title: Prevalence and Genetic Diversity of Giardia duodenalis and Cryptosporidium spp. among School Children in a Rural Area of the Amhara Region, North-West Ethiopia.
abstract: BACKGROUND
  Giardia duodenalis and Cryptosporidium spp. are enteric protozoan causing gastrointestinal illness in humans and animals. Giardiasis and cryptosporidiosis are not formally considered as neglected tropical diseases, but belong to the group of poverty-related infectious diseases that impair the development and socio-economic potential of infected individuals in developing countries.
  
  
  METHODS
  We report here the prevalence and genetic diversity of G. duodenalis and Cryptosporidium spp. in children attending rural primary schools in the Bahir Dar district of the Amhara Region, Ethiopia. Stool samples were collected from 393 children and analysed by molecular methods. G. duodenalis was detected by real-time PCR, and the assemblages and sub-assemblages were determined by multilocus sequence-based genotyping of the glutamate dehydrogenase and β-giardin genes of the parasite. Detection and identification of Cryptosporidium species was carried out by sequencing of a partial fragment of the small-subunit ribosomal RNA gene.
  
  
  RESULTS
  The PCR-based prevalences of G. duodenalis and Cryptosporidium spp. were 55.0% (216/393) and 4.6% (18/393), respectively. A total of 78 G. duodenalis isolates were successfully characterized, revealing the presence of sub-assemblages AII (10.3%), BIII (28.2%), and BIV (32.0%). Discordant typing results AII/AIII and BIII/BIV were identified in 7.7% and 15.4% of the isolates, respectively. An additional five (6.4%) isolates were assigned to assemblage B. No mixed infections of assemblages A+B were found. Extensive genetic variation at the nucleotide level was observed within assemblage B (but no within assemblage A), resulting in the identification of a large number of sub-types. Cryptosporidium diversity was demonstrated by the occurrence of C. hominis, C. parvum, and C. viatorum in the population under study.
  
  
  CONCLUSIONS
  Our data suggest an epidemiological scenario with an elevated transmission intensity of a wide range of G. duodenalis genetic variants. Importantly, the elevated degree of genetic diversity observed within assemblage B is consistent with the occurrence of intra-assemblage recombination in G. duodenalis.
authors.affiliation: Parasitology Service, National Centre for Microbiology, Majadahonda, Madrid, Spain.
authors.forename: Aida
authors.initials: A
authors.lastname: de Lucio
authors.affiliation: National Centre of Tropical Medicine, Madrid, Spain.|Mundo Sano Foundation, Madrid, Spain.
authors.forename: Aranzazu
authors.initials: A
authors.lastname: Amor-Aramendía
authors.affiliation: Parasitology Service, National Centre for Microbiology, Majadahonda, Madrid, Spain.
authors.forename: Begoña
authors.initials: B
authors.lastname: Bailo
authors.affiliation: Parasitology Service, National Centre for Microbiology, Majadahonda, Madrid, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Saugar
authors.affiliation: National Centre of Tropical Medicine, Madrid, Spain.|Mundo Sano Foundation, Madrid, Spain.
authors.forename: Melaku
authors.initials: M
authors.lastname: Anegagrie
authors.affiliation: Microbiology and Parasitology Service, La Paz-Carlos III Hospital, Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Arroyo
authors.affiliation: Microbiology and Parasitology Service, La Paz-Carlos III Hospital, Madrid, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: López-Quintana
authors.affiliation: Department of Microbiology, Immunology and Parasitology, College of Medicine and Health Science, Bahir Dar, Ethiopia.
authors.forename: Derjew
authors.initials: D
authors.lastname: Zewdie
authors.affiliation: Department of Microbiology, Immunology and Parasitology, College of Medicine and Health Science, Bahir Dar, Ethiopia.
authors.forename: Zimmam
authors.initials: Z
authors.lastname: Ayehubizu
authors.affiliation: Department of Microbiology, Immunology and Parasitology, College of Medicine and Health Science, Bahir Dar, Ethiopia.
authors.forename: Endalew
authors.initials: E
authors.lastname: Yizengaw
authors.affiliation: Department of Microbiology, Immunology and Parasitology, College of Medicine and Health Science, Bahir Dar, Ethiopia.
authors.forename: Bayeh
authors.initials: B
authors.lastname: Abera
authors.affiliation: Department of Microbiology, Immunology and Parasitology, College of Medicine and Health Science, Bahir Dar, Ethiopia.
authors.forename: Mulat
authors.initials: M
authors.lastname: Yimer
authors.affiliation: Department of Microbiology, Immunology and Parasitology, College of Medicine and Health Science, Bahir Dar, Ethiopia.
authors.forename: Wondemagen
authors.initials: W
authors.lastname: Mulu
authors.affiliation: Department of Microbiology, Immunology and Parasitology, College of Medicine and Health Science, Bahir Dar, Ethiopia.
authors.forename: Tadesse
authors.initials: T
authors.lastname: Hailu
authors.affiliation: National Centre of Tropical Medicine, Madrid, Spain.
authors.forename: Zaida
authors.initials: Z
authors.lastname: Herrador
authors.affiliation: Parasitology Service, National Centre for Microbiology, Majadahonda, Madrid, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Fuentes
authors.affiliation: Parasitology Service, National Centre for Microbiology, Majadahonda, Madrid, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Carmena
mesh_terms: D002648:Child; D003457:Cryptosporidiosis / Q000453:epidemiology* / Q000469:parasitology; D003458:Cryptosporidium / Q000235:genetics / Q000302:isolation & purification*; D005002:Ethiopia / Q000453:epidemiology; D014644:Genetic Variation; D016829:Giardia lamblia / Q000235:genetics / Q000302:isolation & purification*; D005873:Giardiasis / Q000453:epidemiology* / Q000469:parasitology; D006801:Humans; D016133:Polymerase Chain Reaction; D015995:Prevalence