title: Genetic diversity of Giardia duodenalis: multilocus genotyping reveals zoonotic potential between clinical and environmental sources in a metropolitan region of Brazil.
abstract: BACKGROUND
  Giardia duodenalis is a flagellate protozoan that parasitizes humans and several other mammals. Protozoan contamination has been regularly documented at important environmental sites, although most of these studies were performed at the species level. There is a lack of studies that correlate environmental contamination and clinical infections in the same region. The aim of this study is to evaluate the genetic diversity of a set of clinical and environmental samples and to use the obtained data to characterize the genetic profile of the distribution of G. duodenalis and the potential for zoonotic transmission in a metropolitan region of Brazil.
  
  
  RESULTS
  The genetic assemblages and subtypes of G. duodenalis isolates obtained from hospitals, a veterinary clinic, a day-care center and important environmental sites were determined via multilocus sequence-based genotyping using three unlinked gene loci. Cysts of Giardia were detected at all of the environmental sites. Mixed assemblages were detected in 25% of the total samples, and an elevated number of haplotypes was identified. The main haplotypes were shared among the groups, and new subtypes were identified at all loci. Ten multilocus genotypes were identified: 7 for assemblage A and 3 for assemblage B.
  
  
  CONCLUSIONS
  There is persistent G. duodenalis contamination at important environmental sites in the city. The identified mixed assemblages likely represent mixed infections, suggesting high endemicity of Giardia in these hosts. Most Giardia isolates obtained in this study displayed zoonotic potential. The high degree of genetic diversity in the isolates obtained from both clinical and environmental samples suggests that multiple sources of infection are likely responsible for the detected contamination events. The finding that many multilocus genotypes (MLGs) and haplotypes are shared by different groups suggests that these sources of infection may be related and indicates that there is a notable risk of human infection caused by Giardia in this region.
authors.affiliation: Molecular Biology and Genetic Engineering Center (CBMEG), University of Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Durigan
authors.affiliation: APTA - São Paulo Agency for Agribusiness Technology, Piracicaba, SP, Brazil.
authors.forename: Aluana Gonçalves
authors.initials: AG
authors.lastname: Abreu
authors.affiliation: APTA - São Paulo Agency for Agribusiness Technology, Piracicaba, SP, Brazil.
authors.forename: Maria Imaculada
authors.initials: MI
authors.lastname: Zucchi
authors.affiliation: Department of Animal Biology, Biology Institute, University of Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Regina Maura Bueno
authors.initials: RM
authors.lastname: Franco
authors.affiliation: Molecular Biology and Genetic Engineering Center (CBMEG), University of Campinas (UNICAMP), Campinas, SP, Brazil; Department of Plant Biology, Biology Institute, University of Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Anete Pereira
authors.initials: AP
authors.lastname: de Souza
mesh_terms: D000818:Animals; D001938:Brazil; D002947:Cities; D004777:Environment; D053263:Gene Regulatory Networks; D056426:Genetic Loci; D014644:Genetic Variation; D060005:Genotyping Techniques / Q000379:methods*; D005843:Geography; D005872:Giardia / Q000235:genetics / Q000302:isolation & purification; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing / Q000379:methods*; D010802:Phylogeny; D015047:Zoonoses / Q000469:parasitology*