title: Blastocystis infection in Malaysia: evidence of waterborne and human-to-human transmissions among the Proto-Malay, Negrito and Senoi tribes of Orang Asli.
abstract: BACKGROUND
  Blastocystis has been described as the most common intestinal parasite in humans and has an increased impact on public health. However, the transmission of this parasite has not been conclusively determined.
  
  
  METHODS
  To contribute to a better comprehension of the epidemiology of this infection, a cross-sectional survey aimed at providing the first documented data on the prevalence and risk factors associated with Blastocystis infection was carried out among three Orang Asli tribes (Proto-Malay, Negrito and Senoi) in selected villages at Negeri Sembilan, Perak and Pahang, Peninsular Malaysia. Faecal samples were examined by formalin-ether sedimentation and trichrome staining techniques.
  
  
  RESULTS
  Of 500 individuals, 20.4% (102) were detected positive for Blastocystis; 13.3% (20/150) of Proto-Malays, 21.6% (30/139) of Negritos and 24.7% (52/211) of Senois were positive for Blastocystis, respectively. The positive cases showed a decrease with increasing age and most of the positive cases were observed in individuals less than 15 years old. Multivariate analysis confirmed that drinking untreated water and the presence of other family members infected with Blastocystis were significant risk factors of infection among the three tribes and overall population studied.
  
  
  CONCLUSIONS
  Essentially, the findings highlighted that Blastocystis infection is prevalent among Orang Asli communities in Malaysia. Further studies using molecular approaches to distinguish the subtype of Blastocystis is needed. The present study also revealed that this infection may be transmitted through waterborne and human-to-human contact. Therefore, interventions with the provision of clean water supply for the communities and health education especially to the parents are urgently required.
authors: Department of Parasitology and Medical Entomology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz 50300, Kuala Lumpur, Malaysia.
authors: Tengku Shahrul
authors: TS
authors: Anuar
authors: Mohamed Kamel Abdul
authors: MK
authors: Ghani
authors: Siti Nor
authors: SN
authors: Azreen
authors: Fatmah Md
authors: FM
authors: Salleh
authors: Norhayati
authors: N
authors: Moktar
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016844:Blastocystis / Q000302:isolation & purification*; D016776:Blastocystis Infections / Q000453:epidemiology* / Q000635:transmission*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005243:Feces / Q000469:parasitology; D005260:Female; D006801:Humans; D008296:Malaysia / Q000453:epidemiology; D008297:Male; D008853:Microscopy; D008875:Middle Aged; D010274:Parasitology / Q000379:methods; D044382:Population Groups; D015995:Prevalence; D012307:Risk Factors; D055815:Young Adult