Fulminant hepatitis A virus infection in the United States: Incidence, prognosis, and outcomes

Association of Acetaminophen (Paracetamol) Use With Severity and Outcomes in Patients With Viral Hepatitis-Associated Acute Liver Failure

INTRODUCTION

Acute viral hepatitis (AVH) comprises 11% of acute liver failure (ALF) in North America while acetaminophen (APAP) toxicity represents 46%. The use of APAP to treat prodromal hepatitis symptoms is common. It is unknown if concurrent APAP use impacts liver injury in AVH-induced ALF.

METHODS

In this prospective, multicenter cohort study, 356 patients meeting criteria for AVH including hepatitis A, B, Epstein-Barr virus, and herpes simplex virus, all leading to ALF (hepatic encephalopathy after acute illness, international normalized ratio ≥1.5), or acute liver injury (acute liver injury, international normalized ratio >2.0, no hepatic encephalopathy) were reviewed for evidence of APAP use: APAP ingestion history or measurement of serum APAP level or APAP-CYS adducts, a specific biomarker released into blood with APAP injury. Patients were grouped by APAP exposure level, from high (measurable APAP levels or toxic APAP-CYS), medium (therapeutic APAP-CYS), low (history of APAP ingestion only and/or barely detectable APAP-CYS), or no exposure recorded.

RESULTS

Two hundred five of 356 patients (57.5%) with AVH-ALF had evidence of APAP use: 87 out of 356 (24%) demonstrated high or medium exposures. The aminotransferase and bilirubin levels of high/medium group resembled a mixed APAP-viral injury. Mortality was the highest (51.6%, 21.4%, 28.8%, and 30.5%), and transplant-free survival was the lowest (22.6%, 44.6%, 41.5%, and 40.4%) in the high exposure group compared with medium, low, and no exposure groups. However, the specific comparisons of mortality and transplant-free survival between the high exposure and no exposure groups were not statistically different even after adjusting for baseline patient characteristics differences.

DISCUSSION

APAP use in AVH-ALF is common and may negatively impact outcomes compared with little or no APAP exposure. Prospective studies of the safest and effective dose of APAP to use in patients with AVH are needed.

Hepatitis A hospitalisations in the United States and risk factors for inpatient mortality: A nationwide population study, 1998-2020

Hepatitis A virus infections in the United States have been declining; however, recent widespread outbreaks have brought the disease back into the spotlight. We aim to describe the epidemiology of hepatitis A hospitalisations from 1998 to 2020 in the United States and investigate risk factors for inpatient mortality. We utilised the National Inpatient Sample database and identified hepatitis A-related hospitalisations using ICD-9 and ICD-10 diagnosis codes. Demographic and clinical data including death, coinfections, comorbidities and pregnancy status were extracted. Data were analysed by logistic and Poisson regression. We identified a total of 213,681 hepatitis A-related hospitalisations between 1998 and 2020, with hospitalisation rates ranging between 22.4 per 1,000,000 and 62.9 per 1,000,000. Between 1998 and 2015, the hospitalisation rate for hepatitis A was decreasing (IRR = 0.98; 95% CI: 0.97-0.98; p < .001); however, between 2015 and 2020, it increased overall (IRR = 1.22; 95% CI: 1.21-1.23; p < .001). The overall inpatient mortality rate was 2.7%. Age ≥55 years (OR = 1.84; 95% CI: 1.41-2.40; p < .001), alcoholic cirrhosis (OR = 2.53; 95% CI: 1.64-3.90; p < .001), ascites (OR = 2.65; 95% CI: 1.86-3.78; p < .001), hepatorenal syndrome (OR = 9.04; 95% CI: 5.93-13.80; p < .001), heart failure (OR = 1.76; 95% CI: 1.29-2.39; p < .001), pulmonary hypertension (OR = 2.02; 95% CI: 1.28-3.19; p = .003) and malignant neoplasm (OR = 1.75; 95% CI: 1.25-2.45; p = .001) were associated with increased odds of mortality. Tobacco use disorder (OR = 0.52; 95% CI: 0.38-0.70; p < .001) was associated with decreased odds of mortality. None of the hepatitis A-associated hospitalisations involving pregnant women resulted in death. Hepatitis A hospitalisations initially declined but increased rapidly after 2015. Certain risk factors can be used to predict prognosis of hospitalised patients.

Development of a cell-free toehold switch for hepatitis A virus type I on-site detection

Picornavirus hepatitis A virus (HAV) is a common cause of hepatitis worldwide. It is spread primarily through contaminated food and water or person-to-person contact. HAV I has been identified as the most common type of human HAV infection. Here, we have developed a cell-free toehold switch sensor for HAV I detection. We screened 10 suitable toehold switch sequences using NUPACK software, and the VP1 gene was used as the target gene. The optimal toehold switch sequence was selected by in vivo expression. The best toehold switch concentration was further found to be 20 nM in a cell-free system. 5 nM trigger RNA activated the toehold switch to generate visible green fluorescence. The minimum detection concentration decreased to 1 pM once combined with NASBA. HAV I trigger RNA could be detected accurately with excellent specificity. In addition, the cell-free toehold switch sensor was verified in HAV I entities. The successful construction of the cell-free toehold switch sensor provided a convenient, rapid, and accurate method for HAV I on-site detection, especially in developing countries, without the involvement of expensive facilities and additional professional operators.

Association between adverse outcomes of hepatitis A and acetaminophen use: A population-based cohort study

BACKGROUND

Acetaminophen (APAP) may cause acute liver injury with therapeutic doses in high-risk conditions such as chronic alcohol consumption or malnutrition. In acute hepatitis A (AHA), however, the safety of APAP has not been fully established. This study examined the potential association between APAP use and clinical outcomes of AHA in a nationwide and hospital-based cohort.

METHODS

Adult patients with AHA were identified from claims data of South Korean national healthcare insurance between 2008 and 2016 (n = 43,500). Logistic regression models were used to compare the risk of adverse outcomes (renal replacement therapy, hepatic encephalopathy and/or brain edema, mechanical ventilation, and liver transplantation) in patients exposed to APAP against control and patients exposed to NSAIDs. A propensity score (PS)-matched hospital-based AHA cohort (n = 146) was assessed for biochemical profiles after exposure to APAP or NSAIDs.

RESULTS

AHA patients were exposed to APAP or NSAIDs in 26.4% and 11.5% of cases, respectively. Compared to NSAID treatment, APAP exposure was associated with a higher incidence of hospitalization (98.8% vs. 92.4%; p < 0.0001). APAP exposure was independently associated with increased adverse outcomes (odds ratio [OR] = 5.66, p < 0.0001 against control; OR =1.67, p = 0.0015 against NSAIDs). PS-matched hospital cohort showed higher peak serum bilirubin levels (7.0 vs. 5.3 mg/dL; p = 0.03) and a longer time to recovery of jaundice after APAP use than with NSAID use.

CONCLUSION

APAP exposure was associated with increased adverse outcomes in a nationwide AHA cohort.

Hepatitis A virus infection

Hepatitis A is a vaccine-preventable infection caused by the hepatitis A virus (HAV). Over 150 million new infections of hepatitis A occur annually. HAV causes an acute inflammatory reaction in the liver that usually resolves spontaneously without chronic sequelae. However, up to 20% of patients experience a prolonged or relapsed course and <1% experience acute liver failure. Host factors, such as immunological status, age, pregnancy and underlying hepatic diseases, can affect the severity of disease. Anti-HAV IgG antibodies produced in response to HAV infection persist for life and protect against re-infection; vaccine-induced antibodies against hepatitis A confer long-term protection. The WHO recommends vaccination for individuals at higher risk of infection and/or severe disease in countries with very low and low hepatitis A virus endemicity, and universal childhood vaccination in intermediate endemicity countries. To date, >25 countries worldwide have implemented such programmes, resulting in a reduction in the incidence of HAV infection. Improving hygiene and sanitation, rapid identification of outbreaks and fast and accurate intervention in outbreak control are essential to reducing HAV transmission.

Liver Transplantation for Acute Liver Failure- Indication, Prioritization, Timing, and Referral

Acute liver failure (ALF) is a major success story in gastroenterology, with improvements in critical care and liver transplant resulting in significant improvements in patient outcomes in the current era compared to the dismal survival rates in the pretransplant era. However, the ever-increasing list of transplant candidates and limited organ pool makes judicious patient selection and organ use mandatory to achieve good patient outcomes and prevent organ wastage. Several scoring systems exist to facilitate the identification of patients who need a liver transplant and would therefore need an early referral to a specialized liver unit. The timing of the liver transplant is also crucial as transplanting a patient too early would lead to those who would recover spontaneously receiving an organ (wastage), and a late decision might result in the patient becoming unfit for transplant (delisted) or have an advanced disease which would result in poor post-transplant outcomes. The current article reviews the indications and contraindications of liver transplant in ALF patients, the various prognostic scoring systems, etiology-specific outcomes, prioritization and timing of referral.

Acute Liver Failure Guidelines

Acute liver failure (ALF) is a rare, acute, potentially reversible condition resulting in severe liver impairment and rapid clinical deterioration in patients without preexisting liver disease. Due to the rarity of this condition, published studies are limited by the use of retrospective or prospective cohorts and lack of randomized controlled trials. Current guidelines represent the suggested approach to the identification, treatment, and management of ALF and represent the official practice recommendations of the American College of Gastroenterology. The scientific evidence was reviewed using the Grading of Recommendations, Assessment, Development and Evaluation process to develop recommendations. When no robust evidence was available, expert opinions were summarized using Key Concepts. Considering the variety of clinical presentations of ALF, individualization of care should be applied in specific clinical scenarios.

Etiology of viral induced acute liver failure and defensins as potential therapeutic agents in ALF treatment

Acute liver failure (ALF) is a rare and severe disease, which, despite continuous advances in medicine, is still characterized by high mortality (65-85%). Very often, a liver transplant is the only effective treatment for ALF. Despite the implementation of prophylactic vaccinations in the world, the viral background of ALF is still a problem and leads to many deaths. Depending on the cause of ALF, it is sometimes possible to reverse this condition with appropriate therapies, which is why the search for effective antiviral agents seems to be a very desirable direction of research. Defensins, which are our natural antimicrobial peptides, have a very high potential to be used as therapeutic agents for infectious liver diseases. Previous studies on the expression of human defensins have shown that increased expression of human α and β-defensins in HCV and HBV infections is associated with a better response to treatment. Unfortunately, conducting clinical trials for ALF is very difficult due to the severity of the disease and the low incidence, therefore animal models are important for the development of new therapeutic strategies. One of the best animal models that has real reference to research on acute liver failure (ALF) is rabbit hemorrhagic disease in rabbits caused by the Lagovirus europaeus virus. So far, there have been no studies on the potential of defensins in rabbits infected with Lagovirus europaeus virus.

Prognostic Scores in Acute Liver Failure Due to Viral Hepatitis

Viral infections are among the major causes of acute liver failure (ALF) worldwide. While the role of agents such as hepatitis A, B, C, D and E viruses in precipitating ALF are well known, improvements in serological assays have led to the detection of viral agents such as Epstein Barr virus, cytomegalovirus etc. as atypical causes of ALF. Despite the plethora of literature available on viral hepatitis and ALF, there is very limited large-scale epidemiologic data on the prevalence, risk factors of progression and outcomes in ALF of viral causes. This is important as viral infections remain the leading cause of ALF in the East and in developing countries, while the impact of viral ALF in the West has largely been ameliorated by effective vaccination and sanitization programs. This review focuses specifically on the available prognostic scores that aid in the management of ALF of viral etiologies while also briefly reviewing the current literature on newer viral agents known to cause ALF, risk factors of progression, outcomes and how management algorithms can be developed by incorporation of prognostic scoring systems for referral and transplant listing.

Acute portal venous thrombosis as an extrahepatic manifestation of acute hepatitis A infection

Among the many potential causes and risk factors for acute portal venous thrombosis, viral hepatitis has been regarded as a rare associated condition. We present the first case in the literature of a 30-year-old previously healthy male who presented with acute portal venous thrombosis associated with acute hepatitis A virus (HAV) infection, describing the probable pathophysiology mechanism, work-up and treatment pursued. We encourage that hepatitis A serological markers should be routinely included in the investigation for acute portal venous thrombosis of unknown aetiology, in unvaccinated patients with risk factors of a recent HAV exposure.

Prevalence, severity, duration and resolution of cholestasis after acute liver failure

Objective

Persistent cholestasis may follow acute liver failure (ALF), but its course remains unknown. We aimed to describe the prevalence, onset, severity, duration and resolution of post-ALF cholestasis.

Design

Cohort of 127 adult patients with ALF at a liver transplantation centre identified using electronic databases. We obtained laboratory data every 6 hours for the first week, daily until day 30 and weekly, when documented, until day 180.

Results

Median age was 40.7 (IQR 31.0–52.4) years, median peak alanine aminotransferase level was 5494 (2521–8819) U/L and 87 (68.5%) cases had paracetamol toxicity. Overall, 12.6% underwent transplantation (3.4% for paracetamol vs 32.5% for non-paracetamol; p<0.001). Ninety-day mortality was 20.7% for paracetamol versus 30.0% for non-paracetamol patients. All non-transplanted survivors reached a bilirubin level>50 µmol/L, which peaked 3.5 (1.0–10.1) days after admission at 169.0 (80.0–302.0) µmol/L. At hospital discharge, 18.8% of patients had normal bilirubin levels and, at a median follow-up time from admission to last measurement of 16 (10-30) days, 46.9% had normal levels. Similarly, there was an increase in alkaline phosphatase (ALP) (207.0 (148.0–292.5) U/L) and gamma-glutamyl transferase (GGT) (336.0 (209.5–554.5) U/L) peaking at 4.5 days, with normalised values in 40.3% and 8.3% at hospital discharge.

Conclusion

Post-ALF cholestasis is ubiquitous. Bilirubin, ALP and GGT peak at 3 to 5 days and, return to baseline in the minority of patients at median follow-up of 16 days. These data inform clinical expectations of the natural course of this condition.

Viral hepatitis: Past, present, and future

Each hepatitis virus-Hepatitis A, B, C, D, E, and G-poses a distinct scenario to the patient and clinician alike. Since the discovery of each virus, extensive knowledge regarding epidemiology, virologic properties, and the natural clinical and immunologic history of acute and chronic infections has been generated. Basic discoveries about host immunologic responses to acute and chronic viral infections, combined with virologic data, has led to vaccines to prevent Hepatitis A, B, and E and highly efficacious antivirals for Hepatitis B and C. These therapeutic breakthroughs are transforming the fields of hepatology, transplant medicine in general, and public and global health. Most notably, there is even an ambitious global effort to eliminate chronic viral hepatitis within the next decade. While attainable, there are many barriers to this goal that are being actively investigated in basic and clinical labs on the local, national, and international scales. Herein, we discuss pertinent clinical information and recent organizational guidelines for each of the individual hepatitis viruses while also synthesizing this information with the latest research to focus on exciting future directions for each virus.

Hepatitis A Seroprevalence in Mogadishu, Somalia

BACKGROUND

The hepatitis A virus (HAV) is the most frequent global causes of vaccine-preventable viral hepatitis. Since Somalia is regarded as highly endemic for hepatitis A, the hepatitis A vaccine was not included in the World Health Organization's expanded immunization program. The purpose of this study was to determine the prevalence of hepatitis A infection in the Somalia capital, Mogadishu.

METHODS

The serological results of 1153 individuals presenting to the Mogadishu Training and Research Hospital between January 2019 and January 2021 were examined retrospectively to evaluate the presence of anti-HAV IgG and IgM. The seroprevalence of anti-HAV IgG and IgM was analyzed on the basis of age and sex. The seroprevalence of anti-HAV IgG was also compared among the 11-year age group.

FINDINGS

The seroprevalence of anti-HAV IgG and IgM did not vary significantly between the sexes. Overall, the seroprevalence of anti-HAV IgG was 67.6%. The percentage of seropositivity for anti-HAV IgG was highest in adults aged ≥41 years (88.9%) and lowest in children aged 1-2 years (29.4%). Estimated age at midpoint of population immunity was 5 years which is compatible high endemicity. In addition, a significant rate of hepatitis A infection was also observed in the adolescent age group.

CONCLUSIONS

This study confirms the high HAV endemicity in Mogadishu. These data will be useful towards planning preventive and control measures by improving the sanitation programs in Mogadishu. Furthermore, prospective studies are needed to confirm these findings and evaluate urban-rural heterogeneity.

Acute Liver Failure Requiring Liver Transplantation due to Acute Hepatitis A Virus Infection

Introduction

Hepatitis A infection (HAV) is generally characterized by an acute icteric illness or may have a subclinical self-limited course, although rarely, can result in fulminant hepatitis and death. In 2019, the City of Philadelphia declared a public health emergency due to an HAV outbreak. We are reporting a series of four cases of acute liver failure (ALF) requiring liver transplantation (LT) due to acute HAV.

Methods

Chart review and case descriptions of four patients with acute HAV-related ALF who were expeditiously evaluated, listed as Status 1A, and who underwent LT between August 2019 and October 2019 at Thomas Jefferson University Hospital.

Results

All four patients presented with acute hepatocellular jaundice and had a positive HAV IgM, and all other causes of ALF were excluded. All four cases met the American Association for the Study of Liver Diseases (AASLD) criteria for ALF. Three of the four cases met King's College Criteria of poor prognosis for nonacetaminophen-induced ALF. All four patients underwent successful LT and were discharged six to twelve days postoperatively. One patient died of disseminated Aspergillus infection five months after LT, while the others have had excellent clinical outcomes shown by one-year follow-ups. All four explants had remarkably similar histological changes, revealing acute hepatitis with massive necrosis accompanied by a prominent lymphoplasmacytic inflammatory infiltrate and bile ductular proliferation.

Conclusion

Although rare, patients presenting with acute HAV need close monitoring as they may rapidly progress to ALF. Early referral to a transplant center afforded timely access to LT and yielded overall good one-year survival. Widespread HAV vaccination for high-risk individuals is an essential strategy for preventing disease and curbing such future outbreaks.

Acute Liver Failure due to Hepatitis A Virus

Acute liver failure (ALF) is a syndrome, rather than a specific disease, with several possible causes, and viral hepatitis is a major cause. The relationship between self-limited and ALF hepatitis A is still poorly understood. A 45-year-old woman presented to our hospital with ALF diagnosis (from another hospital). She suffered from hospital-acquired pneumonia. The patient recovered within 4 weeks and returned to her normal life after 6 months of follow-up.

Present and future management of viral hepatitis

Viral hepatitis can result in important morbidity and mortality, with its impact on health conditioned by the specific type of hepatitis, the geographical region of presentation and the development and access to new drugs, among other factors. Most acute presentation forms are self-limiting and may even go unnoticed, with just a small percentage of cases leading to acute liver failure that may necessitate transplantation or even cause the death of the patient. However, when they become chronic, as in the case of hepatitis B virus and C virus, unless they are diagnosed and treated adequately they may have severe consequences, like cirrhosis or hepatocarcinoma. Understanding of the mechanisms of transmission, the pathogenesis, the presence of vaccinations and the development over recent years of new highly-efficient, potent drugs have meant that we are now faced with a new scenario in the management of viral hepatitis, particularly hepatitis B virus and hepatitis C virus. The spectacular advances in hepatitis C virus treatment have led the World Health Organization to propose the objective of its eradication by 2030. The key aspect to achieving this goal is to ensure that these treatments reach all the more vulnerable population groups, in whom the different types of viral hepatitis have a high prevalence and constitute a niche that may perpetuate infection and hinder its eradication. Accordingly, micro-elimination programs assume special relevance at the present time.

T cells protect against hepatitis A virus infection and limit infection-induced liver injury

BACKGROUND & AIMS

Hepatitis A virus (HAV) is a common cause of enterically transmitted viral hepatitis. In non-immune individuals, infection results in typically transient but occasionally fulminant and fatal inflammatory liver injury. Virus-specific T cell frequencies peak when liver damage is at its zenith, leading to the prevalent notion that T cells exacerbate liver disease, as suspected for other hepatotropic virus infections. However, the overall contribution of T cells to the control of HAV and the pathogenesis of hepatitis A is unclear and has been impeded by a historic lack of small animal models.

METHODS

Ifnar1^-/- mice are highly permissive for HAV and develop pathogenesis that recapitulates many features of hepatitis A. Using this model, we identified HAV-specific CD8+ and CD4+ T cells by epitope mapping, and then used tetramers and functional assays to quantify T cells in the liver at multiple times after infection. We assessed the relationships between HAV-specific T cell frequency, viral RNA amounts, and liver pathogenesis.

RESULTS

A large population of virus-specific T cells accumulated within the livers of Ifnar1^-/- mice during the first 1-2 weeks of infection and persisted over time. HAV replication was enhanced and liver disease exacerbated when mice were depleted of T cells. Conversely, immunization with a peptide vaccine increased virus-specific CD8+ T cell frequencies in the liver, reduced viral RNA abundance, and lessened liver injury.

CONCLUSION

These data show that T cells protect against HAV-mediated liver injury and can be targeted to improve liver health.

LAY SUMMARY

Hepatitis A virus is a leading cause of acute viral hepatitis worldwide. T cells were thought to contribute to liver injury during acute infection. We now show that virus-specific T cells protect against infection and limit liver injury.

Clinical outcomes and healthcare utilization of acute hepatitis A virus infection with acute kidney injury in hospitalized patients

BACKGROUND

Patients with acute hepatitis A virus (HAV) infection are at risk of developing acute kidney injury (AKI) which may result in increased healthcare resource utilization and worse clinical outcomes. We investigated the impact of AKI on healthcare utilization and clinical outcomes in patients hospitalized with acute HAV infection utilizing a large database.

METHODS

We queried the National Inpatient Sample (NIS) 2007-2014 to identify acute HAV infection-related hospitalizations with and without AKI. Primary outcomes were prevalence of AKI and its predictors with secondary outcomes included the mean length of stay (LOS), hospitalization cost and mortality in both groups.

RESULTS

Out of 68 364 acute HAV infection-related hospitalizations, 47 620 met our study criteria and 7458 (15.7%) had concurrent AKI. HAV patients with AKI were older (62.5 vs. 53.7 years; P value <0.001). A higher mean LOS (10.03 vs. 5.6 days; P value <0.001) and mean total hospitalization cost ($27 171.35 vs. $12 790.26; P value <0.001) were observed in HAV patients with the AKI group. A total of 1032 patients (13.8%) in the AKI group died during the same hospitalization as compared to 681 patients (1.5%) in the non-AKI group, P value <0.001. AKI in HAV was also found to be an independent predictor of mortality [adjusted odds ratio (aOR), 3.28; 95% confidence interval, 2.23-4.84; P value <0.001) after adjusting for the confounding factors.

CONCLUSION

We found that 15.67% of patients hospitalized with acute HAV had AKI which contributed to increased healthcare utilization and higher mortality which is preventable.

Spectrum of acute hepatitis and its clinical outcome in a central region in Tunisia

Introduction

given the lack of studies on acute hepatitis (AH) in Tunisia, we carried out this study to find the etiological spectrum and clinical profile of AH and to investigate the impact of viral etiology on the outcomes of AH.

Methods

retrospective descriptive study collecting all patients with AH from 2010 to 2017. The data were compared between two groups (viral AH and non-viral AH).

Results

one hundred and three patient´s files were included. The average age of our patients was 30.15 years. An etiology was found in 92 patients (89.3%). The viral etiology was found in 70 patients (76.1%). Hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV) and cytomegalovirus (CMV) were in the cause in 52, 16, 1 and 1 patient respectively. Elsewhere, it was toxic hepatitis in 10 patients (10.9%) including 7 of drug-related AH. Budd-Chiari syndrome and autoimmune hepatitis with acute onset were reported in 3 (3.3%) and 7 (7.6%) patients, respectively. Patients with viral AH were younger than those with non-viral AH (p = 10-³). There was more recourse to hospitalization for non-viral AH. Patients with viral AH had a higher mean aminotransferase (ALT) level than those with non-viral AH. The liver damage was more severe in the non-viral AH group with lower PT. There was more severe form, more transition to chronicity and more deaths in the non-viral AH group. Conclusion: the results found in our study concerning the distribution of the etiologies of AH as well as their evolutionary aspects are consistent with the data in the literature.

Predictors of hepatitis A immunity in adults in California in order to better utilize hepatitis A vaccine

BACKGROUND

Hepatitis A vaccine recommendations now include homelessness, illegal drug use, and HIV, as well as traditional risk factors and travel to areas endemic for hepatitis A. We examined a large diverse population for predictors of Hepatitis A immunity in order to better utilize Hepatitis A vaccine.

METHODS

We performed a cross-sectional descriptive study of members of a large integrated health plan with a test for Hepatitis A Immunoglobulin G (IgG) between January 1st, 2007, and December 31st, 2017. Exclusion criteria included age <18 years, <6 months of continuous enrollment, and Hepatitis A vaccine prior to Hepatitis A test. Variables of interest were age, gender, primary language spoken, ethnicity/race, neighborhood household income, and history of travel or history of jaundice. Multivariable logistic regression was performed to evaluate the association of risk factors on Hepatitis A immunity.

RESULTS

Of the 318,170 persons ≥ 18 years tested for Hepatitis A immunity, 155, 842 persons had a reactive Hepatitis A IgG test (49%). The lowest prevalence was for Whites at 28.1% followed by Blacks at 35.8%. Hispanics and Asian/Pacific Islanders had prevalence rates of 63% and 68.2% respectively. In adjusted analyses, Asian/Pacific Islanders, Hispanics and Blacks were 5.17, 3.44 and 1.42 times more likely to have Hepatitis A immunity than Whites. Those that spoke Spanish or language other than English or Spanish as their primary preferred language were 6.11 and 3.27 time more likely to have immunity than English speakers. Known travel history conferred a 2.16 likelihood of Hepatitis A immunity.

CONCLUSIONS

Persons of Hispanic and Asian/Pacific Islander background as well as persons with a preferred spoken language other than English have a high prevalence of Hepatitis A immunity. Testing for Hepatitis A immunity prior to vaccination should be considered for these groups.

The global trends and regional differences in incidence and mortality of hepatitis A from 1990 to 2019 and implications for its prevention

Background and purpose

Despite decades of improved sanitation and hygiene measures and vaccine introduction, hepatitis A has been spread through numerous outbreaks globally. We used data from the Global Burden of Disease (GBD) study to quantify hepatitis A burden at the global, regional and national levels.

Methods

Annual incident cases, deaths, age-standardized incidence rates (ASIRs), and age-standardized mortality rates (ASMRs) of hepatitis A between 1990 and 2019 were derived from the GBD study 2019. Percentage changes of cases and deaths, and estimated annual percentage changes (EAPCs) of ASIRs and ASMRs were calculated to quantify their temporal trends.

Results

Global hepatitis A incident cases increased by 13.90% from 139.54 million in 1990 to 158.94 million in 2019. ASIR of hepatitis A remained stable (EAPC = 0.00, 95% CI −0.01 to 0.01), whereas ASMR decreased (EAPC = −4.63, 95% CI −4.94 to −4.32) between 1990 and 2019. ASIR increased in low (EAPC = 0.09, 95% CI 0.04 to 0.14) and low-middle (EAPC = 0.04, 95% CI 0.03 to 0.06) socio-demographic index (SDI) regions. For GBD regions, the most significant increases of ASIR were detected in high-income Asia Pacific (EAPC = 0.53, 95% CI 0.41 to 0.66), Oceania (EAPC = 0.31, 95% CI 0.25 to 0.36), and Australasia (EAPC = 0.28, 95% CI 0.13 to 0.44). EAPC of ASIR was positively associated with SDI value in countries and territories with SDI value ≥ 0.7 (ρ = −0.310, p < 0.001).

Conclusion

There is an unfavorable trend that hepatitis A is still pending in hyperendemic regions and is emerging in low endemic regions. These highlight the need of targeted and specific strategies to eliminate hepatitis A, such as sanitation measures and a comprehensive plan for surveillance and vaccination against hepatitis A.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12072-021-10232-4.

An ELIME assay for hepatitis A virus detection

An Enzyme Linked ImmunoMagnetic Electrochemical assay (ELIME) was developed for the detection of the hepatitis A virus (HAV). This system is based on the use of new polydopamine-modified magnetic nanobeads as solid support for the immunochemical chain, and an array of 8 screen-printed electrodes as a sensing platform. Enzymatic-by-product is quickly measured by differential pulse voltammetry. For this purpose, all analytical parameters were optimized; in particular, different blocking reagents were evaluated in order to minimize the nonspecific interaction of bioreagents. Using the ELIME assays, a quantitative determination of HAV can be achieved with a detection limit of 1·10^-11 IU mL^-1 and a working range between 10^-10 - 5 × 10^-7 IU mL^-1. The cross-reactivity of the commercial monoclonal antibodies against HAV used in ELIME assays was tested for Coxsackie B4, resulting very low. The sensitivity was also investigated and compared with spectrophotometric sandwich ELISA. The average relative standard deviation (RSD) of the ELIME method was less than 5% for the assays performed on the same day, and 7% for the measurements made on different days. The proposed system was applied to the cell culture of HAV, which title was quantified by Real-Time Quantitative Reverse Transcription PCR (RT¬qPCR). To compare the results, a correlation between the units used in ELIME (IU mL^-1) and those used in RT¬qPCR (genome mL^-1) was established using a HAV-positive sample, resulting in 1 IU mL^-1-10^-4 gen mL^-1 (R² = 0.978). The ELIME tool exhibits good stability and high biological selectivity for HAV antigen detection and was successfully applied for the determination of HAV in tap water.

Factors Associated With Hepatitis A Mortality During Person-to-Person Outbreaks: A Matched Case-Control Study-United States, 2016-2019

BACKGROUND AND AIMS

During 2016-2020, the United States experienced person-to-person hepatitis A outbreaks that are unprecedented in the vaccine era, during which case-fatality ratios reported by some jurisdictions exceeded those historically associated with hepatitis A.

APPROACH AND RESULTS

To identify factors associated with hepatitis A-related mortality, we performed a matched case-control study (matched on age [±5 years] and county of residence in a 1:4 ratio) using data collected from health department and hospital medical records of outbreak-associated patients in Kentucky, Michigan, and West Virginia. Controls were hepatitis A outbreak-associated patients who did not die. There were 110 cases (mean age 53.6 years) and 414 matched controls (mean age 51.9 years); most cases (68.2%) and controls (63.8%) were male. Significantly (P < 0.05) higher odds of mortality were associated with preexisting nonviral liver disease (adjusted odds ratio [aOR], 5.2), history of hepatitis B (aOR, 2.4), diabetes (aOR, 2.2), and cardiovascular disease (aOR, 2.2), as well as initial Model for End-Stage Liver Disease (MELD) score ≥ 30 (aOR, 10.0), aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio > 2 (aOR, 10.3), and platelet count < 150,000/μL (aOR, 3.7) among hepatitis A outbreak-associated patients in the independent multivariable conditional logistic regression analyses (each model adjusted for sex).

CONCLUSIONS

Preexisting liver disease, diabetes, cardiovascular disease, and initial MELD score ≥ 30, AST/ALT ratio ≥ 1, and platelet count < 150,000/μL among hepatitis A patients were independently associated with higher odds of mortality. Providers should be vigilant for such features and have a low threshold to escalate care and consider consultation for liver transplantation. Our findings support the recommendation of the Advisory Committee on Immunization Practices to vaccinate persons with chronic liver disease, though future recommendations to include adults with diabetes and cardiovascular disease should be considered.

Insight into an acute hepatitis A outbreak in Indiana

Hepatitis A virus (HAV) infection causes an acute enteric hepatitis associated with substantial morbidity and mortality, particularly in older individuals. Incidence of HAV infection is low in the United States, mostly related to consumption of contaminated food. Starting in 2017, Indiana reported a large HAV outbreak. We sought to characterize the risk-exposures, clinical features and outcomes of HAV and examine the differences based on underlying cirrhosis and age. Adults ≥18 years diagnosed with HAV between January 2017 and April 2019 at two large healthcare systems in Indiana were identified. Demographic data, risk-exposures, clinical features, laboratory data and clinical outcomes were collected for analysis. The HAV cohort constituted 264 individuals with mean age of 41-years, 62% male and 94% Caucasian. Risk-exposures identified were illicit drug use (74%), food-borne (15%), person-to-person (11%) and incarceration (11%). Mortality rate was 2%, acute liver failure (ALF) was seen in 4% and acute on chronic liver failure (ACLF) was seen in 30% (6 of 20 with underlying cirrhosis). Admission MELD score was the only factor associated with ALF [OR = 1.17 (1.08-1.2), p < 0.0001], on multivariable logistic regression analysis. Higher proportion of individuals with underlying cirrhosis developed acute kidney injury (AKI) (26% vs. 9%, p = 0.03), ascites (45% vs. 11%, p < 0.0001) and hepatic encephalopathy (35% vs. 4%, p < 0.0001). In conclusion, illicit drug use was the predominant risk-exposure in the current HAV outbreak, which was associated with 2% mortality rate, and those with cirrhosis had worse outcomes (AKI, ascites and HE), of whom 30% developed ACLF.

Contemporary strategy to control viral hepatitis A in the Russian Federation

The problem of choosing a strategy to control hepatitis A in the Russian Federation remains relevant for the health care of our country. By strategy we mean a scientifically based program of action that defines the priorities and resources needed to effectively control hepatitis A.

The aim of the work is to present a strategy to control hepatitis A in the Russian Federation, taking into account the realities of today. Based on the analysis of Russian and international studies, we present answers to the questions that should be addressed before the choosing a strategy to control hepatitis A in the Russian Federation. The low incidence of hepatitis A creates a false image of the favorable situation with this infection. The rationale is given to include vaccination against hepatitis A in the National Vaccination Schedule in the section of mandatory vaccinations. Routine vaccination of children aged 24 and 36 months will lay the foundation for future protection against this infection. We consider the creating a National Hepatitis A Vaccination Program as an important aim. The implementation of such a program will allow full control of hepatitis A in the Russian Federation.

From hepatitis A to E: A critical review of viral hepatitis

Viral infections affecting the liver have had an important impact on humanity, as they have led to significant morbidity and mortality in patients with acute and chronic infections. Once an unknown etiology, the discovery of the viral agents triggered interest of the scientific community to establish the pathogenesis and diagnostic modalities to identify the affected population. With the rapid scientific and technological advances in the last centuries, controlling and even curing the infections became a possibility, with a large focus on preventive medicine through vaccination. Hence, a comprehensive understanding of hepatitis A, B, C, D and E is required by primary care physicians and gastroenterologists to provide care to these patients. The review article describes the epidemiology, pathogenesis, clinical presentation, diagnostic tools and current medication regimens, with a focus on upcoming treatment options and the role of liver transplantation.

Prevalence of hepatitis A in the capitals of the States of North, Southeast and South regions of Brazil: decrease in prevalence and some consequences

Hepatitis A virus (HAV) infection has been considered one of the leading causes of acute hepatitis. The aim of the present study was to estimate the prevalence of HAV among children and adolescents in a population-based study in the capitals of the States of the North, Southeast and South of Brazil and identify predictive factors for the infection. A multi-stage sampling was used to select subjects aged between 5-9 and 10-19 years. Individual and household levels aside from the level of variables in the areas were collected. The outcome was the total IgG antibodies to HAV levels detected using a commercial Enzyme Immuno Assay (EIA). The associations between HAV and the independent variables were assessed using the odds ratio. A multilevel analysis was performed by GLLAMM using the Stata software. The prevalence of HAV infection in the 5-9 and 10-19 age groups was 28.7% and 67.5%, respectively for the North, 20.6% and 37.7%, for the Southeast and 18.9% and 34.5% for the South Region. The prevalence of HAV increased according to age in all sites. Variables related to education at the individual level (North and South), family and area level (South and Southeast) and family income level (Southeast and South) were independently associated with HAV infection. This emphasizes the need for individualized strategies to prevent the infection.

Liver transplant evaluation for fulminant liver failure due to acute hepatitis A infection: Case series and literature review

Hepatitis A virus can cause liver damage ranging from mild illness to fulminant hepatic failure, constituting 0.35% of all cases of fulminant liver failure. While rates of spontaneous remission are higher for hepatitis A, recent outbreaks attributable to vaccine shortages in highly populated urban cities plagued by insufficient affordable housing and inaccessible sanitation, and changes in the epidemiology of viral strains have resulted in increased hospitalizations and deaths. While the prognosis for patients with FHF has improved since the introduction of transplantation, the decision to transplant is often difficult to reach. We present five patients with HAV and subsequent FHF, one of whom successfully received a liver transplant. We have reviewed all published cases of HAV FHF in the literature and report ten patients, seven of whom received liver transplantation. There are few predictive models that attempt to distinguish between fulminant hepatitis A and spontaneous recovery. Patients found to have positive hepatitis A IgM, encephalopathy, worsening LFT's and coagulation should be monitored closely and referred to transplant centers urgently for management.

An Outbreak of Hepatitis A among Young Adult Men in Cyprus

Background: Outbreaks of acute hepatitis A (AHA) have recently been reported in Europe among men who have sex with men (MSM). The aim of this work was to evaluate, for the first time, trends in the reported cases of AHA in Cyprus over the last seven years. Methods: We retrospectively studied all people reported with AHA in Cyprus between January 2013 and December 2019. Demographic data, type of transmission, vaccination status for HAV, laboratory and clinical data were analyzed. Results: The asnalysis involved 33 AHA cases (age 32.7 ± 17.4 years, 78.8% males). An increase in AHA reports was observed between July 2017 and June 2018 when more than a third (n = 13) of the cases of the period 2013–2019 were reported. The reporting rate of AHA doubled from 0.52 cases per 100,000 population (before July 2017) to 1.12 cases per 100,000 population (July 2017–June 2018). The male/female (M/F) ratio increased from one in 2013 to eight in 2018. Conclusion: An increase in AHA reports occurred in Cyprus between July 2017 and June 2018. Many cases with AHA in that period were MSM. Enhanced surveillance and timely public health interventions, like vaccination and awareness promotion, are important for preventing future outbreaks.

Hepatitis A hospitalizations among kidney transplant recipients in the United States: nationwide inpatient sample 2005-2014

BACKGROUND

This study aimed to evaluate the hospitalization rate for Hepatitis A virus (HAV) among kidney transplant (KTx) recipients and its outcomes as well as resource utilization.

METHODS

The 2005-2014 National Inpatient Sample database was used to identify all hospitalized KTx recipients with an associated diagnosis of HAV. The hospital mortality, resource utilization, and associated liver conditions were compared between patients with and without HAV, adjusting for potential confounders.

RESULTS

Of 871 024 KTx recipients identified, 204 had HAV. The overall inpatient prevalence of HAV in KTx recipients over 10 years in the United States was 23.42 cases per 100 000 admissions. There were no statistically significant changes in the inpatient prevalence of HAV in KTx recipients during the study period (P = 0.77), ranging from 9.2 to 34.3 per 100 000 admissions. Among hospitalized KTx recipients with HAV, 27.9% were from Northeast, 29.2% were from Midwest, 23.8% were from South, and 19.1% were from West. HAV was not significantly associated with increased hospital mortality, multiorgan failure, need for abdominal ultrasound, hospital length of stay, and total hospitalization costs and charges when compared with those without HAV. However, it is significantly associated with increased ICU stay, coexisting hepatitis B and C infection, and liver failure.

CONCLUSION

Overall, inpatient prevalence of HAV in KTx recipients in the United States (years 2005-2014) was 23.42 cases per 100 000 admissions. Hospitalization for HAV after KTx is associated with increased ICU stay, coexisting hepatitis B and C infection, and liver failure.

Pathophysiology of Acute Liver Failure

Acute liver failure (ALF) is a rare syndrome resulting from an acute insult to the liver in patients without known underlying chronic liver disease. It is characterized by loss of synthetic function in the form of jaundice and coagulopathy and development of hepatic encephalopathy. Multiorgan failure (MOF) eventually develops, leading to death. Many different etiologies have been identified, with acetaminophen (APAP) overdose and viral hepatitis being the most common causes worldwide. The pathophysiology of ALF can be divided into cause-specific liver injury pathophysiologies and pathophysiology related to occurrence of secondary MOF. In terms of liver injury pathophysiology, APAP toxicity is the most well known. Secondary MOF is often a result of the initial massive proinflammatory response generating a systemic inflammatory response syndrome followed by a compensatory anti-inflammatory response leading to immune cell dysfunction and sepsis. As the liver is a tremendously important metabolic organ involved in energy metabolism, protein synthesis, fat metabolism, and glycemic control, multiple aspects of nutrition also need to be considered as part of the overall pathophysiology of ALF.

Fulminant hepatitis A complicated by Takotsubo syndrome successfully treated with standard volume plasma exchange

Fulminant hepatic failure is an unusual complication of hepatitis A virus infection which, without liver transplantation, is associated with a poor prognosis. We report a case of fulminant hepatitis A complicated by severe cardiac dysfunction, related to Takotsubo syndrome, that was considered a contraindication for transplantation and was successfully managed with standard volume plasma exchange.

Characteristics of acute hepatitis A virus infection before and after 2001: A hospital-based study in Tokyo, Japan

BACKGROUND AND AIM

The incidence of acute hepatitis A [AH (A)] is decreasing because of improvements in hygiene; however, cases of sporadic severe hepatitis are still being reported. We assessed the epidemiology of AH (A) in Japan.

METHODS

This was a hospital-based retrospective study, in which 126 AH (A) patients (96 men [76%], median age 39 [range, 19-66] years) were enrolled. Patients diagnosed with AH (A) before 2001 (n = 79) and after 2001 (n = 47) were compared.

RESULTS

The incidence of AH (A) showed peaks in 1990, 1999, and 2018. After 2001, one patient had hepatitis B virus, four had human immunodeficiency virus, and three had syphilis coinfections. Before and after 2001, HAV was transmitted, respectively, by raw oysters (28% and 26%), overseas travel (19% and 28%), and sexual contact (0% and 19%) (P < 0.01). The frequencies of symptoms were appetite loss (51% and 32%), fever (63% and 81%), and diarrhea (3% and 13%) (all P < 0.05), respectively. On admission, the median levels of alanine aminotransferase (1455 and 3069 U/L) and γ-glutamyl transpeptidase (221 and 345 U/L) were significantly higher (P < 0.01), and the prothrombin time (77.5% and 65.9%) and platelet count (22.7 and 16.4 × 10/μL) were significantly lower after 2001 (P < 0.05). A time to normalization of the bilirubin level ≥ 30 days was associated with older age and a diagnosis of AH (A) after 2001.

CONCLUSIONS

Outbreaks and severe AH (A) cases due to sexual transmission have been reported recently. It is necessary to examine their sexual behavior and other sexual infection.

Acute liver failure

Acute liver failure is a rare and severe consequence of abrupt hepatocyte injury, and can evolve over days or weeks to a lethal outcome. A variety of insults to liver cells result in a consistent pattern of rapid-onset elevation of aminotransferases, altered mentation, and disturbed coagulation. The absence of existing liver disease distinguishes acute liver failure from decompensated cirrhosis or acute-on-chronic liver failure. Causes of acute liver failure include paracetamol toxicity, hepatic ischaemia, viral and autoimmune hepatitis, and drug-induced liver injury from prescription drugs, and herbal and dietary supplements. Diagnosis requires careful review of medications taken, and serological testing for possible viral exposure. Because of its rarity, acute liver failure has not been studied in large, randomised trials, and most treatment recommendations represent expert opinion. Improvements in management have resulted in lower mortality, although liver transplantation, used in nearly 30% of patients with acute liver failure, still provides a life-saving alternative to medical management.

A Model to Predict 1-Month Risk of Transplant or Death in Hepatitis A-Related Acute Liver Failure

Acute liver failure (ALF) caused by hepatitis A is a rare but fatal disease. Here, we developed a model to predict outcome in patients with ALF caused by hepatitis A. The derivation set consisted of 294 patients diagnosed with hepatitis A-related ALF (ALFA) from Korea, and a validation set of 56 patients from Japan, India, and United Kingdom. Using a multivariate proportional hazard model, a risk-prediction model (ALFA score) consisting of age, international normalized ratio, bilirubin, ammonia, creatinine, and hemoglobin levels acquired on the day of ALF diagnosis was developed. The ALFA score showed the highest discrimination in the prediction of liver transplant or death at 1 month (c-statistic, 0.87; 95% confidence interval [CI], 0.84-0.92) versus King's College criteria (KCC; c-statistic, 0.56; 95% CI, 0.53-0.59), U.S. Acute Liver Failure Study Group index specific for hepatitis A virus (HAV-ALFSG; c-statistic, 0.70; 95% CI, 0.65-0.76), the new ALFSG index (c-statistic, 0.79; 95% CI, 0.74-0.84), Model for End-Stage Liver Disease (MELD; c-statistic, 0.79; 95% CI, 0.74-0.84), and MELD including sodium (MELD-Na; c-statistic, 0.78; 95% CI, 0.73-0.84) in the derivation set (all P < 0.01). In the validation set, the performance of the ALFA score (c-statistic, 0.84; 95% CI, 0.74-0.94) was significantly better than that of KCC (c-statistic, 0.65; 95% CI, 0.52-0.79), MELD (c-statistic, 0.74; 95% CI, 0.61-0.87), and MELD-Na (c-statistic, 0.72; 95% CI, 0.58-0.85) (all P < 0.05), and better, but not statistically significant, than that of the HAV-ALFSG (c-statistic, 0.76; 95% CI, 0.61-0.90; P = 0.28) and new ALFSG indices (c-statistic, 0.79; 95% CI, 0.65-0.93; P = 0.41). The model was well-calibrated in both sets. Conclusion: Our disease-specific score provides refined prediction of outcome in patients with ALF caused by hepatitis A.

Emerging Threat: Changing Epidemiology of Hepatitis A and Acute Kidney Injury

In the past decade, hepatitis A has been considered a rare disease in the United States, largely due to targeted vaccination of at-risk children. Evolving epidemiology has resulted in decreasing immunity and increasing hepatitis A infections among adults who are more likely to experience severe disease. A surge in outbreaks has been noted in the past 2 years, resulting in a high volume of hepatitis A related hospitalizations and complications in otherwise healthy individuals. The traditional understanding that acute kidney injury is a rare extrahepatic manifestation is being challenged by the resurgence of hepatitis A in a more vulnerable population. This review examines the epidemiologic factors that contributed to current public health concern and the association between hepatitis A and acute kidney injury.

New 4-phenylcoumarin derivatives as potent 3C protease inhibitors: Design, synthesis, anti-HAV effect and molecular modeling

A new series of 4-phenylcoumarin derivatives was synthesized starting from (2-oxo-4-phenyl-2H-chromen-7-yloxy) acetic acid hydrazide 3. Evaluation of the target compounds for their antiviral activity against hepatitis A virus revealed that the ethylthiosemicarbazide derivative 7b was the most potent virucidal agent (IC50 = 3.1 μg/ml, TI = 83). The Schiff's bases 14c and 14b demonstrated the highest virustatic effects against viral adsorption and replication, respectively (14c; IC50 = 8.5 μg/ml, TI = 88 and 14b; IC50 = 10.7 μg/ml, TI = 91). Furthermore, compounds 7b, 14b and 14c were tested against HAV 3C protease and showed significant inhibition effects (Ki = 1.903, 0.104 and 0.217 μM, respectively). The remarkable inhibitory effect expressed by the three target compounds against HAV 3C protease prompted us to expand our research on HRV 3C protease, a structurally related enzyme of the same family, and interestingly, the three target compounds displayed significant inhibitory effect against HRV 3C protease (IC50 = 16.10, 4.13 and 6.30 μM, respectively). Moreover, the active compounds 7b, 14b and 14c were docked within the pocket site of HAV 3C protease (PDB code: 2HAL) illustrating a strong H-profile with the key amino acids Gly170 and Cys172 similar to the co-crystallized ligand. Furthermore, 3D-pharmacophore and quantitative structure activity relationship (QSAR) models were generated to explore the structural requirements for the observed antiviral activity.

Comparative Pathology of Hepatitis A Virus and Hepatitis E Virus Infection

Hepatitis A virus (HAV) and hepatitis E virus (HEV) cause acute, self-limiting hepatic infections that are usually spread by the fecal-oral route in humans. Naturally occurring and experimental infections are possible in a variety of nonhuman primates and, in the case of HEV, a number of other species. Many advances in understanding the pathogenesis of these viruses have come from studies in experimental animals. In general, animals infected with these viruses recapitulate the histologic lesions seen in infected humans, but typically with less severe clinical and histopathological manifestations. This review describes the histopathologic changes associated with HAV and HEV infection in humans and experimental animals.

Toward development of generic inhibitors against the 3C proteases of picornaviruses

Development of novel antivirals, which requires knowledge of the viral life cycle in molecular detail, is a daunting task, involving extensive investments, and frequently resulting in failure. As there exist significant commonalities among virus families in the manner of host interaction, identifying and targeting common rather than specific features may lead to the development of broadly useful antivirals. Here, we have targeted the 3C protease of Hepatitis A Virus (HAV), a feco-orally transmitted virus of the family Picornaviridae, for identification of potential antivirals. The 3C protease is a viable drug target as it is required by HAV, as well as by other picornaviruses, for post-translational proteolysis of viral polyproteins and for inhibiting host innate immune pathways. Computational screening, followed by chemical synthesis and experimental validation resulted in identification of a few compounds which, at low micromolar concentrations, could inhibit HAV 3C activity. These compounds were further tested experimentally against the 3C protease of Human Rhinovirus, another member of the Picornaviridae family, with comparable results. Computational studies on 3C proteases from other members of the picornavirus family have indicated that the compounds identified could potentially be generic inhibitors for picornavirus 3C proteases.

Natural History, Clinical Manifestations, and Pathogenesis of Hepatitis A

Hepatitis A virus (HAV) is transmitted by the fecal-oral route and is a major cause of acute viral hepatitis. The clinical manifestations of HAV infection range from asymptomatic infection to acute liver failure (ALF), but do not include progression to chronic hepatitis. Risk factors for severe acute hepatitis A are older age (>40 years) and preexisting liver disease. Some patients may show atypical clinical features such as relapsing hepatitis, prolonged cholestasis, or extrahepatic manifestations. Almost all hepatitis A patients spontaneously recover with supportive care. However, in the case of ALF (<1%), intensive care and urgent decision on liver transplantation are required. Liver injury during hepatitis A is not directly caused by HAV but is known to be caused by immune-mediated mechanisms. In this review, the natural history and clinical manifestations of hepatitis A are described. In addition, mechanisms of immunopathogenesis in hepatitis A are discussed.

Case of severe acute hepatitis A virus infection in United Nations peacekeepers in South Sudan

Hepatitis A virus (HAV) is a major cause of acute viral hepatitis, which can lead to severe cases and acute liver failure. A 41-year-old Chinese military officer of the United Nations peacekeeping forces in South Sudan manifested fever, jaundice and coagulation dysfunction. The patient initially had a negative anti-HAV IgM antibody test result but a positive anti-HAV-IgM antibody test result five days after his alanine aminotransferase (ALT) levels peaked. He was given telemedicine consultation and was transferred to a Chinese military hospital specialising in infectious diseases for treatment of severe acute HAV infection. The peak ALT, aspartate aminotransferase, total bilirubin and international standard ratio were 5410 U/L, 3475 U/L, 225.1 µmol/L and 2.12 during hospitalisation, respectively. Military personnel undergoing missions in areas with high prevalence of HAV should be tested for previous HAV infection before departure if they have not been previously vaccinated. If negative results are obtained, they should be vaccinated. Anti-HAV-IgM examination should be repeated after the first negative test result is obtained to eliminate the effects of a window period if a clinical suspicion exists. If a life-threatening case of HAV infection is present, the patient should be transported to a base military hospital specialising in infectious diseases for treatment.

Classification and Epidemiologic Aspects of Acute Liver Failure

Acute liver failure is a rare condition with high short-term morbidity and mortality. The most widely accepted definition is an abnormality in coagulation with any degree of encephalopathy in a patient without cirrhosis and an illness duration of less than 26 weeks. Multiple classifications systems are currently in use to help categorize the condition. This article reviews the most commonly used systems. The epidemiologic aspects of the disease are also reviewed, including incidence, prevalence, demographics, geographic distribution, and racial and cultural factors and are discussed for the various subtypes of acute liver failure.

Viral Hepatitis and Acute Liver Failure: Still a Problem

Although the overall prevalence is on the decline, viral hepatitis still plays a major role in the development of acute liver failure (ALF) worldwide. Hepatitis A, B, D, and E contribute to most fulminant viral courses. These viruses have not gained much attention in recent years yet remain relevant from a clinical perspective as the incidence in certain populations is on the increase. Other viral therapies and immunotherapies are currently being examined as treatments for hepatitis D and hepatitis E. Clinicians should still maintain a high index of suspicion for viral causes in approaching patients with ALF.

Atypical manifestations of hepatitis A virus infection

Acute hepatitis due to the hepatitis A virus usually has a short, benign and self-limited course, without causing chronic hepatitis. However, some cases have an atypical presentation, such as relapsing hepatitis, prolonged or persistent cholestasis, fulminant hepatic failure, or liver failure associated with autoimmune hepatitis. The typical clinical course of acute hepatitis A virus infection is spontaneous remission in 90% of the cases, but atypical cases have a prevalence that varies from less than 1 to 20%, depending on the manifestation (overall prevalence ∼7%). There is little information on the atypical clinical courses of hepatitis A virus infection and the lack of recognizing those presentations in clinical practice often results in carrying out numerous studies and treatments that not only are unnecessary, but can also be harmful. The aim of the present article was to describe 3 clinical cases of atypical hepatitis A infection and provide a literature review of such cases.