Molecular epidemiological studies show that hepatitis A virus is endemic among active homosexual men in Europe

Hepatitis A virus subtype IB outbreak among MSM in Hungary with a link to a frozen berry source

Men who have sex with men (MSM) are at high risk of acquiring hepatitis A virus (HAV) and in recent years several HAV outbreaks mostly affecting MSM have been described. These outbreaks were caused by subtype IA strains circulating in this high-risk population. After years of low incidence, an outbreak among MSM in Hungary caused a significant increase in reported HAV infections in 2022. Samples from 224 HAV IgM-positive patients diagnosed in 2022 were tested for HAV RNA and positive samples were genotyped by sequencing. In 171 patients a unique subtype IB virus was detected with 99.8-100% sequence identity in the VP1/P2A junction. It was distinct from previously published strains, but most closely related to an Egyptian isolate. Sequence analysis revealed one dominant and three minor variants based on VP1/P2A. Whole genome sequencing revealed limited variation among these variants, suggesting a recent common origin. Epidemiological data indicated that sexual transmission was driving the outbreak for most of the year, suggested by the high male to female ratio and the large number of coinfections with HIV and other sexually transmitted infections among the patients. The outbreak was also associated with a restaurant cluster, in which one of the variants was detected and frozen berries were implicated as the source of infections. The outbreak strain was also detected in other countries around Europe and remained frequently detectable in Hungary in 2023. This study provides insights into the molecular and epidemiological characteristics of the described HAV outbreak. The results show that sequencing is not only useful in connecting cases to an outbreak, but also helps to clarify the relatedness of detected variants. Prevention strategies focusing on vulnerable communities may reduce the burden of HAV infections in the future.

Concurrent Outbreaks of Hepatitis A, Invasive Meningococcal Disease, and Mpox, Florida, USA, 2021-2022

In 2022, concurrent outbreaks of hepatitis A, invasive meningococcal disease (IMD), and mpox were identified in Florida, USA, primarily among men who have sex with men. The hepatitis A outbreak (153 cases) was associated with hepatitis A virus genotype IA. The IMD outbreak (44 cases) was associated with Neisseria meningitidis serogroup C, sequence type 11, clonal complex 11. The mpox outbreak in Florida (2,845 cases) was part of a global epidemic. The hepatitis A and IMD outbreaks were concentrated in Central Florida and peaked during March--June, whereas mpox cases were more heavily concentrated in South Florida and had peak incidence in August. HIV infection was more common (52%) among mpox cases than among hepatitis A (21%) or IMD (34%) cases. Where feasible, vaccination against hepatitis A, meningococcal disease, and mpox should be encouraged among at-risk groups and offered along with program services that target those groups.

Hepatitis A and B vaccination in gbMSM in Ireland: findings from the European MSM Internet Survey 2017 (EMIS-2017)

OBJECTIVES

Gay, bisexual and other men who have sex with men (gbMSM) have a higher risk of acquiring hepatitis A and B viruses (HAV and HBV) than the general population and are recommended for vaccination against both in Ireland. This study aims to determine the prevalence of self-reported HAV and HBV infection and vaccination among gbMSM in Ireland and explore factors associated with self-reported HAV and HBV vaccination among gbMSM.

METHODS

This study analysed Irish data from the European MSM Internet Survey 2017 (EMIS-2017) to measure the prevalence of self-reported HAV and HBV infection and vaccination among gbMSM in Ireland. Multivariable logistic regression was used to explore the associations between sociodemographic, healthcare-related and behavioural factors and self-reported vaccination.

RESULTS

There were 2083 EMIS-2017 respondents in Ireland. Among HIV-negative gbMSM, 4.6% and 4.4% reported previous HAV and HBV infection, respectively, and 51% and 57% reported the receipt of one or more vaccine dose for HAV and HBV, respectively. In the multivariable analysis, HIV-negative gbMSM had lower odds of self-reported HAV vaccination if they lived outside the capital, Dublin (aOR 0.61, 95% CI: 0.48 to 0.78), had no third-level education (aOR 0.65, 95% CI: 0.45 to 0.92), were not tested for HIV in the last year (aOR 0.39, 95% CI: 0.31 to 0.50), had never tried to obtain pre-exposure prophylaxis (PrEP, aOR 0.60, 95% CI: 0.38 to 0.96) and had not been diagnosed with a sexually transmitted infection (STI) in the previous year (aOR 0.42, 95% CI: 0.28 to 0.63). Similar associations were observed for self-reported HBV vaccination.

CONCLUSIONS

Self-reported vaccination against HAV and HBV among gbMSM in Ireland is high, but the level of vaccination remains insufficient to protect against future HAV and HBV infections and outbreaks. Efforts to increase vaccination coverage among gbMSM should focus on men who live outside the capital, have lower educational attainment and do not engage with sexual health services.

Sexual Transmission of Viral Hepatitis

Ongoing sexual transmission presents a significant barrier to viral hepatitis control. Endemic transmission of hepatitis A virus continues through communities of men with male sex partners, despite vaccine availability. Increased incidence of hepatitis B virus from 2014-2018 prompted expanded vaccination guidelines, but uptake and physician awareness remain poor. Hepatitis C virus while strongly associated with injection drug use, is also transmitted by high-risk sexual contact. Despite universal screening recommendations and curative treatment, incidence continues to increase. Even with safe and highly effective vaccinations or treatments, sexual transmission of viral hepatitides must be addressed to achieve disease elimination.

Hepatitis A notifications in the EU/EEA, 2010-2019: what can we learn from case reporting to the European Surveillance System?

BackgroundEuropean Union/European Economic Area (EU/EEA) countries annually report hepatitis A (HepA) notifications to The European Surveillance System (TESSy).AimTo describe EU/EEA HepA notifications from 2010 to 2019 and identify infection drivers and surveillance improvements.MethodsWe analysed demographic, clinical and transmission information of HepA confirmed cases from TESSy. We stratified countries by population susceptibility profile and performed time-series analysis to describe trends in notification rates, sex distribution and travel history.ResultsTwenty-nine EU/EEA countries reported 139,793 HepA cases. Six eastern EU countries reported > 60% of these cases. EU/EEA notification rate during the study period was 3.2 cases per 100,000 population (range 2.7-5.6). Notifications peaked in 2014 and 2017, with marked differences in case demographic characteristics. Notification trends varied across different country susceptibility groups. In 2017, the proportion of males (74%) and case median age (31 years) increased steeply, while no changes occurred in 2014. Travel history showed seasonal case peaks following the summer. More than 47,000 hospitalisations were reported. Annual case fatality was < 0.2% for all years. Information on travel history, hospitalisation, death and mode of transmission was suboptimal.DiscussionApart from some countries in its east, the EU/EEA is characterised by low HepA incidence baseline and susceptible to recurrent large cross-border outbreaks. Analysis of European surveillance data highlighted the need for stronger prevention policies for eastern EU countries, men who have sex with men and travellers. Improving surveillance data-quality will enhance knowledge on food-borne, and travel-related exposures to inform more effective and tailored regional prevention policies.

Changing molecular epidemiology of Hepatitis A virus in Santiago, Chile from 2010 to 2021

OBJECTIVES

Hepatitis A (HAV) virus causes asymptomatic to life-treating fulminant hepatitis. During infection, patients show large viral excretion in their stools. Resistance of HAV to environmental conditions, allows us to recover viral nucleotide sequences from wastewater and trace its evolutionary history.

METHODS

We characterize twelve years of HAV circulation in wastewater from Santiago, Chile, and conducted phylogenetic analyses to decipher the dynamics of circulating lineages.

RESULTS

We observed the exclusive circulation of the HAV IA genotype. The molecular epidemiologic analyses showed a steady circulation of a dominant lineage with low genetic diversity (d = 0,007) between 2010 and 2017. An outbreak of Hepatitis A associated with men who have sex with men, in 2017 was associated with the irruption of a new lineage. Remarkably, a dramatic change in the dynamic of HAV circulation was observed in the period post-outbreak; between 2017 and 2021 when 4 different lineages were transiently detected. Exhaustive phylogenetic analyses indicate that these lineages were introduced and possibly derived from isolates from other Latin American countries.

CONCLUSION

The HAV circulation in recent years in Chile is rapidly changing and suggests that this phenomenon could be a consequence of massive population migrations in Latin America caused by political instability and natural disasters.

Hepatitis A virus (HAV) RNA detection in Polish blood donors and likely transmissions through blood components during the 2017-2019 epidemic

BACKGROUND

In Poland, hepatitis A virus (HAV) RNA screening was performed in plasma for fractionation usually immediately before shipment.

OBJECTIVE

Our goal was to study epidemiology, rate of transfusion transmitted HAV during epidemic (2017-2019), and viral characteristics of infected plasma donors.

STUDY DESIGN AND METHODS

HAV RNA was tested in 1,866,590 donations from 1,210,423 donors using RT-PCR in mini pools of 96 (MP96) or TMA in MP16. Virological characteristics included RNA level (RL), antibody testing, and sequencing.

RESULTS

Twenty-one HAV infections were identified (1.13/100,000 donations; 95% confidence interval [95% CI]: 0.74-1.72) and (1.73/100,000 donors; 95% CI: 1.35-2.65). The Blood Transfusion Centers were also informed about three donors, who were hospitalized for hepatitis A soon after their blood donation. In addition, we identified a donor, who had reactive result for HAV after receiving HAV vaccination. He tested positive twice 10 days after receiving the first and the second dose. The highest RL was 16 million IU/ml, mean 1,706,905 IU/ml, and median 220 IU/ml. The longest detectable RL lasted for 113 days. HAV-infected donors were seronegative (36%) or IgM positive (64%). We followed up on 12 HAV contaminated blood components issued for transfusion. In two out of seven identified patients viral transmission was confirmed (28.6%).

CONCLUSION

Based on our results, we propose a 6 month deferral after HAV infection and 14 days post HAV vaccination. The infectivity rate was below 30%. The HAV RNA testing could be considered as an additional safeguard against HAV transmission at the time of increased incidence of HAV infections in the general population.

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.

Brazilian Protocol for Sexually Transmitted Infections, 2020: sexually transmitted enteric infections

The sexually transmitted enteric infections topic is one of the chapters of the Clinical Protocol and Therapeutic Guidelines for Comprehensive Care for People with Sexually Transmitted Infections, published by the Brazilian Ministry of Health in 2020. The document was developed based on scientific evidence and validated in discussions with specialists. This article presents epidemiological and clinical aspects of these infections and guidance for service managers on their programmatic and operational management. The aim is to assist health professionals with screening, diagnosis, and treatment of people with sexually transmitted enteric infections and their sexual partners, in addition to supporting strategies for their surveillance, prevention, and control. The incidence of anorectal sexually transmitted infections has increased over the last years, mainly due to the increase in the practice of unprotected receptive anal sexual intercourse.

[Brazilian Protocol for Sexually Transmitted Infections 2020: sexually transmitted enteric infections]

The topic of sexually transmitted enteric infections is one of the chapters of the Clinical Protocol and Therapeutic Guidelines for Comprehensive Care for People with Sexually Transmitted Infections, published by the Brazilian Ministry of Health in 2020. The document was developed based on scientific evidence and validated in discussions with specialists. This article presents epidemiological and clinical aspects related to these infections, as well as guidance for service managers on their programmatic and operational management. The aim is to assist health professionals with screening, diagnosis and treatment of people with sexually transmitted enteric infections and their sexual partners, in addition to supporting strategies for their surveillance, prevention and control.

A description of a hepatitis A outbreak in men who have sex with men and public health measures implemented in Seine-Maritime department, Normandy, France, 2017

BACKGROUND

In 2016-2017, a European-wide circulation of genotype IA hepatitis A virus was responsible for hepatitis A outbreaks in men who have sex with men (MSM). This study aimed to describe the outbreak investigation in Seine-Maritime department (France) and the control measures implemented accordingly.

METHODS

Outbreak description used data from mandatory reporting and enhanced surveillance of male cases. Confirmed case was genotype IA isolated, possible cases had no reported genotype information. Targeted control measures included communication on sexual practices at risk of hepatitis A transmission and two vaccination campaigns in April 2017 and January 2018. Characteristics of cases and vaccinees were described. We reported the best communication channel for relaying outbreak information and control measures based on the monitoring of social network activities and feedback from vaccinees.

RESULTS

During the outbreak period (December 2016 to December 2017), a total of 48 confirmed outbreak cases and 30 possible outbreak cases were notified. Among them, 69 were male (88%). Two epidemic waves were observed. Cases encountered their partners through gay-dating apps (54%) and in one specific sauna (62%). In response to the outbreak, two vaccination campaigns were deployed. A total of 156 MSM were vaccinated, of whom 56 in a truck parked beside the sauna. Most of the vaccinees had been informed about the campaign through dating apps (44%). Community-based organizations involved in sexual health promotion and other gay social media were very proactive in sharing information about the outbreak and promoting the vaccination campaign through their social media account and also on site (gay venues). Vaccinees reported the same sexual practices at risk of hepatitis A transmission as cases.

CONCLUSIONS

In response to this massive hepatitis A outbreak that affected mostly MSM in Seine-Maritime department, vaccination campaign remained the cornerstone of prevention. Prevention officers from the community-based organization played a key role in vaccination promotion. Gay-dating apps and outdoor sessions of vaccination allowed to effectively reach MSM. Cost-effectiveness studies might analyze the interest of a continuous sexual health promotion including vaccination against hepatitis A in MSM through dating apps and social networks.

Hepatitis A virus-associated fulminant hepatitis with human immunodeficiency virus coinfection

Hepatitis A virus (HAV) commonly causes acute hepatitis in humans and is transmitted through the fecal-oral route or by ingestion of contaminated food or water. HAV infection generally follows a self-limiting course; it can seldom cause fulminant hepatitis that increases the risk of mortality. To the best of our knowledge, this is the first reported fatal case of fulminant hepatitis caused by HAV in a 40-year-old male with human immunodeficiency virus (HIV) infection. The HAV genotype in this case was IA, which has recently become common globally among people living with HIV (PLWHIV), intravenous drug users, and homeless people especially in developed countries. His HIV infection was stabilized by antiretroviral drugs and his CD4 values were stable. He developed acute hepatic encephalopathy, did not respond to repeated plasma exchange therapy, and died rapidly. It is known that HIV co-infection sometimes leads to fulminant non-HAV hepatitis, although evidence supporting a correlation between fulminant hepatitis A risk and HIV infection is still lacking. This case demonstrated the fatal risk of HAV infection in PLWHIV; it was suggested that education about appropriate preventive measures and vaccination are important for preventing HAV infections among PLWHIV.

Emerging hepatitis E virus compared with hepatitis A virus: A new sanitary challenge

Hepatitis A (HAV) and E (HEV) viruses are able to cause liver disease in humans. Among the five classical hepatotropic viruses, they are mainly transmitted via the fecal-oral route. Historically, many similarities have thus been described between them according to their incidence and their pathogenicity, especially in countries with poor sanitary conditions. However, recent advances have provided new insights, and the gap is widening between them. Indeed, while HAV infection incidence tends to decrease in developed countries along with public health improvement, HEV is currently considered as an underdiagnosed emerging pathogen. HEV autochthonous infections are increasingly observed and are mainly associated with zoonotic transmissions. Extra hepatic signs resulting in neurological or renal impairments have also been reported for HEV, as well as a chronic carrier state in immunocompromised patients, arguing in favor of differential pathogenesis between those two viruses. Recent molecular tools have allowed studies of viral genome variability and investigation of links between viral plasticity and clinical evolution. The identification of key functional mutations in viral genomes may improve the knowledge of their clinical impact and is analyzed in depth in the present review.

New Subgenotyping and Consensus Real-Time Reverse Transcription-PCR Assays for Hepatitis A Outbreak Surveillance

Laboratory surveillance plays an important role in the detection and control of hepatitis A outbreaks and requires the application of rapid and accurate molecular diagnostic tools for hepatitis A virus (HAV) RNA detection, subgenotype identification, and sequence-based genotyping. We describe the development and validation of a triplex real-time, reverse transcription-PCR (triplex rRT-PCR) assay for the identification and discrimination of HAV subgenotypes IA, IB, and IIIA and a singleplex rRT-PCR assay designed to detect all HAV genotypes infecting humans. Overall, the accuracy, sensitivity, and specificity of the new assays were >97% for serum and plasma specimens collected during unrelated outbreaks of HAV in California and Michigan compared to a nested RT-PCR genotyping assay and the ISO 15216-1 rRT-PCR method for HAV detection. The new assays will permit the rapid detection of HAV RNA and discrimination among subgenotypes IA, IB, and IIIA in serum and plasma specimens, which will strengthen public health surveillance efforts for HAV outbreak detection and response.

Recent epidemiology of sexually transmissible enteric infections in men who have sex with men

PURPOSE OF REVIEW

Sexual transmission of enteric pathogens in men who have sex with men (MSM) has been described since the 1970s. Recently, an increasing number of enteric infection outbreaks have been reported in MSM. This article summarizes recent outbreaks and discusses the key issues for prevention and control.

RECENT FINDINGS

Sexually transmissible enteric infections (STEIs) can spread rapidly and internationally within highly connected MSM populations and are often associated with antimicrobial resistance (AMR). The infections often cluster in high-risk groups of HIV-positive MSM who are more likely to engage in diverse sexual practices and chemsex, and to have multiple other sexually transmitted infections (STIs).

SUMMARY

The roles of asymptomatic and/or persistent infection and other contextual factors in STEI transmission are not well described. STEI-associated AMR is increasing and has potential to spread rapidly in MSM, warranting further public health attention. A better understanding of the factors associated with sexual transmission will enable the development of more effective control measures. A holistic approach that promotes health and wellbeing as well as infection prevention and management is needed.

Outbreak of hepatitis A virus infection in Taiwan, June 2015 to September 2017

The Taiwan Centers for Disease Control (CDC) were notified of increasing acute hepatitis A (AHA) in June 2015. Serum and/or stool from AHA patients and sewage samples were tested for hepatitis A virus (HAV). We defined outbreak cases as AHA patients with illness onset after June 2015 and with an HAV sequence less than 0.5% different from that of the TA-15 outbreak strain. We analysed characteristics and food exposures between outbreak and non-outbreak cases between January 2014 (start of enhanced surveillance) and February 2016. From June 2015 to September 2017, there were 1,563 AHA patients with a median age of 31 years (interquartile range (IQR): 26-38); the male-to-female ratio was 8.8 and 585 (37%) had human immunodeficiency virus (HIV) infection. TA-15 was detected in 82% (852/1,033) of AHA patients, and 14% (74/540) of sewage samples tested since July 2015. Infection with the TA-15 strain was associated with having HIV, sexually transmitted infections (STI), recent oral-anal sex and men who have sex with men (MSM). The Taiwan CDC implemented an HAV vaccine campaign starting from October 2016 where 62% (15,487/24,879) of people at risk were vaccinated against HAV. We recommend HAV vaccination for at-risk populations and continuous surveillance to monitor control measures.

Evidence for positive selection of hepatitis A virus antigenic variants in vaccinated men-having-sex-with men patients: Implications for immunization policies

Background

A huge outbreak in the men-having-sex-with-men (MSM) has hit Europe during the years 2016–2018. Outbreak control has been hampered by vaccine shortages in many countries, and to minimize their impact, reduction of antigen doses has been implemented. However, these measures may have consequences on the evolution of hepatitis A virus (HAV), leading to the emergence of antigenic variants. Cases in vaccinated MSM patients have been detected in Barcelona, opening the possibility to study HAV evolution under immune pressure.

Methods

We performed deep-sequencing analysis of ten overlapping fragments covering the complete capsid coding region of HAV. A total of 14578255 reads were obtained and used for the analysis of virus evolution in vaccinated versus non-vaccinated patients. We estimated maximum and minimum mutation frequencies, and Shannon entropy in the quasispecies of each patient. Non-synonymous (NSyn) mutations affecting residues exposed in the capsid surface were located, with respect to epitopes, using the recently described crystal structure of HAV, as an indication of its potential role in escaping to the effect of vaccines.

Findings

HAV evolution at the quasispecies level, in non-vaccinated and vaccinated patients, revealed higher diversity in epitope-coding regions of the vaccinated group. Although amino acid replacements occurring in and around the epitopes were observed in both groups, their abundance was significantly higher in the quasispecies of vaccinated patients, indicating ongoing processes of fixation.

Interpretation

Our data suggest positive selection of antigenic variants in some vaccinated patients, raising concerns for new vaccination polices directed to the MSM group.

Successful Use of Advertisement Pictures to Assist Recall in a Food-Borne Hepatitis A Outbreak in The Netherlands, 2017

This study describes an outbreak investigation of 14 hepatitis A cases in the Netherlands. The hepatitis A virus (HAV) genotype IB sequences in cases were highly similar (459/460 nt). The origin of strains could be narrowed to Bulgaria based on information from EPIS-FWD. As an association with consumption of soft fruit was suspected, a case-control study was initiated using a questionnaire and a list of pictures of soft fruit available at the supermarket chain involved. Twelve out of 13 cases consumed a specific frozen raspberry/blueberry product shown on the list (OR 46.0, 95% CI 5.0-27). In multivariable regression analysis this product was the only risk factor (aOR 26.6, 95% CI 2.0-263). Laboratory analyses could not demonstrate HAV-RNA in batches that had been on the market in the incubation period of patients. Trace back of frozen fruit showed that raspberries had been traded by a producer in Bulgaria. After withdrawal of the product from the supermarket no new cases were reported. Use of advertisement pictures of consumed food was helpful in this investigation. Suspicion of the source was strengthened by data from molecular typing and food trace back activities, underlining the importance of good (inter)national cooperation between public health and food safety organisations.

Hepatitis A outbreak disproportionately affecting men who have sex with men (MSM) in the European Union and European Economic Area, June 2016 to May 2017

Between 1 June 2016 and 31 May 2017, 17 European Union (EU) and European Economic Area countries reported 4,096 cases associated with a multi-country hepatitis A (HA) outbreak. Molecular analysis identified three co-circulating hepatitis A virus (HAV) strains of genotype IA: VRD_521_2016, V16-25801 and RIVM-HAV16-090. We categorised cases as confirmed, probable or possible, according to the EU outbreak case definitions. Confirmed cases were infected with one of the three outbreak strains. We investigated case characteristics and strain-specific risk factors for transmission. A total of 1,400 (34%) cases were confirmed; VRD_521_2016 and RIVM-HAV16-090 accounted for 92% of these. Among confirmed cases with available epidemiological data, 92% (361/393) were unvaccinated, 43% (83/195) travelled to Spain during the incubation period and 84% (565/676) identified as men who have sex with men (MSM). Results depict an HA outbreak of multiple HAV strains, within a cross-European population, that was particularly driven by transmission between non-immune MSM engaging in high-risk sexual behaviour. The most effective preventive measure to curb this outbreak is HAV vaccination of MSM, supplemented by primary prevention campaigns that target the MSM population and promote protective sexual behaviour.

Microfluidic PCR Amplification and MiSeq Amplicon Sequencing Techniques for High-Throughput Detection and Genotyping of Human Pathogenic RNA Viruses in Human Feces, Sewage, and Oysters

Detection and genotyping of pathogenic RNA viruses in human and environmental samples are useful for monitoring the circulation and prevalence of these pathogens, whereas a conventional PCR assay followed by Sanger sequencing is time-consuming and laborious. The present study aimed to develop a high-throughput detection-and-genotyping tool for 11 human RNA viruses [Aichi virus; astrovirus; enterovirus; norovirus genogroup I (GI), GII, and GIV; hepatitis A virus; hepatitis E virus; rotavirus; sapovirus; and human parechovirus] using a microfluidic device and next-generation sequencer. Microfluidic nested PCR was carried out on a 48.48 Access Array chip, and the amplicons were recovered and used for MiSeq sequencing (Illumina, Tokyo, Japan); genotyping was conducted by homology searching and phylogenetic analysis of the obtained sequence reads. The detection limit of the 11 tested viruses ranged from 10⁰ to 10³ copies/μL in cDNA sample, corresponding to 10¹–10⁴ copies/mL-sewage, 10⁵–10⁸ copies/g-human feces, and 10²–10⁵ copies/g-digestive tissues of oyster. The developed assay was successfully applied for simultaneous detection and genotyping of RNA viruses to samples of human feces, sewage, and artificially contaminated oysters. Microfluidic nested PCR followed by MiSeq sequencing enables efficient tracking of the fate of multiple RNA viruses in various environments, which is essential for a better understanding of the circulation of human pathogenic RNA viruses in the human population.

Phylogenetic analysis reveals three distinct epidemiological profiles in Dutch and Flemish blood donors with hepatitis B virus infection

During 2006-2016, hepatitis B virus (HBV) was detected in nearly 400 blood donors in the Netherlands and Flanders. Donor demographics and self-reported risk factors as disclosed during the donor exit interview were compared to HBV phylogenies of donor and reference sequences. First-time donors with chronic HBV-infection were often immigrants (67%) infected with genetically highly diverse strains of genotypes A (32%), B (8%), C (6%), D (53%) and E to H (1%). Each subtype was strongly associated with donor ethnicity. In contrast, 57/62 (93%) of acute/recent HBV infections occurred among indigenous donors, of whom 67% was infected with one specific widely circulating epidemic HBV-A2 lineage. HBV typing identified three distinct epidemiological profiles: the import of chronic HBV infections through migration, longstanding transmission of non-epidemic HBV-A2 strains within western-Europe, and the active transmission of one epidemic HBV-A2 strain most likely fueled by sexual risk behavior.

Increase in sexually transmitted infections in a cohort of outpatient HIV-positive men who have sex with men in the Parisian region

OBJECTIVE

To describe the increased incidence of sexually transmitted infections (STIs) in a cohort of HIV-infected men who have sex with men (MSM), followed in a tertiary hospital of the Île-de-France region.

MATERIALS AND METHODS

We performed a monocentric, retrospective, and prospective study. We included symptomatic HIV-infected MSM patients who consulted for their annual consultation.

RESULTS

One hundred and eighty patients were seen between 2008-2011 and 215 between 2012-2015. We observed an increased incidence of STIs between the two periods (14 and 29.3%, respectively). These STIs includes: syphilis, hepatitis C, urethritis, and proctitis due to Chlamydia trachomatis and Neisseria gonorrhea.

CONCLUSION

A better management of symptomatic and asymptomatic STIs is needed for HIV-infected MSM patients.

Hepatitis A outbreak among men who have sex with men (MSM) predominantly linked with the EuroPride, the Netherlands, July 2016 to February 2017

Between July 2016 and February 2017, 48 male cases of hepatitis A were notified in the Netherlands. Of these, 17 identified as men who have sex with men (MSM). Ten of the 13 cases for whom sequencing information was available, were infected with a strain linked with the EuroPride that took place in Amsterdam in 2016. This strain is identical to a strain that has been causing a large outbreak among MSM in Taiwan.

Hepatitis A virus infection and hepatitis A vaccination in human immunodeficiency virus-positive patients: A review

Hepatitis A virus (HAV) is one of the most common infectious etiologies of acute hepatitis worldwide. The virus is known to be transmitted fecal-orally, resulting in symptoms ranging from asymptomatic infection to fulminant hepatitis. HAV can also be transmitted through oral-anal sex. Residents from regions of low endemicity for HAV infection often remain susceptible in their adulthood. Therefore, clustered HAV infections or outbreaks of acute hepatitis A among men who have sex with men and injecting drug users have been reported in countries of low endemicity for HAV infection. The duration of HAV viremia and stool shedding of HAV may be longer in human immunodeficiency virus (HIV)-positive individuals compared to HIV-negative individuals with acute hepatitis A. Current guidelines recommend HAV vaccination for individuals with increased risks of exposure to HAV (such as from injecting drug use, oral-anal sex, travel to or residence in endemic areas, frequent clotting factor or blood transfusions) or with increased risks of fulminant disease (such as those with chronic hepatitis). The seroconversion rates following the recommended standard adult dosing schedule (2 doses of HAVRIX 1440 U or VAQTA 50 U administered 6-12 mo apart) are lower among HIV-positive individuals compared to HIV-negative individuals. While the response rates may be augmented by adding a booster dose at week 4 sandwiched between the first dose and the 6-mo dose, the need of booster vaccination remain less clear among HIV-positive individuals who have lost anti-HAV antibodies.

Outbreak of hepatitis A associated with men who have sex with men (MSM), England, July 2016 to January 2017

Between July 2016 and January 2017, 37 confirmed cases of hepatitis A with two unique IA genotype strains primarily among men who have sex with men, were reported across eight areas in England and Northern Ireland. Epidemiological and laboratory investigations indicate that these strains may have been imported several times from Spain, with secondary sexual transmission in the United Kingdom. Local and national public health services are collaborating to control this ongoing outbreak.

Phylogenetic analysis of a transfusion-transmitted hepatitis A outbreak

A transfusion-associated hepatitis A outbreak was found in the first time in Hungary. The outbreak involved five cases. Parenteral transmission of hepatitis A is rare, but may occur during viraemia. Direct sequencing of nested PCR products was performed, and all the examined samples were identical in the VP1/2A region of the hepatitis A virus genome. HAV sequences found in recent years were compared and phylogenetic analysis showed that the strain which caused these cases is the same as that had spread in Hungary recently causing several hepatitis A outbreaks throughout the country.

Declining Trend of Hepatitis A Seroepidemiology in Association with Improved Public Health and Economic Status of Thailand

Hepatitis A virus (HAV) is transmitted via the fecal-oral route from contaminated food or water. As part of the most recent survey of viral hepatitis burden in Thailand, we analyzed the current seroprevalence of HAV in the country and compared with data dating back to 1971. From March to October, 2014, a total of 4,260 individuals between one month and 71 years of age from different geographical regions (North = 961; Central = 1,125; Northeast = 1,109; South = 1,065) were screened for anti-HAV IgG antibody using an automated chemiluminescent microparticle immunoassay. Overall, 34.53% (1,471/4,260) possessed anti-HAV IgG antibody, and the age-standardized seroprevalence was 48.6%. Seroprevalence rates were 27.3% (North), 30.8% (Central), 33.8% (Northeast) and 45.8% (South) and were markedly lower than in the past studies especially among younger age groups. The overall trend showed an increase in the age by which 50% of the population were anti-HAV IgG antibody: 4.48 years (1971–1972), 6 (1976), 12.49 (1990), 36.02 (2004) and 42.03 (2014).This suggests that Thailand is transitioning from low to very low HAV endemicity. Lower prevalence of HAV correlated with improved healthcare system as measured by decreased infant mortality rate and improved national economy based on increased GDP per capita. The aging HAV immuno-naïve population may be rendered susceptible to potential HAV outbreaks similar to those in industrialized countries and may benefit from targeted vaccination of high-risk groups.

International linkage of two food-borne hepatitis A clusters through traceback of mussels, the Netherlands, 2012

This report describes an outbreak investigation starting with two closely related suspected food-borne clusters of Dutch hepatitis A cases, nine primary cases in total, with an unknown source in the Netherlands. The hepatitis A virus (HAV) genotype IA sequences of both clusters were highly similar (459/460 nt) and were not reported earlier. Food questionnaires and a case–control study revealed an association with consumption of mussels. Analysis of mussel supply chains identified the most likely production area. International enquiries led to identification of a cluster of patients near this production area with identical HAV sequences with onsets predating the first Dutch cluster of cases. The most likely source for this cluster was a case who returned from an endemic area in Central America, and a subsequent household cluster from which treated domestic sewage was discharged into the suspected mussel production area. Notably, mussels from this area were also consumed by a separate case in the United Kingdom sharing an identical strain with the second Dutch cluster. In conclusion, a small number of patients in a non-endemic area led to geographically dispersed hepatitis A outbreaks with food as vehicle. This link would have gone unnoticed without sequence analyses and international collaboration.

Epidemiology of sexually transmitted viral hepatitis in human immunodeficiency virus-positive men who have sex with men in Asia

Both human immunodeficiency virus (HIV) and viral hepatitis constitute major disease burden globally. As with other parts of the world, the HIV epidemic in Asia impacts mainly on men who have sex with men, one of the at-risk populations for sexually transmitted viral hepatitis. With the increasing availability of effective antiretroviral therapy, HIV-related mortality of people living with HIV has markedly reduced. Liver disease has become an important cause of mortality and morbidity in the HIV-infected population. With the improvement of socioeconomic conditions and availability of healthcare in Asian countries in recent years, the epidemiology of sexually transmitted viral hepatitis among HIV-positive men who have sex with men has also evolved. This review updates the epidemiology of different types of sexually transmitted viral hepatitis in this defined population in Asia.

Hepatitis A virus genotype distribution during a decade of universal vaccination of preadolescents

A universal vaccination program among preadolescents was implemented in Catalonia, Spain, during the period of 1999-2013 and its effectiveness has been clearly demonstrated by an overall significant attack rate reduction. However, reductions were not constant over time, and increases were again observed in 2002-2009 due to the occurrence of huge outbreaks. In the following years, in the absence of large outbreaks, the attack rate decreased again to very low levels. However, an increase of symptomatic cases in the <5 age group has recently been observed. This is an unexpected observation since children younger than 6 are mostly asymptomatic. Such a long vaccination campaign offers the opportunity to analyze not only the effectiveness of vaccination, but also the influence of the circulating genotypes on the incidence of hepatitis A among the different age groups. This study has revealed the emergence of genotype IC during a foodborne outbreak, the short-lived circulation of vaccine-escape variants isolated during an outbreak among the men-having-sex-with-men group, and the association of genotype IIIA with the increase of symptomatic cases among the very young. From a public health perspective, two conclusions may be drawn: vaccination is better at an early age, and the vaccination schedule must be complete and include all recommended vaccine doses.

Underdiagnosis of foodborne hepatitis A, The Netherlands, 2008-2010(1.)

Outbreaks of foodborne hepatitis A are rarely recognized as such. Detection of these infections is challenging because of the infection’s long incubation period and patients’ recall bias. Nevertheless, the complex food market might lead to reemergence of hepatitis A virus outside of disease-endemic areas. To assess the role of food as a source of infection, we combined routine surveillance with real-time strain sequencing in the Netherlands during 2008–2010. Virus RNA from serum of 248 (59%) of 421 reported case-patients could be sequenced. Without typing, foodborne transmission was suspected for only 4% of reported case-patients. With typing, foodborne transmission increased to being the most probable source of infection for 16%. We recommend routine implementation of an enhanced surveillance system that includes prompt forwarding and typing of hepatitis A virus RNA isolated from serum, standard use of questionnaires, data sharing, and centralized interpretation of data.

Hepatitis A virus: host interactions, molecular epidemiology and evolution

Infection with hepatitis A virus (HAV) is the commonest viral cause of liver disease and presents an important public health problem worldwide. Several unique HAV properties and molecular mechanisms of its interaction with host were recently discovered and should aid in clarifying the pathogenesis of hepatitis A. Genetic characterization of HAV strains have resulted in the identification of different genotypes and subtypes, which exhibit a characteristic worldwide distribution. Shifts in HAV endemicity occurring in different parts of the world, introduction of genetically diverse strains from geographically distant regions, genotype displacement observed in some countries and population expansion detected in the last decades of the 20th century using phylogenetic analysis are important factors contributing to the complex dynamics of HAV infections worldwide. Strong selection pressures, some of which, like usage of deoptimized codons, are unique to HAV, limit genetic variability of the virus. Analysis of subgenomic regions has been proven useful for outbreak investigations. However, sharing short sequences among epidemiologically unrelated strains indicates that specific identification of HAV strains for molecular surveillance can be achieved only using whole-genome sequences. Here, we present up-to-date information on the HAV molecular epidemiology and evolution, and highlight the most relevant features of the HAV-host interactions.

Sexual transmission of viral hepatitis

Identification and vaccination of adults at risk for hepatitis B virus acquisition through sexual contact is a key strategy to reduce new hepatitis B virus infections among at-risk adults. Hepatitis C has emerged as a sexually transmitted infection among men with male sex partners (MSM). Several biological and behavioral factors have been linked to hepatitis C virus transmission among MSM, including human immunodeficiency virus coinfection; participation in sexual practices that result in mucosal damage or result in exposure to blood; presence of sexually transmitted diseases (STIs), particularly ulcerative STIs; multiple/casual sex partners; and unprotected anal intercourse.

Increased circulation of hepatitis A virus genotype IIIA over the last decade in St Petersburg, Russia

The current study, covering the period 2004-2009, is a part of long-term monitoring for hepatitis A virus (HAV) strains circulating in St Petersburg, Russia. The HAV RNA was isolated directly from the sera of hepatitis A patients and RT-PCR was carried out using primer pairs for VP1/2A and VP1 genomic regions. PCR products were sequenced and 324 nucleotides from VP1/2A and 332 from the VP1 region were used for phylogenetic analysis. The results show that the IA subtype was the most common circulating subtype during the follow-up period, as found in the previous study: almost 90% of the isolated HAV strains belonged to the IA subtype. The large hepatitis A food-borne outbreak in St Petersburg in 2005 was caused by HAV IA. However, the proportion of HAV isolates belonging to subtype IIIA significantly increased in the period 2001-2009 (7.9%) compared to the period 1997-2000 (none found). The subtype IIIA was first found in St Petersburg in 2001 among a group of intravenous drug users. The increase in its circulation during the decade suggests that this previously unusual genotype has been permanently introduced into the general population of St Petersburg. These results indicate the usefulness of molecular epidemiological methods for studying changes in the circulation of HAV strains.

Monophyletic outbreak of Hepatitis A involving HIV-infected men who have sex with men, Rome, Italy 2008-2009

BACKGROUND

Outbreaks of Acute Hepatitis A Virus (HAV) among men who have sex with men (MSM) have been reported in Europe and, recently, in Italy. From July 2008 through January 2010, 162 HAV infections were diagnosed at National Institute for Infectious Diseases, Rome, Italy, with high male-to-female ratio (M:F=7.5).

OBJECTIVES

The aim of this study was to characterize viral strains involved in this outbreak.

STUDY DESIGN

The sequences of VP1-2A junction of HAV genome, obtained from 67/97 HAV-RNA-positive samples, were used for phylogenetic analysis.

RESULTS

All but 1 of the HAV sequences were genotype 1A, 1 was genotype 1B. A monophyletic cluster, including 59/66 genotype IA sequences, was identified by phylogenetic analysis. This cluster included also 2 HAV strains isolated in Germany (2007) and France (2008) from MSM, that, in turn, were reported to be genetically correlated to HAV strains circulating in Tuscany in 2008. Among the males harboring an HAV strain belonging to the cluster, 62% reported to be MSM, and 25% were HIV-positive, 2 with acute HIV infection.

CONCLUSION

The outbreak occurred in Rome in 2008-2010, involving high proportion of HIV-infected MSM, is sustained by a monophyletic HAV strain, circulating around the same period also in other European countries. Possible factors favouring HAV spread among HIV-infected persons, such as high risk behavior and prolonged fecal excretion, need to be further elucidated. Timely identification of outbreaks with one or the same source of infection may be helpful to implement preventive measures addressing at risk populations.

Surveillance study of hepatitis A virus RNA on fig and date samples

A total of 91 fig and 185 date samples were analyzed by reverse transcription (RT) real-time PCR for the presence of hepatitis A virus (HAV) RNA. Two batches of dates tested positive, and the HAV RNA detected was genotyped as IA. These findings warrant further development of methods applicable to food which is consumed untreated and is exported from countries in which HAV is endemic.

Hepatitis A among men who have sex with men in Barcelona, 1989-2010: insufficient control and need for new approaches

Background

Men who have sex with men (MSM) are a known group at risk for hepatitis A and outbreaks among this group are frequent. In Barcelona, vaccination for MSM has been recommended since 1994. In 1998 a vaccination campaign among preadolescents was implemented and an immunization program in gay bathhouses began in 2004. Objective: to asses the incidence of hepatitis A in adults in Barcelona from 1989 to 2010 and to evaluate the outbreaks among MSM including all genotypes involved.

Methods

All cases of acute hepatitis A among young adults notified to the Public Health Agency of Barcelona from 1989 to 2010 were included for analyses. We calculated the annual incidence rate and the incidence ratio male-to-female (M:F) as a marker for MSM. Spearman's coefficient was used to evaluate trends. We also evaluated the outbreaks among MSM and compared their characteristics using Chi-squared and ANOVA test. Fragment amplification of the VP1/P2A region was used for genetic analysis.

Results

The median annual incidence for the period of study was 4.7/100000 among females and 11.7/100000 among males. The rate of hepatitis A for adult woman decreased over time (Spearman' coefficient = -0.63, p = 0.002), whereas there was no decrease for adult men (Spearman' coefficient = 0.097, p = 0.67). During the study period the M:F ratio increased (Spearman' coefficient = 0.73, p < 0.001).

Three large outbreaks among MSM were detected. When comparing outbreaks, there was a decrease in the percentage of bathhouse users (from 47% to 19%, p = 0.0001) and sex workers (from 6.5% to 0%) while the percentage of HIV infected individuals did not change significantly (range: 21%-28%, p = 0.36). The isolated strains were closely related to those circulating in Europe.

Conclusions

Annual incidences remain high among MSM without tendency to decrease. More strategies which effectively reach the whole MSM community are needed.

Hepatitis a virus vaccine escape variants and potential new serotype emergence

Six hepatitis A virus antigenic variants that likely escaped the protective effect of available vaccines were isolated, mostly from men who have sex with men. The need to complete the proper vaccination schedules is critical, particularly in the immunocompromised population, to prevent the emergence of vaccine-escaping variants.

Scientific Opinion on an update on the present knowledge on the occurrence and control of foodborne viruses

A review of the biology, epidemiology, diagnosis and public health importance of foodborne viruses was performed. Data needs to support a risk assessment were also identified. In addition possible control options and their anticipated impact to prevent or reduce the number of foodborne viral human infections were identified, including the scientific reasons for and against the establishment of food safety criteria and process hygiene criteria for viruses for certain food categories. Food may be contaminated by virus during all stages of the food supply chain, and transmission can occur by consumption of food contaminated during the production process (primary production, or during further processing), or contaminated by infected food handlers. Transmission of zoonotic viruses (e.g. HEV) can also occur by consumption of products of animal origin. Viruses do not multiply in foods, but may persist for extended periods of time as infectious particles in the environment, or in foods. At the EU-level it is unknown how much viral disease can be attributed to foodborne spread. The relative contribution of different sources (shellfish, fresh produce, food handler including asymptomatic shedders, food handling environment) to foodborne illness has not been determined. The Panel recommends focusing controls on preventive measures to avoid viral contamination rather than trying to remove/inactivate these viruses from food. Also, it is recommended to introduce a microbiological criteria for viruses in bivalve molluscs, unless they are labelled "to be cooked before consumption". The criteria could be used by food business operators to validate their control options. Furthermore, it is recommended to refine the regulatory standards and monitoring approaches in order to improve public health protection. Introduction of virus microbiological criteria for classification of bivalve molluscs production areas should be considered. A virus monitoring programme for compliance with these criteria should be risk based according to the findings of a sanitary survey.

Multicentric evaluation of new commercial enzyme immunoassays for the detection of immunoglobulin M and total antibodies against hepatitis A virus

A multicentric clinical study was conducted on representative sera from 1,738 European and U.S. subjects for the evaluation of new anti-hepatitis A virus enzyme immunoassays from Bio-Rad Laboratories. Comparison with reference DiaSorin S.p.A. tests confirmed the good performance of Bio-Rad assays (99.85% and 99.47% overall agreement in detecting total antibodies and IgM, respectively).

Use of a Catalytic Model to Estimate Hepatitis A Incidence in a Low-Endemicity Country

Background. Evaluating the cost-effectiveness of vaccine programs with dynamic modeling requires accurate estimates of incidence over time. Because infectious diseases are often underreported, supplementary data and statistical analyses are required to estimate true incidence. This study estimates the true incidence of hepatitis A virus (HAV) infection in Canada using a catalytic model. Methods. A catalytic model was used to reconcile HAV seroprevalence data with the corresponding true cumulative risk of infection estimated from incidence data. Results. The average annual reported incidence was 6.2 cases per 100 000 from 1980 to 1989 and 7.7/100 000 from 1990 to 1999, indicating that Canada is a low-incidence country. The seroprevalence in Canadian-born individuals (n = 7 studies) was approximately 1%−8% in ages <20, 1%−11% in ages 20–29, 7%−29% in ages 30–39, and higher in older age groups. Between 1980 and 1995, the catalytic model estimated an average annual incidence of 60/100 000 (95% confidence interval, 33–524); approximately 7.73 (4.21–67.33) times the average annual reported incidence of 7.78/100 000. For a typical birth cohort of 403 434 Canadians born in 1990, the model predicted 32 750 HAV cases by age 39, with a corresponding seroprevalence of approximately 8.12% by the year 2029. Implications. Reliable estimates of true incidence of infectious disease are required for cost-effectiveness analysis of infectious disease programs. Catalytic models enable the synthesis of dispersed data, quantification of data limitations, and reconciliation of these limitations to estimate true incidence for economic evaluations.

A unique HAV strain circulated in patients with acute HAV infection with different risk exposures in Tuscany, Italy

BACKGROUND

Acute Hepatitis A Virus (HAV) is reported to be an emergent problem in several developed countries.

OBJECTIVES AND STUDY DESIGN

The aim of this study was to analyse the HAV strains circulating among individuals with acute HAV infection, apparently transmitted by different routes, in several districts of Tuscany in central Italy, during the year 2008.

RESULTS

An outbreak of acute HAV infection occurred from May to August 2008 in Arezzo; 32 individuals were admitted to the hospital, in 25 of them at least a linkage with an infected food handler and/or household contacts was reported and in 3 homosexuality was a possible risk factor. In Florence, from January 2008 to August 2008, 41 individuals mainly homosexual men were admitted to two hospitals with the diagnosis of acute HAV. The phylogenetic analysis of VP1/2A region of HAV was used to characterize these HAV isolates. All viral sequences were assigned to genotype IA. All clustered in the same branch (bootstrap 82%) of phylogenetic tree, thus indicating the same circulating isolate. Apart of one isolate from France and one from Germany which were similar with the "Tuscany" strain reported here, high heterogeneity with the other European HAV strains reported in the GenBank in the last years, was observed.

CONCLUSION

The detection of a unique HAV isolate circulating in different Tuscany districts, suggests sequential transmission of HAV infection in this geographical area through possible links among acute hepatitis cases. The application of safe food handling practices and vaccination of homosexual men may contribute to the prevention of HAV infection.

Epidemiology of hepatitis A in Finland in 1990-2007

The seroepidemiology of hepatitis A virus (HAV) for the period 1990-2007 and the molecular epidemiology for the period 1994-2007 in Finland were studied. The incidence of hepatitis A has been very low since 1990, at 0.3-3.6/100,000 inhabitants, excluding two outbreaks in 1994-1995 and 2002-2003, both of which were connected to intravenous drug use. Serum samples (3,217) collected in the period 1997-1998 were tested for hepatitis A antibodies to assess the percentage of seropositive Finns. More than 50% of Finns aged over 55 were seropositive for hepatitis A, while less than 5% of those aged under 40 were seropositive. In addition, patient samples (52,012) from the period 1990 to 2007 were assessed for antibodies against HAV. In these samples the proportion of acute HAV infections stayed at around 2% per year (excluding outbreaks), whereas the overall seropositivity for hepatitis A increased from some 30% to 45%, which was most likely due to increased vaccinations. For molecular epidemiology, samples from 1994 to 2007 were analyzed by RT-PCR and sequencing. The results showed that most of the strains (82%) of HAV were of genotype IA but with an increasing number of genotypes IB and IIIA appearing during the last years of the study. All the cases seemed to be travel related and there was no endemic strain circulating in Finland. The low seroprevalence, especially in younger age groups, makes the population vulnerable to infection, which can be compensated for by increasing the number of vaccinations.

Unlocking pathogen genotyping information for public health by mathematical modeling

Molecular typing and mathematical modeling have gone through rapid development in the past decade. Both offer new insights into the epidemiology of infectious diseases, thereby contributing to a better understanding of transmission dynamics. Infectious disease surveillance and control benefit from the optimum use of these techniques. In this paper, we review recent developments and propose methods to integrate pathogen ecology and molecular evolution based on their common dependence on the underlying host contact patterns.

Epidemiology and genetic characterization of hepatitis A virus genotype IIA

Three hepatitis A virus (HAV) genotypes, I, II, and III, divided into subtypes A and B, infect humans. Genotype I is the most frequently reported, while genotype II is hardly ever isolated, and its genetic diversity is unknown. From 2002 to 2007, a French epidemiological survey of HAV identified 6 IIA isolates, mostly from patients who did not travel abroad. The possible African origin of IIA strains was investigated by screening the 2008 mandatory notification records of HAV infection: 171 HAV strains from travelers to West Africa and Morocco were identified. Genotyping was performed by sequencing of the VP1/2A junction in 68 available sera. Entire P1 and 5' untranslated regions of IIA strains were compared to reference sequences of other genotypes. The screening retrieved 5 imported IIA isolates. An additional autochthonous case and 2 more African cases were identified in 2008 and 2009, respectively. A total of 14 IIA isolates (8 African and 6 autochthonous) were analyzed. IIA sequences presented lower nucleotide and amino acid variability than other genotypes. The highest variability was observed in the N-terminal region of VP1, while for other genotypes the highest variability was observed at the VP1/2A junction. Phylogenetic analysis identified 2 clusters, one gathering all African and two autochthonous cases and a second including only autochthonous isolates. In conclusion, most IIA strains isolated in France are imported by travelers returning from West Africa. However, the unexplained contamination mode of autochthonous cases suggests another, still to be discovered geographical origin or a French reservoir to be explored.

Hepatitis A virus: serology and molecular diagnostics

The diagnosis of hepatitis A virus (HAV) infection is based on the detection of anti-HAV IgM. Shortcomings of this serological approach include the persistence of IgM after normalization of liver enzymes or its detection during polyclonal activation of the immune system due to unrelated viral infection or autoimmune diseases. Molecular diagnosis of HAV along with anti-HAV IgG avidity measurement are helpful in case of positive IgM where laboratory evidence of acute hepatitis is absent and there is no epidemiologic link to other cases. Molecular epidemiology allows us to determine whether viruses from different locations are related to each other and provides further understanding of viral epidemiology by identifying sources and transmission modes. It has been demonstrated that the rapid turnover of HAV strains in low-endemicity countries is caused by their introduction by travelers. Growing sequence databases allow for the identification of geographic origin of viral strains. Collaboration between surveillance laboratories, including database sharing, should be promoted for deeper investigation of outbreaks and improved prevention approaches.