Spread Of Hepatitis B Virus Infection Research Articles

Modeling reveals no direct role of the extent of HBV DNA integrations on the outcome of infection

Hepatitis B virus (HBV) with its high prevalence and death toll is one of the most important infectious diseases to study. Yet, there is very little progress in the development of within-host models for HBV, which has subsequently hindered our understanding of this virus. The uncertainty around the proliferation of infected hepatocytes has been studied but never in association with other important biological continuous events such as integrations and superinfections. This is despite the fact that these processes affect the diversity and composition of infected cell population in the liver and an improved understanding of the cellular composition will undoubtedly assist in strategizing against this viral infection. Here, we developed novel mathematical models that incorporate these key biological processes and analyzed them both analytically and numerically. Unaffected by the extent of integrated DNA (IDNA), the outcome of HBV infection was primarily dictated by the balance between processes generating and killing infected hepatocytes containing covalent closed circular DNA (cccDNA). The superinfection was found to be a key process in the spread of HBV infection as its exclusion could not reproduce experimentally observed composition of infected hepatocytes at peak of acute HBV infection, a stage where our model predicts that infected hepatocytes most likely carry both cccDNA and IDNA. Our analysis further suggested the existence of some form of selective advantage of infected hepatocytes containing only IDNA to explain the viral dynamics observed during antiviral treatment and the transition from peak to acute infection. Finally, the fine line between liver destruction and resolution of acute HBV infection was found to be highly influenced by the fate of cccDNA during cellular proliferation.

Prevalence of Hepatitis B among jaundiced cases in paediatric age group

Background: Hepatitis B virus (HBV) infection is a global health problem. Over two billion people have been infected with hepatitis B virus globally, of whom over 350 million are chronic carriers. Vertical (mother to child) and horizontal early childhood transmission are the main routes of HBV transmission and are responsible for most chronic infections. The aim of this study was to study the role played by different modes of transmission of HBV and to study the burden of hepatitis B in pediatric age group.Methods: All children below 12 years of age, admitted for jaundice, of both sexes, during one year study period were included. 50 patients (control) who were not suffering from jaundice or known liver disease were also included.Results: Prevalence of HBsAg positivity among jaundiced children was 15.24%. There was increase in HBsAg positivity with increase in the age signifying role of horizontal mode of transmission in Hepatitis B virus infection.Conclusions: HBV infection is an important health problem in paediatric age group. Horizontal mode of transmission plays important role in the spread of HBV infection among children.

Profiles of Hepatitis B Virus Serological Markers among Asymptomatic Population in Anambra State, Southeastern Nigeria

Hepatitis B Virus (HBV) infection is apparent in endemic countries affecting millions of people. Further, the asymptomatic nature of the pathogen is a major public health concern. This study was designed to assess the burden of HBV by exploring the serologic markers of infection among consenting asymptomatic community dwellers in two cities in southeastern Nigeria.A total of 405 blood specimens were tested for HBsAg, anti-HBs, HBeAg, anti-HBe, total anti-HBc and anti-HBc-IgM using ELISA technique. Overall, 14 (3.5%) of the participants had detectable HBsAg out of which 1 (7.1%) had HBeAg and 13, anti-HBe. Two of the HBsAg positives (14.3%) had detectable anti-HBc-IgM. Atotal of 144 (35.5%) had detectable anti-HBc, even as 65 (57.0%) of them had the marker as the only serologic evidence of HBV exposure. Thirty-seven (9.1%) participants had anti-HBs only although all of them were born before the start of the childhood HBV vaccination. Altogether, 224 (57.3%) had no detectable serological markers of HBV infection or immunity and were obviously at risk of HBV infection.This study described various patterns of HBV serologic markers of infection in the study population and probable risk of virus spread. Our results support the need for urgent intervention and implementation of measures to control the spread of HBV infection in Nigeria.

Lower chronic hepatitis B in South Asia despite all odds: Bucking the trend of other infectious diseases

Hepatitis B virus (HBV) infection remains a significant global health problem. As per estimates of the World Health Organization (WHO), approximately 2 billion people have been infected worldwide, which represents one-third of the world population. Of these, more than 350 million (5-7% of the world’s population) suffer from chronic HBV infection. Approximately 15-40% of the infected patients will develop life-threatening liver diseases (cirrhosis, liver failure and hepatocellular carcinoma) resulting in 600,000 to 1.2 million deaths per year due to HBV. Epidemiological data on HBV infection is therefore important for strategies to tackle the spread of the disease. Based on the prevalence of hepatitis B surface antigen (HBsAg), countries are classified as having high (>8%), intermediate (2-7%) or low ( 8% of the population is HBsAg positive) include South-East Asia, China, most of Africa, most of Pacific Islands, the Amazon basin and parts of the Middle East. The areas of intermediate endemicity (2-7%) include South Asia, Eastern and Southern Europe, Russia and Central and South America. On the other hand areas with low endemicity (<2%) include United States, Western Europe and Australia. The South Asian countries, a contiguous block of countries which have been classified together as Global Burden of Disease Regions include Afghanistan, Bangladesh, Bhutan, India, Nepal and Pakistan. People in South Asia are at a higher risk of developing infectious diseases due to poverty and its associated problems of unhygienic living conditions, malnutrition, illiteracy, and poor access to clean water, toilet facilities, and quality health care. Spread of HBV infection in many South Asian countries is attributed to unsafe blood supply, reuse of contaminated syringes, lack of maternal screening to prevent perinatal transmission and delay in the introduction of hepatitis B vaccine. However, it is intriguing that bucking the trend of other infectious diseases, the prevalence of HBV in South Asian countries is lower than some of the more affluent neighbors in the South East Asian countries. Re-emphasizing the lower prevalence of HBV in South Asia is an article by Shrestha et al in this issue of Tropical Gastroenterology, which shows that the prevalence of HBV in Nepal is even lower than that in other countries of South Asia.

The Management of Viral Hepatitis in CKD Patients: An Unresolved Problem

Chronic kidney disease (CKD) patients in dialysis (HD) show peculiar, atypical features of clinical presentation and diseases (cardiovascular, metabolic, hematologic). This is also true for viral hepatitis infections, for which CKD patients represent an important risk group. In the past, hepatitis B virus (HBV) was the major cause of viral hepatitis in end-stage renal disease (ESRD). However, the introduction of a rigorous infection-control strategy, routine screening of patients and staff for hepatitis B serologic markers, vaccination of susceptible patients and staff, use of separate rooms and dedicated machines for HD of HbsAg-positive patients have all led to a decline in the spread of HBV infection in dialysis. Despite the prevalence of the antibody-hepatitis C virus (HCV), there has been a marked decrease in HD patients; after the introduction of routine screening for HCV and the use of erythropoietin, its occurrence ranges from 5% to 25% in the United States, with a prevalence of 6.8% in Europe. In CKD and in HD patients, the presence of HBV and HCV is an independent and significant risk factor for death and this risk may be at least partially attributed to chronic liver disease with its attendant complications. Liver disease can progress with modest hepatic inflammation and prominent fibrosis; the natural history of viral hepatitis in these patients is dependent on the immune dysfunction typical of kidney disease. Despite recent advances in antiviral therapy, there are still many uncertainties in regards to the efficacy and long-term outcomes of treatment with antiviral agents.

Epidemiology of hepatitis B infection among expatriates in Nigeria.

Adult expatriates in countries where hepatitis B virus (HBV) is highly endemic have an increased risk of HBV infection, but little is known about risks to their children or about patterns of spread. The epidemiology of HBV infection was studied among 124 unvaccinated Dutch missionaries and family members who lived in a rural area of Nigeria. Antibodies to hepatitis B core antigen were found in 5 (9.8%) of 51 adults (incidence rate, 1.7 per 1000 person-months at risk [PMAR]) and 9 (12.3%) of 73 children (incidence rate, 2.8 per 1000 PMAR). Vertical transmission of HBV was a likely source of infection in 1 child and was a possible source of infection in 2 others. The prevalence of HBV infection showed strong family clustering (P<.0001), was associated with a history of temporary adoption of Nigerian children (P=.004), and increased with both the number of adoptive children (P=.009) and the total time that these children had stayed in the family (P=.036). Horizontal transmission from adoptive Nigerian children probably played an important role in the spread of HBV infection in this expatriate community.

Hepatitis B Prevention Strategies Among Pediatric Hemodialysis Centers

We surveyed pediatric hemodialysis centers (PHDCs) concerning their hepatitis B virus (HBV) prevention strategies. One hundred thirty-one patients were being dialyzed in these PHDCs in December 1996. Although all centers immunized HBV-susceptible hemodialysis patients and had infection control policies to curtail the spread of HBV infection, most centers were not in compliance with all of the Centers for Disease Control and Prevention recommendations for isolating hepatitis B surface antigen-positive patients.

Hepatitis B in the family.

During a 3-year period (1992-1995), 239 index cases of hepatitis B virus (HBV) infection and 459 members of their households from the Osijek-Baranja county were examined. The aim of the study was to determine the spread of HBV infection in the families with a member verified as a virus carrier, and to identify the family members with the highest risk of infection according to kinship degrees. The retrospective and prospective methods were used in the study. The probable route of infection was assessed by the use of an epidemiologic questionnaire, and the serologic status of the study subjects concerning infection with HBV was determined by enzyme immunoassays (HBsAg, anti-HBs, anti-HBe and anti-HBc). The first member of a family identified as a virus carrier was considered an index case. HBV infection was demonstrated in 334 (47.85%) out of a total of 698 subjects. Only 21 (6.28%) of the 334 subjects with verified HBV infection developed the clinical picture of acute hepatitis B. The ratio of clinically manifest vs inapparent infection was 1:16. Serologic traces of infection were detected in 95 of the 459 family members of the index cases, yielding a mean rate of the infection among the virus carrier family members of 20.70%.

Seroprevalence of hepatitis B virus markers and risk factors in patients and staff of an Italian residential institution for the mentally disabled

We conducted a cross-sectional study to evaluate the prevalence rate and risk factors for hepatitis B virus (HBV) infection among residents and staff at the Fatebenefratelli Institute in San Colombano in the province of Milan. We tested serum from 510 patients and 165 staff members. In addition, a medical record and a completed questionnaire were obtained from each patient. A total of 338 (66.5%) residents were found to have markers of HBV infection, including 29 (5.7%) who were identified as carriers. Thirtynine members of staff (24.1%) showed evidence of HBV infection but only 1 (0.6%) was identified as a carrier. Among patients the prevalence rate of HBV was significantly associated with length of stay and age at admission, as it was with length of employment among staff members. The hepatitis B vaccine was offered to all patients and staff in the institution during 1994. A total of 143 (84%) patients and 111 (90%) members of the staff were vaccinated in the same year. To prevent the further spread of HBV infection in this institution, all current and future residents and staff members should be screened for serological markers for HBV and subjects identified as being susceptible should be vaccinated according to a compulsory routine policy.

Risk factors for hepatitis B virus infection among heterosexuals attending a sexually transmitted diseases clinic in Italy: Role of genital ulcerative diseases

The seroprevalence and risk factors for hepatitis B virus (HBV) infection were determined among 1,497 heterosexuals with no history of intravenous drug use (median age 32, range 15-78) treated at a sexually transmitted disease clinic in Rome. A total of 329 (22.0%) had antibodies to HBV core antigen (anti-HBc), a rate nearly four times as high as the 5.8% found recently in a national sample of young male adults, ages 18-26 years. Multiple logistic regression analysis showed that the risk of anti-HBc positivity was independently associated with male sex, increasing age, lower level of education, three or more sexual partners in the previous year, and positive syphilis serology. Lack of condom use, history of nonulcerative sexually transmitted diseases, and genital herpes were not associated with anti-HBc positivity. These findings confirm that heterosexual exposure plays an important role in the spread of HBV infection. Furthermore, these data indicate that individuals with more than two sexual partners a year and those with positive syphilis serology should be immunised against HBV.

Prevalence of HBsAg among parturient pregnant women in northwestern Romania

The objective of this study was to determine the hepatitis B surface antigen (HBsAg) prevalence in pregnant women in northwestern Romania in order to be able to formulate an adequate prevention policy on perinatal transmission of the hepatitis B virus. A cross-sectional serological survey was carried out among parturient women in 18 hospitals in this area in September 1991. Out of 2,354 parturient women, 90 (3.8%) were positive for HBsAg. The prevalence did not differ significantly by age, parity, rural versus urban residence or the district of residence. The prevalence did differ significantly according to the level of medical care. Women who gave birth in level 3 and 4 hospitals had a higher prevalence (5.1%) than those women who gave birth in level 1 and 2 hospitals (3.0%), supporting the assumption that iatrogenic infection has played an important role in the spread of hepatitis B virus (HBV) infection in Romania. Incorporation of universal vaccination with hepatitis B vaccine into the routine childhood immunization programme in Romania would be the best strategy to prevent perinatal transmission of HBV. Further studies are needed to validate the assumption that iatrogenic transmission has played an important role in the spread of HBV infection in Romania.