Etiological role of hepatitis E virus in sporadic fulminant hepatitis

Establishment and Characterization of the First Chinese National Standard for Nucleic Acid Amplification Technology Assays for Hepatitis E Virus Nucleic Acid Detection

The detection of hepatitis E virus (HEV) RNA is the gold standard for HEV infection diagnosis. In order to address the quality control requirements for HEV RNA detection kits within China, we aimed to establish the first Chinese national standard for HEV RNA detection through a collaborative study. The candidate standard was quantified using digital PCR (dPCR). A total of five laboratories were invited to determine the estimated mean value of this national standard relative to the World Health Organization International Standard (WHO IS). Additionally, four commercial kits were used to assess the applicability of the candidate standard. The stability was determined by freeze-thaw cycles and storage at 37 °C, 25 °C and 4 °C. The estimated mean value of this national standard relative to the WHO IS was 5.67 log10 IU/mL. Two out of the four commercial kits can detect as low as the estimated limit of detection (LOD). The degradation rates of samples in the stability study ranged from 4% to 19%. In conclusion, we have established the first Chinese national standard for HEV nucleic acid detection against WHO IS, which can be employed to evaluate the quality of HEV RNA detection kits.

Emerging Pathogen Threats in Transfusion Medicine: Improving Safety and Confidence with Pathogen Reduction Technologies

Emerging infectious disease threats are becoming more frequent due to various social, political, and geographical pressures, including increased human-animal contact, global trade, transportation, and changing climate conditions. Since blood products for transfusion are derived from donated blood from the general population, emerging agents spread by blood contact or the transfusion of blood products are also a potential risk. Blood transfusions are essential in treating patients with anemia, blood loss, and other medical conditions. However, these lifesaving procedures can contribute to infectious disease transmission, particularly to vulnerable populations. New methods have been implemented on a global basis for the prevention of transfusion transmissions via plasma, platelets, and whole blood products. Implementing proactive pathogen reduction methods may reduce the likelihood of disease transmission via blood transfusions, even for newly emerging agents whose transmissibility and susceptibility are still being evaluated as they emerge. In this review, we consider the Mirasol PRT system for blood safety, which is based on a photochemical method involving riboflavin and UV light. We provide examples of how emerging threats, such as Ebola, SARS-CoV-2, hepatitis E, mpox and other agents, have been evaluated in real time regarding effectiveness of this method in reducing the likelihood of disease transmission via transfusions.

Computational identification of hepatitis E virus-encoded microRNAs and their targets in human

microRNAs (miRNAs) are small, noncoding RNAs which regulate eukaryotic gene expression via RNA interference pathway. Recently, miRNAs have been identified in a number of viruses with current evidence suggesting that they regulate gene expression in both virus and host. This makes viral miRNAs potential targets of clinical intervention, with the possibility of inhibiting aberrant host gene expression associated with the disease. In this study, computational approaches were taken to scan the hepatitis E virus (HEV) genome for putative pre-miRNA molecules, which were then analyzed for the presence of mature miRNAs. The 3'-untranslated region (3'-UTR) and 5'-UTR sequences targeted by these miRNAs were identified using Miranda computational tool, followed by the functional annotation of the associated messenger RNAs (mRNAs) using Gene Ontology terms and Kyoto Encyclopaedia of Genes and Genomes pathway analysis. We identified a total of nine viral encoded miRNAs in HEV. After functional annotation, the majority of the viral miRNA targets were found to be associated with cell cycle, cell differentiation, nitrogen compound metabolism, transmembrane transport, and chromosome organization. This in-silico study identified putative viral miRNAs encoded by HEV and their potential human mRNAs targets. These viral miRNAs have the potential to affect host gene expression as well as viral life cycle and pathogenesis and can, therefore, serve as potential therapeutic targets during HEV infection.

Alcohol-related acute-on-chronic liver failure-Comparison of various prognostic scores in predicting outcome

BACKGROUND AND AIMS

Various prognostic scores are available for predicting outcome in acute-on-chronic liver failure (ACLF). We compared the available prognostic models as predictors of outcome in alcohol-related ACLF patients.

METHODS

All consecutive patients with alcohol-related ACLF were included. At admission, prognostic indices-acute physiology and chronic health evaluation score (APACHE II), model for end-stage liver disease (MELD), MELD-Na, Maddrey's discriminant function (DF), age-bilirubin-INR-creatinine (ABIC), and Chronic Liver Failure Consortium (CLIF-C) ACLF score (CLIF-C ACLF) score were calculated. Receiver operator characteristic (ROC) curves were plotted for all prognostic scores with in-hospital, 90-day, and 1-year mortality as outcome.

RESULTS

Of the 171 patients, 170 were males, and grade 1 ACLF in 20 (11.7%), grade 2 in 52 (30.4%), and grade 3 in 99 (57.9%) patients. One hundred and nineteen (69.6%) died in-hospital. The median (IQR) Maddrey's score, MELD, MELD-Na, ABIC, APACHE II, and CLIF-C ACLF were 87.8 (66.5-123.0), 33.1 (27.6-40.0), 34.4 (29.5-40.0), 8.5 (7.3-9.6), 15 (12-21), and 51.1 (44.1-56.4), respectively. On multivariate Cox regression analysis, independent predictors of in-hospital outcome were presence of hepatic encephalopathy (early HR, 2.078; 95%CI, 1.173-3.682, p = 0.012 and advanced, HR, 2.330; 95% CI, 1.270-4.276, p = 0.006), elevated serum creatinine (HR, 1.140; 95% CI, 1.023-1.270, p = 0.018), and infection at admission (HR, 1.874; 95% CI, 1.160-23.029, p = 0.010). On comparison of ROC curves, APACHE II and CLIF-C ACLF AUROC were significantly higher than MELD, MELD-Na, DF, and ABIC (p < 0.05) for predicting in-hospital, 90-day, and 1-year mortality. The AUROC was highest for APACHE II followed by CLIF-C ACLF (Hanley and McNeil, p = 0.660).

CONCLUSIONS

Alcohol-related ACLF has high in-hospital mortality. Among the available prognostic scores, CLIF-C ACLF and APACHE II perform best.

Severity and Outcome of Acute-on-Chronic Liver Failure is Dependent on the Etiology of Acute Hepatic Insults: Analysis of 368 Patients

BACKGROUND

Acute-on-chronic liver failure (ACLF) may be precipitated by various hepatic insults. The present study evaluated the outcomes of ACLF with different acute insults.

PATIENTS AND METHODS

A total of 368 ACLF patients were included. Data collected included etiologies of acute hepatic insult and underlying chronic liver disease, and organ failure. Model for end-stage liver disease (MELD), chronic liver failure consortium (CLIF)-C ACLF, and acute physiology and chronic health evaluation (APACHE) II scores were calculated. Predictors of survival were assessed by the Cox proportional hazard model.

RESULTS

The most frequent acute insult was active alcohol consumption [150 (40.8%) patients], followed by hepatitis B virus (HBV) [71 (19.3%) patients], hepatitis E virus (HEV) superinfection [45 (12.2%) patients], autoimmune hepatitis flare [17 (4.6%) patients], antituberculosis drugs [16 (4.3%) patients], and hepatitis A virus superinfection [2 (0.5%) patients]; 67 (18.2%) cases were cryptogenic. Alcohol-ACLF and cryptogenic-ACLF were more severe. Median CLIF-C, MELD, and APACHE II scores in alcohol-ACLF and cryptogenic-ACLF were significantly higher than those in HBV-ACLF and HEV-ACLF (CLIF-C: 47.1, 47.4 vs. 42.9, 42.0, P=0.002; MELD: 29, 29.9 vs. 28.9, 25.2, P=0.02; APACHE II: 16.5, 18.0 vs. 12, 14, P<0.001, respectively). Frequencies of kidney and brain failures were also higher in alcohol/cryptogenic-ACLF than in HBV/HEV-ACLF (kidney failure: 35.3%/34.3% vs. 23.9%/11.1%, P=0.009; brain failure: 26.0%/22.4% vs. 15.5%/4.4%, P=0.01, respectively). Mortality in the alcohol-ACLF group was the highest (64.0%), followed by that in the cryptogenic-ACLF (62.7%), HBV-ACLF (45.1%), and HEV-ACLF (17.8%) groups (P<0.001). In multivariable analysis, alcohol-ACLF had significantly higher mortality compared with HEV-ACLF (hazard ratio, 3.06; 95% confidence interval, 1.10-8.49, P=0.03).

CONCLUSIONS

Alcohol/cryptogenic-ACLF had more severe phenotypic presentation, more incidence of organ failures, and higher mortality compared with HEV/HBV-ACLF. Alcohol-ACLF had the highest mortality, whereas HEV-ACLF had the best survival.

Role of N-acetylcysteine treatment in non-acetaminophen-induced acute liver failure: A prospective study

BACKGROUND/AIMS

Acute liver failure (ALF) is a rare but severe medical emergency. To date, there is no established treatment for non-acetaminophen-induced acute liver failure (NAI-ALF) other than liver transplantation, and little is known about the use of N-acetylcysteine (NAC) in NAI-ALF. A randomized case control study was conducted with the aim to determine the effect of NAC on the mortality of NAI-ALF patients, as well as to evaluate the safety and efficacy of NAC use.

PATIENTS AND METHODS

A total of 80 patients diagnosed with NAI-ALF were included in the study. Forty patients received NAC infusion for 72 h whereas the control group received placebo. The variables evaluated were demographic characteristics, signs and symptoms, biochemical parameters, and clinical course during hospitalization.

RESULTS

The two groups (NAC and control) were comparable for various baseline characteristics (such as etiology of ALF, INR, alanine aminotransferase, creatinine, albumin, and grade of encephalopathy), except for age. Although majority of patients had undetermined etiology (32.5% in NAC group and 42.5% in control group), the second main cause was acute hepatitis E and drug or toxin-induced ALF. The mortality decreased to 28% with the use of NAC versus 53% in the control group (P = 0.023). The use of NAC was associated with shorter length of hospital stay in survived patients (P = 0.002). Moreover, the survival of patients was improved by NAC (P = 0.025). Also, drug-induced ALF showed improved outcome compared to other etiologies.

CONCLUSION

The findings of the study recommend the use of NAC along with conventional treatments in patients with NAI-ALF in non-transplant centers while awaiting referrals and conclude the use of NAC as safe.

Acute Liver Failure Due to Hepatitis E Virus Infection Is Associated with Better Survival than Other Etiologies in Indian Patients

BACKGROUND AND AIM

Hepatitis E virus (HEV) is a global disease and an important cause of acute liver failure (ALF) in the Indian subcontinent. The aim of this study was to assess the differences in the course of HEV-ALF as compared to other etiologies of ALF.

METHODS

We compared the clinical course, complications, and outcomes of HEV-ALF with other etiologies. We assessed the prognostic factors and compared existing prognostic scores in HEV-ALF patients.

RESULTS

One thousand four hundred and sixty-two ALF patients were evaluated between January 1986 and December 2015. HEV was the etiology of ALF in 419 (28.7%) cases, whereas non-A non-E hepatitis, HBV and anti-tuberculosis therapy (ATT) were the etiologies in 527 (36.0%), 128 (8.8%), and 103 (7.0%) cases, respectively. The frequency of cerebral edema in HEV-ALF (41.3%) was lower than that in non-A non-E ALF (52.9%; P < 0.001) and HBV-ALF (52.8%; P = 0.024). Infection and seizures were significantly less in patients with HEV-ALF compared to non-A non-E and HBV-ALF (P = 0.038 and 0.022, respectively). The survival of HEV-ALF patients was significantly better (55.1%, P < 0.001) than patients of other etiologies-including ATT (30.0%), non-A non-E (38.1%) and HBV (35.9%). In HEV-ALF patients, age, female sex, cerebral edema, prothrombin time >60 s, infection, and total bilirubin were observed as independent predictors of outcome on multivariate logistic regression analysis. Model for end-stage liver disease, acute liver failure study group model and King's College Hospital criteria had poor discriminative accuracy for outcome (area under receiver operator characteristic curve 0.63-0.64) in HEV-ALF.

CONCLUSIONS

Hepatitis E virus-associated ALF has a better outcome than ALF of other etiologies.

Acute on chronic liver failure because of acute hepatic insults: Etiologies, course, extrahepatic organ failure and predictors of mortality

BACKGROUND AND AIM

Acute on chronic liver failure (ACLF) because of precipitating factors (variceal bleed/infections) identifies cirrhotics at risk for high short-term mortality. Information on ACLF because of acute hepatic insults is lacking. The aim of the study was to evaluate acute hepatic insults in ACLF and their effect on the course and outcome.

METHODS

In a prospective study, 213 consecutive patients of ACLF because of acute hepatic insults were included. Etiology of acute hepatic insult, frequency of silent, and overt chronic liver disease (CLD), organ failure (OF), and outcomes were assessed. Prognostic models such as model for endstage liver disease (MELD), acute physiology and chronic health evaluation (APACHE II), and chronic liver failure-sequential organ failure (CLIF-SOFA) were evaluated.

RESULTS

Etiologies of acute hepatic insult were hepatitis virus(es)- 81 (38%; HBV-42, HEV-39), continuous alcohol consumption-77 (33.3%), antituberculosis drugs-11 (5.2%), autoimmune hepatitis flare-5(2.3%), cryptogenic-44 (20.7%). The common causes of CLD were alcohol (n = 85/40%), HBV(n = 52/24%), and cryptogenic(n = 50/20%). The MELD, APACHE II, and CLIF-SOFA scores were similar among silent and overt CLD and did not influence outcome. Predominant etiologies of ACLF were hepatitis virus(es) reactivation or superinfection in silent CLD(52/112, 46.4%) and alcohol among overt CLD(43/101, 43%). Independent predictors of mortality included hepatic-encephalopathy (early, HR: 4.01; advanced, HR: 6.10), serum creatinine ≥1.5 mg/dl (HR: 4.53), CLIF-SOFA ≥8(HR: 1.69), and etiology of acute hepatic insult (alcohol, HR: 4.08; cryptogenic, HR: 3.18). HEV-ACLF had lower mortality (12.8% vs. 33-54% in other etiologies;P < 0.001). OF was major determinant of mortality. With increasing number of OF, mortality increased linearly(P = 0.001).

CONCLUSIONS

Hepatitis virus(es) and continuous alcohol consumption are important causes of ACLF caused by acute hepatic insults. HEV-ACLF has lower mortality. OF is an important prognostic predictor.

Prevalence and Impact of Hepatitis on the Quality of Life of Patients

Background

Hepatitis is a disorder which is emerging as major health problem with increasing morbidity and mortality. Inappropriate management of this disease leads to several complications that can impair the health related quality of life (HRQoL) of the individuals. There, we designed this study to assess the HRQoL in patients suffering from hepatitis.

Materials and methods

This prospective, observational study was conducted for 2 months in patients with hepatitis. All patients with hepatitis were recruited in the study after giving written informed consent. The participants were given both World Health Organization Quality of Life-Bref (WHO QoL-Bref) and short form (SF-36) health survey questionnaires for assessing the quality of life (QoL) of patients. The participants were given counseling of lifestyle modification and underwent a thorough medical examination and a detailed history was taken.

Results

A total of 65 volunteers participated in the study, out of which 30 were control and 35 were patients suffering from hepatitis; hepatitis C was found to be more prevalent. The patients with hepatitis had a significantly poor QoL as compared to control. In hepatitis patients, physical health and physical functioning was better in males as compared to females. Social relationships were also good in males than females. But females had higher score in role limitation due to physical health, emotional wellbeing, social functioning, pain, general health as per SF-36 scores but it was not statistically significant.

Conclusion

Hepatitis affected the HRQoL in Indian population and parameters seem to be heterogeneously affected in males and females.

How to cite this article

Mittal P, Matreja PS, Rao HK, Khanna PML. Prevalence and Impact of Hepatitis on the Quality of Life of Patients. Euroasian J Hepato-Gastroenterol 2015;5(2):90-94.

A Hospital-based Retrospective Study on Frequency and Distribution of Viral Hepatitis

BACKGROUND

Viral hepatitis is a major public health problem throughout the world. It is the inflammation of the liver due to the infection of any of the five main hepatic viruses A to E and it affects the liver through different modes of transmission. This study mainly aims at the frequency and distribution of viral hepatitis based on age and sex during a time period of 5 years.

MATERIALS AND METHODS

This is a hospital-based retrospective study of 5 years at a tertiary level hospital in Kerala state in India. Medical records department of the hospital follow the guidelines of International Classification of Diseases-10 for coding the diseases. The data on frequency and distribution of viral hepatitis based on age and sex during a period of 5 years from April 2005 to March 2010 were collected and analyzed and 'z' test was used for finding out the difference in proportions.

RESULT

Out of 818 cases, 76.03% were males and 23.96% were females. The preponderance of males was apparent in all types of viral hepatitis infection. The high risk groups were the adults in the age group of 20-39 years. The main cause in the present study was hepatitis E virus (HEV) and followed by hepatitis A virus (HAV). Of total viral hepatitis cases, 31.54% were due to HAV, 6.35% hepatitis B virus, 0.85% hepatitis C virus and 61.24% were due to HEV respectively. In the present study, there was no case of hepatitis D virus has reported. The case fatality rate of viral hepatitis in the present study was minor than 1% (0.98%); whereas males were 0.96%; females of 1.02%.

CONCLUSION

Taking the safety measures including vaccination and proper management of waste materials are the only solution to control or eradicate this infection.

Establishment of culture systems for Genotypes 3 and 4 hepatitis E virus (HEV) obtained from human blood and application of HEV inactivation using a pathogen reduction technology system

BACKGROUND

It has been demonstrated that the hepatitis E virus (HEV) can be transmitted via blood transfusion, and the risk of HEV transmission via transfusion has become a major global concern. An HEV culture system for blood-derived HEV has been sought to obtain valuable knowledge of the virus and the risk of HEV infection through blood products.

STUDY DESIGN AND METHODS

We endeavored to establish an HEV culture system using RNA-positive blood specimens for Genotypes (G) 3 and 4 and applied this system to evaluate tissue culture infectious dose (TCID). We applied this method to investigate the potential of the Mirasol pathogen reduction technology (PRT) system (Terumo BCT) to inactivate live HEV in contaminated platelet samples (PLTs). PLTs were spiked with cultured HEV G3 or G4 and then treated with the Mirasol PRT system. PLTs were examined before and after the treatment for HEV load using TCID titration.

RESULTS

We successfully established two strains for HEV production: the JRC-HE3 strain for G3 and the UA1 strain for G4. The Mirasol PRT system expressed more than 3 log inactivation for JRC-HE3 and more than 2 log inactivation for UA1.

CONCLUSION

The Mirasol PRT system inactivated greater than 2 to 3 logs of live HEV in PLTs and can potentially be used to lower the possibility of blood-borne HEV transmission. The G3 and G4 HEV inocula identified in this study and the hepatoma cell culture system provide a new means to assess HEV infectious titer and to evaluate other pathogen reduction strategies.

Prevalence of hepatitis E virus infection in West Bengal, India: a hospital-based study

India is an endemic zone for hepatitis E virus (HEV), which is associated with both epidemic and sporadic infections. In West Bengal, only two hepatitis E outbreaks have been studied to date. However, sporadic cases of HEV infection also occur during inter-epidemic periods. The aim of this hospital-based study was to detect the prevalence of HEV infection in patients with acute sporadic hepatitis in West Bengal, India. Blood samples and clinical information were collected from 285 patients of both sexes and different ages with acute viral hepatitis (AVH) at Calcutta Medical College, Kolkata, a tertiary-care centre. Samples were tested for hepatitis B virus (HBV) surface antigen, anti-hepatitis C virus antibodies, anti-hepatitis A virus IgM and anti-HEV antibodies (IgM and IgG) by ELISA. Only those patients with AVH who were in their first week of illness and negative for all hepatotropic viral antibodies were tested for HEV RNA by reverse transcriptase nested PCR. HEV was identified as the most common cause of AVH (41.8% of patients), followed by HBV (21.4%), hepatitis A virus (17.2%) and hepatitis C virus (4.6%). Co-infections with more than one virus were found in 22 patients, with HBV-HEV the most common co-infection (3.8%). Only 14.7% of patients had no viral marker. To the best of our knowledge, this is the first documented epidemiological study of acute sporadic hepatitis with HEV in the state of West Bengal, India, indicating that this state is an endemic zone for HEV infection.

Phylogenetic analysis of hepatitis e virus in northwest India

Genotyping and subtyping are important to understand epidemiology of the hepatitis E virus so as to improve control measures to prevent transmission of virus in the community. Hence, the aim of the current study was to identify the prevalent HEV genotypes in Rajasthan in acute sporadic hepatitis E cases with varying degree of liver failure. We studied hepatitis E virus (HEV) isolates from hospitalized patients in Rajasthan, western India. In a total of seventeen HEV sequences, six acute viral hepatitis, seven acute liver failure, and 4 acute- on-chronic cases were analyzed. Subtypes 1a and 1c of HEV are prevalent in Northwest India.

Viral hepatitis in India

Hepatitis in India is caused mainly by hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis E virus (HEV). HAV infection occurs frequently in children, though in parts of India there is an evolving epidemiology. HEV is the most common cause of acute sporadic hepatitis in India and has been associated with several large-scale epidemics in the past. India belongs to the intermediate endemicity zone for HBV carriers. HBV is the major cause of chronic liver disease and liver cancer. Horizontal transmission of HBV plays an important role. Genotypes D, A, and C have been reported in India. HCV is transmitted mainly through suboptimal blood banking and injection practices in India. Genotype 3 is the most predominant, followed by genotype 1.

Antituberculosis therapy-induced acute liver failure: magnitude, profile, prognosis, and predictors of outcome

Antituberculosis therapy (ATT)-associated acute liver failure (ATT-ALF) is the commonest drug-induced ALF in South Asia. Prospective studies on ATT-ALF are lacking. The current study prospectively evaluated the magnitude, clinical course, outcome, and prognostic factors in ATT-ALF. From January 1986 to January 2009, 1223 consecutive ALF patients were evaluated: ATT alone was the cause in 70 (5.7%) patients. Another 15 (1.2%) had ATT and simultaneous hepatitis virus infection. In 44 (62.8%) patients, ATT was prescribed empirically without definitive evidence of tuberculosis. ATT-ALF patients were younger (32.87 [+/-15.8] years), and 49 (70%) of them were women. Most had hyperacute presentation; the median icterus encephalopathy interval was 4.5 (0-30) days. The median duration of ATT before ALF was 30 (7-350) days. At presentation, advanced encephalopathy and cerebral edema were present in 51 (76%) and 29 (41.4%) patients, respectively. Gastrointestinal bleed, seizures, infection, and acute renal failure were documented in seven (10%), five (7.1%), 26 (37.1%), and seven (10%) patients, respectively. Compared with hepatitis E virus (HEV) and non-A non-E-induced ALF, ATT-ALF patients had nearly similar presentations except for older age and less elevation of liver enzymes. The mortality rate among patients with ATT-ALF was high (67.1%, n = 47), and only 23 (32.9%) patients recovered with medical treatment. In multivariate analysis, three factors independently predicted mortality: serum bilirubin (>or=10.8 mg/dL), prothrombin time (PT) prolongation (>or=26 seconds), and grade III/IV encephalopathy at presentation.

CONCLUSION

ATT-ALF constituted 5.7% of ALF at our center and had a high mortality rate. Because the mortality rate is so high, determining which factors are predictors is less important. A high proportion of patients had consumed ATT empirically, which could have been prevented.

Hepatitis E: a complex and global disease

Thirty years after its discovery, the hepatitis E virus (HEV) continues to represent a major public health problem in developing countries. In developed countries, it has emerged as a significant cause of non-travel-associated acute hepatitis. HEV infects a wide range of mammalian species and a key reservoir worldwide appears to be swine. Genomic sequence similarity between some human HEV genotypes and swine HEV strains has been identified and we know that humans can acquire HEV infection from animals. Although for the most part the clinical course of HEV infection is asymptomatic or mild, significant risk of serious disease exists in pregnant women and those with chronic liver disease. In addition, there are data on the threat of chronic infections in immunocompromised patients. Beyond management of exposure by public health measures, recent data support that active immunisation can prevent hepatitis E, highlighting the need for vaccination programmes. Here we review the current knowledge on HEV, its epidemiology, and the management and prevention of human disease.

A 20-year single-center experience with acute liver failure during pregnancy: is the prognosis really worse?

Pregnant patients with acute liver failure (ALF) are believed to have a worse outcome than nonpregnant women and men with ALF. However objective data supporting this supposition are scant. Therefore, the current study compared the outcome, complications, and causes of ALF among pregnant women and girls with age-matched nonpregnant women and girls and men and boys with ALF. One thousand fifteen consecutive ALF patients in the reproductive age group, admitted at the All India Institute of Medical Sciences, New Delhi, from January 1986 to December 2006, were included in the study. A total of 249 (38.5%) women were pregnant. They were compared with 341 nonpregnant women and girls and 425 men and boys, aged 15 to 45 years. The mortality rate of pregnant women and girls (53.8%) was similar to age-matched nonpregnant women and girls (57.2%), and men and boys (57.9%); P = 0.572. The clinical and biochemical features, disease severity, and complications were also similar in the three groups. A significantly higher proportion of ALF was attributable to hepatitis E virus (HEV) among women and girls who were pregnant (59.4%), as compared with both nonpregnant women and girls (30.4%), and men and boys (23.1%); P < 0.001. However, the outcome of HEV-related ALF was independent of the sex and pregnancy status of the patients (P = 0.103). Mortality in HEV-ALF and non-HEV-ALF patients in pregnant women and girls was 51% (74/145) and 54.7% (52/95)(P > 0.1), respectively. The outcome of pregnant ALF patients was also unrelated to the trimester of pregnancy. The mortality of non-HEV-related ALF among the pregnant women and girls (54.7%), age-matched nonpregnant women and girls (61.7%), and men and boys (62.8%) were also similar (P > 0.1).

CONCLUSION

The mortality of pregnant patients with ALF is similar to that of nonpregnant women and girls and men and boys and is independent of the cause or trimester. Pregnancy per se should not be regarded as a poor prognostic factor for a patient with ALF.

A 7-day profile of oxidative stress and antioxidant status in patients with acute liver failure

PURPOSE

Acute liver failure (ALF) is characterized by a rapid and massive destruction of hepatocytes. The role of oxidative stress in perpetuating the injury is undefined and may be a potential therapeutic target. Our aim was to study serial variation in oxidative stress and antioxidant status in patients with ALF.

METHODS

The study involved a prospective case-control study set in a tertiary care referral center. Thirty-two consecutive patients admitted with ALF were included with 23 healthy controls for comparison. Level of systemic oxidative stress as defined by superoxide dismutase (SOD), lipid peroxidation products (thiobarbituric acid reactive derivatives [TBARS]), and the total antioxidant capacity as the ferric reducing ability of plasma (FRAP) was measured at baseline on days 3 and 7.

RESULTS

The patients were aged 24 years (range 13-60 years) and included 20 females. Thirteen (40.6%) patients died. Patients with ALF had significantly increased systemic oxidative stress at presentation, as reflected by higher levels of SOD (P < 0.001) and TBARS (P < 0.001) than controls. Both TBARS levels and FRAP decreased progressively from admission to the end of first week among the survivors (P = 0.004 and 0.015, respectively). The antioxidant status reflected by FRAP (P = 0.001) was significantly lower in ALF patients than controls. No relation was found between the level of oxidative stress and the mortality or complications.

CONCLUSION

A high level of systemic oxidative stress exists in ALF, with depletion of antioxidant reserves. Further studies are needed to define the clinical correlation of the large pro-oxidant burden.

Seroprevalence of hepatitis E virus in blood donors in Khuzestan Province, southwest Iran

OBJECTIVE

To determine the seroprevalence of hepatitis E virus (HEV) infection among volunteer blood donors in Khuzestan Province, Iran. Khuzestan is a war stricken area in the southwest of Iran, which shares a land, river, and sea border with Iraq. This region has suffered the heaviest public health system damage of all the Iranian provinces during a 25-year period of war and conflict.

METHODS

A cross-sectional study was carried out among 400 urban volunteer blood donors of the regional blood banks, from May to December 2005. Serum samples from healthy blood donors were tested for IgG anti-HEV antibody using a specific enzyme linked immunoassay (ELISA) kit.

RESULTS

The prevalence of HEV infection was found to be 11.5% (46/400). All patients were negative for anti-HIV, anti-HBV, and anti-HCV antibodies. The data indicate that 14.6% (38/260) of HEV positive subjects were male, compared to 5.7% (8/140) of females; this difference is statistically significant (risk ratio=2.6, p<0.008).

CONCLUSIONS

These findings demonstrate the high prevalence rate of anti-HEV among blood donors, particularly males.

Prolonged fecal shedding of hepatitis E virus (HEV) during sporadic acute hepatitis E: evaluation of infectivity of HEV in fecal specimens in a cell culture system

To investigate the duration of fecal shedding and changing loads of hepatitis E virus (HEV) in feces and serum from patients with acute HEV infection, HEV RNA was quantitated in periodic serum and fecal specimens obtained from 11 patients with sporadic acute hepatitis E. All 11 patients had detectable HEV RNA in serum at admission, with the highest viral load being 1.9 x 10(3) to 1.7 x 10(7) copies/ml, and HEV viremia lasted until days 17 to 48 (mean, 28.3) after the onset of hepatitis. Even at the initial examination on days 10 to 29 (mean, 17.6), the HEV load in fecal supernatant was less than 5.7 x 10(4) copies/ml for 10 of the 11 patients, while for the remaining patient (patient 1) it was markedly high, 2.0 x 10(7) copies/ml on day 22. In addition, although HEV RNA in fecal supernatant continued to be positive until days 14 to 33 (mean, 22.4) for patients 2 to 11, that for patient 1 was detectable even on day 121. HEVs in fecal specimens obtained on days 22, 24, 26, 28, and 30, but not day 121, from patient 1 grew efficiently in PLC/PRF/5 cells, reaching the highest titer of up to 10(7) copies/ml in culture medium on day 50 postinoculation. The HEV genome recovered from patient 1 had 29 unique nucleotides that were not seen in any of the 25 reported HEV isolates of the same genotype over the entire genome, with six amino acid substitutions in the ORF1 protein.

Hepatitis E virus

Hepatitis E virus (HEV) is the aetiological agent of non-HAV enterically transmitted hepatitis. It is the major cause of sporadic as well as epidemic hepatitis, which is no longer confined to Asia and developing countries but has also become a concern of the developed nations. In the Indian subcontinent, it accounts for 30-60% of sporadic hepatitis. It is generally accepted that hepatitis E is mostly self-limited and never progresses to chronicity. It has a higher mortality in pregnant women where the disease condition is accentuated with the development of fulminant liver disease. Currently, no antiviral drug or vaccine is licensed for HEV, although a vaccine candidate is in clinical trials. HEV genome is 7.2kb in size with three open reading frames (ORFs) and 5' and 3' cis acting elements, which have important roles to play in HEV replication and transcription. ORF1 codes for methyl transferase, protease, helicase and replicase; ORF2 codes for the capsid protein and ORF3 for a protein of undefined function. HEV has recently been classified in the genus Hepevirus of the family Hepeviridae. There are four major recognised genotypes with a single known serotype. The absence of a reliable in vitro propagation system is an obstacle to deciphering HEV biology. The genome of HEV has been cloned, sequenced and the infectious nature of these replicons has been established. However, questions related to replication, transcription, virus-host interactions and pathogenesis remain to be answered. This comprehensive review summarises the progress made so far in HEV research, and addresses some of the unanswered questions.

Hepatitis E virus infection and fulminant hepatic failure during pregnancy

BACKGROUND AND AIM

Hepatitis E virus (HEV) infection leading to fulminant hepatic failure (FHF) and high mortality is a common feature in Indian women during the second and third trimesters of pregnancy. An altered status of hormones and immunity are observed during pregnancy but the actual cause of high mortality is still unknown. The present study was carried out to analyze CD3, CD4 and CD8 T cell counts and to assay the level of pregnancy-related hormones such as estrogen, progesterone and beta-HCG in order to discover the role played by these factors.

METHODS

One hundred patients (50 pregnant and 50 non-pregnant women) with FHF and 150 pregnant healthy females without liver disease as controls were recruited for the study. Serological tests for all viral markers using ELISA kits and detection of HEV RNA by reverse transcription-polymerase chain reaction (RT-PCR) were carried out in all cases. CD3, CD4 and CD8 T cell counts were analyzed by fluorescence activated cell sorter (FACS) while hormone assay was performed by commercially available RIA kits.

RESULTS

Serologically (38/50; 76%) as well as by RT-PCR (28/50; 56%), a significantly higher HEV positivity rate was found in pregnant FHF patients compared to non-pregnant women (serologically 15/50; 30%; RT-PCR 7/50; 14%). CD4 counts were lower (P < 0.05), while CD8 counts were higher (P < 0.05), and their ratio (CD4/CD8) in HEV positive pregnant FHF patients was significantly lower (P < 0.01) when compared to that of HEV negative pregnant FHF women or controls. Levels of estrogen, progesterone and beta-HCG were also found to be higher (P < 0.001) in HEV positive pregnant FHF patients when compared to HEV negative patients or controls. HEV infected pregnant FHF patients had a significantly higher mortality rate of 65.8% (25/38) compared to 23.5% (4/15) in HEV positive non-pregnant women (P < 0.001).

CONCLUSIONS

Pregnancy appears to be a potential risk factor for viral replication and an extreme low immune status of Indian/Asian pregnant women. It is suggested that diminished cellular immunity (indicated by a decrease in CD4, an increase in CD8 cell counts and lowered CD4/CD8 cell ratio) and a high level of steroid hormones that influence viral replication/expression during pregnancy appear to be the plausible reasons for severity of the disease.

Global distribution of infectious diseases requiring intensive care

This article describes infectious diseases that are of special importance to intensivists. The emphasis on epidemiology notwithstanding, it also addresses clinical, diagnostic, and treatment issues related to each infection described. The discussion avoids terrorism-related aspects of these infections, because they were very well covered in the October 2005 issue of the Critical Care Clinics.

Expression and processing of the Hepatitis E virus ORF1 nonstructural polyprotein

Background

The ORF1 of hepatitis E virus (HEV) encodes a nonstructural polyprotein of ~186 kDa that has putative domains for four enzymes: a methyltransferase, a papain-like cysteine protease, a RNA helicase and a RNA dependent RNA polymerase. In the absence of a culture system for HEV, the ORF1 expressed using bacterial and mammalian expression systems has shown an ~186 kDa protein, but no processing of the polyprotein has been observed. Based on these observations, it was proposed that the ORF1 polyprotein does not undergo processing into functional units. We have studied ORF1 polyprotein expression and processing through a baculovirus expression vector system because of the high level expression and post-translational modification abilities of this system.

Results

The baculovirus expressed ORF1 polyprotein was processed into smaller fragments that could be detected using antibodies directed against tags engineered at both ends. Processing of this ~192 kDa tagged ORF1 polyprotein and accumulation of lower molecular weight species took place in a time-dependent manner. This processing was inhibited by E-64d, a cell-permeable cysteine protease inhibitor. MALDI-TOF analysis of a 35 kDa processed fragment revealed 9 peptide sequences that matched the HEV methyltransferase (MeT), the first putative domain of the ORF1 polyprotein. Antibodies to the MeT region also revealed an ORF1 processing pattern identical to that observed for the N-terminal tag.

Conclusion

When expressed through baculovirus, the ORF1 polyprotein of HEV was processed into smaller proteins that correlated with their proposed functional domains. Though the involvement of non-cysteine protease(s) could not be be ruled out, this processing mainly depended upon a cysteine protease.

Analysis of the full-length genome of genotype 4 hepatitis E virus isolates from patients with fulminant or acute self-limited hepatitis E

It was suggested that hepatitis E virus (HEV) genotype 4 is associated more closely with the severity of hepatitis E than genotype 3, although the virological basis remains unknown. The aim of this study was to examine whether genomic differences among genotype 4 HEVs are responsible for the development of fulminant hepatitis. Full-length sequences of genotype 4 HEVs from three patients with fulminant hepatitis and six patients with acute self-limited hepatitis were determined. The sequences were analyzed with those of 13 genotype 4 HEV isolates whose entire nucleotide sequence is known. Analysis of 22 full-length sequences (fulminant hepatitis, 5; acute hepatitis, 17) revealed that C at nt 1816 and U at nt 3148 (U3148), both of which do not change the amino acid sequences, were significantly associated with fulminant hepatitis (P = 0.0489, respectively). When partial nucleotide sequences containing nt 1816 or nt 3148 were determined in 16 additional HEV isolates of genotype 4, a closer association between U3148 and fulminant hepatitis (P = 0.0018) was observed. The comparison of 86 HEV isolates of all four genotypes showed that U3148 had a stronger association with fulminant hepatitis than other nucleotides at nt 3148 (P = 0.0006). Patients infected with HEV with U3148 had a significantly lower value of the lowest prothrombin activity (P = 0.0293). Nt 3148 is located within the RNA helicase domain, and 22-nt sequence including nt 3148 was well conserved among all genotypes. A silent substitution of U3148 in HEV may be associated with the development of fulminant hepatitis. Further studies are needed to clarify the underlying mechanism.

Prophylactic phenytoin does not improve cerebral edema or survival in acute liver failure--a controlled clinical trial

BACKGROUND/AIMS

Seizure activity in patients with acute liver failure (ALF) may increase cerebral oxygen requirements and worsen cerebral edema. Recently, prophylactic phenytoin has been recommended to suppress sub-clinical seizure activity evident on electroencephalographic monitoring. To determine the clinical utility of prophylactic phenytoin therapy in patients with ALF.

METHODS

Forty two patients with ALF were randomized. Twenty two patients were given prophylactic phenytoin and 22 patients acted as controls. The baseline clinical and biochemical features were similar in the two groups and patients with > or =2 poor prognostic variables were equally represented.

RESULTS

Sixteen patients in the phenytoin group, and 15 in the control group developed cerebral edema (P=0.38). Mechanical ventilation was required in 10 and 12 patients in the phenytoin and control groups, respectively, (P=0.77). Seizures occurred in 5 (22.7%) control patients and 5 (25%) phenytoin treated patients (P=0.86). Fourteen (70%) patients randomized to phenytoin and 15 (68.2%) control patients died (P=0.89).

CONCLUSIONS

Seizure was common in patients with ALF. Prophylactic use of phenytoin did not prevent cerebral edema, seizures or need for mechanical ventilation, and did not improve survival.

The hepatitis E virus open reading frame 3 protein activates ERK through binding and inhibition of the MAPK phosphatase

The hepatitis E virus causes acute viral hepatitis endemic in much of the developing world and is a serious public health problem. However, due to the lack of an in vitro culture system or a small animal model, its biology and pathogenesis are poorly understood. We have shown earlier that the ORF3 protein (pORF3) of hepatitis E virus activates ERK, a member of the MAPK superfamily. Here we have explored the mechanism of pORF3-mediated ERK activation and demonstrated it to be independent of the Raf/MEK pathway. Using biochemical assays, yeast two-hybrid analysis, and intracellular fluorescence resonance energy transfer we showed that pORF3 binds Pyst1, a prototypic member of the ERK-specific MAPK phosphatase. The binding regions in the two proteins were mapped to the N terminus of pORF3 and a central portion of Pyst1. Expression of pORF3 protected ERK from the inhibitory effects of ectopically expressed Pyst1. This is the first example of a viral protein regulating ERK activation by inhibition of its cognate dual specificity phosphatase.

Acidic pH enhances structure and structural stability of the capsid protein of hepatitis E virus

Hepatitis E virus (HEV) is enterically transmitted and endemic to tropical areas of the world. The major capsid protein of HEV is pORF2 ( approximately 74 kDa), encoded by open reading frame 2 (ORF2). When expressed in insect cells, it is processed into a approximately 55 kDa form (n-pORF2). We also generated a mutant, m-pORF2, lacking a C-terminal hydrophobic region shown earlier to be required for its homo-oligomerization. Circular dichroism was used to measure the secondary structure and stability of these proteins as a function of pH and temperature. With decreasing pH both proteins acquired increasing alpha-helicity and thermal stability in terms of midpoint of denaturation and the Gibbs energy change.

Status of immunodiagnosis and immunocontraceptive vaccines in India

The article focuses on the Indian initiative of making kits for diagnosis of various infectious and non-infectious diseases as well as reproductive hormones and hormones in various other endocrine disorders. Indigenous diagnostic kits for the detection of various infections such as filariasis, typhoid, amebiasis, Japanese encephalitis, hepatitis, HIV, dengue, leishmaniasis, malaria, rabies, toxoplasmosis, rotavirus, and group A streptococci have been developed. Agreements to transfer the know-how of some of these leads to industries have been signed. The know-how of enzyme-linked immunosorbent assay (ELISA) for detection of hepatitis C has been successfully transferred to industry and is being commercially produced. For detection of HIV-1 and HIV-2, indigenous diagnostic kits based on three different formats, namely ELISA, Western blot and rapid test have been developed and are being commercially produced by Indian industries. The factors influencing the successful transfer of laboratory-scale diagnostic assays from academia to industry and their commercial exploitation have been discussed. Indian scientists have made seminal contributions in exploring the possibility to develop an effective and safe contraceptive vaccine to control the increasing human population of India. Achieving contraception by means of vaccine is a novel approach, which entails generation of a specific antibody response against antigens critically involved in the process of mammalian reproduction. In India, three major programs on contraceptive vaccines based on the beta-subunit of human chorionic gonadotrophin ((beta)hCG) for women, ovine follicle stimulating hormone (oFSH) for men, and riboflavin carrier protein for both males and females have been initiated. The work at the National Institute of Immunology, New Delhi on contraceptive vaccine for women, based on (beta)hCG, has demonstrated, for the first time, that it is feasible to regulate fertility by such an approach. Basic research being carried out to achieve immunocontraception by interfering at sperm-oocyte interaction level has been briefly discussed. These developments are still at the research stage. In addition to advances in the area of contraceptive vaccines, a non-steroidal contraceptive oral pill has been developed by Central Drug Research Institute, Lucknow, commercially produced by two Indian pharmaceutical companies and has been incorporated in the National Family Welfare Program. Another interesting approach for fertility regulation in male has been developed in India, which involves vas occlusion with styrene maleic anhydride (SMA) and is currently undergoing clinical trials in human subjects.

Aetiology and prognostic factors in acute liver failure in India

The early prognostic indicators for acute liver failure in endemic zones for hepatitis E virus have not been determined. All consecutive patients with acute liver failure from a geographically defined region endemic for hepatitis E virus were studied over the period April 1989-April 1996. Demographic, clinical and biochemical parameters were recorded at presentation and serum samples were analysed for known viral hepatitis (A-E) markers. Multiple parameters were compared in survivors and non-survivors in a univariate analysis. All significant factors on univariate analysis were entered into a stepwise logistic regression analysis to identify independent variables of prognosis. The sensitivity and specificity of significant prognostic factors was then assessed. A total of 180 [69 males and 111 females: age (mean +/- SD) 31.1 +/- 14.7 years] with acute liver failure were studied. Of these, 131 (72.8%) patients died. Hepatitis E virus was the aetiological cause in 79 (43.9%) patients, while hepatitis A virus, hepatitis B virus, hepatitis C virus and non-A, non-E agent/'s could be incriminated in four (2.1%), 25 (13.9%), 13 (7.2%) and 56 (31.1%) patients respectively. Of 83 women in childbearing age, 49 (59.0%) were pregnant, 33 (67.3%) of these were in the third trimester. Forty-seven (95.8%) pregnant women had HEV infection. Nine variables differed significantly between survivors and non-survivors on univariate analysis. Of these, four variables which predicted the adverse outcome on multivariate analysis were non-hepatitis-E aetiology, prothrombin time >30 s, grade of coma >2 and age >40 years in that order of significance. Pregnancy per se or duration of gestation did not adversely affect the prognosis. In endemic areas, hepatitis E virus is the commonest cause of acute liver failure. Acute liver failure occurs in a high proportion of pregnant women, mostly in third trimester. Early predictors of a poor outcome are non-E aetiology, prothrombin time >30 s, grade of coma >2 and age >40 years.

New perspectives on hepatitis E

The infectious agent causing epidemic non-A, non-B hepatitis was identified in 1983 from a human challenge experiment. The novel hepatitis E virus (HEV) subsequently was cloned in 1990 and the genome sequenced. HEV transmission is highly endemic in Asia, the Middle East, and Africa. Fecal contamination of drinking water is the most common mode of spread. Although usually asymptomatic, HEV infection can cause fulminant hepatitis. Recent studies indicate that hepatitis E may be a zoonotic disease, with pigs and possibly rats serving as reservoirs for human infection. A recombinant HEV vaccine is currently in phase III clinical trials. The characterization of the major types of viral hepatitis during the last 20 years illustrates how modern genetic technology has revolutionized research in infectious diseases. Within less than two decades of the discovery of HEV, its epidemiology has been described, serologic tests have been developed, and a candidate vaccine has been evaluated in clinical trials.

Overview of Hepatitis E Virus

Hepatitis E virus (HEV) is an enterically transmitted virus usually presenting as an acute self-limiting disease. However, mortality increases dramatically from around 1% to 20% in pregnant women. HEV has been the cause of very large outbreaks of hepatitis in developing countries and is also responsible for a significant number of sporadic cases. It is clear that cases occur outside the endemic areas, and new isolates have been identified. HEV-like viruses have also been found in various animal groups, and it is likely that HEV can be regarded as a zoonotic infection. Preventative measures at the moment depend mainly on the provision of clean water supplies, although a vaccine is now undergoing clinical trials.

Spread of hepatitis E virus among different-aged pigs: two-year survey in Taiwan

Swine are reservoirs of hepatitis E virus (HEV). In this study, a 2-year survey of HEV in feces and sera of swine was conducted to determine if: 1) HEV has circulated among pigs for some time in Taiwan; 2) the spread of HEV among different-aged pigs; and 3) there exists HEV strains possibly imported through trading. From 1998-2000, 521 serum samples and 54 fecal specimens from pigs were examined by reverse transcription polymerase chain reaction. None of the 11 pigs in suckling stage (< 2 months) were serum HEV RNA positive. The highest viremia rate (4.5%) was in pigs of 2 months age, followed by 1.2% and 1.8% in pigs of growing (3-4 months) and finishing stages (5-6 months), and none in pigs older than 6 months. Viremia showed little variation in different years and areas. None of the 20 fecal samples from pigs in suckling stage were HEV RNA positive, whereas 9% of the 34 samples from pigs in growing or finishing stages were positive. Most swine HEV isolates in Taiwan clustered within the genotype 4, whereas the three HEV isolates cloned from pigs imported recently from the U.S. belonged to the genotype 3 HEV in the U.S. The results suggest that HEV may infect pigs at an early growing stage and spread unnoticed among pigs and possibly across countries through trading.

The ORF3 protein of hepatitis E virus binds to Src homology 3 domains and activates MAPK

The hepatitis E virus (HEV) is the causative agent of hepatitis E, an acute form of viral hepatitis. The biology and pathogenesis of HEV remain poorly understood. We have used in vitro binding assays to show that the HEV ORF3 protein (pORF3) binds to a number of cellular signal transduction pathway proteins. This includes the protein tyrosine kinases Src, Hck, and Fyn, the p85alpha regulatory subunit of phosphatidylinositol 3-kinase, phospholipase Cgamma, and the adaptor protein Grb2. A yeast two-hybrid assay was used to further confirm the pORF3-Grb2 interaction. The binding involves a proline-rich region in pORF3 and the src homology 3 (SH3) domains in the cellular proteins. Competition assays and computer-assisted modeling was used to evaluate the binding surfaces and interaction energies of the pORF3.SH3 complex. In pORF3-expressing cells, pp60(src) was found to associate with an 80-kDa protein, but no activation of the Src kinase was observed in these cells. However, there was increased activity and nuclear localization of ERK in the pORF3-expressing cells. These studies suggest that pORF3 is a viral regulatory protein involved in the modulation of cell signaling. The ORF3 protein of HEV appears to be the first example of a SH3 domain-binding protein encoded by a virus that causes an acute and primarily self-limited infection.

Simultaneous amplification of DNA and RNA virus using multiplex PCR system

A large number of disease-causing bacteria and viruses are being sequenced and PCR is increasingly used for the diagnosis of the diseases. We have designed a multiplex PCR system for hepatitis B virus (HBV), a DNA virus, and hepatitis E virus (HEV), an RNA virus. A modified technique has been standardized for simultaneous extraction of DNA and RNA, followed by a one-step RT-PCR/PCR.

The 3' end of hepatitis E virus (HEV) genome binds specifically to the viral RNA-dependent RNA polymerase (RdRp)

Hepatitis E virus (HEV) is the major cause of acute epidemic and sporadic hepatitis in the developing world. It is a positive-strand RNA virus with a genome length of about 7.2 kb. The replication mechanism of this virus is virtually unexplored. Identification of the regulatory elements involved in initiation of replication may help in designing specific inhibitors for therapy. In the positive-stranded RNA viruses the initiation of replication requires interaction of the 3' end of genome with its RNA-dependent RNA polymerase (RdRp) and possibly host-derived cofactors for synthesis of the minus-strand replicative intermediate. Secondary structure prediction of the conserved 3' end of the infectious HEV genome was carried out to identify possible stem-loop structures necessary for RNA-protein interaction and the model was confirmed by structure probing experiments. Electrophoretic mobility-shift assays showed specific binding of purified and refolded recombinant HEV RdRp protein to the 3' end of its RNA genome containing the poly(A) stretch. Mutations at the 3' end, in which the stem-loop structures were partially or completely destroyed or recreated revealed that the two stem-loop structures SL1 and SL2 at the 3' end and the poly(A) stretch are necessary for this binding. The interacting nucleotides in such an interaction were further identified by generating footprints of the complex by Pb(II)-induced hydrolysis. This specific binding of viral RdRp to the 3' end of HEV RNA directs the synthesis of complementary-strand RNA and thus such a binding domain might assume the role of a possible cis-acting element as a potential site for the initiation of replication.

Acute liver failure: established and putative hepatitis viruses and therapeutic implications

Any virus that can cause an acute hepatitis will, on occasion, give rise to acute liver failure. Such infections can be separated into those due to the primary hepatitis viral infections A to E and those where hepatitis occurs as part of a systemic viral infection, as with infection with, for instance, Epstein-Barr virus, cytomegalovirus, Varicella zoster virus, adenovirus and Herpes simplex virus. In general, the frequency with which the different hepatitis viruses are responsible for acute liver failure is related to their underlying prevalence in particular countries. An apparent exception is the striking geographical variation in the reported prevalence of acute liver failure due to hepatitis C virus infection, with a much higher proportion of cases generally attributed to this agent in Japan and Taiwan than in Western countries. Recent work has focused on the possible importance of mutant hepatitis B viral strains, co- and super-infection with known hepatitis viruses and certain newly described agents that may account for otherwise unexplained cases of acute liver failure. Despite an improved understanding of the pathogenesis of complicating cerebral oedema and advances in general supportive care, it is likely that the most severely affected patients with acute liver failure due to viral causes will survive only with liver transplantation, at least until approaches for promoting adequate liver regeneration are successfully developed and implemented.

Hepatitis E

Hepatitis E, previously known as enterically transmitted non-A, non-B hepatitis, is an infectious viral disease with clinical and morphologic features of acute hepatitis. Its causative agent, hepatitis E virus, consists of small, 32- to 34-nm diameter, icosahedral, nonenveloped particles with a single-stranded, positive-sense, 7.5-kb RNA. The virus has two main geographically distinct strains, Asian and Mexican; recently, novel isolates from nonendemic areas and a genetically related swine HEV have been described. HEV is responsible for large epidemics of acute hepatitis and a proportion of sporadic hepatitis cases in the Indian subcontinent, southeast and central Asia, the Middle East, parts of Africa, and Mexico. The virus is excreted in feces and is transmitted predominantly by fecal-oral route, usually through contaminated water. Person-to-person transmission is uncommon. Clinical attack rates are the highest among young adults. Recent evidence suggests that humans with subclinical HEV infection and animals may represent reservoirs of HEV; however, further data are needed. Diagnosis of hepatitis E is usually made by detection of specific IgM antibody, which disappears rapidly over a few months; IgG anti-HEV persists for at least a few years. Clinical illness is similar to other forms of acute viral hepatitis except in pregnant women, in whom illness is particularly severe with a high mortality rate. Subclinical and unapparent infections may occur; however, chronic infection is unknown. No specific treatment is yet available. Use of clean drinking water and proper sanitation is currently the most effective method of prevention. Passive immunization has not been proved to be effective, and recombinant vaccines for travelers to disease-endemic areas and for pregnant women currently are being developed.

Fulminant hepatitis associated with hepatitis A virus superinfection in patients with chronic hepatitis C

There have been conflicting reports of the clinical outcome of acute hepatitis A virus (HAV) infection in patients with chronic hepatitis C virus (HCV) infection. A prospective study evaluated 432 patients with chronic hepatitis C (183 with cirrhosis) over a 7-year period. Of the 17 patients with concurrent HAV infection, seven developed fulminant hepatitis and six died. None of these patients had cirrhosis; however, the HLA phenotype (A1; B8:DR3) appeared to be a significant factor in the development of fulminant hepatitis. Patients with this phenotype had high titres of antinuclear antibodies, antismooth muscle antibodies and antiasialoglycoprotein-receptor antibodies, possibly reflecting the induction of autoimmune hepatitis in this group. The high frequency of fulminant hepatitis in patients with HAV/HCV coinfection contrasts with other surveys, although a large Centers for Disease Control and Prevention (CDC) survey demonstrated that HAV infection in patients with pre-existing chronic liver disease (CLD) is associated with increased mortality. It is likely that CLD has some importance as an underlying factor in the development of fulminant hepatitis following HAV infection. Further prospective studies are needed to clarify this issue.

Acute hepatic failure in India: a perspective from the East

Acute hepatic failure (AHF) in India almost always presents with encephalopathy within 4 weeks of the onset of acute hepatitis. Further subclassification of AHF into hyperacute, acute and subacute forms may not be necessary in this geographical area, where the rapidity of onset of encephalopathy does not seem to influence survival. Viral hepatitis is the cause in approximately 95-100% of patients, who therefore constitute a more homogeneous population than AHF patients in the West. In India, hepatitis E (HEV) and hepatitis B (HBV) viruses are the most important causes of AHF; approximately 60% of cases are caused by to these viruses. Hepatitis B virus core mutants are very important agents in cases where hepatitis B results in AHF in this country. Half of the patients with AHF admitted to our centre are female, one-quarter of whom are pregnant. Therefore, pregnant females who contract viral hepatitis constitute a high-risk group for the development of AHF. However, the outcome of AHF in this group is similar to that in non-pregnant women and men. No association with any particular virus has been identified among sporadic cases of AHF. In our centre, approximately one-third of AHF patients survive with aggressive conservative therapy, whereas two-thirds of deaths occur within 72 h of hospitalization. Cerebral oedema and sepsis are the major fatal complications. Both fungal and gram-negative bacteria are major causes of sepsis. Among patients with AHF, despite the presence of sepsis, its overt clinical features (i.e. fever, leucocytosis) may be absent and objective documentation of the presence of sepsis in such patients is achieved by repeated culture of various body fluids. It should be possible to develop simple, clinical prognostic markers for AHF in this geographical region, in order to identify patients suitable for liver transplantation.

Hepatitis E: an overview and recent advances in clinical and laboratory research

Hepatitis E virus (HEV) is a non-enveloped RNA (7.5 kb) virus that is responsible for large epidemics of acute hepatitis and a proportion of sporadic hepatitis cases in southeast and central Asia, the Middle East, parts of Africa and Mexico. Hepatitis E virus infection spreads by the faecal-oral route (usually through contaminated water) and presents after an incubation period of 8-10 weeks with a clinical illness resembling other forms of acute viral hepatitis. Clinical attack rates are the highest among young adults. Asymptomatic and anicteric infections are known to occur. Chronic HEV infection is not observed. Although the mortality rate is usually low (0.07-0.6%), the illness may be particularly severe among pregnant women, with mortality rates reaching as high as 25%. Recent isolation of a swine virus resembling human HEV has opened the possibility of zoonotic HEV infection. Studies of pathogenetic events in humans and experimental animals reveal that viral excretion begins approximately 1 week prior to the onset of illness and persists for nearly 2 weks; viraemia can be detected during the late phase of the incubation period. Immunoglobulin M antibody to HEV (anti-HEV) appears early during clinical illness but disappears rapidly over a few months. Immunoglobulin G anti-HEV appears a few days later and persists for at least a few years. There is no specific treatment available for hepatitis E virus infection. Ensuring a clean drinking water supply remains the best preventive strategy. Recombinant vaccines are being developed that may be particularly useful for travellers to disease-endemic areas and for pregnant women.

The impact of traveling to endemic areas on the spread of hepatitis E virus infection: epidemiological and molecular analyses

Traveling to endemic areas carries a risk of hepatitis E virus (HEV) infection, but no molecular analysis to document sources of infection is available. Eighteen (38%) of 47 patients with acute non-A, non-B, non-C hepatitis were positive for antibody to HEV (anti-HEV), and 9 (50%) of these were also positive for serum HEV RNA by polymerase chain reaction following reverse transcription. Only 1 (5%) of the 21 patients with acute hepatitis A was positive for HEV RNA. Travel to endemic areas (mostly to China; odds ratio, 22.2; 95% confidence interval, 4.7-105.8) and deeper jaundice (odds ratio, 5.2; 95% confidence interval, 1.01-27.2) were the only factors associated with HEV infection in multivariate analysis. The two HEV isolates from two patients who had traveled to China and the HEV isolate from a patient whose travel history was obscure formed a monophyletic group with the isolates from Guangzhou. The HEV isolates from our patients show a homology of 72% to 78% in nucleotide sequence with the Burma, Beijing, India, Pakistan, and Xiangjiang strains; a homology of 81% to 91% with the Guangzhou strains; and a homology of 76% with the Mexico strain. The close relationship between the Taiwan isolates and the Guangzhou strains was further supported by the short Kimura's two-parameter distances among them. In summary, HEV infection does occur in this area. Epidemiological and molecular analyses strongly indicate that most cases of HEV infection originated from travel to HEV-endemic areas.

Detection of hepatitis C and E virus genomes in sera of patients with acute viral hepatitis and fulminant hepatitis by their simultaneous amplification in PCR

A study was undertaken to investigate the role of hepatitis C virus (HCV) and hepatitis E virus (HEV), either alone or together, in the causation of sporadic acute viral hepatitis (AVH) and fulminant hepatitis (FH) by simultaneous detection of their genomes in serum samples using the reverse transcription and nested polymerase chain reaction (RT-PCR). A total of 50 patients were enrolled in the study of which 34 had AVH and 16 had sporadic FH. The serum samples were first tested for hepatitis B surface antigen (HBsAg) and immunoglobulin (Ig)M antibodies against hepatitis A virus (HAV), hepatitis B core antigen (HBcAg) and HEV and also antibodies against HCV using commercially available enzyme-linked immunosorbent assay (ELISA) kits. All samples were then subjected to RT-PCR using primers for both HCV and HEV simultaneously in the same reaction mixture. Hepatitis C or hepatitis E was diagnosed when either the antibodies or PCR or both were positive for the respective viruses. Evidence of hepatitis C was present in six of the 34 (17.6%) cases of AVH and two out of 16 (12.5%) cases of FH. Four patients in the AVH group and one of the fulminant hepatic failure (FHF) group were found to be positive by PCR and the rest by serology. But as a sole aetiological agent, HCV infection was found in only one (2.9%) case of AVH and in none of the FHF cases. Evidence of HEV infection was found in 22/34 (64.7%) and 8/16 (50%) cases of AVH and FHF, respectively. Excluding co-infection with other viruses, HEV was found to be the sole aetiological agent in 15/34 (44.1%) of AVH and 7/16 (43.7%) cases of FHF. In five (10%) (four AVH and one FHF) of the 50 cases, evidence of infection with both HCV and HEV was present. But only in two of these five cases, genomes of both HCV and HEV were co-amplified. In seven (four AVH and three FHF) out of 50 (14%) cases, no known viral agent could be detected. Our results suggest that HEV is the most common aetiological agent for both acute viral hepatitis and fulminant hepatic failure and that HCV is a rare cause of acute liver diseases although along with other viruses, evidence of either present or past HCV infection may be present in a substantial number of cases. Furthermore, advanced-stage pregnancy appears to be a potential risk factor for HEV infection and high rate of mortality in women. The study suggests that the method of simultaneous amplification of both HCV and HEV genomes could reduce the time, labour and cost involved in diagnostic work up of acute liver disease patients.