Characterisation of an epidemic of hepatitis A virus involving intravenous drug abusers--infection by needle sharing?

Vaccination coverage among people who inject drugs: A systematic review

BACKGROUND

People who inject drugs may be at excess risk of acquiring vaccine-preventable diseases and negative associated health outcomes, but experience barriers to vaccination. We aimed to determine vaccination coverage among people who inject drugs globally.

METHODOLOGY

We conducted systematic searches of the peer-reviewed and grey literature, date limited from January 2008 to August 2023, focusing on diseases for which people who inject drugs are at elevated risk for and for which an adult vaccination dose is recommended (COVID-19, hepatitis A, hepatitis B, human papillomavirus, influenza, pneumococcal disease, tetanus). To summarise available data, we conducted a narrative synthesis.

RESULTS

We included 78 studies/reports comprising 117 estimates of vaccination coverage across 36 countries. Most estimates were obtained from high income countries (80%, n=94). We located estimates for hepatitis B vaccination in 33 countries, which included 18 countries with data on serological evidence of vaccine-derived hepatitis B immunity (range: 6-53%) and 22 countries with self-report data for vaccine uptake (<1-96%). Data for other vaccines were scarcer: reported hepatitis A vaccination coverage ranged 3-89% (five countries), COVID-19 ranged 4-84% (five countries), while we located estimates from fewer than five countries for influenza, tetanus, pneumococcal disease, and human papillomavirus.

CONCLUSION

Estimates were sparse but where available indicative of suboptimal vaccination coverage among people who inject drugs. Improving the consistency, timeliness, and geographic coverage of vaccine uptake data among this population is essential to inform efforts to increase uptake.

Hepatitis A virus subgenotypes in Latvia, 2008-2021

BACKGROUND

In Latvia outbreaks of the HAV were observed between 2008 and early 2010 and again in 2017-2018. However, the risks of introducing and spreading infection still exist, as the virus spreads easily when personal hygiene is not followed.

METHODS

To determine the spread of HAV subgenotypes in the territory of Latvia the VP1/P2A genomic region of HAV was amplified and sequenced for 259 case serum samples. The study carried out a molecular biological investigation and molecular epidemiological investigation. Demographic data (sex, age), disease data (hepatitis symptoms, hospitalization, vaccination) and epidemiology data (part of the outbreak, possible source of infection, recent travel) were collected. Based on the obtained sequences, the phylogenetic tree was built and analyzed for the homology and belonging to different isolated HAV clusters from other countries.

RESULTS

From the obtained data, it was concluded that HAV subgenotype IA had 13 clusters and 12 sporadic cases, HAV subgenotype IB had eight clusters and 11 sporadic cases, HAV subgenotype IIIA had one cluster and nine sporadic cases. It was found that the sources of infection among the investigated cases were different, they were mostly associated with contact with a patient with HAV, travel, as well as between persons who inject drugs and men who have sex with men, and the prevalence of HAV similar sequences was observed in different years. It was concluded that patients with HAV subgenotype IA had the longest hospitalization duration and averaged 9.3 days, while patients with subgenotype IB - 7.3 days, subgenotype IIIA - 7.7 days. Analyzing the data on vaccination, it was found that mostly all were not vaccinated or had an unknown vaccination status.

CONCLUSIONS

All of this has led to the conclusion that the application of molecular biological methods of the HAV and a careful analysis of epidemiological data can help to better understand the ways of spreading the infection, investigate local outbreaks, detect cases of imported infection and track the recirculation of the virus.

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.

Acute Viral Hepatitis Due to Co-infection With Hepatitis A and Hepatitis B in an Intravenous Drug User

Injection drug users are at high risk of contracting human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) due to parenteral exposure. Hepatitis A virus (HAV) is classically thought to be transmitted through the fecal-oral route, but injection drug use is increasingly recognized as a risk factor. It is well documented that there is a high prevalence of total antibodies to HAV in injection drug users, although there is limited data about the prevalence of acute HAV in injection drug users. Acute viral hepatitis is most often due to HAV, HBV, or hepatitis E virus (HEV), and it is rare to have acute co-infection with these viruses. We report a case of acute viral hepatitis due to co-infection with both HAV and HBV in an injection drug user.

Challenges posed by COVID-19 to people who inject drugs and lessons from other outbreaks

INTRODUCTION

In light of the COVID-19 pandemic, considerable effort is going into identifying and protecting those at risk. Criminalization, stigmatization and the psychological, physical, behavioural and economic consequences of substance use make people who inject drugs (PWID) extremely vulnerable to many infectious diseases. While relationships between drug use and blood-borne and sexually transmitted infections are well studied, less attention has been paid to other infectious disease outbreaks among PWID.

DISCUSSION

COVID-19 is likely to disproportionally affect PWID due to a high prevalence of comorbidities that make the disease more severe, unsanitary and overcrowded living conditions, stigmatization, common incarceration, homelessness and difficulties in adhering to quarantine, social distancing or self-isolation mandates. The COVID-19 pandemic also jeopardizes essential for PWID services, such as needle exchange or substitution therapy programmes, which can be affected both in a short- and a long-term perspective. Importantly, there is substantial evidence of other infectious disease outbreaks in PWID that were associated with factors that enable COVID-19 transmission, such as poor hygiene, overcrowded living conditions and communal ways of using drugs.

CONCLUSIONS

The COVID-19 crisis might increase risks of homelessnes, overdoses and unsafe injecting and sexual practices for PWID. In order to address existing inequalities, consultations with PWID advocacy groups are vital when designing inclusive health response to the COVID-19 pandemic.

The phylogenetic approach for viral infectious disease evolution and epidemiology: An updating review

In the last decade, the phylogenetic approach is recurrent in molecular evolutionary analysis. On 12 May, 2019, about 2 296 213 papers are found, but typing "phylogeny" or "epidemiology AND phylogeny" only 199 804 and 20 133 are retrieved, respectively. Molecular epidemiology in infectious diseases is widely used to define the source of infection as so as the ancestral relationships of individuals sampled from a population. Coalescent theory and phylogeographic analysis have had scientific application in several, recent pandemic events, and nosocomial outbreaks. Hepatitis viruses and immunodeficiency virus (human immunodeficiency virus) have been largely studied. Phylogenetic analysis has been recently applied on Polyomaviruses so as in the more recent outbreaks due to different arboviruses type as Zika and chikungunya viruses discovering the source of infection and the geographic spread. Data on sequences isolated by the microorganism are essential to apply the phylogenetic tools and research in the field of infectious disease phylodinamics is growing up. There is the need to apply molecular phylogenetic and evolutionary methods in areas out of infectious diseases, as translational genomics and personalized medicine. Lastly, the application of these tools in vaccine strategy so as in antibiotic and antiviral researchers are encouraged.

Hepatitis A-2017 an unusual year in Scotland

BACKGROUND

The number of cases of acute hepatitis A reported in Scotland each year is small, and the majority of cases have been associated with travel to endemic regions. However, in early 2017, in the midst of ongoing outbreaks of hepatitis A among MSM in Europe, there was a sharp rise in the number of cases reported to Health Protection Scotland.

OBJECTIVES

The initial aim of this study was to investigate the reason for the observed increase in cases of hepatitis A at the start of 2017. As cases continued for the remainder of the year, these cases were typed to determine whether these cases were linked to each other, or other outbreaks.

STUDY DESIGN

The study population consisted of 42 hepatitis A infected patients with no obvious source of infection. The patient samples were collected between January and December 2017. The VP1/2 A region was amplified and sequenced.

RESULTS

The majority of samples typed as genotype 1 A (n = 17) or genotype 1B (n = 15). Within genotype 1 A, fifteen samples had strains (VRD_521_2016 or RIVM_HAV16_090) associated with ongoing outbreaks of hepatitis A in MSM in Europe. Within genotype 1B, there were four clusters of infections, with identical cases in geographically distinct regions with no identified epidemiological link.

CONCLUSIONS

Molecular typing proved useful, as it allowed public health to identify clusters, establish links with other outbreaks and compare Scottish strains with those reported elsewhere.

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.

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.

Hepatitis A and B among young persons who inject drugs--vaccination, past, and present infection

BACKGROUND

Our study aims were to assess hepatitis A virus (HAV) and hepatitis B virus (HBV) susceptibility and infection among young persons who inject drugs (PWID) who may have been vaccinated as children and to evaluate self-report of HAV and HBV vaccination.

METHODS

We recruited PWID aged 18-40 years-old in San Diego during 2009 and 2010 and collected demographic, socioeconomic, health, and behavioral factors. Participants were asked if they had been vaccinated against HAV and HBV, and serum samples were collected for HAV and HBV serologic testing.

RESULTS

Of 519 participants, 365 (72%) were male, 252 (49%) were white non-Hispanic, 38 (7%) were Black non-Hispanic, 138 (27%) were White Hispanic, and 22 (4%) were born outside the U. S. Of the total participants, 245 (47%) had surface hepatitis B antibody (anti-HBs) titers <10mIU/ml (i.e., HBV susceptible) and 325 (63%) had no detectable HAV antibodies (HAV susceptible). Hepatitis B surface antigen was detected in 7 (1%) of total participants; and 135 (26%) were anti-HCV-antibody positive. Compared to serologic findings, self-report of HBV and HAV vaccination was 71% and 41% sensitive, and 58% and 73% specific, respectively.

CONCLUSION

HAV and HBV antibodies in half or more of this young PWID population did not have levels indicative of protection, and about a quarter had HCV infection, putting them at risk for complications resulting from co-infection with HAV or HBV. Programs serving this population should vaccinate PWIDs against HAV and HBV and not rely on self-report of vaccination.

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.

Hepatitis A virus genotype and its correlation with the clinical outcome of acute hepatitis A in Korea: 2006-2008

Korea has recently experienced a nationwide outbreak of hepatitis A. This study aimed to investigate hepatitis A virus (HAV) genotypes and to compare clinical features between patients infected with HAV genotype IA and those with genotype IIIA. From September 2006 to August 2008, 595 patients with symptomatic hepatitis A were enrolled prospectively in four hospitals in Korea. Among them, 556 patients participated in this study by providing serum or stool samples for genotypic analysis. HAV RNA was detected in 499 patients (89.7%). Major genotypes included IA (n = 244, 48.9%) and IIIA (n = 244, 48.9%), and the remaining genotype was IB (n = 11, 2.2%). From September 2006 to August 2007, the distribution of genotypes IA and IIIA were 64.6% and 35.6%, respectively, which changed to 42.3% and 54.6%, respectively, from September 2007 to August 2008, indicating change of circulating HAV genotypes in the study period from IA to IIIA. Major patterns of amino acid substitution in the VP3/VP1 junction region were observed at position 512 (P → L) in genotype IA and at 520 (R → K) in genotype IIIA. Patients with genotype IIIA infection showed significantly higher aminotransferase levels, prothrombin time, and leukocyte count, with more severe symptoms than those with genotype IA at the time of admission. These results suggest the occurrence of a change of circulating HAV genotypes in recent community-wide outbreaks of hepatitis A in Korea, and genotype IIIA infection, compared with genotype IA infection, might show more severe clinical manifestations.

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.

Outbreak of hepatitis A in an extended family after importation by non-immune travellers

The incidence of hepatitis A in England has declined in recent years, but travel-related cases and imported infections remain a challenge. We report an outbreak of hepatitis A in an extended family where two primary cases were infected while in Pakistan and two secondary cases were infected in England. All four were infected by the same genotype IIIA virus. Testing of the children in the extended family by dried blood spots (DBS) determined that three had evidence of recent past infections (anti-HAV IgM positive), one had a current asymptomatic infection (anti-HAV IgM and HAV RNA positive) and one was incubating the virus (anti-HAV IgM negative, HAV RNA positive). HAV RNA from the DBS was identical to the adult cases. This outbreak demonstrates secondary spread of hepatitis A by asymptomatic children after importation from abroad and highlights the importance of preventing travel-associated hepatitis A infection.

Hepatitis A infection in recent international adoptees and their contacts in Minnesota, 2007-2009

OBJECTIVE

The goal of this study was to describe hepatitis A-infected adoptees and the risk of transmission to their contacts.

METHODS

This was a retrospective review of adoptee-associated cases of hepatitis A and hepatitis A-infected adoptees identified in Minnesota from 2007 through 2009.

RESULTS

From 2007 through 2009 in Minnesota, 10 cases of hepatitis A, including 1 fulminant case, were associated with international adoptees. Eight cases were direct contacts of a hepatitis A-infected adoptee, and 2 other cases secondary contacts of an adoptee. During the same period, hepatitis A infection was identified in 21 recently arrived foreign-born adoptees; all were younger than 60 months of age, and only 6 were symptomatic.

CONCLUSIONS

Clinicians should be aware that transmission of hepatitis A may occur among both direct and secondary contacts of young children recently adopted from hepatitis A-endemic areas and that infected young children may be asymptomatic. Household members and other close contacts of international adoptees should be counseled about hepatitis A prevention, including vaccination. In addition, screening for hepatitis A should be considered for recently arrived adoptees from endemic areas.

An outbreak of hepatitis A affecting a nursery school and a primary school

Between March and June 2008, 12 cases of hepatitis A were notified in Winchester. Cases were from a primary school and a nursery school with no direct linkage. Hepatitis A virus (HAV) RNA sequenced from nine cases confirmed the strain in both schools to be identical. The outbreak could have affected three other schools and a maternity unit and was controlled by immunization and screening of neonates in the maternity unit by dried blood spots. No neonates were infected and no further cases were reported until 5 months later when the index case's mother became infected with same strain of virus associated with the outbreak despite vaccination. Neither the source of the outbreak or the subsequent infection of the index case's mother was identified; however, with the timing of the cases continued transmission in the community by children with asymptomatic infection or a recurrent source cannot be ruled out.

No evidence of intrauterine transmission of hepatitis A virus from a mother to a premature infant

AIM

To determine whether or not an intrauterine transmission of hepatitis A virus (HAV) occurred from an infected mother to her premature infant delivered by caesarean section.

METHODS

The mother and her child were tested for HAV by serology and reverse transcription PCR.

RESULTS

An outbreak of HAV infection was seen among children and a 33-year-old day-care teacher, pregnant in third trimester, at a day-care centre in southern Sweden. Due to premature labour and diminished foetal movements a caesarean section was performed and a premature girl in gestational weeks 33 + 1 was born. During the 3-week postnatal hospitalization period the child presented no clinical symptoms of HAV infection and anti-HAV IgM antibodies remained undetectable at day 14 and 109 after birth. Furthermore HAV RNA remained undetectable by reverse transcription PCR in the child's blood at birth and in throat and faeces for the first 3 and 4 weeks of life respectively. HAV RNA in the mother's blood was detected at 6 days prior to and at 17 days after delivery. HAV RNA was undetectable in breast milk when tested on day 3 after delivery.

CONCLUSION

There was no evidence of intrauterine transmission of hepatitis A virus from a viraemic mother to her premature child delivered at gestational week 33 + 1 by caesarean section.

Seroprevalence of hepatitis A virus infection in persons with HIV infection in Taiwan: implications for hepatitis A vaccination

OBJECTIVES

To retrospectively determine the prevalence of anti-hepatitis A virus (HAV) antibody in HIV-positive persons with different routes of HIV exposure and to describe its characteristics in order to guide vaccination policy.

METHODS

The prevalence of anti-HAV antibody was compared between 1580 HIV-positive persons seeking medical attention and 2581 HIV-negative controls seeking health check-ups, who had undergone anti-HAV tests between 2004 and 2007. Comparisons were also made among groups of the HIV-positive patients who had acquired HIV via different routes of transmission. A multivariate logistic regression model was built to identify independent variables associated with anti-HAV seropositivity.

RESULTS

The overall prevalence of anti-HAV antibody was 60.9% in the HIV-positive and 48.0% in the controls (p<0.001). The overall adjusted odds ratio (AOR) for positive anti-HAV antibody was 2.604 (95% confidence interval (CI) 2.106-3.219) in HIV-positive persons compared with HIV-negative persons. In addition, HIV-positive men who have sex with men (MSM), heterosexuals, and injecting drug users (IDU) all had significantly higher AOR for positive anti-HAV antibody than HIV-negative persons. In HIV-positive persons, older age (AOR 1.284, 95% CI 1.246-1.322) and IDU (AOR 5.137, 95% CI 3.499-7.542) were independently associated with an increased prevalence of anti-HAV antibody. Nearly 90% of the IDU had become seropositive for HAV after age 36-40 years, compared with heterosexuals and MSM after age 46-50 years, and controls after age 51-55 years.

CONCLUSION

Our findings suggest that age groups to be targeted for HAV vaccination vary with the different routes of HIV exposure.

Outbreaks of hepatitis A in England and Wales associated with two co-circulating hepatitis A virus strains

During 2002, an upsurge in frequency of hepatitis A outbreaks among injecting drug users was observed in England and Wales. As lack of risk factor information and the high mobility of the cases made linkage of outbreaks difficult, the relationship of nucleotide sequences in the VP1/2PA junction of the hepatitis A virus (HAV) genome amplified from serum of case-patients was investigated. A total of 204 HAV RNA positive sera obtained from a network of 23 laboratories were studied. Comparison of the sequences identified two principal strains: ES1 (n=95) belonging to type IB, and ES2 (n=72) to type IIIA. Of the remaining samples, 15 were type IA, 11 were type IB and 11 were type IIIA. ES1 predominated in Doncaster and other towns in Trent and northern England, and ES2 in the Midlands and southern England; the difference in geographical distribution between these two strains was significant (P<0.0001). In comparison to the sporadic cases, cases infected by either ES1 or ES2 tended to be younger, injecting drug users, people in contact with injecting drug users, or those with a history of incarceration in prisons or homelessness (P<0.0001). Cases infected by ES1 tended to be younger than those by ES2 (P<0.0001). The association of the outbreaks to two geographically restricted strains implicates two principal transmission pathways associated with injecting behavior. Identifying these routes may be conducive to preventing further outbreaks.

Molecular epidemiology of hepatitis A in St. Petersburg, Russia, 1997-2003

The molecular epidemiology of hepatitis A virus (HAV) strains circulating in the St. Petersburg and Karelia regions was studied during 1997-2003. Hepatitis A virus RNA was isolated from both clinical samples (stools or sera) and environmental samples (sewage water). RT-PCR was carried out using different primer pairs from the VP1/2A and VP1 genomic regions, the variable parts of the HAV genome. PCR products were sequenced and 306 nucleotides from the VP1/2A and 332 nucleotides from the VP1 region were used for phylogenetic analysis. The results show that the IA subtype was the most common during the follow-up period: >90% of the isolated HAV strains belonged to that subtype. The HAV strains found in intravenous drug users belonged to subtypes IA and IIIA. Only one out of a total of 88 sequenced strains was of the IB subtype. The subtypes IB and IIIA were found only in 2001-2003, which suggests that new strains were introduced into the endemic situation. The results indicate the usefulness of molecular epidemiological methods in studying changes in the circulating HAV strains and in tracing transmission routes.

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

Large outbreaks of hepatitis A have occurred in Denmark, Germany, the Netherlands, Norway, Spain, Sweden, and the United Kingdom during the period 1997-2005 affecting homosexual men. A collaborative study was undertaken between these countries to determine if the strains involved in these hepatitis A outbreaks were related genetically. The N-terminal region of VP1 and the VP1/P2A region of the strains were sequenced and compared. The majority of the strains found among homosexual men from the different European countries formed a closely related cluster, named MSM1, belonging to genotype IA. Different HAV strains circulated among other risk groups in these countries during the same period, indicating that specific strains were circulating among homosexual men exclusively. Similar strains found among homosexual men from 1997 to 2005 indicate that these HAV strains have been circulating among homosexual men for a long time. The homosexual communities are probably too small within the individual countries to maintain HAV in their population over time, whereas the homosexual communities across Europe are probably sufficiently large to sustain continued circulation of homologous HAV strains for years resulting in an endemic situation among homosexual men.

Genetic variability and molecular evolution of hepatitis A virus

Hepatitis A virus (HAV), the causative agent of type A viral hepatitis, was first identified about three decades ago. Recent findings have shown that HAV possess several characteristics that make it unique among the family Picornaviridae, particularly in terms of its mechanisms of polyprotein processing and virion morphogenesis. HAV circulates in vivo as distributions of closely genetically related variants referred to as quasispecies. HAV exploits all known mechanisms of genetic variation to ensure its survival, including mutation and recombination. Only one serotype and six different genetic groups (three humans and three simian) have been described. HAV mutation rate is significantly lower as compared to other members of the family Picornaviridae. The mode of evolution appears, at least in part, to contribute to the presence of only one known serotype.

Prevalence of hepatitis and HIV infections and vaccination rates in patients entering the heroin-assisted treatment in Switzerland between 1994 and 2002

BACKGROUND

Hepatitis C virus (HCV) remains very prevalent in injection drug users (IDUs). In spite of recommended vaccinations against hepatitis A virus (HAV) and hepatitis B virus (HBV), many IDUs remain susceptible to HAV and HBV.

STUDY POPULATION AND METHODS

Patients entering heroin-assisted treatment between 2000 and 2002 (N = 210) were compared for infectious disease status with patients entering this treatment in 1998 (N = 243) and between 1994 and 1996 (N = 1035). Infection status was determined with the aid of questionnaires and blood tests for antibodies against HAV, HBV core antigen, HCV and HIV.

RESULTS

In the cohort 2000-2002 78.3% of the patients were HCV positive, 53.3% were HBV positive, 41.2% were HAV positive and 12.6% were HIV positive. In comparison to the cohorts entering the heroin- assisted treatment at an earlier time, there was a significant reduction of HBV and HAV infections, but not of HCV and HIV infections. 15.6% of the patients entering between 2000 and 2002 were vaccinated against HBV and 10.3% against HAV. 31.1% of patients at entrance were susceptible for HBV and 48.5% for HAV. In comparison to patients entering treatment in 1998 there was no significant increase in patients who were vaccinated against HBV.

CONCLUSIONS

This data illustrates the need for improving HCV prevention and more consequent vaccination against HBV and HAV in IDUs.

Diagnosis of hepatitis a virus infection: a molecular approach

Current serologic tests provide the foundation for diagnosis of hepatitis A and hepatitis A virus (HAV) infection. Recent advances in methods to identify and characterize nucleic acid markers of viral infections have provided the foundation for the field of molecular epidemiology and increased our knowledge of the molecular biology and epidemiology of HAV. Although HAV is primarily shed in feces, there is a strong viremic phase during infection which has allowed easy access to virus isolates and the use of molecular markers to determine their genetic relatedness. Molecular epidemiologic studies have provided new information on the types and extent of HAV infection and transmission in the United States. In addition, these new diagnostic methods have provided tools for the rapid detection of food-borne HAV transmission and identification of the potential source of the food contamination.

An outbreak of hepatitis A virus infection with a high case-fatality rate among injecting drug users

BACKGROUND/AIMS

In 2002, the first reported outbreak of hepatitis A virus (HAV) infection involving mostly intravenous drug users (IDU) occurred in Italy. We attempted a thorough evaluation of the outbreak, including epidemiological, clinical and virological analyses.

METHODS

We conducted an epidemiological investigation, including a case-control study, to identify the source and the modes of HAV transmission. Hepatitis B and C (HCV) viruses and human immunodeficiency virus (HIV) coinfections were clinically analysed. Sequence analysis of the VP1/2A junction of the HAV isolates was also performed.

RESULTS

Of the 47 symptomatic cases, 35 were IDUs. The only associated risk factor was contact (not related to injecting practices) with a jaundiced person (odds ratio: 5.8; 95% confidence interval: 1.3-29.9). Of the cases, 58% were anti-HCV positive and 4.7% anti-HIV positive. Three individuals died of acute liver failure: 2 were HCV-coinfected alcohol abusers, with underlying liver cirrhosis; 1 was HCV/HIV-coinfected. HAV-RNA was found in 15 of the 24 tested patients: genotype IB (8 cases) and IIIA (7 cases) were detected.

CONCLUSIONS

HAV was probably transmitted through the fecal-oral route, although parenteral transmission cannot be excluded. The high fatality rate was probably due to severe underlying liver damage. The occurrence of this outbreak highlights the need for routine HAV vaccination for IDUs.

Prevalence of hepatitis A among drug users in north-eastern Italy. Is vaccination necessary in low prevalence areas?

BACKGROUND

The authors report on the prevalence of, and risk factors for, hepatitis A virus (HAV) in a group of drug users in Italy.

METHODS

404 heroin users were recruited and compared with a control group of 107 subjects in the general population.

RESULTS

Drug users born in north-eastern Italy have a prevalence of anti-HAV similar to the control group. A much higher prevalence was found in drug users born in southern Italy.

CONCLUSION

The similar prevalence of anti-HAV in drug users born in north-eastern Italy and in the general population, suggests that their lifestyle does not involve a substantial additional risk of HAV. The much higher prevalence found in drug users born in southern Italy is more likely to be related to infection during infancy.

Prévalence et facteurs de risque de l'hépatite A au sein d'une population de patients infectés par le virus de l'immunodéficience humaine

BACKGROUND

There are common risk factors between hepatitis A virus (HAV) and human immuno deficiency virus (HIV) infections.

OBJECTIVES

We tried to evaluate if HIV-infected patients could be at risk for HAV. More over, HAV could worsen prognosis of HIV infection and HAV vaccination was then to be considered. Thus we assessed the prevalence and risk factors of HAV infection in an HIV-infected population.

PATIENTS AND METHODS

Seroprevalence and risk factors for HAV were studied among 154 HIV-positive patients followed in a Parisian hospital (mean age: 42 years, male patients: 70.8%, female patients: 29.2%). They were screened for HAV antibodies and answered a questionnaire on risk factors for HAV and means of HIV contamination.

RESULTS

The global prevalence was 72.7% [IC95%: 65.7-79.7]. We excluded patients who were born in highly endemic areas where seroprevalence reached 60% [IC95%: 51.2-70]. The HAV seroprevalence was almost 100% in migrants from highly endemic countries and for those born before 1946. The multivariate analysis showed that risk factors were the geographic origin [OR=20.88; IC95%: 2.40-181], age [OR = 2.33; IC95%: 1.24-4.39], and hemophilia [OR = 13.78; IC95%: 1.34-141].

CONCLUSION

Our results suggest that a screening test for HAV antibodies should be performed before vaccination, especially in HIV-infected patients born after 1946 or in non-endemic countries.

Risk Factors and predictors of human immunodeficiency virus infection among injection drug users

BACKGROUND/AIM

Injection drug users (IDUs) have a high risk of acquiring an infection with the human immunodeficiency virus (HIV). To improve counseling and prevention, a better understanding of risk factors and predictors for an infection must be gained. This retrospective study has the aim to determine the risk factors for acquisition of HIV infection other than sharing of needles/syringes.

METHODS

The study population consisted of all patients admitted to the detoxification unit between 1991 and 1996 who met ICD-10 criteria for opioid dependency, who reported to share needles, and who agreed to have an antibody test. Possible risk factors were assessed by interview. Cross tables based on bivariate logistic regression were constructed to estimate the relative odds. Multiple logistic regression modeling procedures were used to adjust possible confounding factors.

RESULTS

A total of 1,049 out of 1,656 patients admitted were included into the study. 4.8% of the patients were HIV-1 seropositive. The prevalence was higher among older patients and among patients living with a significant other substance drug user with substance dependency, after a longer duration of drug use, and after coinfection with hepatitis B virus and/or hepatitis C virus (HCV). Using multiple logistic regression analyses and including all individually significant risk factors, we found only coinfection with HCV to remain significant. 92% of the HIV-infected patients were also HCV infected. In the group younger than 23 years of age, a total of 53.5% of the IDUs were still seronegative for HIV, hepatitis A and B virus, and HCV.

CONCLUSIONS

Despite the high rate of HCV coinfection (92%) in HIV-infected patients, we found more than 50% of IDUs younger than 23 years to be neither infected with HCV nor with HIV. Early prevention strategies against infectious diseases should especially focus on young IDUs.

Genetic analysis of hepatitis A virus isolates from Brazil

A limited number of hepatitis A virus (HAV) isolates from South America have been characterised at the genomic level. IgM anti-HAV positive serum samples collected from patients with hepatitis A living in the five geographical regions of Brazil (North, Northeast, Central, South, and Southeast) were used to obtain HAV isolates and determine their genetic relatedness. Of the 232 case isolates, sequence data were obtained from the VP1/2A junction region of the HAV genome. All isolates were classified in genotype I; 231 belonged to subgenotype IA, and one to subgenotype IB. HAV isolates from four States formed distinct clusters of highly related sequences. However, isolates from other states did not cluster and the sequences from those states were intermingled with sequences found in the other states. The amino acid sequences of all but two isolates showed a Leu --> Ile substitution at position 42 in the 2A protein. This substitution appeared to be a characteristic geographic fingerprint of HAV sequences within Brazil.

Genetic variability of hepatitis A virus isolates in Rio de Janeiro: implications for the vaccination of school children

The epidemiology of hepatitis A virus (HAV) infection is shifting from high to intermediate endemicity in Brazil, resulting in increased numbers of susceptible individuals and a greater potential for the emergence of outbreaks. Universal vaccination against HAV has been recommended for children, but updated sero-epidemiological data are necessary to analyze the level of natural immunity and to identify candidates for preventive measures. In addition, more molecular studies are necessary to characterize the genotypes involved in HAV infections and outbreaks. Sera from 299 school children (5-15 years old) and 25 school staff members, collected during an outbreak of HAV at a rural public school in June 2000, were tested for IgM and total anti-HAV antibodies (ELISA). Viral RNA was amplified by RT-PCR from anti-HAV IgM-positive sera and from 19 fecal samples. Direct nucleotide sequencing of the VP1/2A region was carried out on 18 PCR-positive samples. Acute HAV infection was detected by anti-HAV IgM in 93/299 children and in 3/25 adult staff members. The prevalence of total anti-HAV antibodies in IgM-negative children under 5 years of age was only 10.5%. HAV-RNA was detected in 46% IgM-positive serum samples and in 16% stool samples. Sequence analysis showed that half the isolates belonged to subgenotype IA and the other half to IB. On the basis of these data, mass vaccination against HAV is recommended without prevaccination screening, especially for children before they enter school, since nearly 90% of the children under 5 years were susceptible. Molecular characterization indicated the endemic circulation of specific HAV strains belonging to subgenotypes IA and IB.

Characterization of the complete genomic sequence of genotype II hepatitis A virus (CF53/Berne isolate)

The complete genomic sequence of hepatitis A virus (HAV) CF53/Berne strain was determined. Pairwise comparison with other complete HAV genomic sequences demonstrated that the CF53/Berne isolate is most closely related to the single genotype VII strain, SLF88. This close relationship was confirmed by phylogenetic analyses of different genomic regions, and was most pronounced within the capsid region. These data indicated that CF53/Berne and SLF88 isolates are related more closely to each other than are subtypes IA and IB. A histogram of the genetic differences between HAV strains revealed four separate peaks. The distance values for CF53/Berne and SLF88 isolates fell within the peak that contained strains of the same subtype, showing that they should be subtypes within a single genotype. The complete genomic data indicated that genotypes II and VII should be considered a single genotype, based upon the complete VP1 sequence, and it is proposed that the CF53/Berne isolate be classified as genotype IIA and strain SLF88 as genotype IIB. The CF53/Berne isolate is cell-adapted, and therefore its sequence was compared to that of two other strains adapted to cell culture, HM-175/7 grown in MK-5 and GBM grown in FRhK-4 cells. Mutations found at nucleotides 3889, 4087 and 4222 that were associated with HAV attenuation and cell adaptation in HM175/7 and GMB strains were not present in the CF53/Berne strain. Deletions found in the 5'UTR and P3A regions of the CF53/Berne isolate that are common to cell-adapted HAV isolates were identified, however.

Genetic variability of hepatitis A virus

Knowledge of the molecular biology of hepatitis A virus (HAV) has increased exponentially since its identification. HAV exploits all known mechanisms of genetic variation to ensure survival, including mutation and genetic recombination. HAV has been characterized by the emergence of different genotypes, three human antigenic variants and only one major serotype. This paper reviews the genetic variability and molecular epidemiology of HAV. Its evolutionary mechanisms are described with particular emphasis on genetic recombination and HAV mutation rate. Genotypic classification methods are also discussed.

HAV replication in acute hepatitis with typical and atypical clinical course

The correlation between the length of viremia as detected by reverse transcriptase-polymerase chain reaction (RT-PCR) and the clinical course of hepatitis A virus (HAV) infection was studied. Sixty-six consecutive patients with acute hepatitis A who were admitted to hospital in two infectious disease units in southern Italy were enrolled: 57 had a self-limited course of the disease (typical course), 4 a prolonged course, and 5 relapsing hepatitis. Plasma HAV RNA was sought by RT-PCR, using primers made at 5'-NTR of HAV, designed to amplify a 273-bp fragment and detected by 2% agarose gel and by hybridization with a specific biotinylated probe. In four patients with prolonged acute hepatitis A, the plasma HAV RNA, which was positive on the day of admission to hospital, was found to be negative from day 62, 46, 84, and 105, respectively, after the onset of the symptoms. In patients with relapsing hepatitis, HAV viremia paralleled the clinical and biochemical course of disease. In all patients with a typical self-limiting course, clearance of plasma HAV RNA was observed within 20 days of the onset of symptoms. In most patients, plasma HAV viremia became undetectable before the normalization of serum aminotransferases, underlining the importance of the immune reaction in the pathogenesis of acute hepatitis A. The data also suggest that the detection of plasma HAV RNA after 20 days of illness may predict a prolonged course of the disease, but relapsing hepatitis remains unpredictable on the basis of plasma HAV determination.

Outbreak of hepatitis A in the injecting drug user and homeless populations in Bristol: control by a targeted vaccination programme and possible parenteral transmission

OBJECTIVE

To study the use of hepatitis A virus (HAV) vaccination in controlling an outbreak of HAV in inner-city Bristol among injecting drug users (IDUs). To study whether hepatitis C virus (HCV) and hepatitis B virus (HBV) co-infection increases morbidity.

DESIGN

Community-based cohort study.

SETTING

Avon Health Authority area, UK.

PARTICIPANTS

All laboratory-confirmed cases of HAV infection notified in 2000.

INTERVENTION

Administration of a targeted vaccination, education and liaison programme.

MAIN OUTCOME MEASURES

Number of cases of HAV before and after introduction of HAV vaccination programme. Mortality and number of patients requiring hospital admission. Association of HCV and HBV co-infection with hospital admission.

RESULTS

Ninety cases of HAV were reported in the first 6 months of 2000, of whom a substantial number were IDUs and/or inner-city hostel residents. In the second 6 months of 2000, following the introduction of a vaccination programme among homeless people, hostel residents, and IDUs, the number of HAV cases fell to 33. Sixteen patients had evidence of HCV co-infection. No patient had chronic HBV infection. Two patients died as a result of HAV, and two subsequently died from drug misuse. Fifty-six per cent of HCV-co-infected patients required admission to hospital compared with 28% non-HCV-co-infected patients.

CONCLUSIONS

This is the first reported successful use of vaccination to control an outbreak of HAV in a population of IDUs and to prevent transmission to the wider population. HCV co-infection appears to increase the severity of HAV illness, as demonstrated by increased incidence of hospital admission.

Risk groups for hepatitis A virus infection

We report the conduct and results of a systematic search for evidence of risk of infection with hepatitis A virus (HAV) among blood transfusion recipients, travellers, the military, healthcare workers, sewage workers, foodhandlers, day care assistants, institutionalised subjects, blood transfusion recipients, drug addicts, homosexuals, prisoners and other risk groups such a liver transplantees. We report our recommendations for the use of the HAV vaccine in these groups.

HAV infection in chronic liver disease: a rationale for vaccination

We report the conduct and results of a systematic search of the literature to assess whether exposure to HAV could induce a fatal deterioration of liver diseases. We assessed 30 studies and found evidence of progressive decrease of natural immunity against HAV in Italy. HAV vaccine seems as safe in chronic liver diseases than in general population. On the basis of the evidence we recommend that subjects with chronic liver disease should be vaccinated against HAV, especially if younger than 40 years.

Genetic characterization of hepatitis A virus isolates from Buenos Aires, Argentina

The Hepatitis A virus (HAV) has been classified in seven different genotypes, which include human (I, II, III, and VII) and simian (IV, V, and VI) groups. The sequence analysis of HAV strains contributes to the molecular epidemiology of the virus. Although the infection with HAV is endemic in Argentina and vaccination is being implemented in this country, using both IA and IB strains, there are very few data on the genotypes of the circulating viruses. On the basis of the sequences of 20 isolates collected in Buenos Aires during a 2-year period (extended to 3 years by two additional specimens), we observed the presence of a single sub-genotype, IA, but with a high genetic diversity. We analyzed the VP1-2A junction and also the VP3-VP1 region. Most of the Argentine isolates grouped in at least two clusters. One of these was related to South American strains, thus suggesting a co-circulation of related isolates in neighbor countries. The other cluster was composed only of Argentine specimens. Other sequences were more scattered along the phylogenetic tree. However, we demonstrated that a consistent genetic relatedness of sequences could only be inferred on the basis of a more extensive sequencing of each isolate.

Sexually acquired hepatitis

OBJECTIVES

To assess current knowledge of sexually transmitted viral hepatitis in relation to epidemiology, clinical presentation, management, and diagnosis with particular reference to resource-poor settings.

METHOD

A search of published literature identified through Medline from 1966 to October 2001, the Cochrane Library, and reference lists taken from each article obtained. Textword and MeSH searches for hepatitis A, B, C, D, E, G, delta, GB virus, GBV-C, and TT virus were linked to searches under the textword terms sex$, prevent$, and MeSH subheadings, microbiology, complications, drug therapy, therapy, diagnosis, epidemiology, transmission, and prevention and control.

CONCLUSIONS

In heterosexual relationships, hepatitis B is readily transmitted sexually and hepatitis C and D less so, with no evidence for sexual transmission of hepatitis A. Hepatitis types A-D are all transmissible sexually in male homosexual relationships under certain conditions. In resource-poor countries sexual transmission is generally only a significant route of transmission for hepatitis B.

Influence of human immunodeficiency virus type 1 infection on acute hepatitis A virus infection

To assess the possible influence of human immunodeficiency virus type 1 (HIV-1) infection on the clinical course of acute hepatitis A virus (HAV) infection, 15 HIV-1-infected homosexual men and 15 non-HIV-infected age-matched subjects were compared. HAV load was higher in HIV-1-infected than in non-HIV-infected patients (P<.001). Duration of viremia in HIV-1-infected patients (median, 53 days) was significantly (P<.05) longer than in non-HIV-infected patients (median, 22 days). HIV-1-infected patients had lower elevations in alanine aminotransferase levels than did non-HIV-infected patients (P<.01) but had higher elevations in alkaline phosphatase levels than did non-HIV-infected patients (P<.001). Some HIV-1-infected patients still had HAV viremia when clinical symptoms had disappeared and alanine aminotransferase levels had returned to normal (60-90 days after the onset of symptoms). HIV-1 infection was associated with prolongation of HAV viremia, which might cause a long-lasting outbreak of HAV infection in HIV-1-infected homosexual men.

High prevalence of hepatitis E antibodies among Danish prisoners and drug users

Injecting drug users and prisoners have high prevalences of antibodies to hepatitis A-C. The aim of this study was to determine the prevalence of antibodies to hepatitis E virus (anti-HEV) in two Danish high-risk populations and correlate anti-HEV with risk factors for transmission. Three hundred thirty male prisoners and 137 patients at a drug treatment center were tested for anti-HEV with an in-house enzyme-linked immunoassay (EIA) utilizing antigens derived from open reading frame 2 (ORF2). This was compared with a commercial test with antigens derived from ORF2 and ORF3 (Abbott HEV EIA). In addition the samples were tested for antibodies against hepatitis A-C viruses, human immunodeficiency virus (HIV) 1 and 2, human T lymphotropic virus (HTLV) I and II and herpes simplex virus type 2 (HSV2). The participants were interviewed about risk factors for transmission. The anti-HEV prevalence was 16.9% (95% CI 14-21) for the in-house assay compared to 4.1% (95% CI 2.5-6.3) with the commercial assay. The correlation between the two assays was low (87% overall agreement; kappa value 0.32). One sample was strongly anti-HEV IgM positive, suggesting recent HEV infection inside Denmark. The presence of anti-HEV was associated significantly with anti-HAV among prisoners and increased with age in both groups. In contrast, associations were not found with injecting drug use or sexual risk factors. With the commercial assay an increased prevalence of anti-HEV was found among participants who had spent more than 5 years outside Northern Europe. In conclusion, anti-HEV was highly prevalent among Danish prisoners and drug users but not related to risk factors for blood-borne or sexual transmission.

Hepatitis A: old and new

The hepatitis A virus (HAV), a picornavirus, is a common cause of hepatitis worldwide. Spread of infection is generally person to person or by oral intake after fecal contamination of skin or mucous membranes; less commonly, there is fecal contamination of food or water. Hepatitis A is endemic in developing countries, and most residents are exposed in childhood. In contrast, the adult population in developed countries demonstrates falling rates of exposure with improvements in hygiene and sanitation. The export of food that cannot be sterilized, from countries of high endemicity to areas with low rates of infection, is a potentially important source of infection. After ingestion and uptake from the gastrointestinal tract, the virus replicates in the liver and is excreted into the bile. Cellular immune responses to the virus lead to destruction of infected hepatocytes with consequent development of symptoms and signs of disease. Humoral immune responses are the basis for diagnostic serologic assays. Acute HAV infection is clinically indistinguishable from other causes of acute viral hepatitis. In young children the disease is often asymptomatic, whereas in older children and adults there may be a range of clinical manifestations from mild, anicteric infection to fulminant hepatic failure. Clinical variants include prolonged, relapsing, and cholestatic forms. Management of the acute illness is supportive, and complete recovery without sequelae is the usual outcome. Research efforts during World War II led to the development of passive immunoprophylaxis. Pooled immune serum globulin is efficacious in the prevention and attenuation of disease in exposed individuals. More recently, active immunoprophylaxis by vaccination has been accomplished. Future eradication of this disease can now be contemplated.

The cost-effectiveness of hepatitis A vaccination in patients with chronic hepatitis C

Infection with hepatitis A virus (HAV) occasionally leads to acute liver failure and has a higher fatality rate in patients with chronic hepatitis C virus (HCV). Vaccination of patients with HCV against HAV is effective and well tolerated. This study examines the cost-effectiveness of HAV vaccination in North American patients with chronic HCV. A decision analysis model was constructed to compare 3 HAV vaccination strategies in adult patients with chronic HCV over a period of 5 years: (1) vaccinate no patients (treat none); (2) vaccinate only susceptible (anti-HAV negative) patients (selective); or (3) vaccinate all patients without prior testing of immune status (universal). Probabilities and direct costs were estimated from hospital data and the literature. The cost per patient for the 3 vaccination strategies were: treat none, $2.00; selective, $56.00; and universal, $82.00. For every 1,000,000 patients with HCV vaccinated over a 5-year period, the selective strategy prevented 128 symptomatic cases of HAV, 3 liver transplantations, and 3 deaths owing directly to HAV compared with the treat none strategy. In addition, the selective strategy costs an additional $427,000 per patient with HAV prevented, and $23 million per HAV-related death averted, compared with the treat none strategy. The results were most sensitive to the incidence of HAV infection; vaccination increased costs if the annual rate of infection was less than 0.56% (baseline, 0.01%). Vaccination of North American patients with chronic HCV against HAV infection is not a cost-effective therapy.

Molecular biology of hepatitis A virus: significance of various substitutions in the hepatitis A virus genome

Hepatitis A virus (HAV) is the sole member of the hepatogenus of Picorna viridae. This virus can now be propagated in cell culture and in primates. Molecular biological studies of HAV have disclosed its genomic structure and the functional significance of the viral proteins to some extent. Hepatitis A virus has a positive-stranded RNA of approximately 7.5 kb that encodes a large polyprotein. Translation of the protein is influenced by the function of the internal ribosomal entry site in the 5' non-translating region. It is generally agreed that the polyprotein is processed to four structural and seven non-structural proteins by the proteinase encoded in the 3C region. Replication efficiency seems to be controlled by amino acid substitutions in the 2B and 2C regions. The virulence of HAV in primates may be determined by substitutions in the 2C region. Although the severity of hepatitis A was thought to be determined by immunological reactions of the host to the virus, the potential virulence of the variant viruses themselves may need further examination. Recent progress in polymerase chain reaction technology has made possible an analysis of the HAV sequence in clinical specimens; such analysis is of importance in the disclosure of differences in HAV subspecies in different clinical conditions.

Viral hepatitis A, B, and C

Mankind probably has known viral hepatitis for many centuries; however, the major and most dramatic developments in our knowledge of these diseases have taken place during the second half of the 20th century. During this relatively short period of time, the infectious nature of hepatitis A, B, and C has been proven, leading to their identification and description. The advent of serologic markers has provided the means for establishing the diagnosis. Epidemiologic studies have provided important information that led to exciting achievements in detection and prevention of transmission. Molecular biology studies and cell culture techniques have established our knowledge of the viral genomes, and led to the development of specific vaccines for hepatitis A and B. Anti-viral therapy has been developed and aggressive combination therapy has emerged as a promising strategy for chronic hepatitis B and C. This article reviews some of the main fields of progress and achievement related to viral hepatitis A, B, and C in the 20th century.

Hepatitis A outbreaks among illicit drug users and their contacts in Queensland, 1997

OBJECTIVE

To describe five outbreaks of hepatitis A virus (HAV) infection associated with illicit drug use during a statewide outbreak of HAV infection in Queensland.

DESIGN

Risk factor prevalence survey.

PATIENTS AND SETTING

All 875 cases of HAV infection notified to Public Health Units in Queensland in the 12 months to 30 November 1997.

MAIN OUTCOME MEASURE

Type and prevalence of illicit drug use.

RESULTS

Risk factor assessment was completed for 804 cases (91.9%). We identified five outbreaks of HAV infection linked to illicit drug use. These outbreaks accounted for 24.6% (215/875) of all notified cases and 39% (190/482) of notified cases in the 15-34 years age group. The main type of illicit drug use in four of the five outbreaks was injecting drug use (74%; 118/160), while in the other outbreak it was sharing of smoking implements for marijuana (38%; 21/55).

CONCLUSION

Illicit drug use may be an under-recognised risk factor for HAV infection, particularly in young people. Faecal-oral transmission through poor personal hygiene, including sharing of implements for smoking marijuana, is the most probable route of transmission in these drug-linked outbreaks. The role of contaminated drug and needle-sharing remains to be clarified.

The re-use of irrigating equipment for flexible cystoscopy is not safe

OBJECTIVE

To determine the incidence of fluid reflux from the lower urinary tract into the connecting tubing used for irrigation in patients undergoing flexible cystoscopy.

PATIENTS AND METHODS

The study was conducted in 94 consecutive male and female patients attending routine outpatient flexible cystoscopy lists. A sensor was designed and constructed to determine the presence of any retrograde flow of irrigating fluid, and the volume of any reflux through the connecting tubing. The mean (sd) cystoscope internal channel volume was 2.56 (0.25) mL; the level of significant reflux was set at >/=2. 25 mL.

RESULTS

Reflux of irrigating fluid occurred in 11 males (17%) and was significant in six (9%) of 65 male patients, with the irrigating fluid reservoir set at a height of 0.78 m above the patient's mid-coronal level. No reflux occurred in the 29 females studied.

CONCLUSIONS

Significant reflux can occur in males and hence the connecting tubing should be regarded as contaminated. Infection-control measures must include the prevention of transmission of blood-borne infections, e.g. hepatitis B and C viruses, and human immunodeficiency virus, because of the risk that blood may contaminate urine, and they should be implemented in all cases regardless of patient risk factors. From the available evidence, flexible cystoscopy should always be performed with single-use irrigation systems.