Home Economics American Trypanosomiasis Chagas Disease, Second Edition: One Hundred Years of Research
Modes of transmission
Transmission through vectors
Chagas disease is a zoonosis transmitted in natural foci or ecological units within a well-defined geographical environment. The ecological unit is composed of sylvan or domestic mammals and of sylvan Triatoma bugs, both infected with T. cruzi. Continuous transmission is assured with or without the involvement of human beings.
These conditions of transmission are present from latitude 42°N to latitude 40° S and so T. cruzi infection occurs from the south of the United States to the south of Argentina.
There are two stages of the human disease: the acute stage, which appears shortly after the infection; and the chronic stage, which may last several years and after several years of a silent asymptomatic period, 25% of those infected develop cardiac symptoms that may lead to chronic heart failure and sudden death, 6% develop digestive damage, mainly mega-colon and mega-esophagus, and 3% will suffer peripheral nervous involvement.2—4
Transmission via blood transfusion
The rural-to-urban migration movements that occurred in Latin America in the decades of the1970s and 1980s changed the traditional epidemiological pattern of Chagas disease as a rural condition and transformed it into an urban infection that can be transmitted by blood transfusion.
In most countries in Latin America it is now compulsory to screen for infected blood in blood banks and systems have been established to do so.
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