Very low prevalence of anti-HAV in Japan: high potential for future outbreak. Sci Rep. 2019;9:1493. [PMID: 30728377 PMCID: PMC6365493 DOI: 10.1038/s41598-018-37349-1]

Identifying the panorama of potential pandemic pathogens and their key characteristics: a systematic scoping review

The globe has recently seen several terrifying pandemics and outbreaks, underlining the ongoing danger presented by infectious microorganisms. This literature review aims to explore the wide range of infections that have the potential to lead to pandemics in the present and the future and pave the way to the conception of epidemic early warning systems. A systematic review was carried out to identify and compile data on infectious agents known to cause pandemics and those that pose future concerns. One hundred and fifteen articles were included in the review. They provided insights on 25 pathogens that could start or contribute to creating pandemic situations. Diagnostic procedures, clinical symptoms, and infection transmission routes were analyzed for each of these pathogens. Each infectious agent's potential is discussed, shedding light on the crucial aspects that render them potential threats to the future. This literature review provides insights for policymakers, healthcare professionals, and researchers in their quest to identify potential pandemic pathogens, and in their efforts to enhance pandemic preparedness through building early warning systems for continuous epidemiological monitoring.

The Shifting Epidemiology of Hepatitis A in the World Health Organization Western Pacific Region

Within the past few decades, improvement in sanitation and economic growth has driven a changing epidemiology of hepatitis A in the Western Pacific Region (WPR) of the World Health Organization (WHO). In this review, we gathered available published information on hepatitis A epidemiology of the countries in the WPR and reviewed the trends reported in the literature from the years 2000 to 2021. Many countries have shifted from high endemicity to low endemicity. Moreover, the administration of the hepatitis A vaccine among children in recent years has shifted disease susceptibility to the older population. Seroprevalence among children has decreased in most countries, while nearly 100% seropositivity is seen in mid adulthood. This is contrary to the epidemiology seen in previous decades when most children achieved immunity by age ten. This also presents a paradox in that better living conditions have caused more vulnerability to the older age groups who are at higher risk for severe disease. Given these trends, we recommend vaccination of vulnerable populations such as the older age groups and inclusion of the hepatitis A vaccine in government immunization programs.

Characteristics of preventive intervention acceptance for international travel among clients aged 60 years and older from a Japanese multicenter pretravel consultation registry

OBJECTIVES

Pretravel consultation (PTC) is important for older adults owing to health problems associated with overseas travel. Although older adults in Japan, their PTC characteristics are less known. This study aimed to investigate the epidemiology of clients aged ≥ 60 years based on data from the Japan Pre-travel Consultation Registry (J-PRECOR).

METHODS

Clients aged ≥ 60 years who visited J-PRECOR cooperative hospitals from February 1, 2018, to May 31, 2022, were included. The primary endpoint was a comparison of prescriptions for vaccines for hepatitis A, tetanus toxoid, and malaria prophylaxis in travelers to high-risk malaria countries in yellow fever vaccination (YFV)-available facilities with and without YFV.

RESULTS

In total, 1000 clients (median age: 67 years) were included. Although 523 clients were immunized with YFV, only 38.6% of the 961 unimmunized clients were vaccinated with the tetanus toxoid-containing vaccine. Malaria chemoprophylaxis was prescribed to 25.7% of clients traveling for ≤55 days. At YFV-capable institutes, 557 clients traveling to yellow fever risk countries took PTC, 474 of whom received YFV and 83 were unvaccinated. Lower age (odds rate 0.85 per 1 year; 95% CI 0.80-0.90) and lower hepatitis A vaccination rate (0.29; 95% CI 0.14-0.63) were significantly associated with YFV.

CONCLUSIONS

Preventive interventions other than YFV should be offered to older adults.

Impact of frequency and duration of freeze-dried inactivated tissue culture hepatitis A vaccine (Aimmugen®) vaccination on antibody titers; a japanese cross-sectional study

BACKGROUND

The effect of the timing of additional doses and the long-term persistence of lyophilized inactivated tissue culture hepatitis A (HA) vaccine (Aimmugen®) on antibodies is unknown.

METHODS

A single-center, cross-sectional, observational study was conducted in collaboration with the Japan Air Self-Defense Force, whose personnel were immunized with Aimmugen® when deployed to endemic areas. Patients who consented to this study after a medical examination with blood sampling between June 2022 and February 2023 were included; HA-IgG level in the residual serum was measured using the chemiluminescent immunoassay method. The exact vaccination history was investigated based on immunization records maintained by the Ministry of Defense, and a questionnaire was used to collect confounding factors.

RESULTS

Of the 181 participants observed, 49 were in the unvaccinated group, and 132 were in the vaccinated group. Out of the vaccinated group, 6.8 % received either one or two doses, 40.9 % received three doses, and 52.3 % received more than four doses. IgG antibody titers (S/CO value) in each group (0, 1 or 2, 3, and over 4) increased in a frequency-dependent manner, with those vaccinated over four times showing significantly higher IgG antibody titers than all other groups (0.19 ± 0.10 vs 3.66 ± 3.00 vs 7.63 ± 3.57 vs 10.57 ± 1.86, respectively). When the number of months elapsed from the last vaccination to the date of blood collection in each group was plotted against IgG antibody titer, the slope of the regression line flattened out from a decreasing trend in the order 1 or 2, 3, over 4.

CONCLUSIONS

Three doses of Aimmugen® are efficacious, but four or more doses induce more robust and sustained antibody production. Additionally, four or more doses may be effective when there is a need to ensure long-term immunity or risk of prolonged exposure.

Application of a high-throughput quantitative PCR system for simultaneous monitoring of SARS-CoV-2 variants and other pathogenic viruses in wastewater

Variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are continuously emerging, highlighting the importance of regular surveillance of SARS-CoV-2 and other epidemiologically significant pathogenic viruses in the current context. Reverse transcription-quantitative PCR (RT-qPCR) is expensive, time-consuming, labor-intensive, requires a large reagent volume, and only tests a few targets in a single run. High-throughput qPCR (HT-qPCR) utilizing the Biomark HD system (Fluidigm) can be used as an alternative. This study applied an HT-qPCR to simultaneously detect SARS-CoV-2, SARS-CoV-2 nucleotide substituted RNA, and other pathogenic viruses in wastewater. Wastewater samples were collected from the coronavirus disease 2019 (COVID-19) quarantine facility between October 2020 and February 2021 (n = 4) and from the combined and separated sewer lines of a wastewater treatment plant (WWTP) in Yokkaichi, Mie Prefecture, Japan, between March and August 2021 (n = 23 each). The samples were analyzed by HT-qPCR using five SARS-CoV-2, nine SARS-CoV-2 spike gene nucleotide substitution-specific, five pathogenic viruses, and three process control assays. All samples from the quarantine facility tested positive for SARS-CoV-2 and the nucleotide substitutions N501Y and S69-70 del (Alpha variant) were detected in the December 2020 sample, coinciding with the first clinical case in Japan. Only three WWTP samples were positive when tested with a single SARS-CoV-2 assay, whereas more than eight samples were positive when tested with all assays, indicating that using multiple assays increases the likelihood of detection. The nucleotide substitution L452R (Delta variant) was detected in the WWTP samples of Mie Prefecture in April 2021, but the detection of Delta variant from patients had not been reported until May 2021. Aichi virus 1 and norovirus GII were prevalent in WWTP samples. This study demonstrated that HT-qPCR may be the most time- and cost-efficient method for tracking COVID-19 and broadly monitoring community health.

Acute Hepatitis A Virus Infection in Tobruk, Eastern Libya: Increasing Trends After 2017

Acute hepatitis A is a self-limited liver inflammation caused by hepatitis A virus (HAV) infection. The infection is transmitted by direct contact from person to person via fecal-oral routes, or through consuming contaminated food and water. This study aims to estimate the frequency of HAV infection from medical records of Tobruk Medical Center, eastern Libya and its distribution during 6 years. The medical records department of Tobruk Medical Center follows guidelines of the international classification of diseases-10 for coding the diseases. The research estimates the frequency and distribution of HAV infection based on age and sex during the period from January 2015 to December 2020. HAV screening assay was performed using commercially available enzyme-linked immunosorbent assays HAV IgM microwell. 245 cases were recorded, 53.5% of cases were males. HAV infection was the most prevalent (92.6%) in age groups of < 5-20 years. A significant rise in the occurrence of HAV infection in the last three years was reported (p < 0.05). More than half of the cases (68%) were reported in 2019 and 2020. No case fatality rate was reported in the present study. There is an increase in the frequency of HAV infection in the last 3 years and the younger age groups (under 20 years old) are more vulnerable to HAV infection. More prevention and control efforts towards this age group should be a top public health priority to avoid the possibility of HAV outbreaks in the future.

Status of Immunity Against the Hepatitis A Virus in Healthy Population: A Report From Southeastern Iran

Background: Recently, epidemiological studies on hepatitis A virus (HAV) infection showed the seroprevalence has been changing due to changes in lifestyle. To the best of our knowledge, there have been no published data on the seropositivity of HAV in Zahedan, southeastern Iran. Objectives: This study aimed to investigate the seroprevalence of HAV immunoglobulin G (IgG) antibody in Zahedan, southeastern Iran, to provide the required information for better planning in preventive strategies. Methods: In this cross-sectional study, using the available sampling method, a total of 250 serum samples (18 years and above) in both the urban and rural areas of Zahedan were evaluated for anti-HAV IgG by enzyme-linked immunosorbent assay. Results: Based on the results, it was observed that 228 out of 250 (91.2%) serum samples were positive for HAV IgG antibody. Male gender, family size, parents’ education, mother’s occupation, and history of jaundice before the age of 12 years were associated with positive HAV antibody (P < 0.001). The seroprevalence HAV rates were not statistically different between the residents of urban and rural regions. Conclusions: The seropositivity of HAV is high in both the urban and rural areas of Zahedan, Iran. Therefore, the HAV vaccination of the general population is not necessary. It is recommended to monitor HAV seroprevalence in the general population to determine high-risk groups, including anti-HAV seronegative individuals, for HAV vaccination in the residents of the southeast border.

Knockdown of Mitogen-Activated Protein Kinase Kinase 3 Negatively Regulates Hepatitis A Virus Replication

Zinc chloride is known to be effective in combatting hepatitis A virus (HAV) infection, and zinc ions seem to be especially involved in Toll-like receptor (TLR) signaling pathways. In the present study, we examined this involvement in human hepatoma cell lines using a human TLR signaling target RT-PCR array. We also observed that zinc chloride inhibited mitogen-activated protein kinase kinase 3 (MAP2K3) expression, which could downregulate HAV replication in human hepatocytes. It is possible that zinc chloride may inhibit HAV replication in association with its inhibition of MAP2K3. In that regard, this study set out to determine whether MAP2K3 could be considered a modulating factor in the development of the HAV pathogen-associated molecular pattern (PAMP) and its triggering of interferon-β production. Because MAP2K3 seems to play a role in antiviral immunity against HAV infection, it is a promising target for drug development. The inhibition of MAP2K3 may also prevent HAV patients from developing a severe hepatitis A infection.

Prevalence of Hepatitis A Immunity and Decision-tree Analysis Among Men Who Have Sex With Men and Are Living With Human Immunodeficiency Virus in Tokyo

BACKGROUND

Hepatitis A virus (HAV) can be sexually transmitted. However, the level of HAV immunity among patients living with human immunodeficiency virus (HIV) in Japan is unknown. Determining the epidemiology of HAV infections among men who have sex with men (MSM) and who are living with HIV is essential for an HAV vaccination program. This study examined HAV immunity in patients living with HIV and applied the decision-tree analysis to explore the factors of immunoglobulin G (IgG)-hepatitis A (HA) antibodies in MSM living with HIV.

METHODS

We examined the presence of IgG-HA antibodies among patients living with HIV from January to December 2017 in The Hospital of The Institute of Medical Science, The University of Tokyo. We recorded each patient's age, sex, mode of HIV transmission, year of HIV diagnosis, HAV vaccine status, history of HAV infection, and history of other infectious diseases. A decision-tree algorithm was used to reveal the factors and profiles most relevant to the anti-HAV prevalence.

RESULTS

Overall, 378 MSM patients living with HIV were examined for IgG-HA antibodies. After excluding 24 patients who had received a HAV vaccine, the data of 354 MSM were analyzed (median age 45 years, interquartile range 39-51 years). Of the 354 patients, 60 (16.9%) were positive for IgG-HA antibodies. The HA positivity rate increased with patients' age, and age (> 63.5 years) was extracted as the most important variable by classification of the decision-tree algorithm.

CONCLUSIONS

Our study, conducted just before the HAV outbreak among MSM in Tokyo, showed that age was the most relevant factor in anti-HAV prevalences. An extensive HAV vaccination program for MSM patients living with HIV is urgently needed, particularly for younger people.

Artificial intelligence and machine learning could support drug development for hepatitis A virus internal ribosomal entry sites

Hepatitis A virus (HAV) infection is still an important health issue worldwide. Although several effective HAV vaccines are available, it is difficult to perform universal vaccination in certain countries. Therefore, it may be better to develop antivirals against HAV for the prevention of severe hepatitis A. We found that several drugs potentially inhibit HAV internal ribosomal entry site-dependent translation and HAV replication. Artificial intelligence and machine learning could also support screening of anti-HAV drugs, using drug repositioning and drug rescue approaches.

Prevalence of total hepatitis A antibody among 5 to 7 years old children and their mothers in Cambodia

This study determined the prevalence of total hepatitis A antibody (anti-HAV) among 5-7 years old children and their mothers in the whole Cambodia, using a nationwide study, and examined the differences between the two cohorts. A total of 4535 dried blood spot-driven (DBS) samples (2021 mothers and their 2514 children of 5-7 years old) and the concomitant 922 whole blood samples (subset of the whole participants) were collected using a multistage random sampling strategy throughout Cambodia in 2017. Total anti-HAV was detected using the chemiluminescence enzyme immunoassay method. Compared to gold standard whole blood samples, the sensitivity and specificity of DBS mediated anti-HAV detection were 94.8% and 98%, respectively. Total anti-HAV prevalence among mothers was 91.2% (95%CI: 90.0-92.5%), and that of their children was 31.5% (95%CI: 29.7-33.3%). In our study, the low prevalence of total anti-HAV among children indicates the country's improvement of safe water and food supply, hygiene and sanitation. If the hygiene and sanitation are consistently improved in Cambodia, the prevalence might be no longer increased when the children become adults.

Male-Dominant Hepatitis A Outbreak Observed among Non-HIV-Infected Persons in the Northern Part of Tokyo, Japan

Recently, we experienced an outbreak of acute hepatitis A virus (HAV) infection between 2018 and 2020. Herein, we describe this male-dominant HAV infection outbreak observed among non-human immunodeficiency virus (HIV)-infected persons in the northern part of Tokyo, Japan. Clinical information was collected from patient interviews and from medical record descriptions. In the present study, 21 patients were retrospectively analyzed. A total of 90.4 and 33.3% of patients were males, and men who have sex with men (MSM), respectively. The total bilirubin levels and platelet counts tended to be lower in the MSM group than in the non-MSM group. C-reactive protein (CRP) levels tended to be higher in acute liver failure (ALF) patients than in non-ALF patients. Prolonged cholestasis was observed in one patient (4.8%). We also found that 18 HAV isolates belonged to HAV subgenotype IA/subgroup 13 (S13), which clustered with the HAV isolate (KX151459) that was derived from an outbreak of HAV infection among MSM in Taiwan in 2015. Our results suggest that the application of antivirals against HAV, as well as HAV vaccines, would be useful for the treatment and prevention of severe HAV infection.

Co-Occurrence of Hepatitis A Infection and Chronic Liver Disease

Hepatitis A virus (HAV) infection occasionally leads to a critical condition in patients with or without chronic liver diseases. Acute-on-chronic liver disease includes acute-on-chronic liver failure (ACLF) and non-ACLF. In this review, we searched the literature concerning the association between HAV infection and chronic liver diseases in PubMed. Chronic liver diseases, such as metabolic associated fatty liver disease and alcoholic liver disease, coinfection with other viruses, and host genetic factors may be associated with severe hepatitis A. It is important to understand these conditions and mechanisms. There may be no etiological correlation between liver failure and HAV infection, but there is an association between the level of chronic liver damage and the severity of acute-on-chronic liver disease. While the application of an HAV vaccination is important for preventing HAV infection, the development of antivirals against HAV may be important for preventing the development of ACLF with HAV infection as an acute insult. The latter is all the more urgent given that the lives of patients with HAV infection and a chronic liver disease of another etiology may be at immediate risk.

Hepatitis A virus and hepatitis E virus prevalence relates to human immunodeficiency virus infection in Japanese male blood donors

Hepatitis A virus (HAV) has begun to spread globally among men who have sex with men (MSM). Hepatitis E virus (HEV) also may be transmitted through sexual contact among MSM. To assess the current status of these viruses among MSM in Japan, the seroprevalence of both viruses using 503 plasma samples collected between 2009 and 2018 from human immunodeficiency virus (HIV)-positive male donors who were presumed to be mainly MSM was investigated. Our results suggested that HAV may be spreading within this population, as reported elsewhere. By contrast, the spread of HEV was confirmed only among younger HIV-positive donors.

Immunity to hepatitis A among men who have sex with men attending a large sexual health clinic in Melbourne, Australia, 2012-2018

BACKGROUND

Outbreaks of hepatitis A are being reported more commonly among men who have sex with men (MSM) globally. Australia has also reported a sharp increase in the number of cases of hepatitis A in 2017. This study aimed to determine the level of immunity to hepatitis A among MSM attending a large urban sexual health clinic in Victoria in the lead up to recent outbreak.

METHODS

This was a retrospective audit of serological testing data from first-time MSM attendees at Melbourne Sexual Health Centre (MSHC) in Australia from 1 January 2012 to 31 December 2018. We determined the proportion of MSM who were tested and who had serological detection of hepatitis A IgG, stratified by age and calendar year. We used univariable and multivariable logistic regression to investigate factors associated with testing for and detection of hepatitis A IgG.

RESULTS

There were 16 609 first-time MSM attendees at MSHC over the 7-year period, of which 9718 (59%, 95% CI 58% to 60%) were tested for hepatitis A IgG. There was a 2% annual increase in the proportion of men tested (from 60% in 2012 to 69% in 2018; OR=1.02, 95% CI 1.00 to 1.03, p=0.025). Men born outside of Australia/New Zealand, and younger men <30 years had higher odds of being tested. Of those tested, 44% (n=4304, 95% CI 43% to 45%) had hepatitis A IgG detected at their first visit, with no change over time (OR=1.01, 95% CI 0.99 to 1.03, p=0.210). Detection of hepatitis A IgG was associated with being aged 30 years or older (adjusted OR=2.06, 95% CI 1.89 to 2.24, p<0.001) or being born overseas versus Australia/New Zealand (AOR=1.21, 95% CI 1.11 to 1.31, p<0.001).

CONCLUSION

Hepatitis A immunity among MSM remains below the estimated 70% required to prevent outbreaks. Measures including increased testing and higher vaccination coverage are needed to prevent outbreaks and to limit the number of cases and deaths.

Hepatitis E Infection in Nigeria: A Systematic Review

BACKGROUND:

Research done globally on hepatitis E virus (HEV) infection is far fewer compared with other types of hepatitis virus infection. Little is known on the prevalence of HEV in Nigeria.

AIM:

The present study presents the prevalence of HEV infection in Nigeria from a few available research papers on HEV. The detailed statistical analysis was used to analyse the prevalence of HEV in humans and animals.

MATERIAL AND METHODS:

A literature search in Web of Science, Scopus and PubMed databases was done, and a final 7 articles were selected. Minitab 17.0 was used to perform the correlational and binary logistic analyses.

RESULTS:

Serum and faecal analysis of blood and stool samples of 1178 humans and 210 pigs (animals) were done, and the presence of anti-HEV IgG or HEV RNA in the study samples were 127 and 138 respectively. Further analysis showed the prevalence of HEV are 10.8% and 65.7% in humans and animals, respectively. Weak positive non-significant association (r = 0.327, p-value = 0.474) was obtained between the target (humans and animal) and the HEV infection (positive) groups. The application of binary logistic regression yielded an equation that can be used to predict the target group from the HEV positive humans or animals. Generally, the logistic model was not statistically significant (p-value = 0.376), and the model was able to explain 9.3% of the deviation or variability of the model. The odds ratio is OR = 1.0344 with 0.9550, 1.204 95% Confidence Interval (CI). Thus, in Nigeria, the odds of prevalence of HEV in animals are 1.0344 higher than humans.

CONCLUSION:

The risk factors obtained from the few available articles are consistent with the global epidemiology of HEV infection. Food and animal handlers and those that consume unsafe water are the key people at risk of HEV infection in Nigeria.