title: Molecular characterization of intestinal protozoa in two poor communities in the State of São Paulo, Brazil.
abstract: BACKGROUND
  Several species of protozoa cause acute or chronic gastroenteritis in humans, worldwide. The burden of disease is particularly high among children living in developing areas of the world, where transmission is favored by lower hygienic standards and scarce availability of safe water. However, asymptomatic infection and polyparasitism are also commonly observed in poor settings. Here, we investigated the prevalence of intestinal protozoa in two small fishing villages, Porto Said (PS) and Santa Maria da Serra (SM), situated along the river Tietê in the State of São Paolo, Brazil. The villages lack basic public infrastructure and services, such as roads, public water supply, electricity and public health services.
  
  
  METHODS
  Multiple fecal samples were collected from 88 individuals in PS and from 38 individuals in SM, who were asymptomatic at the time of sampling and had no recent history of diarrheal disease. To gain insights into potential transmission routes, 49 dog fecal samples (38 from PS and 11 from SM) and 28 river water samples were also collected. All samples were tested by microscopy and PCR was used to genotype Giardia duodenalis, Blastocystis sp., Dientamoeba fragilis and Cryptosporidium spp.
  
  
  RESULTS
  By molecular methods, the most common human parasite was Blastocystis sp. (prevalence, 45% in PS and 71% in SM), followed by D. fragilis (13.6% in PS, and 18.4% in SM) and G. duodenalis (18.2% in PS and 7.9% in SM); Cryptosporidium spp. were not detected. Sequence analysis revealed large genetic variation among Blastocystis samples, with subtypes (STs) 1 and 3 being predominant, and with the notable absence of ST4. Among G. duodenalis samples, assemblages A and B were detected in humans, whereas assemblages A, C and D were found in dogs. Finally, all D. fragilis samples from humans were genotype 1. A single dog was found infected with Cryptosporidium canis. River water samples were negative for the investigated parasites.
  
  
  CONCLUSIONS
  This study showed a high carriage of intestinal parasites in asymptomatic individuals from two poor Brazilian villages, and highlighted a large genetic variability of Blastocystis spp. and G. duodenalis.
authors.affiliation: Parasitology Department, Institute of Bioscience, São Paulo State University (UNESP), Campus de Botucatu, Botucatu, São Paulo, PO Box: 510, CEP: 18618-970, Brazil. ericaboarato@yahoo.com.br.
authors.forename: Érica Boarato
authors.initials: ÉB
authors.lastname: David
authors.affiliation: Parasitology Department, Institute of Bioscience, São Paulo State University (UNESP), Campus de Botucatu, Botucatu, São Paulo, PO Box: 510, CEP: 18618-970, Brazil. sgviana@ibb.unesp.br.
authors.forename: Semíramis
authors.initials: S
authors.lastname: Guimarães
authors.affiliation: Parasitology Department, Institute of Bioscience, São Paulo State University (UNESP), Campus de Botucatu, Botucatu, São Paulo, PO Box: 510, CEP: 18618-970, Brazil. annapaula.botucatu@gmail.com.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: de Oliveira
authors.affiliation: Parasitology Department, Institute of Bioscience, São Paulo State University (UNESP), Campus de Botucatu, Botucatu, São Paulo, PO Box: 510, CEP: 18618-970, Brazil. sequeira@ibb.unesp.br.
authors.forename: Teresa Cristina
authors.initials: TC
authors.lastname: Goulart de Oliveira-Sequeira
authors.affiliation: Parasitology Department, Institute of Bioscience, São Paulo State University (UNESP), Campus de Botucatu, Botucatu, São Paulo, PO Box: 510, CEP: 18618-970, Brazil. gabiibittencourt@hotmail.com.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Nogueira Bittencourt
authors.affiliation: Department of Animal Biology, Biology Institute, State University of Campinas, Rua Monteiro Lobato 255, Campinas, São Paulo, PO Box: 6109, CEP: 13083-970, Brazil. nardi.vet@gmail.com.
authors.forename: Ana Rita
authors.initials: AR
authors.lastname: Moraes Nardi
authors.affiliation: Parasitology Department, Institute of Bioscience, São Paulo State University (UNESP), Campus de Botucatu, Botucatu, São Paulo, PO Box: 510, CEP: 18618-970, Brazil. pribolla@ibb.unesp.br.
authors.forename: Paulo Eduardo
authors.initials: PE
authors.lastname: Martins Ribolla
authors.affiliation: Department of Animal Biology, Biology Institute, State University of Campinas, Rua Monteiro Lobato 255, Campinas, São Paulo, PO Box: 6109, CEP: 13083-970, Brazil. mfranco@unicamp.br.
authors.forename: Regina Maura
authors.initials: RM
authors.lastname: Bueno Franco
authors.affiliation: Department of Animal Biology, Biology Institute, State University of Campinas, Rua Monteiro Lobato 255, Campinas, São Paulo, PO Box: 6109, CEP: 13083-970, Brazil. branco@unicamp.br.
authors.forename: Nilson
authors.initials: N
authors.lastname: Branco
authors.affiliation: Department of Infectious, Parasitic and Immunomediated Diseases, IstitutoSuperiore di Sanità, Viale Regina Elena, 299, Rome, 00161, Italy. fabio.tosini@iss.it.
authors.forename: Fabio
authors.initials: F
authors.lastname: Tosini
authors.affiliation: Department of Infectious, Parasitic and Immunomediated Diseases, IstitutoSuperiore di Sanità, Viale Regina Elena, 299, Rome, 00161, Italy. antonino.bella@iss.it.
authors.forename: Antonino
authors.initials: A
authors.lastname: Bella
authors.affiliation: Department of Infectious, Parasitic and Immunomediated Diseases, IstitutoSuperiore di Sanità, Viale Regina Elena, 299, Rome, 00161, Italy. edoardo.pozio@iss.it.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Pozio
authors.affiliation: Department of Infectious, Parasitic and Immunomediated Diseases, IstitutoSuperiore di Sanità, Viale Regina Elena, 299, Rome, 00161, Italy. simone.caccio@iss.it.
authors.forename: Simone M
authors.initials: SM
authors.lastname: Cacciò
mesh_terms: D000818:Animals; D058070:Asymptomatic Diseases / Q000453:epidemiology; D001938:Brazil / Q000453:epidemiology; D002353:Carrier State / Q000453:epidemiology* / Q000469:parasitology; D004285:Dogs; D005243:Feces / Q000469:parasitology; D006801:Humans; D007411:Intestinal Diseases, Parasitic / Q000453:epidemiology* / Q000469:parasitology / Q000662:veterinary; D008853:Microscopy; D016133:Polymerase Chain Reaction; D011204:Poverty Areas; D015995:Prevalence; D011528:Protozoan Infections / Q000453:epidemiology* / Q000469:parasitology; D011529:Protozoan Infections, Animal / Q000469:parasitology; D045483:Rivers / Q000469:parasitology