Current epidemiological trends of Chagas disease in Latin America and future challenges: epidemiology, surveillance, and health policies
A Moncayo and A.C. Silveiraf
Academia Nacional de Medicina, Bogota, Colombia
Chapter Outline
Introduction 60 Modes of transmission 60
Transmission through vectors 60 Transmission via blood transfusion 60
Methods and measurement of epidemiological trends in the continent from 1980 to 2006 61
Transmission through vectors 62 Transmission through blood transfusion 63 Feasibility of interruption of transmission 63 Current control programs 66 Economic impact 66
Program costs and cost-effectiveness of control interventions 66
Epidemiological impact in the region 67
Initiative of the Southern Cone countries: epidemiological trends 68 Initiative of the Andean countries: epidemiological trends 72 Initiative of the Central American countries: epidemiological trends 74 Amazon initiative 76 Epidemiological impact 77 Future challenges 78 Epidemiological 78 Technical 82
Political and structural factors 83
References 84
Introduction
Chagas disease, named after Carlos Chagas who first described it in 1909, exists only on the American Continent.1 It is caused by a flagellate parasite, Trypanosoma cruzi, transmitted to humans by blood-sucking triatomine bugs and by blood transfusion, the two main ways of transmission.
Chagas disease has two successive phases, acute and chronic. The acute phase lasts 6—8 weeks. Once the acute phase subsides, most of the infected patients recover an apparent healthy status, where no organ damage can be demonstrated by the current standard methods of clinical diagnosis. The infection can only be verified by serological or parasitological tests. This form of the chronic phase of Chagas disease is called indeterminate form. Most patients remain in this form of the disease.
However, after several years of starting the chronic phase, 20—35% of the infected individuals, depending on the geographical area will develop irreversible lesions of the autonomous nervous system in the heart, esophagus, colon, and the peripheral nervous system. The chronic phase lasts the rest of the life of the infected individual.
Chagas disease represents the first cause of cardiac lesions in young, economically productive adults in the endemic countries in Latin America.
Thanks to a coordinated multicountry program in the Southern Cone countries the transmission of Chagas disease by vectors and by blood transfusion has been interrupted in Uruguay in 1997, Chile in 1999, and in Brazil in 2006.
