Andrew L.
Corwin1, Nguyen T.K. Tien2, Khanthong Bounlu3,
Jarot Winarno4,
Maidy P. Putri1, Kanti Laras1, Ria P. Larasati1,
Nono Sukri1, Timothy Endy5, H.A. Sulaiman6
Kenneth C. Hyams7
1U.S. Naval Medical
Research Unit No. 2, Jakarta, Indonesia, 2Pasteur Institute, Ho Chi
Minh City, Vietnam,
3Center of National Laboratory and Epidemiolgy, Vientiane, Lao PDR,
4Provincial Health Service Sintang District, West Kalimantan,
Indonesia,
5Armed Forces Research Institute of Medical Sciences, Bangkok
Thailand,
6Medical Faculty, University of Indonesia, Jakarta, Indonesia,
7Naval Medical Research Institute, Bethesda, Maryland, USA
The ecology of HEV
transmission in Southeast
Asia was assessed via a hepatitis
outbreaks investigations, cross-sectional prevalence studies, and hospital
based case-control studies. Findings from Indonesia and Vietnam showed epidemic
foci centered in jungle, riverine environments. In contrast, few cases of
acute, clinical hepatitis from cities in Indonesia, Vietnam, Laos, could be attributed to HEV. When
communities in Indonesia were grouped into areas of low (<40%), medium (40 –
59%), and high (>60%) anti-HEV prevalence, uses of river water for drinking
and cooking, personal washing, and human excreta disposal were all
significantly associated with high prevalence of infection. Conversely, boiling
river drinking water was negatively associated with higher prevalence
(p<0.01). The protective value of boiling river water was also shown in
sporadic HEV transmission in Indonesia and in epidemic and sporadic spread in Vietnam. Evidence from Indonesia indicated decreased dilution of HEV in
river water due to unusually dry weather contributed to the risks of epidemic
HEV transmission. But the flood conditions and contamination added to the risk
of HEV infection in Vietnam. These findings attested to a unique
combination of ecological and environmental conditions in predisposing epidemic
HEV spread in Southeast
Asia.