Emerging Chagas disease: Trophic network and cycle of transmission of Trypanosoma cruzi from palm trees in the Amazon

A trophic network involving molds, invertebrates, and vertebrates, ancestra lly adapted to the palm tree (Attalaea phalerata) microhabitat, maintains e nzootic Trypanosoma cruzi infections in the Amazonian county Paco do Lumiar , state of Maranhao, Brazil. We assessed seropositivity for T. cruzi infect ions in the human population of the county, searched in palm trees for the triatomines that harbor these infections, and gathered demographic, environ mental, and socioeconomic data. Rhodnius pictipes and R. neglectus in palm- tree frond clefts or in houses were infected with T. cruzi (57% and 41%, re spectively). Human blood was found in 6.8% of R. pictipes in houses, and 9 of 10 wild Didelphis marsupialis had virulent T. cruzi infections. Increasi ng human population density, rain forest deforestation, and human predation of local fauna are risk factors for human T. cruzi infections.