title: Molecular Characterization of Cryptosporidium Species and Giardia duodenalis from Symptomatic Cambodian Children.
abstract: In a prospective study, 498 single faecal samples from children aged under 16 years attending an outpatient clinic in the Angkor Hospital for Children, northwest Cambodia, were examined for Cryptosporidium oocysts and Giardia cysts using microscopy and molecular assays.
  
  
  
  Cryptosporidium oocysts were detected in 2.2% (11/498) of samples using microscopy and in 7.7% (38/498) with molecular tests. Giardia duodenalis cysts were detected in 18.9% (94/498) by microscopy and 27.7% (138/498) by molecular tests; 82% of the positive samples (by either method) were from children aged 1-10 years. Cryptosporidium hominis was the most common species of Cryptosporidium, detected in 13 (34.2%) samples, followed by Cryptosporidium meleagridis in 9 (23.7%), Cryptosporidium parvum in 8 (21.1%), Cryptosporidium canis in 5 (13.2%), and Cryptosporidium suis and Cryptosporidium ubiquitum in one sample each. Cryptosporidium hominis and C. parvum positive samples were subtyped by sequencing the GP60 gene: C. hominis IaA16R6 and C. parvum IIeA7G1 were the most abundant subtypes. Giardia duodenalis was typed using a multiplex real-time PCR targeting assemblages A and B. Assemblage B (106; 76.8% of all Giardia positive samples) was most common followed by A (12.3%) and mixed infections (5.1%). Risk factors associated with Cryptosporidium were malnutrition (AOR 9.63, 95% CI 1.67-55.46), chronic medical diagnoses (AOR 4.51, 95% CI 1.79-11.34) and the presence of birds in the household (AOR 2.99, 95% CI 1.16-7.73); specifically C. hominis (p = 0.03) and C. meleagridis (p<0.001) were associated with the presence of birds. The use of soap was protective against Giardia infection (OR 0.74, 95% CI 0.58-0.95).
  
  
  
  This is the first report to describe the different Cryptosporidium species and subtypes and Giardia duodenalis assemblages in Cambodian children. The variety of Cryptosporidium species detected indicates both anthroponotic and zoonotic transmission in this population. Interventions to improve sanitation, increase hand washing after defecation and before preparing food and promote drinking boiled water may reduce the burden of these two parasites.
authors.affiliation: Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.|Cambodia-Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia.|Modernising Medical Microbiology Consortium, Nuffield Department of Clinical Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom.|Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.
authors.forename: Catrin E
authors.initials: CE
authors.lastname: Moore
authors.affiliation: Cryptosporidium Reference Unit, Public Health Wales Microbiology, Singleton Hospital, Swansea, United Kingdom.|Swansea University Medical School, Grove Building, Swansea University, Singleton Park, Swansea, United Kingdom.
authors.forename: Kristin
authors.initials: K
authors.lastname: Elwin
authors.affiliation: Angkor Hospital for Children, Siem Reap, Cambodia.
authors.forename: Nget
authors.initials: N
authors.lastname: Phot
authors.affiliation: Angkor Hospital for Children, Siem Reap, Cambodia.
authors.forename: Chanthou
authors.initials: C
authors.lastname: Seng
authors.affiliation: Angkor Hospital for Children, Siem Reap, Cambodia.
authors.forename: Saroeun
authors.initials: S
authors.lastname: Mao
authors.affiliation: Angkor Hospital for Children, Siem Reap, Cambodia.
authors.forename: Kuong
authors.initials: K
authors.lastname: Suy
authors.affiliation: Angkor Hospital for Children, Siem Reap, Cambodia.
authors.forename: Varun
authors.initials: V
authors.lastname: Kumar
authors.affiliation: Clinical Sciences Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
authors.forename: Johanna
authors.initials: J
authors.lastname: Nader
authors.affiliation: Microbiology Department, Addenbrooke's Hospital, Cambridge, United Kingdom.
authors.forename: Rachel
authors.initials: R
authors.lastname: Bousfield
authors.affiliation: Modernising Medical Microbiology Consortium, Nuffield Department of Clinical Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom.
authors.forename: Sanuki
authors.initials: S
authors.lastname: Perera
authors.affiliation: Clinical Sciences Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
authors.forename: J Wendi
authors.initials: JW
authors.lastname: Bailey
authors.affiliation: Clinical Sciences Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.|NIHR Health Protection Research Unit (HPRU) in Gastrointestinal Infections, University of Liverpool, Liverpool, United Kingdom.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Beeching
authors.affiliation: Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.|Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.
authors.forename: Nicholas P J
authors.initials: NP
authors.lastname: Day
authors.affiliation: Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.|Cambodia-Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia.|London School of Hygiene and Tropical Medicine, London, United Kingdom.|School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Parry
authors.affiliation: Cryptosporidium Reference Unit, Public Health Wales Microbiology, Singleton Hospital, Swansea, United Kingdom.|Swansea University Medical School, Grove Building, Swansea University, Singleton Park, Swansea, United Kingdom.
authors.forename: Rachel M
authors.initials: RM
authors.lastname: Chalmers
mesh_terms: D000293:Adolescent; D000818:Animals; D002160:Cambodia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003457:Cryptosporidiosis / Q000175:diagnosis / Q000453:epidemiology / Q000469:parasitology*; D003458:Cryptosporidium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D005243:Feces / Q000469:parasitology; D005260:Female; D005872:Giardia / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D005873:Giardiasis / Q000175:diagnosis / Q000453:epidemiology / Q000469:parasitology*; D006801:Humans; D007223:Infant; D008297:Male; D011446:Prospective Studies