Assessment of Risk and Sero-Prevalence of Helicobacter pylori Colonization among Remote Orang Asli Tribes in Peninsula Malaysia.

Kavitha Thevakumar,Barry J Marshall,Mun Fai Loke,Eng Guan Chua,Alex Hwong Ruey Leow,Mohd Zaki Salleh,Li Ping Wong,Lay Kek Teh,Guillermo Ignacio Perez-Perez,Josephine Rebecca Chandren,Jin Ai Mary Anne Tan,Jamuna Vadivelu,Khean Lee Goh,Alfred Chin Yen Tay,Yoshio Yamaoka

doi:10.1371/journal.pone.0159830

Abstract

The epidemiology of Helicobacter pylori (H. pylori) infection is related to human poverty with marked differences between developing and developed countries. Socioeconomic factors and living standards are the main determinants of the age-dependent acquisition rate of H. pylori, and consequently its prevalence. The aim of this study was to assess the risk and sero-prevalence of H. pylori colonization among Orang Asli in Peninsula Malaysia. This cross-sectional study was conducted on Orang Asli subjects in seven isolated settlements spanning across all three major tribes (Negrito, Proto Malay and Senoi) in Malaysia. Socio-demographic characteristics of the subjects were obtained through interview. Subjects were tested for H. pylori colonization based on CagA and whole cell (WC) antigen serological assays. A total of 275 subjects participated in this study. Among these subjects, 115 (44.7%) were H. pylori sero-positive with highest sero-prevalence among Negrito (65.7%). Among subjects who were H. pylori sero-positive, CagA sero positivity was also significantly higher among Negrito. The highest proportion of respondents reported to be H. pylori sero-positive was from age group 30 years old and below (57.9%), males (56.2%), Negrito (48.6%) and live in bamboo house (92.3%). The highest proportion of respondents reported to be CagA sero-positive was from age group 30 years old and below (41.4%), males (35.6%) and Negrito (48.6%). The results of this study demonstrate that H. pylori colonization can be related to age, gender, tribes and house materials and CagA sero-positive stain closely associated with age, gender and tribes.

Highlights

Helicobacter pylori (H. pylori) is a Gram-negative bacillus capable of colonizing the human stomach [1]
480 Orang Asli from a settlement in northeastern Malaysia (210 km off Kota Bahru, Kelantan), the prevalence of H. pylori colonization was reported to be 19% based on serological test for Immunoglobulin G (IgG) [20]. These findings indicate that H. pylori colonization does not follow the common national pattern and there is a need for further assessment of the prevalence of H. pylori colonization and socio-demographic characteristics of the Orang Asli from other settlements
This study provided us the opportunity to investigate the risk factors and prevalence rate associated with H. pylori colonization among Orang Asli tribes residing in less accessible areas of Peninsular Malaysia

Summary

Introduction

Helicobacter pylori (H. pylori) is a Gram-negative bacillus capable of colonizing the human stomach [1]. Chronic colonization with H. pylori is shown to be related to gastric mucosal atrophy, intestinal metaplasia and gastric cancer [1,3,4]. The probable routes of transmission are fecal-oral and oral-oral and the risk factors are closely related to food and personal hygiene [5]. H. pylori colonization may be diagnosed through invasive (rapid urease test, histology and culture of biopsy specimens) and non-invasive techniques (serological tests, fecal antigen assessment and urea breath test) [7]. Serological assessment determines the presence of Immunoglobulin G (IgG) against H. pylori [7]. Serological test may provide additional data on the virulence of the H. pylori by detecting antibodies against CagA antigen [8]

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Conclusion