Home Economics American Trypanosomiasis Chagas Disease, Second Edition: One Hundred Years of Research
In 1909, Carlos Chagas identified Trypanosoma cruzi as the agent of Chagas disease. In 1910, Chagas discovered that Triatoma bugs are vectors of the parasite and that various animals (first, the armadillo) are wild reservoirs for the parasite. The parasite was named in honor of Oswaldo Cruz, the great Brazilian epidemiologist of yellow fever, smallpox, and bubonic plague. In 1986, Michel Tibayrenc and collaborators discovered that the reproduction of the parasite is clonal, rather than sexual. The disease is, of course, much older than Chagas’ discovery. It may have been associated with humans shortly after they arrived in the Americas some
15,000 years ago. T. cruzi has been found in mummies from northern Chile and southern Peru that are nearly 9000 years old.
Chagas disease is endemic in Mexico and Central and South America, with significant prevalence of human infection in 22 Latin American countries, where it affects 10—12 million people and kills more than 10,000 humans each year. There are several hundred thousand people infected with T. cruzi in other parts of the world. Mostly, in the United States, Canada, Australia, Japan, Spain, and Portugal, where the carriers are typically Latin American immigrants, who are often unaware of their infection, but cause the infection of others through blood transfusions and otherwise. In the United States, the annual cost of treatment is about $900 million. The global cost is estimated to be more than $7 billion.
In spite of counting among mankind’s worst scourges, Chagas disease has received relatively little attention from investigators and institutions. Pharmaceutical corporations typically have little or no interest in diseases that affect the world’s poorest. In the United States, Europe, and other industrialized countries, Chagas is largely perceived as a foreign disease, which does not motivate government agencies, foundations, and other institutions to invest substantial resources to discover curative drugs and medical treatments.
This neglect has been changing. In 1943, the Oswaldo Cruz Institute’s Prophylaxis and Study Center for Chagas Disease was created in Bambul, Brazil. In 1974, the World Health Organization set a special program for the study of Chagas disease. In 1991, Argentina, Bolivia, Brazil, Chile, Paraguay, and Uruguay started the Southern Cone initiative for vector control. The Drugs for Neglected Diseases Initiative (DNDi) was established the same year to promote research against Chagas and other tropical diseases. In 2013, the DNDi received the Carlos Slim Health Award, as well as a Next Century Innovator’s Award from the Rockefeller Foundation. The first complete genome sequence of T. cruzi was published in 2005, culminating an effort pioneered since 1998 by Bjorn Andersson and others. There are now very few treatment drugs in use, notably benznidazole and posacona- zole, but research and testing of several other drugs are in the pipeline.
American Trypanosomiasis Chagas Disease: One Hundred Years of Research is a wonderful addition to current efforts. The coverage is broad, almost all-inclusive: from history and geography—through vectors and nonhuman hosts, the biology and modes of transmission of the parasite, and the host—parasite immune interactions— to the pathology, diagnosis, and treatment of the disease. I anticipate that this Second Edition will be hailed as a landmark in the history and control of Chagas disease, as the First Edition was also recognized.
Francisco J. Ayala
University of California, Irvine, United States
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