Molecular characterization of an acute hepatitis A outbreak among healthcare workers at a Korean hospital

An outbreak of hepatitis A associated with salted clams in Busan, Korea

OBJECTIVES

In July 2019, there were multiple reports on patients with hepatitis A among the visitors of a restaurant in Busan. The current study presents the results of an epidemiological investigation and outlines the supplementary measures that would help with hepatitis A control.

METHODS

A cohort study was conducted for all 2,865 customers who visited restaurant A from June to July. Using a standardized questionnaire, participants reported the presence of hepatitis A symptoms and whether they had consumed any of 19 food items. As for participants who had visited public health centers, their specimens were collected.

RESULTS

From the study cohort, 155 participants (5.4%) had confirmed hepatitis A. The epidemic curve was unimodal, and the median number of days from the restaurant visit to symptom onset was 31 days. A genotype analysis indicated that 89 of 90 tested patients had hepatitis A virus (HAV) genotype 1A. The results of a multivariate logistic regression analysis indicated that the ingestion of salted clams increased the risk of hepatitis A by 68.12 times (95% confidence interval [CI], 9.22 to 510.87). In an unopened package of salted clams found and secured through traceback investigation, HAV genotype 1A was detected.

CONCLUSIONS

To prevent people from ingesting uncooked clams, there needs to be more efforts to publicize the dangers of uncooked clams; the food sampling test standards for salted clams should also be expanded. Furthermore, a laboratory surveillance system based on molecular genetics should be established to detect outbreaks earlier.

Nosocomial hepatitis A outbreak among healthcare workers and patients in a community hospital during an ongoing statewide outbreak

OBJECTIVE

The Tennessee Department of Health (TDH) investigated a hepatitis A virus (HAV) outbreak to identify risk factors for infection and make prevention recommendations.

DESIGN

Case series.

SETTING

Community hospital.

PARTICIPANTS

Healthcare workers (HCWs) or patients with laboratory-confirmed acute HAV infection during October 1, 2018-January 10, 2019.

METHODS

HCWs with suspected or confirmed hepatitis A infections were interviewed to assess their exposures and activities. Patient medical records and hospital administrative records were reviewed to identify common exposures. We conducted a site investigation to assess knowledge of infection control practices among HCWs. Serum specimens from ill persons were tested for HAV RNA by polymerase chain reaction (PCR) and genotyped.

RESULTS

We identified 6 HCWs and 2 patients with laboratory-confirmed HAV infection. All cases likely resulted from exposure to a homeless patient with a history of recreational substance use and undiagnosed HAV infection. Breaches in hand hygiene and use of standard precautions were identified. HAV RNA was detected in 7 serum specimens and all belonged to an identical strain of HAV genotype 1b.

CONCLUSIONS

A hepatitis A outbreak among hospital patients and HCWs resulted from exposure to a single patient with undiagnosed HAV infection. Breakdowns in infection control practices contributed to the outbreak. The likelihood of nosocomial transmission can be reduced with proper hand hygiene, standard precautions, and routine disinfection. During community outbreaks, medical providers can better prevent ongoing transmission by including hepatitis A in the differential diagnosis among patients with a history of recreational substance use and homelessness.

Prevalence and evaluation strategies for viral contamination in food products: Risk to human health-a review

Nowadays, viruses of foodborne origin such as norovirus and hepatitis A are considered major causes of foodborne gastrointestinal illness with widespread distribution worldwide. A number of foodborne outbreaks associated with food products of animal and non-animal origins, which often involve multiple cases of variety of food streams, have been reported. Although several viruses, including rotavirus, adenovirus, astrovirus, parvovirus, and other enteroviruses, significantly contribute to incidence of gastrointestinal diseases, systematic information on the role of food in transmitting such viruses is limited. Most of the outbreak cases caused by infected food handlers were the source of 53% of total outbreaks. Therefore, prevention and hygiene measures to reduce the frequency of foodborne virus outbreaks should focus on food workers and production site of food products. Pivotal strategies, such as proper investigation, surveillance, and reports on foodborne viral illnesses, are needed in order to develop more accurate measures to detect the presence and pathogenesis of viral infection with detailed descriptions. Moreover, molecular epidemiology and surveillance of food samples may help analysis of public health hazards associated with exposure to foodborne viruses. In this present review, we discuss different aspects of foodborne viral contamination and its impact on human health. This review also aims to improve understanding of foodborne viral infections as major causes of human illness as well as provide descriptions of their control and prevention strategies and rapid detection by advanced molecular techniques. Further, a brief description of methods available for the detection of viruses in food and related matrices is provided.

[Hepatitis A immunity in refugees in Germany during the current exodus]

BACKGROUND

Germany is facing a huge humanitarian challenge with rapidly rising numbers of refugees entering the country. Data on hepatitis A seroprevalence and infection in refugees and asylum seekers in Europe during the current refugee exodus is scarce.

OBJECTIVES

To assess hepatitis A (HAV) seroprevalence and immunity in refugees arriving in northern Germany in 2015.

MATERIALS AND METHODS

A cross-sectional study of 235 refugees seeking shelter in reception centers in Northern Germany in August 2015 was performed, as acute Hepatitis A had been detected in one refugee in this camp. In order to analyze acute HAV infection and overall immunity, serological screening for HAV antibodies (combined IgG and IgM) was performed. The immunity threshold was defined as <20 IU/l. In all positive screening results, separate IgM testing was performed to detect acute infections.

RESULTS

Males accounted for 84.3 % of HAV screened refugees and the mean age of refugees was 29.1 ± 11.2 years. Children and adolescents below the age of 18 years made up 8.8 % of the migrants. Overall HAV immunity within the cohort was 90 %, and a mild age-dependent increase in HAV immunity was observed, with 81.1 % immunity in children <18 years and a 100 % seropositivity in subjects >50 years. One 20-year-old female refugee had positive IgM results with high HAV antibodies, most likely due to subacute HAV infection.

CONCLUSIONS

This comparably high rate of HAV protected refugees in our cohort supports the notion that the probability of large HAV outbreaks in current German refugee centers is low. However, depending on their current living situation, HAV vaccination should be considered for each refugee child, and healthcare providers and personnel working in refugee centers should be vaccinated against HAV.

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.

Hepatitis A antibody seroprevalence among medical school students

A total of 324 first- to third-year medical school students were examined for anti-hepatitis A virus IgG. Of these 324 students, 37 were found to be anti-hepatitis A virus IgG positive (11.4%). Mass screening of medical students for seropositivity and vaccination of nonimmune students should be considered before starting medical clerkships.

Infection control nurse specialist education in Korea

With the amendment of the Medical Service Act in 2003, the infection control nurse specialist system was launched as one of several specialties for nursing in Korea. Nurse specialists are certified through the national qualifying examination after graduating from a specialist nursing program with core and specialty courses at a graduate school approved by the Ministry of Health and Welfare. This article describes graduate preparation and certification for infection control nurse specialists in Korea.

[Hepatitis A virus seropositivity among healthcare workers at a university hospital in Korea]

BACKGROUND

Healthcare workers (HCW) are known as a risk group of hepatitis A virus (HAV) infection and vaccination of this group against HAV has been suggested. However, the seroprevalence of HAV antibody among HCW in Korea has not been reported. We investigated the seropositivity of HAV antibody in HCW, to obtain a baseline data.

METHODS

We measured serum total HAV antibody using chemiluminescent immunoassay (ADVIA Centaur, Germany) in 174 HCW at one university hospital in Seoul, Korea.

RESULTS

Serum HAV antibody was positive in 48 (27.6%) of 174 subjects tested. The seropositivity of HAV antibody was significantly increased with increasing age: 21.1% (26/123), 55% (22/40), and 100% (11/11) in the age groups of 20's, 30's, and 40's, respectively (P<0.001). However it was not significantly different among different occupations (physicians 38%, nurses 24.6%, other workers 31.4%, P=0.376) and work places (medical ward 29.1%, pediatric ward 25.9%, emergency room 34.4%, laboratory 0%, P=0.140). The seroprevalence rate of HAV antibody in the age groups of 20's and 30's in this study was not higher than that of previous studies on non-HCW populations in Korea since 2006.

CONCLUSIONS

The seroprevalence of HAV antibody among HCW in the age groups of 20's and 30's in a Korean hospital was not higher than that of non-HCW populations, and the seropositivity increased with increasing age. Further studies are needed for the age-specific strategy for vaccination, considering the increased risk of exposure in HCW to HAV infection in hospital environment with the increase of symptomatic patients with HAV.

Molecular epidemiology of hepatitis A virus in the South-East area of Gyeonggi-do in Korea

PURPOSE

Hepatitis A virus (HAV) has been a leading cause of acute hepatitis in Korea. The reported genotypes of acute hepatitis A in Korea are the subgenotype IA and IB. The aim of the present study is to investigate HAV genotypes in the south-east area of Gyeonggi-do in Korea.

MATERIALS AND METHODS

From June 2004 to June 2006, 46 acute hepatitis A patients were enrolled prospectively. All had sporadic acute hepatitis A patients. All suspected cases of acute hepatitis A were tested for IgM anti-HAV antibodies. We sequenced 168 bp of nucleotides of the putative VP1/P2A junction and determined the HAV genotype with reverse transcriptase polymerase chain reaction. The clinical and laboratory results of all patients were recorded.

RESULTS

HAV-ribonucleic acid (RNA) was detected in 41 samples out of 46 samples. Among the 41 samples, 25 (60%) were shown to have subgenotype IIIA and the other 16 (40%) were subgenotype IA. Several amino acid substitutions were found.

CONCLUSION

In these HAV sporadic cases, IIIA and IA were identified, and this may reflect co-circulation of various genotypes in Korea. This study provides valuable new data on the genetic distribution of HAV and important information to help design appropriate public health measures.

Molecular characterization of hepatitis A virus isolated from acute gastroenteritis patients in the Seoul region of Korea

Hepatitis A virus (HAV) is a major public health problem throughout the world. As a result of declining HAV endemic in Korea, an increasing number of children and adolescents have become susceptible to HAV infection. HAV is related with sanitation conditions of the environment and is transmitted via the fecal-oral route, either through person-to-person contact or by contaminated water and food. The present study has been carried out to determine the phylogenetic analysis and circulating patterns of HAV strains detected from hospitalized patients with acute gastroenteritis (AGE) in the Seoul region of Korea. In total, 2,782 stool specimens from hospitalized patients with AGE collected in October 2006 to September 2007 in Seoul were tested for HAV. A pair comparison of the nucleic acid sequence of a 159-bp base region at the putative VP1/2A junction of 85 Seoul isolates revealed that the most common HAV strain circulating in the region during 2006-2007 was subgenotype IA. HAV phylogenetic studies can provide important information on the genetic characteristics of HAV from AGE patients who may subsequently become the source of infection in Korea.

Sero-epidemiology of hepatitis A virus infection among healthcare workers in Korean hospitals

Hepatitis A virus (HAV) has been increasingly reported in Korea as has an outbreak in Korean healthcare workers (HCWs). This 2008 study evaluated the sero-epidemiology of HAV infections among 3696 HCWs in four Korean hospitals. HCWs were tested for immunoglobulin G anti-HAV antibodies using commercially available kits. Data including demographic characteristics, occupation, workplace and serological status for other hepatitis viruses were collected. Statistical analyses were conducted to identify variables related to HAV seropositivity. Among the 3696 participants, 2742 (74%) were women and the majority (96%) were aged 20-39 years (median: 28; range: 19-68). Eighteen percent were physicians, 46% nurses, 10% nurses' aides, 11% paramedical technicians and 15% administrative staff. Seropositivity for HAV significantly increased with age (P<0.001): 1.8% for < or =24 years, 14.7% for 25-29 years, 41.8% for 30-34 years, 75.5% for 35-39 years, and 93.7% for > or =40 years. Among those aged 20-39 years, age-specific HAV seroprevalence was significantly lower in physicians than in the other occupational groups (P<0.001). In Korea, mass vaccination to HCWs aged < or =29 years or screening for seropositivity and vaccinating non-immune subjects aged 30-39 years should be considered, especially in physicians.