cases the abnormality of heart rhythm could cause sudden death.
According to Doctors without Borders, in Latin America eight million people currently have Chagas disease and 25 million are at risk of infection, of which 30% will develop heart problems; in Mexico it affects 1.1 million people.
The disease can be treated with medication; however, less than 1% of those infected have access to it, plus it requires care in its administration. Bottazzi said the experimental vaccine has been tested in laboratory rodents and dogs infected with T. cruzi and it was observed that the disease stopped in 80% of cases and, when administered pre-emptively, it protects against the parasite in the bloodstream.
Its effectiveness is being analysed in a control group of infected human patients in Mexico, and it is expected that in the next three years all tests to obtain a vaccine will be finalised and it will be available to the population.
