PLoS ONE (Jan 2016)

Prevalence and Genetic Diversity of Giardia duodenalis and Cryptosporidium spp. among School Children in a Rural Area of the Amhara Region, North-West Ethiopia.

  • Aida de Lucio,
  • Aranzazu Amor-Aramendía,
  • Begoña Bailo,
  • José M Saugar,
  • Melaku Anegagrie,
  • Ana Arroyo,
  • Beatriz López-Quintana,
  • Derjew Zewdie,
  • Zimmam Ayehubizu,
  • Endalew Yizengaw,
  • Bayeh Abera,
  • Mulat Yimer,
  • Wondemagen Mulu,
  • Tadesse Hailu,
  • Zaida Herrador,
  • Isabel Fuentes,
  • David Carmena

DOI
https://doi.org/10.1371/journal.pone.0159992
Journal volume & issue
Vol. 11, no. 7
p. e0159992

Abstract

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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.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.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.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.