Distantiae transmission of Trypanosoma cruzi: a new epidemiological feature of acute Chagas disease in Brazil.
BACKGROUND
The new epidemiological scenario of orally transmitted Chagas disease that has emerged in Brazil, and mainly in the Amazon region, needs to be addressed with a new and systematic focus. Belém, the capital of Pará state, reports the highest number of acute Chagas disease (ACD) cases associated with the consumption of açaí juice.


RESULTS
The wild and domestic enzootic transmission cycles of Trypanosoma cruzi were evaluated in the two locations (Jurunas and Val-de Cães) that report the majority of the autochthonous cases of ACD in Belém city. Moreover, we evaluated the enzootic cycle on the three islands that provide most of the açaí fruit that is consumed in these localities. We employed parasitological and serological tests throughout to evaluate infectivity competence and exposure to T. cruzi. In Val-de-Cães, no wild mammal presented positive parasitological tests, and 56% seroprevalence was observed, with low serological titers. Three of 14 triatomines were found to be infected (TcI). This unexpected epidemiological picture does not explain the high number of autochthonous ACD cases. In Jurunas, the cases of ACD could not be autochthonous because of the absence of any enzootic cycle of T. cruzi. In contrast, in the 3 island areas from which the açaí fruit originates, 66.7% of wild mammals and two dogs displayed positive hemocultures, and 15.6% of triatomines were found to be infected by T. cruzi. Genotyping by mini-exon gene and PCR-RFLP (1f8/Akw21I) targeting revealed that the mammals and triatomines from the islands harbored TcI and Trypanosoma rangeli in single and mixed infections.


CONCLUSIONS
These findings show that cases of Chagas disease in the urban area of Belém may be derived from infected triatomines coming together with the açaí fruits from distant islands. We term this new epidemiological feature of Chagas disease as "Distantiae transmission".
Laboratory of Trypanosomatid Biology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Rio de Janeiro, Brazil.
Samanta Cristina das Chagas
SC
Xavier
Laboratory of Trypanosomatid Biology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Rio de Janeiro, Brazil.
André Luiz Rodrigues
AL
Roque
Laboratory of Trypanosomatid Biology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Rio de Janeiro, Brazil.
Daniele
D
Bilac
Laboratory of Trypanosomatid Biology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Rio de Janeiro, Brazil.
Vitor Antônio Louzada
VA
de Araújo
Laboratory of Biology and Parasitology of Wild Reservoir Mammals, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Rio de Janeiro, Brazil.
Sócrates Fraga da Costa
SF
da Costa Neto
International and National Laboratory of Reference for Triatominae Taxonomy, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Rio de Janeiro, Brazil.
Elias Seixas
ES
Lorosa
Laboratory of Cartography, Military Institute of Engineering, IME, Rio de Janeiro, Rio de Janeiro, Brazil.
Luiz Felipe Coutinho Ferreira
LF
da Silva
Laboratory of Trypanosomatid Biology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Rio de Janeiro, Brazil.
Ana Maria
AM
Jansen
D000818:Animals; D000835:Animals, Wild / Q000469:parasitology*; D001938:Brazil / Q000453:epidemiology; D014355:Chagas Disease / Q000453:epidemiology / Q000635:transmission* / Q000662:veterinary*; D004283:Dog Diseases / Q000469:parasitology; D004285:Dogs; D065748:Euterpe / Q000469:parasitology*; D005511:Food Handling; D006801:Humans; D015995:Prevalence; D012424:Rural Population; D062206:Spatial Analysis; D014224:Triatoma / Q000469:parasitology*; D014349:Trypanosoma cruzi / Q000235:genetics / Q000302:isolation & purification*; D014505:Urban Population