Prevalence of enteric hepatitis A and E viruses in the Mekong River delta region of Vietnam.
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 < 0.01) in age-specific anti-HEV IgG. A notable increase in anti-HAV IgG prevalence (P < 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. (+info)
A hepatitis E virus variant from the United States: molecular characterization and transmission in cynomolgus macaques.
The partial sequence of a hepatitis E virus (HEV-US1) isolated from a patient in the United States (US), suffering from acute viral hepatitis with no known risk factors for acquiring HEV, has been reported. These sequences were significantly different from previously characterized HEV isolates, alluding to the existence of a distinct human variant. In this paper, we report the near full-length sequences of HEV-US1 and a second US isolate (HEV-US2). HEV-US2 was identified in a US patient suffering from acute viral hepatitis. These sequences verify the presence of a new HEV strain in North America and provide information as to the degree of variability between variants. The HEV-US nucleotide sequences are 92% identical to each other and only 74% identical to the Burmese and Mexican strains. Amino acid and phylogenetic analyses also demonstrate that the US isolates are genetically distinct, suggesting the presence of three genotypes of HEV. Serum from the second US patient induced hepatitis following inoculation into a cynomolgus macaque. Within 2-4 weeks, HEV-US2 RNA was detectable in both the serum and faecal material coinciding with elevated serum alanine transaminase levels. Infection resolved as antibody titres increased 8 weeks post-inoculation. (+info)
Analysis of hepatitis G virus (HGV) RNA, antibody to HGV envelope protein, and risk factors for blood donors coinfected with HGV and hepatitis C virus.
Serologic, biochemical, and molecular analyses were used to study hepatitis G virus (HGV), antibody to the HGV envelope protein (anti-E2), risk factors, clinical significance, and the impact of HGV on coexistent hepatitis C virus (HCV). Among 329 donors with confirmed HCV infection, 12% were HGV RNA-positive and 44% were anti-E2-positive (total exposure, 56%). HGV RNA and anti-E2 were mutually exclusive except in 9 donors (1.5%); 8 of 9 subsequently lost HGV RNA but anti-E2 persisted. HGV had little impact on alanine aminotransferase, aspartate aminotransferase, or gamma-glutamyl transpeptidase in donors with HGV infection alone or those coinfected with HCV. A multivariate analysis showed that intravenous drug abuse was the leading risk factor for HGV transmission, followed by blood transfusion, snorting cocaine, imprisonment, and a history of sexually transmitted diseases. In summary, HGV and HCV infections were frequently associated and shared common parenteral risk factors; HGV did not appear to cause hepatitis or to worsen the course of coexistent hepatitis C. (+info)
Age-dependent acquisition of hepatitis G virus/GB virus C in a nonrisk population: detection of the virus by antibodies.
Until now there have been few seroepidemiological data for hepatitis G virus/GB virus type C (HGV/GBV-C). A four-antigen HGV/GBV-C immunoblot was established to examine 446 serum specimens from healthy individuals without risk factors for parenteral viral transmission. These individuals were divided into seven groups according to age. Seroprevalence rates were low for children and adolescents (5.6%) and increased for the age groups assumed to be the most sexually active (15.3 to 26.8%). Remarkably, none of the 80 individuals who tested positive for HGV/GBV-C antibodies were simultaneously positive for HGV/GBV-C viremia. From our data we conclude that HGV/GBV-C infection is widespread in the general population (16 to 25%). The development of an antibody response is associated with clearance of HGV/GBV-C viremia. Due to the lack of risk factors for HGV/GBV-C infection of blood, other efficient transmission routes must exist. It must be assumed that HGV/GBV-C transmission may be linked to sexual activity. (+info)
Interferon-alpha may exacerbate cryoblobulinemia-related ischemic manifestations: an adverse effect potentially related to its anti-angiogenic activity.
The discovery of the strong association between hepatitis C virus (HCV) infection and the development of mixed cryoglobulinemia has motivated active testing of antiviral-directed alternative therapies. Several trials have demonstrated that classic cryoglobulinemia-associated manifestations improve with interferon-alpha (IFNalpha) treatment. Herein we report on 3 HCV-infected patients with severe cryoglobulinemia-related ischemic manifestations who were closely followed up during IFNalpha therapy. Clinical evaluations with special attention to ischemic lesions, liver function tests, and cryocrit determinations were serially performed. In addition to prednisone and immunosuppressive agents, the patients received IFNalpha at 3 x 10(6) units, 3 times per week for 2 months, 3 months, and 4 months, respectively. In all 3 patients, systemic features improved, liver function results returned to normal, and cryocrit values decreased. However, ischemic lesions became less vascularized and ischemia progressed, leading to transmetatarsal and subcondylar amputation, respectively, in 2 of the patients and fingertip necrosis and ulcer enlargement in the third. Skin biopsies performed before IFNalpha therapy and after 2 months of IFNalpha therapy in the third patient showed a significant decrease in subepidermal microvessels. When IFNalpha was discontinued, the lesions finally healed. Cryoglobulinemia-related ischemic lesions may worsen during IFNalpha treatment, presumably through a decrease in inflammation-induced angiogenesis. The anti-angiogenic activity of IFNalpha may delay the appropriate healing of ischemic lesions. (+info)
The epidemiology of viral hepatitis in children in South Texas: increased prevalence of hepatitis A along the Texas-Mexico border.
An initial retrospective study of 194 children demonstrated a high prevalence of hepatitis A but not hepatitis B or C infection among children living along the Texas-Mexico border. A larger prospective study of hepatitis A was conducted with 285 children (aged 6 months to 13 years) living in 3 sociodemographically dissimilar areas of South Texas. Children living in colonias along the border had a significantly higher prevalence of hepatitis A virus infection (37%) than children living in urban border communities (17%) or in a large metropolitan area (San Antonio [6%]). Independent risk factors for hepatitis A infection included increased age, colonia residence, and history of residence in a developing country. Use of bottled water (vs. municipal or spring/well water) and years of maternal secondary education were protective. Improved sanitation or routine hepatitis A vaccination in early childhood may reduce the prevalence of hepatitis A in these areas. (+info)
Prevalence of GB virus C/hepatitis G virus among blood donors in north-eastern Brazil.
We tested 70 blood donors from Fortaleza (Ceara state, Brazil) for GB virus C/hepatitis G virus (GBV/HGV) infection by polymerase chain reaction and detection of antienvelope antibodies. Twenty-seven (38.6%) showed signs of an active or resolved infection. Sixty-four percent of those with indications of other blood-borne viral infections showed signs of GBV-C/HGV infection also. (+info)
Age distribution of Helicobacter pylori seroprevalence among young children in a United States/Mexico border community: evidence for transitory infection.
Helicobacter pylori infection has been linked to a spectrum of gastroduodenal diseases of broad public health impact, yet the natural history of this frequently asymptomatic infection remains poorly understood. Evidence suggests that initial acquisition occurs primarily during childhood and may persist throughout life. The seroprevalence of H. pylori antibodies was examined in 365 primary schoolchildren aged 4-7 years in a low-income United States/Mexico border community from January to May 1996. Overall, 21% of the 365 children tested positive, with a significant monotonic decrease in seroprevalence by 1-year age intervals (36% in children aged 4 years, 24% in those aged 5 years, 20% in those aged 6 years, and 14% in those aged 7 years). The odds ratio for each 1-year age increase was 0.76 (95% confidence interval: 0.6, 1.0) after adjustment for relevant covariates. Given that H. pylori antibodies diminish after infection clears, this trend suggests that transient infection may be common in young children. In contrast, hepatitis A virus seroprevalence increased with age. There was a moderate association (odds ratio = 1.47, 95% confidence interval: 0.8, 2.9) of H. pylori with hepatitis A virus seroprevalence that weakened after adjustment for age and socioeconomic status (odds ratio = 1.26, 95% confidence interval: 0.6, 2.5). Follow-up studies are needed to clarify the natural history of Helicobacter pylori infection and identify predictors of initial acquisition, persistence, and recurrence. (+info)