Outbreak of acute viral hepatitis due to hepatitis E virus in Hyderabad

PURPOSE: A waterborne outbreak of viral hepatitis occurred in the old city of Hyderabad from March through August 2005. An attempt was made to study the outbreak clinically, serologically, and etiologically. METHODS: Five hundred and forty-six clinically and biochemically documented cases were screened for the hepatotropic viral markers, hepatitis A, B, C, and E by the ELISA method. Their demographic characteristics and outcomes were analyzed. Point source contamination of the water supply with sewerage was identified. RESULT: Our data confirms hepatitis E as the major cause of the outbreak (78.57%). Occasionally, mixed infection of HEV-HAV (5.31%) or HEV-HBV (0.91%) was detected in the present series of acute viral hepatitis. CONCLUSIONS: HEV was confirmed as the major etiological agent in this outbreak that was transmitted by contaminated drinking water. The study highlights the importance of screening for both enterically transmitted hepatotropic viral markers as well as the parenterally transmitted hepatotropic viral markers during outbreaks of acute viral hepatitis.     

Early viral kinetics and treatment outcome in combination of high-dose interferon induction vs. pegylated interferon plus ribavirin for naive patients infected with hepatitis C virus of genotype 1b and high viral load

An investigation was carried out to determine whether early viral monitoring could predict efficiently the virological response to combination therapy of two different regimens in treatment-naive chronic hepatitis C patients infected with genotype 1b with high baseline viral load. Patients were randomly assigned to receive interferon (IFN) alpha-2b induction (6 MU daily for 2 weeks) followed by 6 MU thrice weekly for 46 weeks (IFN/R group; n = 20), or pegylated IFN alpha-2b (1.5 microg/kg) weekly for 48 weeks (PEG/R group; n = 28), in combination with ribavirin (600-1,000 mg daily). Serum HCV RNA was quantitated at 0, 6, 12, 24, and 48 hr post-dose, weekly during the first 4 weeks, and thereafter viral kinetics were assessed every 4 weeks. The sustained virological response rates in the IFN/R and PEG/R groups were 40% (8/20) and 43% (12/28), respectively. The non-virological response rates were 40% (8/20) and 39% (11/28), respectively. The cumulative virological response rates were similar in both groups. Multivariate analyses identified no independent baseline variables linked to sustained virological or non-virological response. Early log viral load changes from baseline in both groups were significantly greater at all time-points after 24 hr in virological response patients than in non-virological response patients (P < 0.001 for all). On the receiver operating characteristics curves for prediction of non-virological response, the area under the curves (0.951-1.000), sensitivity (90%-100%), and negative predictive value (96%- 100%) were similar at any time-points after 24 hr. For prediction of sustained virological response, sensitivity of 80% with 86% negative predictive value was observed for negative HCV RNA at week 12, with the highest area under the curves value of 0.919. The results suggest that early monitoring of viral kinetics is a useful measure to predict virological response, and might facilitate development of rational and effective therapeutic strategies.     

Chronic viral hepatitis B and C: an argument against the conventional classification of chronic hepatitis

The classification of chronic hepatitis distinguishing benign chronic persistent hepatitis from severe chronic active hepatitis was constructed without knowledge of well-defined aetiological factors. Better understanding of the different hepatitis-viruses has shed new light on this subject. Chronic viral hepatitis B and C each show typical histological patterns. The validity of the conventional classification has been evaluated by a comparative study of chronic viral hepatitis B and C. 130 biopsies from 110 patients with chronic hepatitis C (CH-C) proven serologically by antibodies (second generation testing) were compared with 105 biopsies from 73 patients with chronic hepatitis B (CH-B). These were scored semi-quantatively. In CH-C, lymphoid follicles and/or aggregates were found in 88.5%, fatty degeneration in 51%, bile duct lesions in 46.2%, and Mallory body-like material in the hepatocytes in 9.2%. The portal lymphocytic infiltration generally predominated over the necro-inflammatory lesions of the parenchyma. Chronic persistent hepatitis (defined by the presence of portal hepatitis) was present exclusively in CH-C. Chronic lobular hepatitis was found exclusively in CH-B. We conclude that the histological criteria described for CH-C are highly suggestive of the diagnosis, that the artificial subdivision of chronic hepatitis into CPH and CAH is obsolete and that the histological assessment of chronic hepatitis should consist of a grading of inflammatory activity (minimal, mild, moderate, severe) and staging of fibrosis (extent of distortion of architecture). The final diagnosis should be based on the demonstration of the aetiological agent.     

Quasispecies dynamics of a hepatitis E virus 4 from the feces and liver biopsy of an acute hepatitis E patient during virus clearance

The presence of a quasispecies in hepatitis E virus (HEV) infection has been documented, however, the implications of a quasispecies in HEV-host interaction are poorly understood. Here, we analyzed the whole genome sequences of a HEV 4d from the feces and liver biopsy of a patient during the icteric and convalescent phases in an acute hepatitis E infection. Viral RNAs were extracted, reversely transcribed and seven fragments encompassing the entire viral genome were amplified and cloned. By sequencing multiple colonies of each cloned viral genome amplicon with Sanger sequencing, we verified the existence of the HEV quasispecies or intra-host genetic variations within the fecal and liver biopsy samples. There were broader genetic variations in the HEV ORF1 region including the PCP, HPX, and RdRp regions during the convalescent phase whereas more genetic variations in the ORF2 P domain during the icteric phase. The quasispecies dynamics might reflect host immune pressure during viral clearance.     

Comparison of viral load and duration of virus shedding in symptomatic and asymptomatic neonatal rotavirus infections

A single rotavirus strain causing asymptomatic infections as well as severe gastrointestinal disease has been described in the neonatal nurseries of the Christian Medical College, Vellore. In this study, quantitative real‐time RT‐PCR was used to determine the association of viral load with the presence of gastrointestinal symptoms in neonates. Viral load was estimated in terms of the crossing point [C(t) value] at which the amplicon could be detected in the real‐time PCR assay. The study was carried out on 103 neonates, including 33 asymptomatic neonates and 70 neonates with different gastrointestinal symptoms. The duration of virus shedding was also compared between five symptomatic and four asymptomatic neonates using real‐time RT‐PCR. There was no significant difference in viral load between symptomatic and asymptomatic neonates (P = 0.087). Among neonates with different gastrointestinal symptoms, those presenting with feed intolerance and abdominal distension had a significantly higher viral load than those with other gastrointestinal symptoms (P = 0.02). For the study on virus shedding, nine neonates were followed up for a median duration of 53 days, with a median of 31 samples tested per child. Extended shedding of low copies of rotavirus was found, with no significant differences in pattern of shedding between symptomatic and asymptomatic neonates. The lack of correlation between viral load and gastrointestinal disease demonstrates yet another difference between neonatal rotavirus infection and infection in older children where higher viral load correlates with severe disease. J. Med. Virol. 82:1803–1807, 2010. © 2010 Wiley‐Liss, Inc.     

Concurrent hepatitis C virus and hepatitis delta virus superinfection in patients with chronic hepatitis B virus infection.

Since hepatitis C virus (HCV) and hepatitis delta virus (HDV) are transmitted by the same routes as hepatitis B virus (HBV), simultaneous or concurrent HCV and HDV infection in patients with chronic HBV infection may occur. To test this hypothesis and to examine the clinicohistological and immunopathological presentations of such multiple hepatitis virus infections, acute and/or convalescent serum specimens from 86 patients with acute HDV superinfection were tested by enzyme immunoassay for antibodies to HCV. Of the 86 patients, 18 (20.9%) were associated with HCV infection. Although patients with early mortality cannot be evaluated by the HCV markers used in this study, the results showed that the clinical and histologic features were similar except that patients with HCV infection were older than those without HCV infection (P less than 0.01). Immunopathological studies carried out within 2 months after the onset of acute HDV superinfection demonstrated that hepatitis B core antigen (HBcAg) was not detected in any patient and HDV antigen was detected in 18.2% of the patients with HCV infection whereas HBcAg and HDAg were found in 7% and 65.1%, respectively, of those without HCV coinfection (P less than 0.02). It is concluded that concurrent HCV and HDV superinfections can and do occur in patients with chronic HBV infection. In these triple viral infections, HCV may even transiently suppress HDV and HBV.     

Characterization of viral kinetics in patients with hepatitis B e antigen-positive chronic hepatitis B

A study was conducted during a 1 year follow-up to characterize the viral kinetics in hepatitis B e antigen (HBeAg)-positive chronic hepatitis B and to develop a model of predicting the probability of spontaneous HBeAg seroconversion. Fifty-seven patients with HBeAg-positive chronic hepatitis B were enrolled with monthly follow-ups from three Phase III clinical trial placebo groups. According to serial viral loads, 30 patients (52.6%) with the stationary pattern maintained stable HBV DNA levels with fluctuations of less than 1.5 log copies/ml. Twenty patients (35.1%) with the declining pattern exhibited a spontaneous decline of more than 1.5 log copies/ml without a following rebound of at least 1.5 log copies/ml. The remaining seven patients (12.3%) had the wavering pattern. Both declining and wavering patterns, when compared with the stationary pattern, had significantly higher hepatic necroinflammation in terms of ALT and Knodell scores at the baseline and peak ALT levels during the follow-up period. The declining pattern had a significantly better clinical outcome in terms of the lowest final HBV DNA and a reduction in the necroinflammatory score after 1 year. Furthermore, the declining pattern had a favorable HBeAg seroconversion rate (40%) compared with the wavering (14.3%) and stationary patterns (0%). A regression equation, incorporating simultaneous serum bilirubin, ALT, and HBV DNA levels, predicted the probability of HBeAg seroconversion with a sensitivity of 76.8% and a specificity of 74.7%. In conclusion, different viral kinetic patterns in patients with chronic hepatitis B implicate distinct clinical significance and immunologic perspective.     

Association of viral load with HPV16 positive cervical cancer pathogenesis: Causal relevance in isolates harboring intact viral E2 gene

We tested the hypothesis that cervical cancers (CaCx) harbor high HPV16 viral load compared to controls and this is influenced by E2 status and age of subjects. Viral load (natural log transformed values) per 100 ng genomic DNA was estimated (152 cases and 87 controls) by Taqman assay. Median viral load was significantly higher (Mann-Whitney U test) among cases (17.21) compared to controls (9.86), irrespective of E2 status or upon considering E2 status as a covariate in logistic regression model (p < 0.001). Viral load of E2 intact cases (17.80) was significantly higher (p < 0.001) compared to those with disrupted E2 (9.78). At equivalent probability of being a case, viral load was higher among individuals (i) of lower age, irrespective of E2 status, and (ii) with intact E2 but of similar age as those with disrupted E2. Thus viral load in association with E2 status and/or age might be of causal relevance in CaCx pathogenesis.     

Detection of IgA class antibody to hepatitis E virus in serum samples from patients with hepatitis E virus infection

A newly developed assay for IgA class antibody to hepatitis E virus (IgA anti-HEV) was used to study 145 serum samples collected during an outbreak of an enterically transmitted hepatitis that occurred in 3 villages in the lower Shebeli region of Southern Somalia between January, 1988 and November, 1989. A total of 52.4% of the afflicted patients were found positive for IgA anti-HEV, and 73.1% of these were also positive for IgM. Both antibodies disappeared during the convalescence period. Similar results were also seen in serum obtained from sporadic cases of acute waterborne hepatitis in Pakistan. © 1993 Wiley-Liss, Inc.     

Imported and autochthonous hepatitis E virus strains in Spain

Hepatitis E virus (HEV) causes hepatitis E, an acute liver disease displaying diverse epidemiological patterns that correlate with the genetic diversity of the virus. Only a few strains have been characterized to date from cases of hepatitis E in Spain. Using three sets of new, HEV‐specific primers, viral genome fragments were amplified from serum samples from 13 patients with acute hepatitis in different regions of Spain. Direct sequencing of these fragments and analysis of sequences lead to identify six genotype 1, six genotype 3, and one genotype 4 viral strains. Genotype 1 sequences were found in the clade with subtype 1a strains, and were amplified from travelers from India and Bangladesh, and from an African immigrant. Genotype 3 sequences were found in the clade with subtype 3f strains, were always amplified from patients who did not travel abroad recently, and were closely related to sequences from swine strains isolated in Spain. Patients infected by these strains lived in different regions and were mainly men aged above 50 years. The single genotype 4 sequence detected was amplified from a traveler returning from Vietnam. Hepatitis E is both an imported and an autochthonous disease in Spain, and closely related HEV genotype 3f strains are responsible for infections acquired locally in different regions of the country within a given time. Studies involving a significant number of human, swine, and environmental viral strains collected prospectively are, however, required in order to confirm a swine origin for autochthonous HEV genotype 3 human infections. J. Med. Virol. 81:1743–1749, 2009. © 2009 Wiley‐Liss, Inc.     

Serological studies of an enterically transmitted non-A,non-B hepatitis in Somalia

An outbreak of an acute sporadic viral hepatitis occurring at three villages in the lower Shebli region of southern Somalia was studied. Sera were examined for antibodies to hepatitis E virus (HEV) antigen by a recently developed enzymelinked immunosorbent assay. The prevalence of anti-HEV ranged from 77.8% to 94.0% among the three villages. Anti-HEV prevalence did not differ significantly with age or sex. HEV infections were widely distributed among all age groups, without a preponderance in any specific age category. Overall, 97.6% of afflicted patients who were examined 6–10 days after onset of jaundice developed either IgM or IgG anti-HEV. © 1993 Wiley-Liss, Inc.     

Influence of hepatitis C virus infection on the mortality of antiretroviral-treated patients with HIV disease

The aims of this study were to analyze the mortality directly attributable to chronic viral hepatitis in HIV-1 infected patients and to investigate the influence of hepatitis virus infections on the survival of this population. A cohort of 328 HIV-1 infected, antiretroviral-treated patients, followed up from 1989 to 1996, was investigated in the study. The median follow-up period of the cohort was 120 weeks. The median baseline CD4+cell count of the cohort was 303 cells/mm³. Hepatitis C virus, hepatitis B virus and hepatitis D virus infections were present in 214 (65%), 16 (4.9%) and 9 (2.7%) patients, respectively. Sixty-seven (20.4%) subjects died but there was no information on the vital status of 36 patients (11%). The causes of mortality were AIDS in 49 (73%), liver failure in 3 (4.5%) and other causes in 15 (22.4%). The cohort was divided into two groups for survival analysis, the groups consisting of persons infected by a hepatitis virus and persons without hepatitis virus infection. There was no difference in survival between the two groups (p=0.31, log-rank). It is concluded that mortality among HIV-1/hepatitis virus coinfected patients with moderate to severe immunosuppression is mostly due to AIDS, and that the survival of these subjects is not influenced by the presence of hepatitis virus infections, particularly hepatitis C virus.     

Prolonged viral shedding in pandemic influenza A(H1N1): clinical significance and viral load analysis in hospitalized patients

The clinical significance of prolonged viral shedding (PVS) and viral load (VL) dynamics has not been sufficiently assessed in hospitalized patients with pandemic 2009 influenza A(H1N1). We performed a prospective study of adults with confirmed influenza A(H1N1) virus infection admitted to our hospital from 20 September 2009 to 31 December 2009. Consecutive nasopharyngeal swabs were collected every 2 days during the first week after diagnosis, and then every week or until viral detection was negative. Relative VL was measured on the basis of haemagglutinin and RNaseP gene analysis. PVS was defined as positive detection of influenza A(H1N1) virus by real-time RT-PCR at day 7 after diagnosis. We studied 64 patients: 16 (25%) presented PVS. The factors associated with PVS were admission to the intensive-care unit (69% vs. 33%, p 0.02), purulent expectoration (75% vs. 44%, p 0.04), higher dosage of oseltamivir (62.5% vs. 27%, p 0.016), corticosteroid treatment (50% vs. 21%, p 0.05), mechanical ventilation (MV) (50% vs. 12.5%, p 0.004), and longer stay (34 vs. 7 median days, p 0.003). Multivariate analysis revealed the factors independently associated with PVS to be immunosuppression (OR 5.15; 95% CI 1.2–22.2; p 0.03) and the need for MV (OR 11.7; 95% CI 2.5–54.4; p 0.002). VL at diagnosis correlated negatively with age and septic shock. VL dynamics of patients with acute respiratory distress syndrome and/or mortality were very different from those of other patients. PVS was detected in 25% of hospitalized patients with pandemic 2009 influenza A(H1N1) and was strongly associated with immunosuppression and the need for MV. Diagnostic VL and viral clearance varied with the clinical course.     

Identification of genotype 4 hepatitis E virus strains from a patient with acute hepatitis E and farm pigs in Bali, Indonesia

A previous study revealed that antibodies to hepatitis E virus (HEV) (anti-HEV) are highly prevalent among healthy individuals and farm pigs in Bali, Indonesia, and suggested that HEV infection may occur via zoonosis among Balinese people. However, there were no reports of acute hepatitis E in Bali. To elucidate whether Balinese HEV strains recovered from infected humans and pigs have significant sequence similarity, serum samples obtained from 57 patients (age, mean +/- standard deviation, 31.1 +/- 11.9 years) with sporadic acute hepatitis and from one hundred and one 2- or 3-month-old farm pigs in Bali were tested for anti-HEV and HEV RNA. Among the 57 patients, 2 (3.5%) had high-titer IgM/IgA class anti-HEV antibodies and one of them had detectable HEV RNA (BaliE03-46). Overall, 58 pigs (57.4%) tested positive for anti-HEV, while 5 pigs (5.0%) had detectable HEV RNA. Based on the 412-nucleotide sequence within open reading frame 2, the BaliE03-46 isolate and the 5 swine HEV isolates recovered from the viremic pigs were phylogenetically classified in genotype 4, but were only 77.3-90.8% identical to the genotype 4 HEV isolates reported thus far in China, India, Japan, Taiwan, and Vietnam. The BaliE03-46 isolate of human origin shared high identities of 97.3-98.3% with 4 of the 5 Balinese swine isolates, but differed by 16.1% from the remaining swine isolate. These results suggest that indigenous HEV strains of genotype 4 with marked heterogeneity are circulating in Bali, Indonesia, and that pigs are reservoirs of HEV for Balinese people who have a habit of ingesting uncooked pigs.     

Distinct changing profiles of hepatitis A and E virus infection among patients with acute hepatitis, patients on maintenance hemodialysis and healthy individuals in Japan

To compare the epidemiologic profiles of hepatitis A virus (HAV) and hepatitis E virus (HEV) infections in Japan, the prevalence of clinical or subclinical HAV and HEV infections was investigated serologically and molecularly among 128 consecutive patients (age, mean +/- standard deviation, 37.5 +/- 14.7 years) who contracted acute hepatitis between 1989 and 2005 in a city hospital, and among 416 hemodialysis patients (60.1 +/- 12.6 years) and 266 medical staff members (34.6 +/- 11.4 years) at the same hospital, using stored periodic serum samples collected since the start of hemodialysis or employment, respectively. Between 1989 and 1995, among 93 patients with acute hepatitis, 51 (54.8%) were diagnosed with hepatitis A and only one patient with hepatitis E. Between 1996 and 2005, however, among 35 patients, only 3 (8.6%) were diagnosed with hepatitis A and 2 (5.7%) with hepatitis E. Although subclinical HEV infection was recognized in four hemodialysis patients (one each in 1979, 1980, 1988, and 2003) and two medical staff members (1978 and 2003) in previous studies, none of the 191 hemodialysis patients who had been negative for anti-HAV at the start of hemodialysis contracted HAV infection during the observation period of 7.6 +/- 6.4 years. Only one (0.4%) of the 246 medical staff members who had been negative for anti-HAV at the start of employment acquired hepatitis A during the observation period of 7.9 +/- 8.0 years: none had subclinical HAV infection. Clinical or subclinical HEV infection has occurred rarely during the last three decades, while HAV infection has markedly decreased at least since 1996.     

Hepatitis E virus seroprevalence in acute viral hepatitis in a developed country confirmed by a supplemental assay

Hepatitis E virus (HEV) infection is prevalent among cases of acute viral hepatitis in young adults in developing countries. HEV infection is not restricted to endemic areas, but would appear to be worldwide in distribution. In order to document the incidence of HEV infection in acute hepatitis cases in a developed country, IgG and IgM anti-HEV antibodies and HEV RNA were tested in 101 Caucasian patients with acute viral hepatitis; 92 of these cases had markers of acute viral hepatitis other than HEV. Forty-seven (46.5%) cases had IgG anti-HEV; IgM anti-HEV and HEV viremia were not detected. As the incidence of anti-HEV was higher than would be expected, the possibility of the occurrence of false positive results was subsequently investigated. Supplemental antibody testing, using a broadly reactive epitope region, reduced the frequency of anti-HEV to 17%. Therefore, supplemental antibody testing confirms the hepatitis E virus seroprevalence in a developed country. Since IgM anti-HEV and HEV viremia were not detected, persons with IgG anti-HEV may be “subclinical HEV cases,” or have long-lived antibodies in their circulation. © 1996 Wiley-Liss, Inc.     

Prolonged hepatitis A infection in an HIV-1 seropositive patient

Hepatitis A virus (HAV) is a worldwide disease; in most cases, it causes an acute self-limited illness that does not lead to a chronic state. The course of HAV viremia in a homosexual male with human immunodeficiency virus type 1 (HIV-1) and the correlation between HIV and HAV viral load, alanine aminotranferase (ALT) level, and CD4(+) lymphocyte count were investigated during the course of the infection. HAV RNA was detected quantitatively up to 256 days after clinical onset. To our knowledge, this specific case is the first report of a prolonged infection with hepatitis A in a male with HIV-1. The ALT levels decreased gradually; however, 286 days after clinical onset of hepatitis, ALT levels were three times higher than normal values. HIV viral load was not affected by the infection with HAV and CD4(+) cell count was stable during the course of the co-infection. The duration and the high-titer viremia of hepatitis A virus in an immunodeficient patient constitute a serious risk of the spread of hepatitis A within this population. As inactivated HAV vaccine is safe in HIV-positive subjects, it would be wise to establish a strategy of preventive vaccination in this high-risk group.     

Infection with hepatitis E virus in kidney transplant recipients in southeastern France

Hepatitis E virus (HEV) is an emerging cause of acute hepatitis in Europe, particularly in southern France, and HEV is a new causative agent of chronic hepatitis and cirrhosis in immunocompromised patients. However, the data regarding HEV infection after kidney transplantation are still scarce with respect to the clinical issues that have been raised, and no study has specifically focused on kidney transplant recipients. This study described the clinical features and outcomes of HEV infections in a cohort of kidney transplant recipients living in southeastern France. The epidemiological, clinical, and virological characteristics of HEV infections diagnosed by PCR over a 53‐month period were retrospectively analyzed in a cohort of 1,350 kidney transplant recipients monitored at the Marseille University Hospital. Sixteen HEV infections were diagnosed, all of which were autochthonous and involved genotype 3 viruses (HEV‐3). Chronic infections occurred in 80% of these patients and resolved in half of the cases after a median time of 39 months. The rate of HEV clearance was 54% after a decrease in the dose of immunosuppressants. One patient developed liver cirrhosis 14 months after infection and experienced acute rejection after a decrease in the dose of immunosuppressants. Autochthonous HEV‐3 infections in kidney transplant recipients progress to chronicity in most cases and might be complicated by early liver cirrhosis. Chronic HEV infection can resolve following the reduction of immunosuppressive therapy, but ribavirin may be required if reduction of the immunosuppressant dose is not associated with HEV clearance or is inappropriate for the patient management. J. Med. Virol. 85:462–471, 2013. © 2012 Wiley Periodicals, Inc.     

Spectrum of hepatitis E virus infection in India

A solid phase enzyme linked immunosorbent assay (ELISA) that detects IgM and IgG to hepatitis E virus (HEV) was used to study seroepidemiology in 40 healthy subjects and 227 consecutive patients with liver diseases in an endemic area. Fifty-two of the liver diseases patients (22.9 percent) had acute hepatitis E. In contrast, none of the 40 healthy subjects were positive for IgM anti-HEV, validating the ELISA assay. Twenty-three of 25 (92%) patients with epidemic non-A, non-B hepatitis were confirmed as having acute hepatitis E. Only 1 of the 10 patients with sporadic, fulminant hepatic failuire of non-A, non-B, non-C etiology was positive for IgM anti-HEV. Five (31.2%) of the 16 patients with acute hepatitis in HBsAg carriers were positive for IgM anti-HEV. One patient with acute hepatitis B wascoinfected with acute hepatitis E. Acute hepatitis was a disease of the adult population, with peak attack rates in the second and third decades of life. This disease was seen in only 4 (16%) of the 25 patients with acute viral hepatitis occurring below 14 years of age. Cholestasis was predominant in 25% of patients, enzyme elevation was monophasic, and all patients had clinical and biochemical recovery from the disease. The data suggest that the majority of patients with acute sporadic non-A, non-B, non-C hepatitis in India have hepatitis E. However, fulminant hepatic failure to sporadic nature is rarely from hepatitis E. © 1994 Wiley-Liss, Inc.     

Modeling chronic hepatitis B or C virus infection during antiviral therapy using an analogy to enzyme kinetics: Long-term viral dynamics without rebound and oscillation

The basic model for chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection during therapy enables us to analyze short-term viral kinetics. However, the model is not useful for analyzing long-term viral kinetics. Here, I suggest a new model that was obtained by introducing Michaelis–Menten kinetics into the basic model. The new model can exhibit long-term viral kinetics without rebound and oscillation, unlike the basic model. The value of the parameter K in the new model is analogous to the Michaelis constant K_m and is predicted to be approximately less than 10¹⁰/ml.