Partial interruption of vectorial transmission has also been achieved in Argentina, Bolivia, and Paraguay. This initiative, based on the spraying of infested dwellings with pyrethroid insecticides, resulted in successful interruption of parasite transmission by Triatome infestans (a major domiciliary vector species) in Uruguay in 1997, Chile in 1999, and Brazil in 2006. A major achievement in this context is illustrated by the success of the Southern Cone Countries Initiative, launched since 1991 in Argentina, Brazil, Bolivia, Chile, Paraguay, and Uruguay, and covering an area responsible for roughly 60% of the global prevalence of T cruzi infection. The overall decline in the prevalence and incidence of chronically infected people is the result of several factors, the most important of which is related to effective control of vectorial transmission. 5 Nevertheless, Chagas disease still constitutes the third largest parasitic disease burden globally, after malaria and schistosomiasis. It is also estimated that the incidence of new cases of the infection steadily declined from 700 000/year in 1983 to 200 000/year in 2000 and to 50 000/year currently. There has been a clear decline in the number of patients estimated to harbor the T cruzi, from the 16-18 millions in the 1990s to 8-10 million persons nowadays.
Several epidemiological trends have been observed for Chagas disease over the last decades. 3 Of note, in 2009, we also celebrated the bicentennial of the birth of Charles Darwin, who may have contracted Chagas disease during his expedition to South America, as suggested by his vivid description of suffering the triatomine sting and by some of his late life symptoms. 2 Paleoparasitology studies allowing the recovery of T cruzi DNA from human mummies indicate that Chagas disease already afflicted mankind as early as 9000 years ago. 1Ī few years later, the main clinical form of this new morbid entity-Chagas heart disease-was fully characterized. In 1909 Carlos Chagas discovered a new parasite, the Trypanosoma cruzi (T cruzi) and described, in greater detail, its cycle of transmission (vector, hosts) and the acute clinical manifestations of the first human case of the disease that bears his name.
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