title: Spatial and Molecular Epidemiology of Giardia intestinalis Deep in the Amazon, Brazil.
abstract: BACKGROUND
  Current control policies for intestinal parasitosis focuses on soil-transmitted helminths, being ineffective against Giardia intestinalis, a highly prevalent protozoon that impacts children's nutritional status in developing countries. The objective of this study was to explore spatial and molecular epidemiology of Giardia intestinalis in children of Amerindian descent in the Brazilian Amazon.
  
  
  RESULTS
  A cross sectional survey was performed in the Brazilian Amazon with 433 children aged 1 to 14 years. Fecal samples were processed through parasitological techniques and molecular characterization. Prevalence of G. intestinalis infection was 16.9% (73/433), reaching 22.2% (35/158) among children aged 2-5 years, and a wide distribution throughout the city with some hot spots. Positivity-rate was similar among children living in distinct socioeconomic strata (48/280 [17.1%] and 19/116 [16.4%] below and above the poverty line, respectively). Sequencing of the β-giardin gene revealed 52.2% (n = 12) of assemblage A and 47.8% (n = 11) of assemblage B with high haplotype diversity for the latter. The isolates clustered into two well-supported G. intestinalis clades. A total of 38 haplotypes were obtained, with the following subassemblages distribution: 5.3% (n = 2) AII, 26.3% (n = 10) AIII, 7.9% (n = 3) BIII, and 60.5% (n = 23) new B genotypes not previously described.
  
  
  CONCLUSIONS
  Giardia intestinalis infection presents a high prevalence rate among Amerindian descended children living in Santa Isabel do Rio Negro/Amazon. The wide distribution observed in a small city suggests the presence of multiple sources of infection, which could be related to environmental contamination with feces, possibly of human and animal origin, highlighting the need of improving sanitation, safe water supply and access to diagnosis and adequate treatment of infections.
authors.affiliation: Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Coronato Nunes
authors.affiliation: Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
authors.forename: Márcio G
authors.initials: MG
authors.lastname: Pavan
authors.affiliation: Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
authors.forename: Lauren H
authors.initials: LH
authors.lastname: Jaeger
authors.affiliation: Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
authors.forename: Kerla J L
authors.initials: KJ
authors.lastname: Monteiro
authors.affiliation: Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
authors.forename: Samanta C C
authors.initials: SC
authors.lastname: Xavier
authors.affiliation: Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
authors.forename: Fernando A
authors.initials: FA
authors.lastname: Monteiro
authors.affiliation: Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
authors.forename: Márcio N
authors.initials: MN
authors.lastname: Bóia
authors.affiliation: Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.|Oswaldo Cruz Foundation, Teresina, Piauí, Brazil.
authors.forename: Filipe A
authors.initials: FA
authors.lastname: Carvalho-Costa
mesh_terms: D000293:Adolescent; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D016829:Giardia lamblia / Q000235:genetics*; D005873:Giardiasis / Q000453:epidemiology* / Q000235:genetics* / Q000517:prevention & control; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D017720:Molecular Epidemiology; D015995:Prevalence; D015800:Protozoan Proteins / Q000235:genetics*
chemical_list: D015800:Protozoan Proteins