Murhekar M V, Murhekar K M, Das D, Arankalle V A, Sehgal S C
Regional Medical Research Centre (ICMR), Port Blair.
Indian J Med Res. 2000 Jun;111:199-203.
BACKGROUND & OBJECTIVES: Andaman and Nicobar Islands, is the home of six primitive tribes. No information is available on the prevalence of hepatitis B virus (HBV) infection among them. Hence a study was undertaken with the objective of assessing the sero-prevalence of HBV infection among the four accessible tribes of these islands.
A total of 1266 serum samples were collected from four tribes i.e., Nicobarese, Shompens, Onges and Great Andamanese and tested for the presence of HBsAg and anti-HBs. Information about different risk factors associated with HBV infection was also collected from the Nicobarese tribe.
The overall seropositivity rate of HBsAg among the Nicobarese was 23.3 per cent (95% C.I. 21.0-25.9). Hepatitis B was also found to be an important health problem among the Shompens and Onges with HBsAg positivity of 37.8 and 31.0 per cent respectively. The age-wise distribution of these serological markers among Nicobarese tribe indicate that the infection is very common in all the age groups. The sero-prevalence was also found to be very high among the children.
CONCLUSIONS & INTERPRETATION: The findings of the present study indicate that hepatitis B infection is hyper endemic among the primitive tribes of these islands. Though none of the risk factors studied in the Nicobarese was found to be significantly associated with HBV infection, the fact that almost 20 per cent of the women in the reproductive age group were positive for HBsAg indicates the possibility of vertical transmission among the Nicobarese. Further studies are required to find out other modes of transmission.
安达曼和尼科巴群岛是六个原始部落的家园。目前尚无关于这些部落中乙型肝炎病毒（HBV）感染率的信息。因此，开展了一项研究，旨在评估这些岛屿上四个可接触部落中HBV感染的血清流行率。
从四个部落，即尼科巴人、森滕人、昂格人和大安达曼人那里共采集了1266份血清样本，检测其中HBsAg和抗-HBs的存在情况。还从尼科巴部落收集了与HBV感染相关的不同风险因素的信息。
尼科巴人中HBsAg的总体血清阳性率为23.3%（95%置信区间21.0 - 25.9）。在森滕人和昂格人中，乙型肝炎也是一个重要的健康问题，HBsAg阳性率分别为37.8%和31.0%。尼科巴部落中这些血清学标志物按年龄的分布表明，感染在所有年龄组中都很常见。在儿童中血清流行率也很高。
本研究结果表明，乙型肝炎感染在这些岛屿的原始部落中高度流行。虽然在尼科巴人身上研究的风险因素均未发现与HBV感染有显著关联，但育龄组中近20%的女性HBsAg呈阳性这一事实表明，尼科巴人之间存在垂直传播的可能性。需要进一步研究以找出其他传播方式。
