title: Presence of Cryptosporidium parvum and Giardia lamblia in water samples from Southeast Asia: towards an integrated water detection system.
abstract: BACKGROUND
  Access to clean and safe drinking water that is free from pathogenic protozoan parasites, especially Cryptosporidium parvum and Giardia lamblia that cause gastrointestinal illness in humans, is still an issue in Southeast Asia (SEA). This study is the first attempt to detect the aforementioned protozoan parasites in water samples from countries in SEA, using real-time polymerase chain reaction (qPCR) assays.
  
  
  METHODS
  A total of 221 water samples of 10 l each were collected between April and October 2013 from Malaysia (53), Thailand (120), the Philippines (33), and Vietnam (15). A physicochemical analysis was conducted. The water samples were processed in accordance with the US Environmental Protection Agency's methods 1622/1623.1, microscopically observed and subsequently screened using qPCR assays.
  
  
  RESULTS
  Cryptosporidium oocysts were detected in treated water samples from the Philippines (1/10), with a concentration of 0.06 ± 0.19 oocyst/L, and untreated water samples from Thailand (25/93), Malaysia (17/44), and the Philippines (11/23), with concentrations ranging from 0.13 ± 0.18 to 0.57 ± 1.41 oocyst/L. Giardia cysts were found in treated water samples from the Philippines (1/10), with a concentration of 0.02 ± 0.06 cyst/L, and in untreated water samples from Thailand (20/93), Vietnam (5/10), Malaysia (22/44), and the Philippines (16/23), with concentrations ranging from 0.12 ± 0.3 to 8.90 ± 19.65 cyst/L. The pathogens C. parvum and G. lamblia were detected using using qPCR assays by targeting the 138-bp fragment and the small subunit gene, respectively. C. parvum was detected in untreated water samples from the Philippines (1/23) and Malaysia (2/44), whilst, G. lamblia detected was detected in treated water samples from the Philippines (1/10) and in untreated water samples from Thailand (21/93), Malaysia (12/44), and the Philippines (17/23). Nitrate concentration was found to have a high positive correlation with (oo)cyst (0.993).
  
  
  CONCLUSIONS
  The presence of (oo)cysts in the water samples means that there is potential risk for zoonotic disease transmission in the studied countries. Detection using qPCR is feasible for quantifying both pathogenic C. parvum and G. lamblia in large water samples.
authors.affiliation: Department of Parasitology (Southeast Asia Water Team), Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Thulasi
authors.initials: T
authors.lastname: Kumar
authors.affiliation: Department of Parasitology (Southeast Asia Water Team), Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Mohamad Azlan
authors.initials: MA
authors.lastname: Abd Majid
authors.affiliation: Department of Parasitology (Southeast Asia Water Team), Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Subashini
authors.initials: S
authors.lastname: Onichandran
authors.affiliation: Department of Parasitology (Southeast Asia Water Team), Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.|Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand.
authors.forename: Narong
authors.initials: N
authors.lastname: Jaturas
authors.affiliation: Department of Parasitology (Southeast Asia Water Team), Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Hemah
authors.initials: H
authors.lastname: Andiappan
authors.affiliation: Biological Science Department, College of Science and Computer Studies, De La Salle University-Dasmariñas, Dasmariñas, Philippines.
authors.forename: Cristina C
authors.initials: CC
authors.lastname: Salibay
authors.affiliation: Biological Science Department, College of Science and Computer Studies, De La Salle University-Dasmariñas, Dasmariñas, Philippines.
authors.forename: Hazel A L
authors.initials: HA
authors.lastname: Tabo
authors.affiliation: Biological Science Department, College of Science and Computer Studies, De La Salle University-Dasmariñas, Dasmariñas, Philippines.
authors.forename: Norbel
authors.initials: N
authors.lastname: Tabo
authors.affiliation: School of Science and Technology, Centro Escolar University, Manila, Philippines.
authors.forename: Julieta Z
authors.initials: JZ
authors.lastname: Dungca
authors.affiliation: School of Allied Health Sciences and Public Health, Walailak University, Nakhon Si Thammarat, Thailand.
authors.forename: Jitbanjong
authors.initials: J
authors.lastname: Tangpong
authors.affiliation: Graduate School, Kasem Bundit University, Bangkok, Thailand.
authors.forename: Sucheep
authors.initials: S
authors.lastname: Phiriyasamith
authors.affiliation: Regional Medical Sciences Center, Department of Medical Sciences, Ministry of Public Health, Nakhon Ratchasima, Thailand.
authors.forename: Boonyaorn
authors.initials: B
authors.lastname: Yuttayong
authors.affiliation: Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand.
authors.forename: Raxsina
authors.initials: R
authors.lastname: Polseela
authors.affiliation: Department of Parasitology, Faculty of Medicine, Vietnam Military Medical University, 160 Phung Hung Road, Phuc La Ward, Ha Dong District, Hanoi, Vietnam.
authors.forename: Binh Nhu
authors.initials: BN
authors.lastname: Do
authors.affiliation: Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Thailand.
authors.forename: Nongyao
authors.initials: N
authors.lastname: Sawangjaroen
authors.affiliation: Department of Parasitology (Southeast Asia Water Team), Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Tian-Chye
authors.initials: TC
authors.lastname: Tan
authors.affiliation: Department of Parasitology (Southeast Asia Water Team), Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Yvonne A L
authors.initials: YA
authors.lastname: Lim
authors.affiliation: Department of Parasitology (Southeast Asia Water Team), Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia. veeranoot@um.edu.my.
authors.forename: Veeranoot
authors.initials: V
authors.lastname: Nissapatorn
mesh_terms: D001210:Asia, Southeastern; D016785:Cryptosporidium parvum / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D060766:Drinking Water / Q000737:chemistry / Q000469:parasitology*; D016829:Giardia lamblia / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D033661:Oocysts / Q000145:classification / Q000254:growth & development; D060888:Real-Time Polymerase Chain Reaction; D018508:Water Purification; D060753:Water Quality
chemical_list: D060766:Drinking Water