No abstract

The ecology of hepatitis E virus (HEV) transmission in South-East Asia was assessed from a review of 6 published and 3 unpublished NAMRU-2 reports of hepatitis outbreak investigations, cross-sectional prevalence studies, and hospital-based case-control studies. Findings from Indonesia and Viet Nam show epidemic foci centred in jungle, riverine environments. In contrast, few cases of acute, clinical hepatitis from cities in Indonesia, Viet Nam and Laos could be attributed to HEV. When communities in Indonesia were grouped into areas of low (< 40%), medium (40-60%), and high (> 60%) prevalence of anti-HEV antibodies, 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 of 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 Viet Nam. Evidence from Indonesia indicated that the decreased dilution of HEV in river water due to unusually dry weather contributed to risk of epidemic HEV transmission. But river flooding conditions and contamination added to the risk of HEV infection in Viet Nam. These findings attest to a unique combination of ecological and environmental conditions predisposing to epidemic HEV spread in South-East Asia.

No abstract

No abstract

Abstract. A study of antibody prevalence for hepatitis A virus (HAV) and hepatitis E virus (HEV) was carried out in southwestern Vietnam in an area adjacent to a known focus of epidemic HEV transmission. The purpose of this investigation was first to provide a prevalence measure of hepatitis infections, and second to determine the outbreak potential of HEV as a function of the susceptible population. Blood specimens collected from 646 persons in randomly selected village hamlets were examined by an ELISA for anti-HEV IgG and anti-HAV IgG. The prevalences of anti-HEV IgG and anti-HAV IgG were 9% and 97%, respectively. There was a significant increase (P Ͻ 0.01) in age-specific anti-HEV IgG. A notable increase in anti-HAV IgG prevalence (P Ͻ 0.0001) occurred between child populations 0-4 (64%) and 5-9 (95%) years of age. No evidence of familial clustering of anti-HEV IgG-positive individuals was detected, and household crowding was not associated with the spread of HEV. Boiling of water was found to be of protective value against HEV transmission. A relatively low prevalence of anti-HEV indicates considerable HEV outbreak potential, against a background of 1) poor, water-related hygiene/sanitation, 2) dependence on a (likely human/animal waste)-contaminated Mekong riverine system, and 3) periodic river flooding.Epidemic and sporadic hepatitis E virus (HEV) transmission has been documented throughout the developing world 1 (Balayan MS, unpublished data). In southeast Asia (in contrast to other geographic regions), HEV occurrence is generally reported as a rural rather than urban phenomenon.2 The proportion of (sporadic) acute hepatitis cases attributed to HEV reported in cities such as Jakarta (Indonesia) and Hanoi (Vietnam) has been found to be very low: 3% and Ͻ 1%, respectively 3 (Persahabatan Hospital, Jakarta, Indonesia, unpublished data). Conversely, foci of epidemic HEV transmission have been recognized in jungle/ riverine areas of Indonesian Borneo (Kalimantan) 4,5 and the Mekong River delta region of Vietnam.6 Transmission determinants associated with worldwide spread of enteric HEV are principally water-related. 4 In developing areas, the spread of hepatitis A virus (HAV) is also related to waterborne transmission, whereas in more developed settings, infections are predominately acquired through contact with an infected person, usually a child with inapparent infection, and occasionally from contaminated food or drink. Dependence on a single (contaminated) water source for drinking/hygiene/sanitary purposes has been implicated in both epidemic and sporadic (community-acquired) spread of HEV and HAV. Epidemic HEV infections were attributed to well water in Somalia 7 and river water in Indonesia 4,5 and Vietnam. 6 However, unlike HAV transmission, there is little evidence of person-to-person spread of HEV. Also, HEV infections, when compared with HAV, are characterized by 1) a longer incubation period, 2) case-fatalities in pregnant women (10-24%), and 3) poor protection by gamma globulin.7-9 An investigati...

No abstract

Abstract. Cholera-specific surveillance in Indonesia was initiated to identify the introduction of the newly recognized Vibrio cholerae non-O1, O139 serotype. Findings from seven years (1993)(1994)(1995)(1996)(1997)(1998)(1999) of surveillance efforts also yielded regional profiles of the importance of cholera in both epidemic and sporadic diarrheal disease occurrence throughout the archipelago. A two-fold surveillance strategy was pursued involving 1) outbreak investigations, and 2) hospital-based case recognition. Rectal swabs were transported to Jakarta for culture and isolates were characterized by serotypic identification. Outbreak findings showed that V. cholerae O1, Ogawa serotype, was the predominant etiology in all 17 instances of investigated epidemic transmission. Monitoring of eight hospitals representing seven provinces provided 6,882 specimens, of which 9% were culture positive for V. cholerae: 589 (9%) for O1 and 20 (Ͻ 1%) for non-O1 strains. Proportional representation of V. cholerae O1 among cases of sporadic diarrheal illness was variable, ranging from 13% in Jakarta to Ͻ 1% in Batam. Overall, 98% of V. cholerae O1 cases were the Ogawa serotype. There was no instance of non-

Analysis of serum samples from patients with acute jaundice by means of enzyme-linked immunosorbent assay and polymerase chain reaction testing provided the first profile of this condition in Vientiane, Lao PDR, in 1995 and 1996. In a case-control, hospital-based study, evidence of acute infections due to hepatitis A and B viruses was found in 14% and 10% of cases, respectively. Hepatitis E virus, however, did not appear to contribute to clinically recognized acute jaundice. Similarly, antibody to hepatitis C virus was recognized in almost equal proportions of cases (8%) and controls (6%), thus representing probable background infections. The detection of hepatitis G virus marks the first report of this virus in Lao PDR. The large proportion (21%) of new leptospiral infections in cases without acute hepatitis A or B was notable. This finding suggests significant regional underreporting of leptospirosis as a cause of acute jaundice. The limited laboratory diagnostic capabilities for confirming a differential diagnosis of leptospirosis contribute to the lack of attention paid to this important health problem.