CHAGAS DISEASE EPIDEMIOLOGY
The etiological agent of Chagas disease, Trypanosoma cruzi, is a single celled protozoal parasite primarily transmitted through the infected feces of blood feeding triatomine insects. The parasite was discovered in 1909 by a Brazilian scientist and physician named Carlos Chagas.1 Infected humans and animals may suffer a spectrum of acute and chronic health issues including fatal cardiac disease. Domestic and wild mammals serve as reservoirs for the parasite. The triatomine insect vector, commonly known as a kissing bug, is widely dispersed throughout the Americas, including South America, Central America, Mexico, and the southern United States (U.S.). Chagas disease may be found in other areas of the world where the vector is not present due to migration or travel of infected individuals into nonendemic countries.2
Chagas disease is classified as a neglected tropical disease due to its distribution in tropical and subtropical climates, disproportionate impact on people living in poverty, and relative neglect from research and funding arenas.3 Estimates by the World Health Organization suggest Chagas disease affects approximately 6–8 million individuals in Latin America,4 and a more liberal estimate suggests 17 million people are infected and 100 million are at risk of contracting the parasite.5 Of 21 Latin American countries, the majority of cases occur in Argentina, Brazil, and Mexico.4,6 Active transmission of T. cruzi in Latin American countries places 13% of the Latin American population at risk for T. cruzi infection.6 Vector transmission in the domestic environment has been interrupted or diminished in some Latin American countries through targeted vector interventions, but wildlife and sylvatic vectors in these areas maintain transmission cycles.7 The average annual economic burden of health-care cost related to Chagas disease in Latin America is approximately U.S.$500 million.8 In Latin America, the disease is responsible for 772,304 disability-adjusted life years (DALYs) which comprises over 95% of DALYs attributed to Chagas disease worldwide.8
In the United States, there is increasing recognition of Chagas disease in the human health community. The majority of human cases in the United States are identified through blood banks and occur in individuals who likely acquired the infection while living or visiting an endemic region in Latin America.9 However, locally acquired infections in the United States are increasingly recognized.10,11 The first documented case of locally acquired Chagas disease in the United States was in Corpus Christi, Texas in 1955.12 The 2012 estimate of over 238,000 cases of T. cruzi infection in the United States may be higher when undocumented immigrant populations are considered.13 Individuals living in impoverished and medically underserved communities along the U.S.-Mexico border may be at heightened risk for infection.14
Triatomine insects, comprised of approximately 150 species in the subfamily Triatominae, are known by many different names in Latin America and are commonly referred to as “chinche besuconas” or ...