Hepatitis A Virus in Lao People’s Democratic Republic: Seroprevalence and Risk Factors

Abstract

Despite several recent reports of outbreaks of hepatitis A, little is known about the disease burden in Lao People's Democratic Republic (PDR). We conducted a cross-sectional age-stratified seroprevalence study of antihepatitis A virus (HAV) IgG and risk factors in a rural province (Xiengkhouang) and Vientiane capital in Lao PDR. Overall, 62% of participants were anti-HAV positive in Xiengkhouang Province compared with 45.5% in Vientiane capital. In Xiengkhouang, 23.7% of 5-to 10-year-olds were already seropositive compared with 5% in Vientiane. A dramatic increase in seroprevalence occurred between 15-to 20-year and 21-to 30-year age-groups (35.7-62.4%, Xiengkhouang, and 11.5-69.7%, Vientiane) until essentially all older adults were positive in both locations. The main risk factors for HAV antibodies were age, non-Lao-Tai ethnicity, and food-related risk factors. In conclusion, Lao children seem to be exposed very early to HAV, particularly in rural settings, and exposure continues throughout their lives, mostly without being reported. In the older birth cohorts, the high seroprevalence may largely reflect poor sanitation and exposure during childhood. In Vientiane capital, the lower seroprevalence at young ages may reflect better water sanitation since the late 1990s. A comparison with neighboring Thailand indicates that the impact of improved sanitation in Lao PDR began only two decades later. Further improvements in water sanitation, in particular in the rural districts, and better food hygiene are warranted. Our study also suggests that HAV infections are underreported. Improved reporting would provide guidance for targeted interventions to further reduce HAV infections.

Additive Effects of Zinc Chloride on the Suppression of Hepatitis A Virus Replication by Interferon in Human Hepatoma Huh7 Cells

“…Medium with or without 5 μM zinc chloride was exchanged on days 1, 3, 5. After 120 h of HAV infection and treatment with or without 5 μM zinc chloride, cellular RNA was extracted using the RNeasy Mini kit (Qiagen), and cDNA synthesis was performed using RT 2 First Strand kit (Qiagen), on a GeneAmp PCR system 5700 (Applied Biosystems).…”

“…Inflammasome associated signaling pathways were analyzed by an RT 2 Profiler PCR array (Qiagen) on a 7500 Fast real-time PCR system (Applied Biosystems), according to the manufacturer's instruction. Data were analyzed by the RT 2 Profiler PCR array Data Analysis software (Qiagen). Relative gene expression levels were normalized to housekeeping genes by ddCt method (12).…”

“…HAV is transmitted through the fecal-oral route and usually causes self-limited acute hepatitis, however, it occasionally leads to acute liver failure, causing death or the requirement of liver transplantation (1). Higher seroprevalence of anti-HAV antibodies reflects poorer water sanitation and increased exposure during childhood in developing countries (2). Sexual contact among men who have sex with men (MSM), and blood transfusion are other known transmission routes (3,4).…”

Seroprevalence and incidence of hepatitis A in Southeast Asia: A systematic review

“…A recent study from Lao PDR suggests a shift taking place in that country towards a low HAV endemicity profile, suggesting exposure to HAV of 50% among individuals around 20 years of age [ 17 ].…”

The Shifting Epidemiology of Hepatitis A in the World Health Organization Western Pacific Region

“…Higher seroprevalence (35.7–62.4%, Xiengkhouang, and 11.5–69.7%, Vientiane) was seen in the 15–20 and 21–30 age groups, with almost all individuals in the older population testing positive. The lower prevalence in the urban areas was attributed to better sanitation and living conditions since the 1990s [ 69 ]. Hepatitis A is not included in their national immunization program [ 70 ].…”