Acute sporadic non-A, non-B hepatitis in India

Discovery of Hepatitis E and Its Impact on Global Health: A Journey of 44 Years about an Incredible Human-Interest Story

The story of the discovery of hepatitis E originated in the late 1970s with my extreme belief that there was a hidden saga in the relationship between jaundice and pregnancy in developing countries and the opportunity for a massive epidemic of viral hepatitis, which hit the Gulmarg Kashmir region in November 1978. Based on data collected from a door-to-door survey, the existence of a new disease, epidemic non-A, non-B hepatitis, caused by a hitherto unknown hepatitis virus, was announced. This news was received by the world community with hype and skepticism. In the early 1980s, the world watched in awe as an extreme example of human self-experimentation led to the identification of VLP. In 1990, a cDNA clone from the virus responsible for epidemic non-A, non-B hepatitis was isolated. Over the years, we traversed three eras of ambiguity, hope, and hype of hepatitis E research and conducted several seminal studies to understand the biology of HEV and manifestations of hepatitis E. Many milestones have been reached on the long and winding road of hepatitis E research to understand the structure, biology, and diversity of the agent, changing the behavior of the pathogen in developed countries, and the discovery of a highly effective vaccine.

Hepatitis E and Pregnancy: An Unholy Alliance Unmasked from Kashmir, India

The adverse relationship between viral hepatitis and pregnancy in developing countries had been interpreted as a reflection of retrospectively biased hospital-based data collection by the West. However, the discovery of hepatitis E virus (HEV) as the etiological agent of an epidemic of non-A, non-B hepatitis in Kashmir, and the documenting of the increased incidence and severity of hepatitis E in pregnancy via a house-to-house survey, unmasked this unholy alliance. In the Hepeviridae family, HEV-genotype (gt)1 from genus Orthohepevirus A has a unique open reading frame (ORF)4-encoded protein which enhances viral polymerase activity and viral replication. The epidemics caused by HEV-gt1, but not any other Orthohepevirus A genotype, show an adverse relationship with pregnancy in humans. The pathogenesis of the association is complex and at present not well understood. Possibly multiple factors play a role in causing severe liver disease in the pregnant women including infection and damage to the maternal-fetal interface by HEV-gt1; vertical transmission of HEV to fetus causing severe fetal/neonatal hepatitis; and combined viral and hormone related immune dysfunction of diverse nature in the pregnant women, promoting viral replication. Management is multidisciplinary and needs a close watch for the development and management of acute liver failure. (ALF). Preliminary data suggest beneficial maternal outcomes by early termination of pregnancy in patients with lower grades of encephalopathy.

The expression patterns of immune response genes in the Peripheral Blood Mononuclear cells of pregnant women presenting with subclinical or clinical HEV infection are different and trimester-dependent: A whole transcriptome analysis

Hepatitis E is an enteric disease highly prevalent in the developing countries. The basis for high mortality among pregnant hepatitis E patients remains unclear. Importantly, a large proportion of infected pregnant women present with subclinical infection as well. In order to understand the possible mechanisms influencing clinical presentation of hepatitis E in pregnant women, we explored a system biology approach. For this, PBMCs from various categories were subjected to RNAseq analysis. These included non-pregnant (NPR, acute and convalescent phases) and pregnant (PR, 2^nd and 3^rd trimesters, acute phase and subclinical HEV infections) patients and corresponding healthy controls. The current study deals with immune response genes.

In contrast to exclusive up-regulation of nonspecific, early immune response transcripts in the NPR patients, the PR patients exhibited broader and heightened expression of genes associated with innate as well as adaptive T and B cell responses. The study identified for the first time (1) inverse relationship of immunoglobulin (Ig) genes overexpression and (2) association of differential expression of S100 series genes with disease presentation. The data suggests possible involvement of TLR4 and NOD1 in pregnant patients and alpha defensins in all patient categories suggesting a role in protection. Induction of IFNγ gene was not detected during the acute phase irrespective of pregnancy. Association of response to vitamin D, transcripts related to NK/NKT and regulatory T cells during subclinical infection are noteworthy.

The data obtained here could be correlated with several studies reported earlier in hepatitis E patients suggesting utility of PBMCs as an alternate specimen. The extensive, informative data provided here for the first time should form basis for future studies that will help in understanding pathogenesis of fulminant hepatitis E.

Epidemiology of Genotype 1 and 2 Hepatitis E Virus Infections

Hepatitis E virus (HEV) genotypes 1 and 2 are responsible for the majority of acute viral hepatitis infections in endemic areas in South Asia and sub-Saharan Africa. In addition to frequent sporadic illnesses throughout the year, these viruses often cause large epidemics in association with monsoon rains in Asia or during humanitarian crises in Africa. Clinical hepatitis commonly involves adults more often than young children, with an overall mortality of ∼1%. However, the mortality among pregnant women is often 30% or higher. HEV infection in pregnant women frequently leads to infant mortality or premature delivery. Hepatitis E is an important, yet largely neglected, global public health problem.

Indian National Association for the Study of the Liver-Federation of Obstetric and Gynaecological Societies of India Position Statement on Management of Liver Diseases in Pregnancy

Liver diseases occurring during pregnancy can be serious and can progress rapidly, affecting outcomes for both the mother and fetus. They are a common cause of concern to an obstetrician and an important reason for referral to a hepatologist, gastroenterologist, or physician. Liver diseases during pregnancy can be divided into disorders unique to pregnancy, those coincidental with pregnancy, and preexisting liver diseases exacerbated by pregnancy. A rapid differential diagnosis between liver diseases related or unrelated to pregnancy is required so that specialist and urgent management of these conditions can be carried out. Specific Indian guidelines for the management of these patients are lacking. The Indian National Association for the Study of the Liver (INASL) in association with the Federation of Obstetric and Gynaecological Societies of India (FOGSI) had set up a taskforce for development of consensus guidelines for management of patients with liver diseases during pregnancy, relevant to India. For development of these guidelines, a two-day roundtable meeting was held on 26-27 May 2018 in New Delhi, to discuss, debate, and finalize the consensus statements. Only those statements that were unanimously approved by most members of the taskforce were accepted. The primary objective of this review is to present the consensus statements approved jointly by the INASL and FOGSI for diagnosing and managing pregnant women with liver diseases. This article provides an overview of liver diseases occurring in pregnancy, an update on the key mechanisms involved in its pathogenesis, and the recommended treatment options.

Toward Mucosal DNA Delivery: Structural Modularity in Vaccine Platform Design

Hepatitis E virus is a small, nonenveloped RNA virus that is feco-orally transmitted and causes viral hepatitis in humans. A virus-like particle (VLP) expressed and purified from insect cells shares several properties with the virion but can be manipulated quite extensively through genetic engineering or chemical modification. This has exciting implications for exploiting the VLP as a nanocarrier for foreign epitopes or encapsulated deliverables. By exhaustively studying the structure of the virus, we have been successful in designing and synthesizing chimerized VLPs that either carry foreign epitopes, are capable of encapsulating foreign DNA, or both. Preliminary studies show that these particles provide specific and strong immune responses in mice when orally delivered. To appreciate the full potential of HEV VLPs, we have highlighted various properties of the virus with a strong focus on the VLP structure and the key features that make it suitable for oral delivery.

Transmission of Hepatitis E Virus in Developing Countries

Hepatitis E virus (HEV), an RNA virus of the Hepeviridae family, has marked heterogeneity. While all five HEV genotypes can cause human infections, genotypes HEV-1 and -2 infect humans alone, genotypes HEV-3 and -4 primarily infect pigs, boars and deer, and genotype HEV-7 primarily infects dromedaries. The global distribution of HEV has distinct epidemiological patterns based on ecology and socioeconomic factors. In resource-poor countries, disease presents as large-scale waterborne epidemics, and few epidemics have spread through person-to-person contact; however, endemic diseases within these countries can potentially spread through person-to-person contact or fecally contaminated water and foods. Vertical transmission of HEV from infected mother to fetus causes high fetal and perinatal mortality. Other means of transmission, such as zoonotic transmission, can fluctuate depending upon the region and strain of the virus. For instance, zoonotic transmission can sometimes play an insignificant role in human infections, such as in India, where human and pig HEV infections are unrelated. However, recently China and Southeast Asia have experienced a zoonotic spread of HEV-4 from pigs to humans and this has become the dominant mode of transmission of hepatitis E in eastern China. Zoonotic HEV infections in humans occur by eating undercooked pig flesh, raw liver, and sausages; through vocational contact; or via pig slurry, which leads to environmental contamination of agricultural products and seafood. Lastly, blood transfusion-associated HEV infections occur in many countries and screening of donors for HEV RNA is currently under serious consideration. To summarize, HEV genotypes 1 and 2 cause epidemic and endemic diseases in resource poor countries, primarily spreading through contaminated drinking water. HEV genotypes 3 and 4 on the other hand, cause autochthonous infections in developed, and many developing countries, by means of a unique zoonotic food-borne transmission.

Hepatitis E: an emerging global disease - from discovery towards control and cure

Hepatitis E is a systemic disease affecting the liver predominantly and caused by infection with the hepatitis E virus (HEV). HEV has marked genetic heterogeneity and is known to infect several animal species including pigs, boar, deer, mongoose, rabbit, camel, chicken, rats, ferret, bats and cutthroat trout. HEV is the sole member of the family Hepeviridae and has been divided into 2 genera: Orthohepevirus (mammalian and avian HEV) and Piscihepevirus (trout HEV). Human HEVs included within the genus Orthohepevirus are designated Orthohepevirus A (isolates from human, pig, wild boar, deer, mongoose, rabbit and camel). Hepatitis E is an important public health concern, and an estimated one-third of the world population has been infected with HEV. In recent years, autochthonous hepatitis E is recognized as a clinical problem in industrialized countries. Several animal species especially domestic swine, wild boar and wild deer are reservoirs of genotype HEV-3 and HEV-4 in these countries. Human infections occur through intake of uncooked or undercooked meat of the infected animals and pig livers or sausages made from these livers and sold in supermarkets. HEV can be transmitted through blood and blood component transfusions, and donor screening for HEV is under serious consideration. Chronic hepatitis E resulting in rapidly progressive liver cirrhosis and end-stage liver disease has been described in organ transplant patients. Ribavirin monotherapy attains sustained virological response in most patients. HEV 239 vaccine has been marketed in China and its long-term efficacy over four and a half years reported.

Epidemiological investigation of the jaundice outbreak in lalkuan, nainital district, uttarakhand

BACKGROUND

In March 2013, cases of acute hepatitis were reported from Lalkuan, Nainital district. We investigated the outbreak to identify the source of infection and to facilitate control measures.

OBJECTIVES

To study the distribution of hepatitis cases, to find the source of infection, and to initiate the control measures in the affected area.

MATERIALS AND METHODS

WE DEFINED A CASE OF ACUTE HEPATITIS AS THOSE CASES THAT HAD JAUNDICE WITH AT LEAST ONE OF THE FOLLOWING SYMPTOMS: Dark urine, fever, pain in abdomen, vomiting, and loss of appetite in the affected area between January and March 2013. Door-to-door survey was carried out. Thirteen blood samples were randomly collected from jaundice cases for immunoglobulin M (IgM) antibody for hepatitis A virus (HAV) and hepatitis E virus (HEV). Water samples were collected to test residual chlorine.

RESULTS

Total 2,785 individuals were surveyed; of which 240 were suffering from acute viral hepatitis (attack rate (AR) = 8.61%). Out of 13 serum samples, 10 were found positive for HEV IgM antibodies and three cases had IgM antibodies for both HAV and HEV, which confirmed a hepatitis E outbreak. The difference in attack rate of hepatitis of both the sexes was statistically significant (P < 0.001). The attack rate was significantly higher in age groups >12 years of age (P < 0.001). Environmental investigation also confirmed the sewage contamination of drinking water in the distribution system. The attack rate was much higher (29.4%) among those who were exposed to the leaking pipeline than the nonexposed (χ(2) = 574.26, P < 0.01).

CONCLUSION

HEV was confirmed as the major etiological agent in this outbreak that was transmitted by contaminated drinking water. The recognition of early warning signals, timely investigation, and application of specific control measures can contain the outbreak.

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.

A brief history of hepatitis milestones

Hepatitis has been a major plague of mankind. The history of the discovery of causative viruses is one of the most fascinating scientific adventures of this half century. Individualization of several types of hepatitis only emerged after world war two. Their identification has been associated with milestones which revolutionized medicine and public health. The discovery of HBV brought the first ever vaccine not prepared by tissue culture but initially directly from plasma and soon the first vaccine produced by genetic engineering. HBV vaccine proved to be the first "anti-cancer" vaccine by preventing hepatocellular carcinoma and practically eradicating it from childhood in Taiwan. Successful vaccines became also available for HAV and more recently HEV. The discovery of HCV in 1989 opened a new era since it was the first virus was identified by a direct molecular approach. Two billion people are infected with HBV and 350 million are chronic carriers of the virus. The extraordinary effectiveness of HBV vaccination was best illustrated in Taiwan and Singapore where in less than 2 decades HBs Ag carriers dropped from 9,1% to 2,7% and HCC from 27% to 17%. Successful development of nucleos(t)ides analogs make it now possible to fully control disease progression with a daily pill long term therapy. The progress in HCV therapy has been even more spectacular and successful treatment jumped from 6 % with interferon alone in 1986 to more than 80% in 2013 with triple combination therapies. Remarkably chronic hepatitis C is the only chronic disease which is curable. It will be soon possible to eradicate HCV infection with, an all oral, daily single pill (containing several molecules) for 3 to 6 months which will cure over 90% of patients. This unprecedented therapeutic victory benefiting hundred millions of people matches the triumphs over small pox, polio and tuberculosis. The next 10 years should undoubtedly witness cure or full control over all forms of acute and chronic hepatitis.

Fetal and neonatal health consequences of vertically transmitted hepatitis E virus infection

Hepatitis E virus (HEV) infections lead to tens of thousands of deaths annually, mostly in developing countries. Hepatitis E poses a significant threat to the health of expectant mothers, a well-noted epidemiologic feature of the disease, but the contribution of vertically transmitted HEV infection to fetal and neonatal morbidity and mortality has received limited attention. Evidence assembled to date suggests that mother-to-child HEV transmission may be frequent and deleterious to the fetus and newborn in pregnancies affected by hepatitis E. Additional work is required to resolve key questions. (1) What risks do subclinical maternal HEV infections and infections early in pregnancy pose to fetal health and development? (2) Does vertical transmission occur during labor and/or breastfeeding and contribute appreciably to neonatal morbidity and mortality? (3) How do treatment decisions for severely ill mothers affect fetal and neonatal outcomes? (4) Can maternal vaccination effectively prevent vertical transmission of HEV?

Hepatitis e and acute liver failure in pregnancy

Hepatitis E virus is a positive strand RNA virus with three open reading frames which is transmitted predominantly through the fecal contamination of water and food. It is the most common cause of acute liver failure in endemic areas. Pregnant women especially from the Indian subcontinent and Africa are at increased risk of contracting acute HEV infection as well as developing severe complications including ALF. Transmission of HEV occurs from mother to unborn child. Both maternal and fetal complications may occur, including abortion, fetal demise, preterm labor and maternal or neonatal death. The precise reasons for increased susceptibility to HEV infection during pregnancy and associated severe disease are still an enigma. Management is supportive and termination of pregnancy is not recommended as a general rule. Prevention of infection is of vital importance, as availability of clean drinking water can reduce the burden of this disease in the community. There is a need for future research to focus on prevention of ALF in pregnancy and to study the disease pathogenesis, which is not explicitly understood at present. The availability of a vaccine may alter the natural course of the disease in this select population which is at risk.

Hepatitis e: epidemiology and natural history

Hepatitis E is a disease caused by infection with hepatitis E virus (HEV). The virus has four genotypes, named 1 to 4, with one shared serotype. Genotypes 1 and 2 infect only humans, whereas genotypes 3 and 4 primarily infect several mammalian animals, with occasional transmission to humans. Evidence of infection with HEV has been found in most parts of the world, with two distinct epidemiological patterns. In areas with high disease endemicity, primarily developing countries in Asia and Africa, the disease occurs as outbreaks and as sporadic cases of acute hepatitis, and is caused exclusively by infection with genotypes 1 or 2 HEV, which is acquired through fecal-oral route, usually through contamination of water supplies. The disease in these areas occurs most commonly in young adults, and is particularly severe in pregnant women and persons with pre-existing chronic liver disease; chronic infection has not been reported. In areas with lower endemicity, which are mainly developed areas with robust water supply and sanitation systems, occasional sporadic cases of locally-acquired genotype 3 or 4 HEV infection are observed. The affected persons are often elderly and have other coexisting illnesses. The reservoir of infection in these areas is believed to be in animals, such as pigs, wild boar and deer, with zoonotic transmission to humans, possibly through consumption of undercooked meat. Also, in these areas, persistent HEV infection has been well documented among immunosuppressed persons such as organ transplant recipients, and is believed to lead to chronic liver injury, including liver cirrhosis. Further work is needed to better understand the biological basis underlying these widely-differing epidemiological patterns.

Fatal outbreaks of jaundice in pregnancy and the epidemic history of hepatitis E

Space-time clustering of people who fall acutely ill with jaundice, then slip into coma and death, is an alarming phenomenon, more markedly so when the victims are mostly or exclusively pregnant. Documentation of the peculiar, fatal predisposition of pregnant women during outbreaks of jaundice identifies hepatitis E and enables construction of its epidemic history. Between the last decade of the 18th century and the early decades of the 20th century, hepatitis E-like outbreaks were reported mainly from Western Europe and several of its colonies. During the latter half of the 20th century, reports of these epidemics, including those that became serologically confirmed as hepatitis E, emanated from, first, the eastern and southern Mediterranean littoral and, thereafter, Southern and Central Asia, Eastern Europe, and the rest of Africa. The dispersal has been accompanied by a trend towards more frequent and larger-scale occurrences. Epidemic and endemic hepatitis E still beset people inhabiting Asia and Africa, especially pregnant women and their fetuses and infants. Their relief necessitates not only accelerated access to potable water and sanitation but also vaccination against hepatitis E.

Discovery of hepatitis E: the epidemic non-A, non-B hepatitis 30 years down the memory lane

Hepatitis E was first recognised during an epidemic of hepatitis, which occurred in Kashmir Valley in 1978. The epidemic involved an estimated 52,000 cases of icteric hepatitis with 1700 deaths. The disease had unique clinical and epidemiological features. The epidemic was water-borne with highly compressed epidemic curve. Following the epidemic, secondary waves of hepatitis did not occur. Clinical profile was characterized by cholestasis in around 20% of patients. The disease predominantly occurred in young adults. There was increased incidence and severity of the disease in pregnant women. A subset of patients had distinctive liver histology with bile plugs in the canaliculi and formation of pseudo-ductules by hepatocytes around the bile plugs. All surviving patients had self limiting disease. Sera lacked serological markers of acute hepatitis A and hepatitis B. Based on these data, the possibility of another human hepatitis virus distinct from post-transfusion non-A, non-B hepatitis was postulated. Balayan et al. (1983) successfully transmitted the disease into himself by oral administration of pooled stool extracts of 9 patients from a non-A, non-B hepatitis outbreak which had occurred in a Soviet military camp located in Afghanistan. Reyes et al. (1990) cloned and sequenced hepatitis E virus genome. Over the years, hepatitis E was identified as a major health problem in developing countries with unsafe water supplies and poor sanitary disposal. Data from sero-surveys forced re-evaluation of the epidemiology of hepatitis E and gave an indirect indication to vocationally acquired HEV infections in industrialized countries. Soon, autochthonous hepatitis E was recognised as a clinical problem in such countries. Several animal species especially domestic swine, wild boar and wild deer were found to be reservoirs of hepatitis E virus genotype 3 & 4 in these countries. Human infections occur through intake of uncooked or undercooked meat of the infected animals and pig livers or sausages made from these livers and sold in supermarkets. Chronic hepatitis E resulting in rapidly progressive liver cirrhosis and end stage liver disease was described in organ transplant patients and those with other immunodeficiency states from many European countries. Two recombinant hepatitis E virus vaccines have successfully undergone phase 3 trials.

Clinical presentation of hepatitis E

Hepatitis E is a form of acute hepatitis, which is caused by infection with hepatitis E virus. The infection is transmitted primarily through fecal-oral route and the disease is highly endemic in several developing countries with opportunities for contamination of drinking water. In these areas with high endemicity, it occurs as outbreaks and as sporadic cases of acute hepatitis. The illness often resembles that associated with other hepatotropic viruses and is usually self-limiting; in some cases, the disease progresses to acute liver failure. The infection is particularly severe in pregnant women. Patients with chronic liver disease and superimposed HEV infection can present with severe liver injury, the so-called acute-on-chronic liver failure. In recent years, occasional sporadic cases with locally acquired hepatitis E have been reported from several developed countries in Europe, United States, and Asia. In these areas, in addition to acute hepatitis similar to that seen in highly endemic areas, chronic hepatitis E has been reported among immunosuppressed persons, in particular solid organ transplant recipients. HEV-infected mothers can transmit the infection to foetus, leading to premature birth, increased fetal loss and hypoglycaemia, hypothermia, and anicteric or icteric acute hepatitis in the newborns. Occasional cases with atypical non-hepatic manifestations, such as acute pancreatitis, hematological abnormalities, autoimmune phenomena, and neurological syndromes have been reported from both hyperendemic and non-endemic regions. The pathogenesis of these manifestations remains unclear.

Hepatitis E: Historical, contemporary and future perspectives

Hepatitis E was suspected for the first time in 1980 during a waterborne epidemic of acute hepatitis in Kashmir, India. In the 30 years since then, a small virus with single-stranded RNA genome has been identified as the cause of this disease and named as hepatitis E virus (HEV). The virus has four genotypes; of these, genotypes 1 and 2 are known to infect only humans, whereas genotypes 3 and 4 primarily infect other mammals, particularly pigs, but occasionally cause human disease. In highly-endemic areas, the disease occurs in epidemic and sporadic forms, caused mainly by infection with genotype 1 or 2 virus, acquired through the fecal-oral route, usually through contaminated water supplies. The disease is characterized by particularly severe course and high mortality among pregnant women. In persons with pre-existing chronic liver disease, HEV superinfection can present as acute-on-chronic liver disease. In low-endemic regions, sporadic cases of locally-acquired HEV infection are reported; these are caused mainly by genotype 3 or 4 HEV acquired possibly through zoonotic transmission from pigs, wild boars or deer. In these areas, chronic infection with genotype 3 HEV, which may progress to liver cirrhosis, has been reported among immunosuppressed persons. Two subunit vaccines containing recombinant truncated capsid proteins of HEV have been shown to be highly effective in preventing the disease; however, these are not yet commercially available. These vaccines should be of particular use in groups that are at high risk of HEV infection and/or of poor outcome.

Epidemiology of hepatitis E: current status

Hepatitis E, caused by infection with hepatitis E virus (HEV), is a common cause of acute hepatitis in areas with poor sanitation. The virus has four genotypes with one serotype: genotypes 1 and 2 exclusively infect humans, whereas genotypes 3 and 4 also infect other animals, particularly pigs. In endemic areas, both large outbreaks of acute hepatitis as well as sporadic cases occur frequently. These cases are usually due to genotype 1 or 2 HEV and are predominantly caused by fecal-oral transmission, usually through contamination of drinking water; contaminated food, materno-fetal (vertical spread) and parenteral routes are less common modes of infection. The acute hepatitis caused by this virus has the highest attack rates in young adults and the disease is particularly severe among pregnant women. HEV superinfection can occur among persons with pre-existing chronic liver disease. In non-endemic regions, locally acquired disease was believed to be extremely uncommon. However, in recent years, an increasing number of cases, due mostly due to genotype 3 or 4 HEV, have been recognized. These are more often elderly men who have other coexisting illnesses, and appear to be related to zoonotic transmission from pigs, wild boars and deer, either food-borne or otherwise. Also, chronic infection with genotype 3 HEV has been reported among immunosuppressed persons in these regions. A subunit vaccine has been shown to be effective in preventing clinical disease, but is not yet commercially available. Our understanding of hepatitis E epidemiology has undergone major changes in recent years, and the future may hold even more surprises.

Hepatitis E: an emerging awareness of an old disease

Although hepatitis E was recognized as a new disease in 1980, the virus was first visualized in 1983 and its genome was cloned and characterized in 1991, the disease is probably ancient but not recognized until modern times. Hepatitis E is the most important or the second most important cause of acute clinical hepatitis in adults throughout Asia, the Middle East and Africa. In contrast, hepatitis E is rare in industrialized countries, but antibody (anti-HEV) is found worldwide. HEV is a small round RNA-containing virus that is the only member of the genus Hepevirus in the family Hepeviridae. Although similar to hepatitis A virus in appearance, there are significant differences between the two viruses. Hepatitis E is principally the result of a water-borne infection in developing countries and is thought to be spread zoonotically (principally from swine) in industrialized countries. Because diagnostic tests vary greatly in specificity, sensitivity and availability, hepatitis E is probably underdiagnosed. At present, control depends upon improved hygiene; a highly efficacious vaccine has been developed and tested, but it is not presently available.

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.

Characterization of hepatitis E virus from outbreak and sporadic cases in Turkmenistan

Large outbreaks and sporadic cases of hepatitis E have been reported in Central Asia. We assessed the genetic relatedness of hepatitis E virus (HEV) strains from outbreak and sporadic cases in Turkmenistan. Specimens from outbreak and sporadic cases of acute hepatitis non-A, non-B were tested by reverse transcription (RT)-polymerase chain reaction (PCR) to identify the presence of HEV RNA; nucleotide sequences were analyzed. HEV RNA was detected from 23/156 (15%) outbreak cases and 2/23 (9%) sporadic cases. The HEV outbreak isolates represented 14 unique sequences with genetic distances varying between 0.3% and 8.6%, 12 of which were closely related, with distances between 0.3% and 5.6%. Two unique sequences from outbreak cases 32 and 42 were closely related (99.7%) and shared 91.8-93.4% of sequence with the other 12 strains. The two strains were closely related to the previously published isolates from Burma (99.7-100%) and India-Madras (95.7-96.1%). The two 1994 sporadic HEV strains were 97.4% distinct, wile revealing 91.4-94.1% homology to 1985 strains, and 94.4-94.7% to HEV from the neighboring China and Pakistan. Genetic diversity of HEV that caused the hepatitis E outbreak in Turkmenistan in 1985 suggests heterogeneity of viral sources. Sporadic hepatitis E that occurred in 1994 was caused by viral strains genetically distinct from those causing the outbreak in 1985, yet closely related to HEV from neighboring countries. The study suggests that circulation of a broad variety of strains of HEV may occur in Central Asia, regardless of international borders, presenting a significant public health threat to the population of the region.

Viral hepatitis and the surgeon

BACKGROUND

Viral hepatitis is an infection of the liver caused by one or more of six known (HAV-HGV) hepatotropic viruses. It is a common problem among health care workers and their patients. Surgeons are at particular risk of both acquiring and transmitting some of these viruses from and to their patients. Unfortunately, specific immunoprophylaxis for viral hepatitis is presently limited to protecting against the spread of hepatitis A and B viral infections, leaving a high degree of vigilance and careful surgical technique as the only means available to prevent the transmission of other viruses relative to the surgeon. The purpose of this paper is to review the various forms of viral hepatitis including the nature of the virus, serologic testing, clinical features, epidemiology (with specific reference to those issues that arise in surgical practice), treatment and prevention.

Detection of immunoglobulin M antibodies to hepatitis E virus by class capture enzyme immunoassay

The measurement of antibodies to hepatitis E virus (anti-HEV) has been essential for understanding the epidemiology of hepatitis E. Studies to determine the prevalence of HEV infections require a reliable serologic assay that is sensitive and specific. It is also important to distinguish the acute from the convalescent phase of an infection; this usually requires the detection of the immunoglobulin M (IgM) class of antibody. Few enzyme immunoassays (EIAs) that measure IgM anti-HEV have been described, and most have utilized the sandwich method. The present study describes an EIA that detects IgM anti-HEV by antibody class capture methodology. The assay was validated by using serum and/or plasma panels from experimentally infected nonhuman primates. It was used to demonstrate an anamnestic response and the reappearance of IgM anti-HEV in a chimpanzee experimentally challenged with HEV at two different times 45 months apart. The class capture method was more sensitive than the sandwich EIA when used to test clinical samples from two hepatitis E epidemics in Pakistan; it also had the advantage of distinguishing IgM anti-HEV in the presence of high titers of IgG anti-HEV.

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.

Aetiology, clinical course and outcome of sporadic acute viral hepatitis in pregnancy

Hepatitis E causes large-scale epidemics in endemic areas. The disease, during epidemics, has increased incidence and severity in pregnant women. Sporadic acute viral hepatitis (AVH) is common in endemic areas. The relationship of sporadic AVH and pregnancy has not been well studied. Over a 3-year period we prospectively studied 76 pregnant women and 337 non-pregnant women of childbearing age with sporadic acute viral hepatitis for aetiology, clinical course and outcome of disease. The aetiology in sporadic AVH was hepatitis A virus (HAV) in six (1.5%), hepatitis B virus (HBV) in 62 (15%), hepatitis C virus (HCV) in seven (1.7%), hepatitis D virus (HDV) co-infection in six (1.5%), hepatitis E virus (HEV) in 205 (49.6%), and hepatitis non-A-to-E (HNAE) in 127 (30.7%). Sixty-five (85.5%) pregnant women and 140 (41.5%) nonpregnant women had hepatitis E. The proportion of pregnant women was 31.7% in HEV group and 5.3% in non-HEV group [P < 0.001; OR=8.3 (95%C1 4.2-16.3)]. The prevalence of HEV in pregnant women in first trimester (76.9%), second trimester (88.9%), third trimester (83.8%) and puerperium (100%) did not differ significantly (P=0.09). Forty-seven (61.8%) of the 76 pregnant women developed fulminant hepatic failure (FHF), 69.2% in HEV group and 10% in non-HEV group (P < 0.001). Thirty-four (10.1%) nonpregnant women developed fulminant hepatic failure, 10% in HEV group and 9.7% in non-HEV group (P=0.86). FHF had occurred in four (40%) of 10 patients with HE in first trimester as against 41 (74.5%) of 55 patients in second trimester and beyond (P=0.015). Amongst the major complications of fulminant hepatic failure, cerebral oedema (53.2%) and disseminated intravascular coagulation (21.3%) occurred more often in pregnant women than in nonpregnant women (29.4% and 2.8%; P=0.03 and 0.016, respectively) while infections occurred more often in nonpregnant women (36.1%) than in pregnant women (10.6%; P=0.003). Fifty (61.7%) patients with FHF died [25 (53.2%) pregnant women and 25 (69.5%) nonpregnant women (P=0.06)]. Cerebral oedema and HEV aetiology were independent variables of survival in patients with FHF. Patients with cerebral oedema had worse prognosis and patients with HEV aetiology had best chances of survival. Hence HEV was the most common cause of sporadic AVH in this endemic area. High proportion of pregnant women and increased severity of disease in pregnancy were limited to patients with hepatitis E. Sporadic AVH caused by agents other than HEV did not show any special predilection to or increased severity in pregnancy. FHF in pregnant women caused by HEV was an explosive disease with short pre- encephalopathy period, rapid development of cerebral oedema and high occurrence of disseminated intravascular coagulation and may represent a severe manifestation of a Schwartzmann-like phenomenon.

Role of hepatitis E and other hepatotropic virus in aetiology of sporadic acute viral hepatitis: a hospital based study from urban Delhi

Major hepatotropic virus continues to be an important cause of acute viral hepatitis (AVH) in developing countries like India. While epidemics of AVH have been well studied few serious sporadic cases from developing countries have been reviewed. We studied prospectively 75 cases of sporadic AVH who reported to our hospital and were evaluated for the presence of various hepatotropic viruses. The seroprevalence of IgG anti-HEV antibodies was studied in the general population as a control. We found 53.3% (40/75) of sporadic AVH cases were due to hepatitis E virus while 11% (8/75) were due to hepatitis B virus. Hepatitis C virus was responsible for 8% (6/75) of the sporadic AVH cases and hepatitis A was found in 5% (4/75) of the cases. No causative agent was found in 23% (17/75) of the sporadic AVH cases. The sporadic AVH cases due to HEV were not clinically or biochemically not different from AVH due to other viruses. We found a high prevalence of IgG anti-HEV in 35.6% (178/500) among the general population of urban Delhi. The study suggested that hepatitis E was the most common cause of sporadic AVH in urban Delhi. High seroprevalence of IgG anti-HEV antibodies in the general population and amongst the sporadic AVH cases suggests that it is unlikely to be protective antibody. IgM anti-HEV positive serology is considered diagnostic of acute hepatitis E infection in India, where hepatitis E is endemic.

Viral hepatitis during pregnancy

OBJECTIVE

A great degree of controversy prevails over the existing reports on the severity and outcome of acute viral hepatitis (AVH) during pregnancy. The present study describes the outcome of AVH associated with pregnancy. A correlation was also assessed for gestation period, viral etiology and outcome of AVH.

METHOD

The serum samples of 273 females with viral hepatitis (age group 18--23 years) were included in the study. Among them, 127 females were pregnant and 146 were non-pregnant cases (as a control group). The sera were screened for seromarkers of the hepatitis A virus (HAV) through to the hepatitis E virus (HEV) by the latest available generation ELISA kits. Among the 127 pregnant females, 83 were AVH cases, while 44 were fulminant hepatic failure (FHF) cases. Among the 146 non-pregnant females, 129 were AVH and 17 were FHF cases.

RESULT

Among the AVH pregnant females, 73 (57.5%) had HEV infection. Fifty-eight percent of the HEV infected pregnant females were associated with FHF. Among non-pregnant females HEV was documented in 67 (46%) cases. HBV infection was observed in 19% and 18% of the pregnant and non-pregnant females, respectively. Twenty percent of the pregnant and 33% of the non-pregnant females remained non-reactive for seromarkers of HAV-HEV. The mortality rate was highest (56%) among HEV infected FHF cases during third trimester of pregnancy. The chi(2) test was applied to check the statistical significance for the differences over the prevalence in various groups.

CONCLUSION

In the present study, HEV was found to be the chief etiological agent, associated with higher morbidity and mortality. However, the incidence of HEV in pregnant females was not significantly different from non-pregnant females. The prevalence of HAV, HCV and HDV were very low in the study. An increased incidence of FHF was noted among HEV infected pregnant females, while infection with an agent other than A-E was commonly associated with FHF among non-pregnant females.

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.

The in vitro-synthesized RNA from a cDNA clone of hepatitis E virus is infectious

Hepatitis E virus (HEV) is an important etiological agent of epidemic and sporadic hepatitis, which is endemic to the Indian subcontinent and prevalent in most of the developing parts of the world. The infection is often associated with acute liver failure and high mortality, particularly in pregnant women. In order to develop methods of intervention, it is essential to understand the biology of the virus. This is particularly important as no reliable in vitro culture system is available. We have constructed a cDNA clone encompassing the complete HEV genome from independently characterized subgenomic fragments of an Indian epidemic isolate. Transfection studies were carried out with HepG2 cells using in vitro-transcribed RNA from this full-length HEV cDNA clone. The presence of negative-sense RNA, indicative of viral replication, was demonstrated in the transfected cells by strand-specific reverse transcription-PCR and slot blot hybridization. The viral proteins pORF2 and pORF3 and processed components of the pORF1 polyprotein (putative methyltransferase, helicase, and RNA-dependent RNA polymerase) were identified in the transfected cells by metabolic pulse-labeling with [(35)S]methionine-cysteine, followed by immunoprecipitation with respective antibodies. The expression of viral proteins in the transfected cells was also demonstrated by immunofluorescence microscopy. Viral replication was detected in the transfected cells up to 33 days posttransfection (six passages). The culture supernatant from the transfected cells was able to produce HEV infection in a rhesus monkey (Macaca mulatta) following intravenous injection, indicating the generation of viable HEV particles following transfection of cells with in vitro-synthesized genomic RNA. This transient cell culture model using in vitro-transcribed RNA should facilitate our understanding of HEV biology.

Hepatitis E virus in Cuba

The hepatitis E virus (HEV) has a global distribution and is known to have caused large waterborne epidemics of icteric hepatitis. The transmission is primarily fecal-oral. Some reports have suggested parenteral transmission of HEV from its association to hepatitis B or hepatitis C infection, or due to the development of hepatitis E after blood transfusion. Though most of the developing countries in Asia and Africa have been shown to be endemic for HEV infection, studies in the Latin American countries have been limited to Mexico, Brazil and Venezuela. We have developed an enzyme immunoassay (EIA) for IgM and IgG antibodies to a recombinant protein containing antigenic epitopes of the ORF3 region of the HEV. This system, as well as a commercial kit that includes ORF2 and ORF3 antigenic epitopes, were used to study the prevalence of anti-HEV antibodies in a sample of Cuban blood donors, acute hepatitis cases and individuals subjected to plasmapheresis. The incidence of anti-HEV IgM was compared with other viral hepatitis markers. Our findings suggest that infections due to HEV are an important viral cause of sporadic hepatitis in Cuba, and that HEV is endemic to this region of the world.

Role of hepatitis E and other hepatotropic virus in aetiology of sporadic acute viral hepatitis: a hospital based study from urban Delhi

Major hepatotropic virus continues to be an important cause of acute viral hepatitis (AVH) in developing countries like India. While epidemics of AVH have been well studied few serious sporadic cases from developing countries have been reviewed. We studied prospectively 75 cases of sporadic AVH who reported to our hospital and were evaluated for the presence of various hepatotropic viruses. The seroprevalence of IgG anti-HEV antibodies was studied in the general population as a control. We found 53.3% (40/75) of sporadic AVH cases were due to hepatitis E virus while 11% (8/75) were due to hepatitis B virus. Hepatitis C virus was responsible for 8% (6/75) of the sporadic AVH cases and hepatitis A was found in 5% (4/75) of the cases. No causative agent was found in 23% (17/75) of the sporadic AVH cases. The sporadic AVH cases due to HEV were not clinically or biochemically not different from AVH due to other viruses. We found a high prevalence of IgG anti-HEV in 35.6% (178/500) among the general population of urban Delhi. The study suggested that hepatitis E was the most common cause of sporadic AVH in urban Delhi. High seroprevalence of IgG anti-HEV antibodies in the general population and amongst the sporadic AVH cases suggests that it is unlikely to be protective antibody. IgM anti-HEV positive serology is considered diagnostic of acute hepatitis E infection in India, where hepatitis E is endemic.

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.

Shift of hepatitis E virus RNA from hepatocytes to biliary epithelial cells during acute infection of rhesus monkey

Hepatitis E virus (HEV) has been considered to be the major cause of enterically transmitted non-A, non-B hepatitis in developing countries. However, little is known about viral replication and localization in the liver. The aim of this study was to examine the distribution of HEV-infected cells in experimentally infected animals. Seven captured wild rhesus monkeys were inoculated intravenously with faecal extract derived from a Myanmar strain of HEV. Animals were killed at different time-points of clinical illness: during early infection, during prehepatitis with viral-like particles in bile, during acute hepatitis and during convalescence. Intrahepatic localization of HEV was analysed using non-isotopic thymine dimer in situ hybridization (NITDISH). Both plus and minus strands of HEV RNA were found in hepatocytes during the early infection period. Staining in the submembranous cytoplasmic region of hepatocytes was observed. In the prehepatitis period, both plus and minus strand HEV RNAs appeared in the canalicular side of isolated bile epithelial cells. Subsequently, HEV RNA became universally distributed in the cytoplasm of medium-size bile epithelial cells. After recovery, HEV RNA disappeared.

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.

Hepatitis E in South Africa: evidence for sporadic spread and increased seroprevalence in rural areas

Hepatitis E virus (HEV) is a major cause of non-A, non-B hepatitis in developing countries. Factors influencing sporadic spread of hepatitis E are unclear. We examined anti-HEV seroprevalence and demographic data from 407 urban and 360 rural black South African adults living in formal housing, squatter camps, or mud huts. Anti-HEV sero-prevalence ranged from 5.8% to 19.1% (mean 10.7%) in the different regions. Mean urban and rural rates were 6.6% and 15.3%, respectively (P = 0.0001). Rural mud hut dwellers, using unchlorinated river water, were at greater risk (17.4%) than rural villagers (5.3%; P = 0.008). A linear relation was found between seroprevalence and age, suggesting sporadic spread. The high prevalence in mud hut dwellers suggests that contaminated water plays a major role in HEV spread in South Africa. Routine chlorination or boiling of river drinking water before consumption may reduce HEV infection.

Prevalence of hepatitis E virus infection in Thailand

Hepatitis E, also known as epidemic, non-A, non-B hepatitis, is an acute, enteric, infectious disease. The disease is usually mild, except in pregnant women, who suffer a high fatality rate from fulminant hepatic failure. Information on the disease in Thailand is limited. The prevalence of antibodies to the aetiological agent, hepatitis E virus (HEV), was therefore studied, in various groups of subjects from several regions of this country, using commercial ELISA for anti-HEV IgG and IgM. The prevalence of anti-HEV IgG, which was 9%-22% in the adult subjects (blood donors, pregnant women, patients with acute hepatitis and cases seen during an outbreak of hepatitis), increased with age. It was relatively low in children and adolescents from Bangkok (3.6%) and in children from the north-east (1.8%-6.2%) and south (2.3%) of the country. Five (7%) of the 68 patients with acute viral hepatitis who were tested for anti-HEV IgM were found positive. Although these five cases had jaundice (four cases), diarrhoea (three) and/or dark urine (at least four cases), all of these clinical signs were self-limiting and had no sequelae. Given the apparently high prevalence of HEV infection in young adults in Thailand, control measures, including provision of clean water supplies and better personal sanitation and food hygiene, should be implemented to prevent an epidemic of the disease.

Purification of a baculovirus-expressed hepatitis E virus structural protein and utility in an enzyme-linked immunosorbent assay

We report on the purification of the full-length structural protein encoded by open reading frame 2 (ORF-2) of hepatitis E virus. The ORF-2 protein, expressed in Sf9 cells by using a recombinant baculovirus vector system, was successfully purified to homogeneity. Gel electrophoresis of the purified ORF-2 protein showed a single polypeptide of 75 kDa by Coomassie blue staining and by Western blot (immunoblot) analysis. We demonstrated that the partially purified ORF-2 protein could be used successfully in a sensitive and specific enzyme-linked immunosorbent assay for the detection of antibodies to hepatitis E virus.

An Indian strain of hepatitis E virus (HEV): cloning, sequence, and expression of structural region and antibody responses in sera from individuals from an area of high-level HEV endemicity

Hepatitis E virus (HEV) is responsible for a majority of sporadic and epidemic viral hepatitides in India and other developing countries. Even though the genomes of four geographically distinct strains of HEV have been cloned and sequenced, the Indian strain of HEV remains largely uncharacterized. We have cloned and sequenced about 2.2 kb of the HEV genome constituting the structural region from an Indian strain of HEV. The nucleotide and amino acid sequences show a high degree of conservation with sequences from other HEV strains. Open reading frames (ORF) 2 and 3 were expressed in Escherichia coli as N-terminal hexahistidine epitope fusions. The purified proteins were then used in an immunoblot assay to evaluate the antibody status in sera from individuals from an area of high-level HEV endemicity. The anti-ORF2 antibodies were found to be nonspecific and could not be correlated to clinical disease. The immunoglobulin M anti-ORF3 was found to be specific for the presence of acute disease. The implications of these findings in HEV diagnosis and vaccine development are discussed.

Detection of hepatitis E virus genome and gene products in two patients with fulminant hepatitis E

Non-isotopic in situ hybridization (digoxigenin-labeled probe directed towards hepatitis E virus ORF1) and immunohistochemistry (against hepatitis E virus ORF2 and ORF3) were applied to detect hepatitis E virus genome and gene product in the liver tissue of two patients with fulminant hepatitis E seropositive for hepatitis E virus RNA. Both hepatitis E virus RNA and hepatitis E virus antigens were detected exclusively in the cytoplasm of hepatocytes and not detected in other cell types. In both patients, more than 50% of the hepatocytes were positive for both hepatitis E virus RNA and hepatitis E virus antigens, most of which showed degenerative changes. This is consistent with the histological appearance of marked loss of hepatocytes with acinar collapse. Interestingly, denaturation of the RNA before in situ hybridization was found to enhance hepatitis E virus RNA detection. We conclude that: (1) hepatitis E virus RNA and hepatitis E virus antigens can be demonstrated in the liver in hepatitis E virus-related fulminant hepatitic failure, (2) hepatitis E virus is hepatocyte-tropic within the liver, (3) cytoplasmic localization of hepatitis E virus RNA and hepatitis E virus antigens is consistent with cytoplasmic replication, and (4) the presence of degenerative changes in hepatitis E virus positive cells, together with the histological appearance of hepatocyte loss in the absence of significant inflammatory infiltrate, suggests that hepatitis E virus-related fulminant hepatitic failure is mediated by a cytopathic mechanism.

Isolation of the novel agent from human stool samples that is associated with sporadic non-A, non-B hepatitis

The agent(s) responsible for sporadic non-A, non-B hepatitis in humans was serially transmitted in rhesus monkeys by intravenous inoculation of the stool extract from a patient. A novel agent called HFV (hepatitis French [origin] virus) was present as 27- to 37-nm particles in the infectious stool extract. Hepatopathic lesions were noticed in infected monkeys during the acute phase of illness. The purified viral 27- to 37-nm particles consist of a double-stranded DNA of approximately 20 kb and are detected in infected monkey liver. Analysis of cell culture detects the approximately 20-kb-long viral DNA in stool samples from infected monkeys and sporadic enteric non-A, non-B hepatitis patients. Furthermore, the 27- to 37-nm viral particles were able to protect monkeys challenged with infectious stool extract. Our results indicate that 27- to 37-nm virus like particles are responsible for sporadic non-A, non-B hepatitis in rhesus monkeys.