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Title:	Epidemiology and molecular characterization of entamoeba histolytica, entamoeba dispar and entamoeba moshkovskii among Orang Asli population in Peninsular Malaysia
Authors:	Tengku Shahrul Anuar Tengku Ahmad Basri (P59425)
Supervisor:	Norhayati Moktar, Prof. Datin Dr.
Keywords:	Public health
Issue Date:	20-May-2013
Description:	Entamoeba histolytica is an enteric anaerobic protozoan parasite that causes about 50 million infections with about 100,000 annual deaths worldwide. Entamoeba dispar and Entamoeba moshkovskii are non-pathogenic species that are morphologically similar but genetically distinct from E. histolytica. Thus, this cross-sectional study was carried out among the Proto-Malay, Negrito, and Senoi tribes in selected villages in Negeri Sembilan, Perak, and Pahang, Peninsular Malaysia to determine the prevalence rates and risk factors associated with E. histolytica/E. dispar/E. moshkovskii complex infection in three Orang Asli tribes. Socioeconomic data were collected using a pre-tested questionnaire. Faecal samples were examined by formalin-ether sedimentation and trichrome staining techniques and then samples were subjected to single-round PCR assay. A total of 500 faecal samples from three Orang Asli tribes were randomly collected. The overall prevalence rate of E. histolytica/E. dispar/E. moshkovskii complex determined by microscopy was 18.6%; 8.7% (Proto-Malay), 29.5% (Negrito), and 18.5% (Senoi). Single-round PCR assay revealed that most Entamoeba-positive subjects were infected with E. dispar (13.4%), followed by E. histolytica (3.2%), and E. moshkovskii (1%). The Proto-Malays harbouring 10.7% and 2% of E. dispar and E. moshkovskii, respectively. Followed by Negrito tribe; 10.1% (E. histolytica), 18.7% (E. dispar) and 0.7% (E. moshkovskii) and Senoi tribe; 1% (E. histolytica), 11.9% (E. dispar) and 0.5% (E. moshkovskii). Multivariate analysis indicated that the dynamic of transmission are different from each tribe and Entamoeba species. Not washing hands after playing with soil or gardening and the presence of other family members infected with E. histolytica/E. dispar/E. moshkovskii complex were found to be significant risk factors in all tribes studied. Moreover, eating with hands, being a consumer of raw vegetables, and close contact with dogs and cats were also identified as significant risk factors in Senois. Only three variables were retained as significant risk factors for E. histolytica infection in the logistic regression model which include not washing hands after playing with soil or gardening, indiscriminate defecation in the river or bush, and close contact with domestic animals. However, individuals who had family members infected with E. histolytica/E. dispar/E. moshkovskii complex and those who consume raw vegetables were more likely to be infected with E. dispar. On the other hand, no associated factor was identified with E. moshkovskii infection. Nevertheless, diarrhoea and other gastroenteritis symptoms were only associated with E. histolytica infection. Detection rate of E. histolytica/E. dispar/E. moshkovskii complex was highest in combination of two microscopic techniques (18.6%), followed by trichrome staining (13.4%), and formalin-ether sedimentation (11.2%). In conclusion, this present study provides new insights into the distribution and risk factors of E. histolytica, E. dispar, and E. moshkovskii infections among Orang Asli in Malaysia. The discovery of low prevalence of E. histolytica in Orang Asli population indicates that this infection is not a public health problem in this population. However, identification of significant association and high proportion of clinical symptoms among individuals positive with E. histolytica warrants further study to determine the causes.,Ph.D
Pages:	351
Call Number:	WA20.5.T289e 2013 9 HUKM
Publisher:	UKM, Kuala Lumpur
Appears in Collections:	Faculty of Medicine / Fakulti Perubatan

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