Epidemiology

Chagas disease is endemic in 21 Latin American countries and it is estimated that 6-7 million people worldwide are infected with Trypanosoma cruzi, including 300,000 people residing in the US and 80,000 in Spain.[11] WHO: Chagas disease (American trypanosomiasis) Opens in new window Infected residents have also been reported in Switzerland, France, Italy, Canada, Australia, and Japan.[2] Globally, there are 30,000-40,000 new cases per year.[27][28]

The disease is associated with poverty and poor housing conditions. As a consequence of a co-ordinated multi-country programme, targeting reduction of transmission by vectors and via blood transfusion in the Southern Cone, Andean, Amazonian, and Central American countries, the transmission of Chagas disease has been significantly reduced. The incidence of new infections by T. cruziacross the South American continent has decreased from an estimated 700,000 new cases per year in the region to 29,925 in 2010 (96% reduction).[27][29]​​ However, oral transmission has significantly increased in many endemic countries.[9]​​[30]​​

Human migration and travel from endemic areas contributes to the increasing prevalence of Chagas disease in non-endemic countries, including the US, Canada, and some European and Western Pacific countries.[31][32][33][34][35]​ However, the US cannot be classified as a typically non-endemic country as the southern states (from Georgia to California) have established enzootic cycles of T. cruzi, involving several triatomine vector species and mammalian reservoir hosts (e.g., raccoons, opossums, domestic dogs).​​[36][37]​​ Enzootic T. cruzi transmission has also been reported in states as far north as Virginia and Maryland. Despite the presence of these triatomine bugs (mostly Triatoma sanguisuga), vector-borne human cases of Chagas disease have only rarely been documented in the US.[38] In general, the probability of infection has reduced (due to measures such as better housing), but some populations continue to be at risk (e.g., migrant populations living in temporary housing along the US/Mexico border). Considering the increasing domestic presence of vectors, globalisation, and possible future rises in temperature, the disease has the potential to become well established in the US.[39][40][41]

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