title: Evaluation of natural foci of Panstrongylus megistus in a forest fragment in Porto Alegre, State of Rio Grande do Sul, Brazil.
abstract: Panstrongylus megistus is commonly found in wild environments of the State of Rio Grande do Sul, Brazil. The aim of this study was to characterize the network of refuges used by triatomine in a forest fragment of Porto Alegre and to identify Trypanosoma cruzi infection, associated hosts and the epidemiological importance of both hosts and triatomines.
  
  
  
  Techniques including the spool-and-line method and active searching (transects) were used to identify natural foci.
  
  
  
  The food source for each triatomine was determined using the precipitin test, and the infection of marsupials was determined by xenodiagnosis. A total of 33 adults (domestic environment) and 27 nymphs (wild environment) of P. megistus were found in addition to 43 Didelphis albiventris specimens. The infection rates of triatomine adults, triatomine nymphs and opossums with T. cruzi I were 64%, 73% and 69%, respectively. Birds, rodents and opossums were the main resources used by triatomine.
  
  
  
  This work presents the first characterization of a natural focus of P. megistus in Rio Grande do Sul. The natural characteristics of this focus and its implication in the transmission of T. cruzi are discussed.
authors.affiliation: Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo HorizonteMG.
authors.forename: José Eloy Dos
authors.initials: JE
authors.lastname: Santos
authors.forename: Mariana Gubert
authors.initials: MG
authors.lastname: Viola
authors.forename: Elias Seixas
authors.initials: ES
authors.lastname: Lorosa
authors.forename: Evandro Marques de Menezes
authors.initials: EM
authors.lastname: Machado
authors.forename: Antonio Leite
authors.initials: AL
authors.lastname: Ruas Neto
authors.forename: Elio
authors.initials: E
authors.lastname: Corseuil
mesh_terms: D000818:Animals; D001717:Birds; D001938:Brazil; D014355:Chagas Disease / Q000469:parasitology* / Q000635:transmission; D004197:Disease Reservoirs / Q000469:parasitology*; D005243:Feces / Q000469:parasitology; D006790:Host-Parasite Interactions; D007303:Insect Vectors / Q000469:parasitology / Q000502:physiology*; D009893:Opossums; D010203:Panstrongylus / Q000469:parasitology / Q000502:physiology*; D012377:Rodentia; D014197:Trees; D014349:Trypanosoma cruzi / Q000302:isolation & purification*