Neglected tropical diseases, bioinformatics, and vaccines.

More than 2.5 billion individuals living in the tropics are estimated at risk of contracting at least 1 neglected tropical disease. Half of these individuals may be exposed to or have concomitantly ≥2 neglected tropical diseases, including those caused by helminths, schistosomes, parasitic protozoans, and viruses. Although the death toll caused by all neglected tropical diseases is not as high as for AIDS or tuberculosis, neglected tropical diseases still affect more than a million individuals, most of whom live in the poorest regions of Africa, Asia, and the Americas. In addition to the high mortality, most neglected tropical diseases are due to chronic infections and, therefore, have an enormous impact on childhood growth, disability-adjusted life-years, and productivity-associated economic losses targeting mainly the rural and poorest urban areas of developing countries [1]. Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, is a prototypical example of an neglected tropical disease of Latin America, with an estimated 10 million people chronically infected, causing a large burden of disability-adjusted life-years and billions of annual costs [2]. Chagas disease is endemic in 21 countries, and, in some instances, the number of individuals coming in contact with the parasite (estimated on the basis of seroprevalence) can be as high as 6.75% of the population, as in Bolivia [2, 3]. In addition, because of the migration of chagasic individuals, the disease has also been considered a health problem in developed countries where the disease is not endemic, such as the United States and Spain [4]. Upon contact with the parasite, human hosts may develop a patent parasitemia (acute phase) that, in most cases, will resolve after a few weeks. Two-thirds of individuals will become serologically positive for T. cruzi antigens but will never develop symptoms (the indeterminate form of the disease); a decade or more later, one-third of patients will develop chronic forms of the disease, which can be either cardiac (most common), digestive (megaesophagus and megacolon), or cardiodigestive. The pathogenesis of chronic Chagas disease is still a matter of intense debate. Some researchers initially proposed that there is an autoimmune response supporting the chronic inflammatory process [5, 6]. More recently, the identification of parasite DNA in the lesions has led to the hypothesis that parasite persistence is the main driving force leading to tissue inflammation and destruction [6, 7]. However, very recent observations have described heart tissue pathology in the absence of living parasites [8]. Treatment for Chagas disease is effective for acute cases and for children up to 14 years old, with cure rates as high as 100%, and is therefore recommended by the World Health Organization [9]. In adults, treatment success depends on the type of evaluation, using clinical and/or serologic indicators. Although definitive results of large randomized clinical trials (TRAENA and BENEFIT) are still forthcoming, based on previous nonrandomized studies, the Latin American Network for Chagas Disease proposes that treatment should be mandatory [10]. Similar to other neglected tropical diseases, prevention needs to be inexpensive, considering the poor economic situation of the regions where much of the disease is transmitted. The most-effective traditional methods for the prevention of Chagas disease are based on control of the triatomine vector, using insecticides and blood screening prior to transfusions. Southern Cone countries (Argentina, Brazil, Chile, and Uruguay) have developed Received and Accepted 23 July 2014; electronically published 28 July 2014. Correspondence: Mauricio Martins Rodrigues, PhD, Centro de Terapia Celular e Molecular, UNIFESP–Escola Paulista de Medicina, Rua Mirassol, 207, São Paulo-SP 04044-010, Brazil ([email protected]). The Journal of Infectious Diseases 2015;211:175–7 © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals. [email protected]. DOI: 10.1093/infdis/jiu420