A multistate, foodborne outbreak of hepatitis A. National Hepatitis A Investigation Team

Hepatitis A Seroprevalence Among HIV-Exposed and Unexposed Pediatric Populations in South Africa

Background: There is limited evidence comparing hepatitis A seroprevalence among HIV-exposed uninfected (HEU), HIV-infected (HIV), and unexposed uninfected (HUU) children. This compromises rational vaccine decision-making. Methods: This study comprised a retrospective health facility-based population of children aged 1 month-12 years. Archival sera were tested for markers of acute (anti-HAV IgM) or past (total anti-HAV) HAV infection. Subgroup analysis was conducted based on perinatal HIV exposure or infection status. Results: Among 513 children, the median age was 10 (IQR: 4-25) months. The median maternal age was 29 (IQR: 25-34) years. An anti-HAV seropositivity of 95.1% (117/122 [95% CI 90.2-98.4]) was found among those ≤6 months of age, indicative of the rate of transplacental antibody transfer. Among 1-12-year-olds, hepatitis A seroprevalence was 19.3% (37/192 [95% CI 14.1-25.7]), while 1.1% (2/188 [95% CI 0.12-2.76]) had evidence of acute infection. Compared to HIV-exposed subgroups (HIV = 60%, 6/10 [95% CI 27.4-86.3] and HEU = 45%, 9/20 [95% CI 23.8-68]), hepatitis A seroprevalence among HUU children was low (29.2%, 47/161 [95% CI 22.4-37.0]). Conclusions: Natural immunity among HIV-exposed and unexposed children in South Africa is insufficient to protect against severe liver complications associated with HAV infection later in adulthood.

High Incidence of Acute Liver Failure among Patients in Egypt Coinfected with Hepatitis A and Hepatitis E Viruses

Hepatitis A virus (HAV) and Hepatitis E virus (HEV) are transmitted through the fecal-oral route. HAV outbreaks and one HEV outbreak have been reported in Egypt. However, the impact of HAV-HEV co-infection is not known. In this study, we assessed HEV markers in acute HAV-infected patients (n = 57) enrolled in Assiut University hospitals. We found that 36.8% of HAV-infected patients were also positive for HEV markers (anti-HEV IgM and HEV RNA), while 63.2% of the patients were HAV mono-infected. Demographic and clinical criteria were comparable in both HAV mono-infected patients and HAV-HEV co-infected patients. Although liver enzymes were not significantly different between the two groups, liver transaminases were higher in the co-infected patients. Six patients developed acute liver failure (ALF); five of them were HAV-HEV-co-infected patients. The relative risk of ALF development was 8.5 times higher in HAV-HEV co-infection compared to mono-infection. Three cases of ALF caused by HAV-HEV co-infection were reported in children (below 18 years) and two cases were reported in adults. All patients developed jaundice, coagulopathy, and encephalopathy; all were living in rural communities. In conclusion: HAV-HEV co-infection can be complicated by ALF. The risk of ALF development in HAV-infected patients is higher when coinfection with HEV is present.

Epidemiological characteristics of acute hepatitis A, 2013-2016: a cross-sectional study in Morocco

BACKGROUND

Hepatitis A virus (HAV) is the common cause of acute hepatitis worldwide. Indeed, hepatitis A is endemic in developing countries such in Morocco and most residents are exposed in childhood. The characterisation of circulating strains of HAV remains crucial to understand the virological evolution and geo-temporal characteristics, which are essential for controlling infections and outbreaks. The purpose of the current study was the detection and characterisation of HAV strains circulating in Morocco by performing serological test, RT-PCR, sequencing and phylogenetic analysis.

METHODS

In this cross-sectional study, 618 suspected acute hepatitis cases were examined by Architect HAV abIgM. Of the 162 positives, 64 underwent RNA extraction. None of the suspected cases was immune to HAV and none of them had received a blood transfusion. Samples found positive by RT-PCR using primers targeting the VP1/VP2A junction and the VP1/VP3 capsid region of HAV were subjected to sequencing and phylogenetic analyses.

RESULTS

HAV Acute infection rate was 26.2% [95% CI, 22.8-29.9], while viraemia reached 45% (29/64) after amplification of the VP3/VP1 region. Phylogenetic analysis of the VP1/2A segment revealed the presence of sub-genotypes IA and IB. Eighty-seven percent of the strains belonged to the subgenotype IA, while twelve percent to IB subgenotype.

CONCLUSION

This first molecular study of acute hepatitis A in Morocco provided information about genetic diversity of HAV, revealing the co-circulating of only two subgenotypes (IA and IB). Notably, subgenotype IA was found to be the predominant subgenotype in Morocco.

Hepatitis a Vaccine as Opportunity of Primary Prevention for Food Handlers: A Narrative Review

The hepatitis A virus (HAV) is still a leading cause of viral hepatitis worldwide. After a long incubation period, the clinical manifestations range from asymptomatic infection to acute liver failure. The severity of the disease increases with age and pre-existing liver disease. The transmission is mainly via person-to-person contact or ingestion of contaminated food or water. Food contamination can occur at any step of the food chain, especially when infected people handle not-heated or otherwise-treated food. HAV is endemic in low-income countries because of poor sanitary and sociodemographic conditions. The populations of developed countries are highly susceptible, and large outbreaks occur when HAV is introduced from endemic countries due to globalization, travel, and movement of foodstuffs. HAV prevention includes hygiene practices, immunoglobulins, and vaccination. Safe and effective inactivated and live attenuated vaccines are available and provide long-term protection. The vaccine targets are children and subjects at increased risk of HAV exposure or serious clinical outcomes. This review discusses the critical role of food handlers in the spread of HAV and the opportunity for food industry employers to consider food handler immunization a tool to manage both food safety in compliance with HACCP principles and food operators' biologic risk.

Genotyping and Molecular Diagnosis of Hepatitis A Virus in Human Clinical Samples Using Multiplex PCR-Based Next-Generation Sequencing

Hepatitis A virus (HAV) is a serious threat to public health worldwide. We used multiplex polymerase chain reaction (PCR)-based next-generation sequencing (NGS) to derive information on viral genetic diversity and conduct precise phylogenetic analysis. Four HAV genome sequences were obtained using multiplex PCR-based NGS. HAV whole-genome sequence of one sample was obtained by conventional Sanger sequencing. The HAV strains demonstrated a geographic cluster with sub-genotype IA strains in the Republic of Korea. The phylogenetic pattern of HAV viral protein (VP) 3 region showed no phylogenetic conflict between the whole-genome and partial-genome sequences. The VP3 region in serum and stool samples showed sensitive detection of HAV with differences of quantification that did not exceed <10 copies/μL than the consensus VP4 region using quantitative PCR (qPCR). In conclusion, multiplex PCR-based NGS was implemented to define HAV genotypes using nearly whole-genome sequences obtained directly from hepatitis A patients. The VP3 region might be a potential candidate for tracking the genotypic origin of emerging HAV outbreaks. VP3-specific qPCR was developed for the molecular diagnosis of HAV infection. This study may be useful to predict for the disease management and subsequent development of hepatitis A infection at high risk of severe illness.

Exploration of a new hepatitis a surveillance system in Beijing, China: based on molecular epidemiology

Background

The incidence of hepatitis A virus (HAV) infection is low in Beijing, China, but the risk of outbreaks still exists. It is difficult to identify possible sources of infection among sporadic cases based on a routine surveillance system. Therefore, a more effective surveillance system needs to be established.

Methods

The epidemiological data of hepatitis A were obtained from a routine surveillance system. Patients with HAV confirmed at the local hospitals were asked to complete a questionnaire that included additional case information and possible sources of infection. Serum and fecal specimens were also collected for testing HAV RNA by polymerase chain reaction. In addition, the 321-nucleotide segment of the VP1/2A junction region was sequenced to determine the HAV genotype.

Results

In 2019, 110 HAV cases were reported in Beijing, with an incidence rate of 0.51/100,000. 61(55.5%) of these patients were male. The greatest proportion of these patients were aged from 30 to 60 years. The rate was lower in suburban and rural areas compared to urban areas. Contaminated food consumption, particularly seafood consumption, was the primary potential source of infection. Among the 16 specimens of confirmed HAV cases that could be sequenced, 93.8% were HAV IA, and 6.3% were HAV IB. In addition, the samples collected from all HAV sequences in this investigation showed 89.4–100% nucleotide homology. Two groups (each with three sporadic cases) showed 100% nucleotide homology. The three sporadic cases in one group had the same possible source of infection: contaminated salad with raw vegetables and seafood. In the other group, the three sporadic cases did not have an epidemiological connection.

Conclusions

In a low HAV prevalent area, such as in Beijing, incorporating molecular epidemiology into the routine surveillance system could help inform possible clusters of outbreaks and provide support for earlier control of HAV transmission. Nevertheless, increased sampling from detected cases and improved specimen quality are needed to implement such a system.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06872-4.

Efficient capturing and sensitive detection of hepatitis A virus from solid foods (green onion, strawberry, and mussel) using protamine-coated iron oxide (Fe3O4) magnetic nanoparticles and real-time RT-PCR

Hepatitis A virus (HAV) continues to be a public health concern and has caused large foodborne outbreaks and economic losses worldwide. Rapid detection of HAV in foods can help to confirm the source of outbreaks in a timely manner and prevent more people getting infected. In order to efficiently detect HAV at low levels of contamination in foods, rapid and easy-to-use techniques are required to separate and concentrate viral particles to a small volume. In the current study, HAV particles were eluted from green onion, strawberry, and mussel using glycine buffer (0.05 M glycine, 0.14 M NaCl, 0.2% (v/v) Tween 20, pH 9.0) and suspended viral particles were captured using protamine-coated magnetic nanoparticles (PMNPs). This process caused a selective concentration of the viral particles, which could be followed by quantitative real-time RT-PCR analysis. Results showed that pH, NaCl concentration, and PMNP amount used for the capturing had significant effects on the recovery efficiency of HAV (P < 0.05). The highest recovery rate was obtained at pH 9.0, 0.14 M NaCl, and 50 μL of PMNPs. The optimized PMNP capturing method enabled the rapid capture and concentration of HAV. A sensitive real-time RT-PCR test was developed with detection limits of 8.3 × 10⁰ PFU/15 g, 8.3 × 10¹ PFU/50 g, and 8.3 × 10⁰ PFU/5 g of HAV in green onion, strawberry, and mussel, respectively. In conclusion, the PMNP method is rapid and convenient in capturing HAV from complex solid food samples and can generate concentrated HAV sample solutions suitable for high-sensitivity real time RT-PCR detection of the virus.

Detection of Hepatitis A Virus in Strawberries Implicated in an Outbreak in the USA in 1997

Hepatitis A virus (HAV) was detected in frozen strawberries which had been implicated in a large outbreak of hepatitis A in 1997. The sample was analysed after over 20 years of storage, following a standard method not available at the time of the outbreak. This is the first study in which the HAV associated with the 1997 outbreak of foodborne hepatitis has finally been detected.

Implementing sequencing-based surveillance in developing countries: findings from a pilot rollout for hepatitis A in China

Background

The emergence of SARS-Cov2 variants has highlighted the need to implement sequencing-based surveillance in developing countries for early response to mutant viruses of concern. However, limited information on how to implement sequencing-based surveillance is available, and the feasibility and performance of this new type of surveillance are still in question.

Methods

To understand the challenges with the implementation and to promote sequencing-based surveillance, we reported findings from a pilot for hepatitis A (HepA) in five sentinel provinces in China as an example of sequencing-based surveillance implementation. The performance of the surveillance system was evaluated by indicators related to acceptability, data quality, simplicity, utility, and timeliness. We use a scale from 1 to 3 was used to provide a score for each aspect.

Results

During the pilot, 306 cases of HepA were reported, and 49.79% of samples were available for sequencing. Eleven genomic clusters were found, of which seven clusters were potentially related to a foodborne outbreak oyster based on identical viral sequence and epidemiologic investigations. The greatest strength of the system was its simplicity (Score: 2.63). The acceptability (Score: 2.0) and utility (Score: 2.33) were modest, but data quality (Score: 1.75) and timeliness (Score: 1.75) were the main challenges.

Conclusions

Overall, the system performed satisfactorily and proved to be useful for virological characterization of cases and early outbreak detection, with a great potential for scale-up. Further efforts are required to address financial and human resource constraints and inadequate support among physicians. Education should be given to health care professionals to improve the data quality. The establishment of decentralized surveillance networks can be an approach to improve timeliness for emerging infections.

Persistence of Hepatitis A Virus RNA in Water, on Non-porous Surfaces, and on Blueberries

Enteric viruses, such as human norovirus and hepatitis A virus (HAV), are the leading cause of transmissible foodborne illness. Fresh produce such as berries are often contaminated by infected food handlers, soiled water, or food contact surfaces. The gold-standard method for virus detection throughout the food chain is RT-qPCR, which detects portions of genomes including non-infectious viral particles and naked viral RNA. The aim of this study was to evaluate the persistence of heat-inactivated HAV in water, phosphate-buffered saline, on stainless steel and polyvinyl chloride, and on blueberries at −80°C, −20°C, 4°C, and room temperature. In water and phosphate-buffered saline, viral RNA could be detected for up to 90 days regardless of temperature when the initial load was 2.5 × 10⁴ or 2.5 × 10⁶ genome copies. It was detected on polyvinyl chloride and blueberries under most conditions. On stainless steel, the large initial load persisted for 90 days, while the medium-level load was detected only up to 16 days at room temperature or 60 days at 4°C. The detection of non-infectious viral RNA can confound investigations of gastroenteritis outbreaks. Pretreatments that discriminate between naked RNA, non-infectious virions and infectious virions need to be included in the RT-qPCR method in order to reduce the risk of positive results associated with non-infectious viral particles.

Enterically transmitted hepatitis in the third millennium in northeastern Romania

While the incidence of hepatitis A virus (HAV) infections has decreased in the last few years, the incidence of hepatitis E virus (HEV) is increasing in developed countries. Both infections remain a worldwide reality, strongly related to socio-economic conditions. We retrospectively analyzed the medical files of patients with viral hepatitis hospitalized in the Infectious Disease Hospital Iasi, Romania between 2018 and 2019. The serological confirmed cases of HAV and HEV infections were included in the analysis; included in our analysis were 269 HAV-infected patients. The most affected were males (53.9% cases) aged between 8 and 15 years (53.6% cases). Severe infections were recorded at admission in 2.24% cases and evolution was favorable under supportive and symptomatic treatment. Only three adult males, with no recent history of travel, were confirmed with HEV infection. Even though we have identified a small number of cases, recent studies performed in our region found a seroprevalence of 32.5% in the general population, possibly related to zoonotic transmission. While outbreaks of HAV infection are still noted in our region, a lack of hospitalized HEV-infected patients suggest that most cases are asymptomatic or underdiagnosed. HEV infection remains an underreported disease, possibly due to misdiagnosis, subclinical or dual hepatitis infection, but with a significant risk in vulnerable categories, such as pregnant women or immunosuppressed patients.

Foodborne transmission of hepatitis A and hepatitis E viruses: A literature review

Foodborne viruses have been recognized as a growing concern to the food industry and a serious public health problem. Hepatitis A virus (HAV) is responsible for the majority of viral outbreaks of food origin worldwide, while hepatitis E virus (HEV) has also been gaining prominence as a foodborne viral agent in the last years, due to its zoonotic transmission through the consumption of uncooked or undercooked infected meat or derivatives. However, there is a lack of scientific reports that gather all the updated information about HAV and HEV as foodborne viruses. A search of all scientific articles about HAV and HEV in food until March 2020 was carried out, using the keywords "HAV", "HEV", "foodborne", "outbreak" and "detection in food". Foodborne outbreaks due to HAV have been reported since 1956, mainly in the USA, and in Europe in recent years, where the number of outbreaks has been increasing throughout time, and nowadays it has become the continent with the highest foodborne HAV outbreak report. Investigation and detection of HAV in food is more recent, and the first detections were performed in the 1990s decade, most of them carried out on seafood, first, and frozen food, later. On the other hand, HEV has been mainly looked for and detected in food derived from reservoir animals, such as meat, sausages and pate of pigs and wild boars. For this virus, only isolated cases and small outbreaks of foodborne transmission have been recorded, most of them in industrialized countries, due to HEV genotype 3 or 4. Virus detection in food matrices requires special processing of the food matrix, followed by RNA detection by molecular techniques. For HAV, a real-time PCR has been agreed as the standard method for virus detection in food; in the case of HEV, a consensus assay for its detection in food has not been reached yet. Our investigation shows that there is still little data about HAV and HEV prevalence and frequency of contamination in food, prevalent viral strains, and sources of contamination, mainly in developing countries, where there is no research and legislation in this regard. Studies on these issues are needed to get a better understanding of foodborne viruses, their maintenance and their potential to cause diseases.

Hepatitis A Virus Strains Circulating in the Campania Region (2015-2018) Assessed through Bivalve Biomonitoring and Environmental Surveillance

The genetic diversity of Hepatitis A Virus (HAV) circulating in the Campania Region in years 2015–2018 was investigated through the monitoring of sentinel bivalve shellfish and water matrices. Overall, 463 water samples (71 sewage samples, 353 coastal discharge waters, and 39 seawaters samples), and 746 bivalve shellfish samples were analyzed. Positivity for HAV was detected in 20/71 sewage samples, 14/353 coastal discharge waters, 5/39 seawaters, and 102/746 bivalve shellfish. Sixty-one of the positive samples were successfully sequenced and were characterized as genotype IA (n = 50) and IB (n = 11). The prevalent strain circulating in 2015 in both bivalves and waters was the IA strain responsible for the outbreak occurring around the same time in the Naples area. This variant was no longer identified in subsequent years (2017–2018) when, instead, appeared two of the IA variants of the multistate outbreak affecting men who have sex with men (MSM), VRD_521_2016, and RIVM-HAV16–090, with the former prevailing in both shellfish and water environments. HAV IB isolates were detected over the years in shellfish and in water matrices, but not in clinical samples, suggesting that this genotype had been circulating silently. An integrated surveillance system (environment/food/clinical cases) can be a useful tool to monitor changes in viral variants in the population, as well as an early warning system.

Disease burden of viral hepatitis A, B, C and E: A systematic analysis

Viral hepatitis has been recognized as a leading cause of deaths worldwide. We aimed to analyse the disease burden of viral hepatitis at the global, regional and national levels. We collected the data of death number, mortality rate, and disability-adjusted life years (DALYs) of viral hepatitis by sex, age, geography and type of disease from the Global Health Data Exchange platform. Estimated average percentage change (EAPC) was used to quantify the age-standardized mortality rate (ASMR) of viral hepatitis between 1990 and 2017. Globally, the number of deaths from viral hepatitis increased from 980.9 thousand in 1990 to 1412.3 thousand in 2017, accompanying by the DALYs increased from 35.2 million to 43.1 million in the same period. Hepatitis B and C accounted for 97.6% of total viral hepatitis-related deaths worldwide in 2017. While the death number and DALYs were decreased in acute hepatitis A, B, C and E, a significant increase was found in liver cancer and cirrhosis due to hepatitis B and C. The ASMRs of liver cancer and cirrhosis caused by hepatitis B and C were decreased at the global level and in most regions. However, a significant increase was observed in several developed countries, such as the USA and the UK. The disease burden of viral hepatitis continues to increase worldwide, which was driven by the increase in burden of chronic hepatitis B and C.

A new assay for quantitative detection of hepatitis A virus

Hepatitis A virus (HAV) is mainly transmitted via contaminated food or water or through person-to-person contact. Here, we describe development and evaluation of a reverse transcription droplet digital PCR (RT-ddPCR) and reverse transcription real-time PCR (RT-qPCR) assay for detection of HAV in food and clinical specimens. The assay was evaluated by assessing limit of detection, precision, matrix effects, sensitivity and quantitative agreement. The 95 % limit of detection (LOD95 %) was 10 % higher for RT-ddPCR than for RT-qPCR. A Bayesian model was used to estimate precision on different target concentrations. From this, we found that RT-ddPCR had somewhat greater precision than RT-qPCR within runs and markedly greater precision between runs. By analysing serum from naturally infected persons and a naturally contaminated food sample, we found that the two methods agreed well in quantification and had comparable sensitivities. Tests with artificially contaminated food samples revealed that neither RT-ddPCR nor RT-qPCR was severely inhibited by presence of oysters, raspberries, blueberries or leafy-green vegetables. For this assay, we conclude that RT-qPCR should be considered if rapid, qualitative detection is the main interest and that RT-ddPCR should be considered if precise quantification is the main interest. The high precision of RT-ddPCR allows for detection of small changes in viral concentration over time, which has direct implications for both food control and clinical studies.

Prevention of Hepatitis A Virus Infection in the United States: Recommendations of the Advisory Committee on Immunization Practices, 2020

HEPATITIS A IS A VACCINE-PREVENTABLE, COMMUNICABLE DISEASE OF THE LIVER CAUSED BY THE HEPATITIS A VIRUS (HAV). THE INFECTION IS TRANSMITTED VIA THE FECAL-ORAL ROUTE, USUALLY FROM DIRECT PERSON-TO-PERSON CONTACT OR CONSUMPTION OF CONTAMINATED FOOD OR WATER. HEPATITIS A IS AN ACUTE, SELF-LIMITED DISEASE THAT DOES NOT RESULT IN CHRONIC INFECTION. HAV ANTIBODIES (IMMUNOGLOBULIN G [IGG] ANTI-HAV) PRODUCED IN RESPONSE TO HAV INFECTION PERSIST FOR LIFE AND PROTECT AGAINST REINFECTION; IGG ANTI-HAV PRODUCED AFTER VACCINATION CONFER LONG-TERM IMMUNITY. THIS REPORT SUPPLANTS AND SUMMARIZES PREVIOUSLY PUBLISHED RECOMMENDATIONS FROM THE ADVISORY COMMITTEE ON IMMUNIZATION PRACTICES (ACIP) REGARDING THE PREVENTION OF HAV INFECTION IN THE UNITED STATES. ACIP RECOMMENDS ROUTINE VACCINATION OF CHILDREN AGED 12-23 MONTHS AND CATCH-UP VACCINATION FOR CHILDREN AND ADOLESCENTS AGED 2-18 YEARS WHO HAVE NOT PREVIOUSLY RECEIVED HEPATITIS A (HEPA) VACCINE AT ANY AGE. ACIP RECOMMENDS HEPA VACCINATION FOR ADULTS AT RISK FOR HAV INFECTION OR SEVERE DISEASE FROM HAV INFECTION AND FOR ADULTS REQUESTING PROTECTION AGAINST HAV WITHOUT ACKNOWLEDGMENT OF A RISK FACTOR. THESE RECOMMENDATIONS ALSO PROVIDE GUIDANCE FOR VACCINATION BEFORE TRAVEL, FOR POSTEXPOSURE PROPHYLAXIS, IN SETTINGS PROVIDING SERVICES TO ADULTS, AND DURING OUTBREAKS.

A new pattern in hepatitis A virus infection in an urban population

INTRODUCTION

hepatitis A virus (HAV) infection is a common cause of acute hepatitis worldwide. Since the generalization of vaccination, its incidence had markedly declined. Nevertheless, several HAV-outbreaks have been described in the last decade, mainly related to contaminated alimentary products. In recent years, a new pattern of acute HAV infection has been described with changes in the demographic profile of the infected population, which is more common in healthy young men.

PATIENTS AND METHODS

a retrospective case series study was performed to evaluate this possible change in the pattern of HAV infection. The case series included all patients with a diagnosis of HAV acute infection in our hospital between January 2005 and May 2017.

RESULTS

a total of 196 cases were diagnosed which were comprised of two probable outbreaks: one starting in November 2008 of 26 cases and one starting in 2016 with 69 cases at the time of data collection. The two outbreak populations were comparable. While the sporadic cases group was predominantly formed by pediatric and third-age patients with a slight male tendency, the outbreak related cases showed a clear predominance for young males (proportion of males: 63.2% vs 85.3%, p < 0.001). A possible chronological relationship with the national gay festivity celebrated in Madrid was observed. Outbreak related cases had higher bilirubin, alanine aminotransferase and longer APPT at diagnosis as well as a lower albumin concentration. The clinical relevance was minimal with a similar hospitalization rate and clinical outcome in both groups. There were no related deaths, acute liver failure or need for liver transplantation in our cohort.

CONCLUSION

these epidemiological findings emphasize the importance of implementing preventive measures as well as social awareness campaigns.

Outbreaks, occurrence, and control of norovirus and hepatitis a virus contamination in berries: A review

Foodborne enteric viruses, in particular HuNoV and HAV, are the most common cause of the berry-linked viral diseases, and outbreaks around the world, and have become an important concern for health authorities. Despite the increased importance of berry fruits as a vehicle for foodborne viruses, there is limited information concerning the fate of foodborne viruses in the berry supply chain from farm to consumer. A comprehensive understanding of berry-associated viral outbreaks - with a focus on contamination sources, persistence, survival, and the effects of current postharvest and processing interventions and practices - is essential for the development of effective preventative strategies to reduce risk of illness. The purpose of this paper is twofold; (i) to critically review the published literature on the current state of knowledge regarding berry-associated foodborne viral outbreaks and the efficiency of berry processing practices and (ii) to identify and prioritize research gaps regarding practical and effective mechanism to reduce viral contamination of berries. The review found that fecally infected food handlers were the predominant source of preharvest and postharvest pathogenic viral contamination. Current industrial practices applied to fresh and frozen berries demonstrated limited efficacy for reducing the viral load. While maintaining best practice personal and environmental hygiene is a key intervention, the optimization of processing parameters (i.e., freezing, frozen storage, and washing) and/or development of alternative processing technologies to induce sufficient viral inactivation in berries along with retaining sensory and nutritional quality, is also an important direction for further research.

Molecular Genotyping of Hepatitis A Virus, California, USA, 2017-2018

We implemented subgenomic and whole-genome sequencing to support the investigation of a large hepatitis A virus outbreak among persons experiencing homelessness, users of illicit drugs, or both in California, USA, during 2017-2018. Genotyping data helped confirm case-patients, track chains of transmission, and monitor the effectiveness of public health control measures.

Understanding temporal and spatial variations of viral disease in the US: The need for a one-health-based data collection and analysis approach

Viral diseases exhibit spatial and temporal variation, and there are many factors that can affect their occurrence. The identification of these factors is critical in the efforts to predict and lessen viral disease burden. Because viral infection is able to spread to humans from the environment, animals, and other humans, the One-Health framework can be used to investigate the critical pathways through which viruses are transported and transmitted. A holistic approach, incorporating publicly available clinical data for human, livestock, and wildlife disease occurrence, together with environmental data reported in federal and state databases such as parameters related to land use, environmental quality, and weather, can enhance the understanding of variations in disease patterns, leading to the design and implementation of surveillance systems. An example analysis approach is presented for Michigan, United States, which is a state with large urban centers as well as a sizeable rural and agricultural population. Analysis of publicly available data from 2017 indicates that gastrointestinal (GI) and influenza-associated illnesses in Michigan may have been related with agricultural land use to a higher extent than with developed land use during that year. Meanwhile, hepatitis A virus appears to be most closely related with developed land use in dense population areas. GI illnesses may be related to precipitation, and this relationship is strongest in the springtime, although GI illnesses are most common in the winter months. Integration of human-related clinical data, animal disease data, and environmental data can ultimately be used for prioritization of the most critical locations and times for viral outbreaks in both urban and rural environments.

A Multistate Outbreak of Human Salmonella Agona Infections Associated With Consumption of Fresh, Whole Papayas Imported From Mexico-United States, 2011

Background

Nontyphoidal Salmonella causes ~1 million food-borne infections annually in the United States. We began investigating a multistate outbreak of Salmonella serotype Agona infections in April 2011.

Methods

A case was defined as infection with the outbreak strain of Salmonella Agona occurring between 1 January and 25 August 2011. We developed hypotheses through iterative interviews. Product distribution analyses and traceback investigations were conducted. The Food and Drug Administration (FDA) tested papayas from Mexico for Salmonella.

Results

We identified 106 case patients from 25 states. Their median age was 21 years (range, 1-91). Thirty-nine of 61 case patients (64%) reported Hispanic/Latino ethnicity; 11 of 65 (17%) travelled to Mexico before illness. Thirty-two of 56 case patients (57%) reported papaya consumption. Distribution analyses revealed that three firms, including Distributor A, distributed papaya to geographic areas that aligned with both the location and timing of illnesses. Traceback of papayas purchased by ill persons in four states identified Distributor A as the common supplier. FDA testing isolated the outbreak strain from a papaya sample collected at distributor A and from another sample collected at the US-Mexico border, destined for distributor A. FDA isolated Salmonella species from 62 of 388 papaya import samples (16%). The investigation led to a recall of fresh, whole papayas from Distributor A and an FDA import alert for all papayas from Mexico.

Conclusions

This is the first reported Salmonella outbreak in the United States linked to fresh, whole papayas. The outbreak highlights important issues regarding the safety of imported produce.

Microbial Contamination of Fresh Produce: What, Where, and How?

Promotion of healthier lifestyles has led to an increase in consumption of fresh produce. Such foodstuffs may expose consumers to increased risk of foodborne disease, as often they are not subjected to processing steps to ensure effective removal or inactivation of pathogenic microorganisms before consumption. Consequently, reports of ready-to-eat fruit and vegetable related disease outbreak occurrences have increased substantially in recent years, and information regarding these events is often not readily available. Identifying the nature and source of microbial contamination of these foodstuffs is critical for developing appropriate mitigation measures to be implemented by food producers. This review aimed to identify the foodstuffs most susceptible to microbial contamination and the microorganisms responsible for disease outbreaks from information available in peer-reviewed scientific publications. A total of 571 outbreaks were identified from 1980 to 2016, accounting for 72,855 infections and 173 deaths. Contaminated leafy green vegetables were responsible for 51.7% of reported outbreaks. Contaminated soft fruits caused 27.8% of infections. Pathogenic strains of Escherichia coli and Salmonella, norovirus, and hepatitis A accounted for the majority of cases. Large outbreaks resulted in particular biases such as the observation that contaminated sprouted plants caused 31.8% of deaths. Where known, contamination mainly occurred via contaminated seeds, water, and contaminated food handlers. There is a critical need for standardized datasets regarding all aspects of disease outbreaks, including how foodstuffs are contaminated with pathogenic microorganisms. Providing food business operators with this knowledge will allow them to implement better strategies to improve safety and quality of fresh produce.

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.

Hepatitis A Outbreak in the General Population due to a MSM-Associated HAV Genotype Linked to a Food Handler, November 2017-February 2018, Germany

Hepatitis A (HAV) is a viral infection causing a range of symptoms, sudden onset of fever, malaise, diarrhea, and jaundice. It is mostly transmitted fecal-oral through contaminated food, with immediate household and sexual contacts having a higher risk of infection. Since 2016 an increased number of HAV infections, mostly affecting men who have sex with men (MSM) have been noticed worldwide, with three main genotypes circulating. We report here on the first spillover outbreak of the MSM-associated HAV genotype RIVM-HAV16-090 in the German general population in November 2017-February 2018. In total, twelve cases could be attributed to the outbreak with the index case and a coworker in a butchers shop being the most probable source of the outbreak. The identical HAV genotype was detected in two environmental samples in the premises of the butchers shop and in nine cases. Outbreak control measures included detailed contact tracing and stool examinations, several environmental investigations, thorough cleaning, and disinfection of the premises of the butchers shop. Post-exposure vaccination was recommended to all unprotected contacts during the investigation. Furthermore, although hand-washing facilities were in accordance with the required law, additional installment of soap and disinfectant dispensers and contactless faucets has been recommended.

Foodborne Bacterial, Viral, and Protozoan Pathogens in Field and Market Strawberries and Environment of Strawberry Farms

Field-grown strawberries, the environment of strawberry farms and fresh strawberries from marketplaces were examined for bacterial, viral, and protozoan pathogens. The presence of bacteria was determined using culture and real-time PCR (qPCR), presence of protozoa and viruses using qPCR and reverse transcription qPCR, respectively. The highest proportion of positivity was observed for Escherichia coli both in field and purchased strawberries (up to 48.6%). Finding of Cronobacter ranged from 0.6% to 9% both for field and market strawberries. The prevalence of other pathogens (Listeria monocytogenes, Giardia intestinalis, Cryptosporidium sp., and Norovirus) in strawberries was below 4.5%; HAV was not detected at all. Positivity of the environment was determined to be lower than 2.1% for all microorganisms, except for E. coli. The concentration of pathogens in most samples did not exceed 100 CFU/g using culture and 1.8 × 10² GE/g of strawberries or swabbing area 6.1 × 10² GE/mL or swabbing area of environmental samples using qPCR. All studied farms applied preventive measures such as drip irrigation, avoidance of organic fertilizers, and use of mulch foils or gloves for workers to decrease contamination of strawberries. Despite this, certain pathogens were found in fresh strawberries. Even at low concentrations, these pathogens can be a source of infection for consumers. Thus, their presence in strawberries is of particular significance as these are mostly consumed fresh and without any thermal processing. PRACTICAL APPLICATION: Nonlegislatively monitored pathogens of bacterial, viral and parasitic origin were found in strawberries. Monitoring the presence of these pathogens in ready-to-eat food is therefore meaningful and important in terms of food safety, especially in relation to pathogens with low infectious dose (for example, viruses, parasites).

Public health investigation and response to a hepatitis A outbreak from imported scallops consumed raw—Hawaii, 2016

During the summer of 2016, the Hawaii Department of Health responded to the second-largest domestic foodborne hepatitis A virus (HAV) outbreak in the post-vaccine era. The epidemiological investigation included case finding and investigation, sequencing of RNA positive clinical specimens, product trace-back and virologic testing and sequencing of HAV RNA from the product. Additionally, an online survey open to all Hawaii residents was conducted to estimate baseline commercial food consumption. We identified 292 confirmed HAV cases, of whom 11 (4%) were possible secondary cases. Seventy-four (25%) were hospitalised and there were two deaths. Among all cases, 94% reported eating at Oahu or Kauai Island branches of Restaurant Chain A, with 86% of those cases reporting raw scallop consumption. In contrast, a food consumption survey conducted during the outbreak indicated 25% of Oahu residents patronised Restaurant Chain A in the 7 weeks before the survey. Product trace-back revealed a single distributor that supplied scallops imported from the Philippines to Restaurant Chain A. Recovery, amplification and sequence comparison of HAV recovered from scallops revealed viral sequences matching those from case-patients. Removal of product from implicated restaurants and vaccination of those potentially exposed led to the cessation of the outbreak. This outbreak further highlights the need for improved imported food safety.

Behavior of Salmonella Typhimurium on Fresh Strawberries Under Different Storage Temperatures and Wash Treatments

Fresh strawberries are one of the most popular fruits in China and are vulnerable to microbial contamination. In this study, the behavior of Salmonella Typhimurium on fresh strawberries stored at refrigeration and room temperatures, as well as the effectiveness of mild heat wash treatments at 47, 50, and 53°C on bacterial survival was investigated. The modified Gompertz, Huang, log-linear, and Weibull models were used to fit bacterial growth and survival curves under different treatments. A secondary model based on linear regression was developed to describe the effect of washing temperature on the kinetic parameters of S. Typhimurium survival derived from the Weibull model. During 72 h storage, S. Typhimurium on fresh strawberries stored at 4°C was reduced by 1.35 log CFU/g and growth of 5.64 log CFU/g was observed when strawberries were stored at 25°C. Bacterial reductions of 1.22 ± 0.15, 1.92 ± 0.06, 2.27 ± 0.07 log CFU/g were obtained when washing was carried out at 47, 50 and 53°C for 240 s, respectively. The wash temperature was an important parameter for bacterial inactivation and bacterial populations declined significantly in conjunction with washing time (p < 0.05). Warm wash treatments lead the visible color changes of strawberries, showing a slightly darker appearance while acceptable. The goodness-of-fit indices indicated that the log-linear model provided a satisfactory fit to describe the bacterial survival at 4°C. According to the smaller Akaike information criterion (AIC) value, the modified Gompertz model performed slightly better than the Huang model in describing bacterial growth at 25°C. The high adj-R2 (≥0.90) and small RMSE (≤0.22) indicated the Weibull model better described bacterial behavior under mild heat treatments. We found a close linear relationship between wash temperatures and ln k and ln n. These models were validated by independent experimental data and the values of the bias and accuracy factors fell into the acceptable range.

Persistence of Hepatitis A Virus in Fresh Produce and Production Environments, and the Effect of Disinfection Procedures: A Review

Although information is limited, it is evident that prolonged persistence of infectious Hepatitis A virus (HAV) is a factor in the transmission of the virus via fresh produce. Consequently, data on persistence of the virus on produce, and in environments relevant to production, such as soils, water and surfaces, are required to fully understand the dynamics of transmission of HAV via foods. Furthermore, information on effective disinfection procedures is necessary to implement effective post-harvest control measures. This review summarises current information on HAV persistence in fresh produce and on relevant disinfection procedures. On vegetables, HAV can remain infectious for several days; on frozen berries, it can persist for several months. HAV can remain infectious on surfaces for months, depending on temperature and relative humidity, and can survive desiccation. It can survive for several hours on hands. Washing hands can remove the virus, but further data are required on the appropriate procedure. Chlorination is effective in water, but not when HAV is associated with foodstuffs. Bleach and other sodium hypochlorite disinfectants at high concentrations can reduce HAV on surfaces, but are not suitable for use on fresh produce. There is only limited information on the effects of heating regimes used in the food industry on HAV. HAV is resistant to mild pasteurisation. Some food components, e.g. fats and sugars, can increase the virus' resistance to higher temperatures. HAV is completely eliminated by boiling. Quantitative prevalence data are needed to allow the setting of appropriate disinfection log reduction targets for fresh produce.

Genotype I hepatitis A virus introduction in Italy: Bayesian phylogenetic analysis to date different epidemics

Despite a significant decrease in acute hepatitis A in the last 2 decades in Italy, outbreaks were observed occurring mostly in southern Italy. In this study, Bayesian phylogenetic analysis was used to analyze the origin of these epidemics. With this aim, 5 different data sets of hepatitis A virus sequences were built to perform genotyping by the neighbor-joining method to estimate the evolutionary rates by using a Bayesian Markov chain Monte Carlo approach and to investigate the demographic history by independent Markov chain Monte Carlo runs enforcing both a strict and relaxed clock. The estimated mean value of the evolutionary rate, representing Ia and Ib strains, was 1.21 × 10-3 and 2.0 × 10-3 substitutions/site/year, respectively. The Bayesian maximum clade credibility tree of hepatitis A virus (HAV) Ia and Ib strains showed that Italian sequences mostly formed separate clusters. The root of the time for the most recent common ancestor (tMRCA) for HAV Ia and Ib strains dated back to 1981 and to 1988, respectively, showing in both cases different epidemic entrances. Phylodynamic analysis showed that genotype Ia increased in 1997, when the Apulia epidemic started, then suffered a bottleneck, probably consequent to vaccination and to the herd immunity, followed by a new increase in virus population in the years 2013-2014 consequent to the epidemic caused by the ingestion of mixed frozen berries. A similar trend without an evident bottleneck was observed also in the case of genotype Ib. In conclusion, the Bayesian phylogenetic analysis represents a good tool to measure the effectiveness of the public health plans used for HAV control.

Sources and contamination routes of microbial pathogens to fresh produce during field cultivation: A review

Foodborne illness resulting from the consumption of contaminated fresh produce is a common phenomenon and has severe effects on human health together with severe economic and social impacts. The implications of foodborne diseases associated with fresh produce have urged research into the numerous ways and mechanisms through which pathogens may gain access to produce, thereby compromising microbiological safety. This review provides a background on the various sources and pathways through which pathogenic bacteria contaminate fresh produce; the survival and proliferation of pathogens on fresh produce while growing and potential methods to reduce microbial contamination before harvest. Some of the established bacterial contamination sources include contaminated manure, irrigation water, soil, livestock/ wildlife, and numerous factors influence the incidence, fate, transport, survival and proliferation of pathogens in the wide variety of sources where they are found. Once pathogenic bacteria have been introduced into the growing environment, they can colonize and persist on fresh produce using a variety of mechanisms. Overall, microbiological hazards are significant; therefore, ways to reduce sources of contamination and a deeper understanding of pathogen survival and growth on fresh produce in the field are required to reduce risk to human health and the associated economic consequences.

Viral outbreaks linked to fresh produce consumption: a systematic review

AIMS

Α systematic review to investigate fresh produce-borne viral outbreaks, to record the outbreak distribution worldwide and to analyse the implication of different types of fresh produce and viral types as well.

METHODS AND RESULTS

Four databases (PubMed/Medline, Scopus, Eurosurveillance Journal and Spingerlink electronic journal) and a global electronic reporting system (ProMED-mail) were searched up to 2016. One hundred and fifty-two viral outbreaks linked to fresh produce consumption were identified. The majority of the reported outbreaks was reported in Europe, followed by North America, Asia, Australia, Africa and South America. A great number of the outbreaks was recorded in Denmark and Finland. The most common viral pathogens were norovirus (48·7%) and hepatitis A virus (46·1%). The most frequent type of fresh produce involved was frozen raspberries (23·7%). Differences in the reporting of outbreaks were recorded between the scientific literature and ProMED.

CONCLUSIONS

The number of reported illnesses linked to fresh produce has increased in several countries. Consumption of contaminated fresh produce represents a risk to public health in both developed and developing countries, but the impact will be disproportionate and likely to compound existing health disparities. For this reason, all countries should systematically collate and report such data through a disease surveillance system, in order to adopt risk management practices for reducing the likelihood of contamination.

Sensitive Genotyping of Foodborne-Associated Human Noroviruses and Hepatitis A Virus Using an Array-Based Platform

Human noroviruses (NoV) are the leading cause of human gastroenteritis in populations of all ages and are linked to most of the foodborne outbreaks worldwide. Hepatitis A virus (HAV) is another important foodborne enteric virus and is considered the most common agent causing acute liver disease worldwide. In the present study, a focused, low-density DNA microarray was developed and validated for the simultaneous identification of foodborne-associated genotypes of NoV and HAV. By employing a novel algorithm, capture probes were designed to target variable genomic regions commonly used for typing these foodborne viruses. Validation results showed that probe signals, specific for the tested NoV or HAV genotypes, were on average 200-times or 38-times higher than those detected for non-targeted genotypes, respectively. To improve the analytical sensitivity of this method, a 12-mer oligonucleotide spacer sequence was added to the capture probes and resulted in a detection threshold of less than 10 cRNA transcripts. These findings have indicated that this array-based typing sensor has the accuracy and sensitivity for identifying NoV and HAV genotypic profiles predominantly linked to food poisoning. The implementation of this typing sensor would thus provide highly relevant and valuable information for use in surveillance and outbreak attribution.

Inactivation of viruses and bacteria on strawberries using a levulinic acid plus sodium dodecyl sulfate based sanitizer, taking sensorial and chemical food safety aspects into account

The efficacy of levulinic acid (LVA) in combination with sodium dodecyl sulfate (SDS) in removal of foodborne viruses, enteric bacterial pathogens and their surrogates on fresh strawberries was investigated. Inoculated strawberries were treated with potable water, sodium hypochlorite solution (50ppm), 0.5% LVA plus 0.5% SDS solution, and 5% LVA plus 2% SDS solution respectively for 2min, followed by spray-rinsing with potable water. Water washing removed at least 1.0-log of the tested viral and bacterial strains from the strawberries' surfaces. The 50ppm chlorine wash induced 3.4, 1.5 and 2.1-log reductions for hepatitis A virus (HAV), murine norovirus-1 (MNV-1) and MS2 bacteriophage, respectively. In comparison, the tested bacterial strains showed uniform reductions around 1.6-log CFU/ml. The 0.5% LVA plus 0.5% SDS wash induced 2.7, 1.4 and 2.4-log reductions for HAV, MNV-1 and MS2, which were comparable with the reductions induced by chlorine (P>0.05). For bacteria, over 2.0-log reductions were obtained for Enterococcus faecium, Listeria monocytogenes and Salmonella, while Escherichia coli O157:H7 and Escherichia coli P1 showed reductions of 1.9 and 1.8-log CFU/ml. Higher concentration of LVA plus SDS showed no significantly higher reductions (P>0.05). Sensory tests of washed strawberries and chemical residue analysis of LVA on strawberries after washing were also performed. In conclusion, this study demonstrates good performance of 0.5% LVA plus 0.5% SDS to reduce the levels of enteric pathogens if present on strawberries without altering taste and introducing chemical safety issues.

Hepatitis A virus seroepidemiology of elementary school children in New Taipei City in Taiwan

BACKGROUND

To establish the seroepidemiologic data of hepatitis A virus (HAV) vaccine-preventable HAV diseases among school children (7-12 years old) attending elementary schools in New Taipei City, Taiwan. This is a pilot study of an ongoing nationwide study, and will be the reference for a national immunization program.

METHODS

The school children were selected for samplings, based on a multistage stratified sampling method that included 14 variables (4 socioeducational variables, 4 socioeducational variables, and 6 medical facilities' variables). The 29 administrative districts of New Taipei City were categorized into five strata. In total, 936 school children from 14 schools were recruited and bled for the serologic tests of HAV by enzyme-linked immunosorbent assay method.

RESULTS

The seropositive rate for HAV was 8.33% among the 936 children. From each school, the difference in the seropositive rate for HAV ranged 0-18.75%. There was no significant difference between each stratum (p = 0.059) or grade (p = 0.570); however, there was a difference between schools in the first stratum (p = 0.033) that was associated with different vaccination rates. This study also revealed a significantly greater seropositive rate in the vaccination group (p < 0.001) and in females (p = 0.02).

CONCLUSION

The seropositive rate for the HAV was <10% and was mostly associated with the vaccination status. Because of the low HAV vaccination rate and low seropositive rate for the HAV, an effective hepatitis A vaccine is a useful tool to prevent HAV infection. It is worthy to discuss whether to include the HAV vaccine as part of a routine vaccination program in Taiwan.

Survival of Enteric Viruses in the Environment and Food

Enteric viruses are those human viruses that are primarily transmitted by the fecal-oral route, either by person-to-person contact or by ingestion of contaminated food or water. The importance of viral foodborne diseases is increasingly being recognized, and several international organizations have found that there is an upward trend in their incidence. Thus, in this review, state-of-the-art information regarding virus persistence in food and the environment is compiled.

Salmonella and Escherichia coli O157:H7 Inactivation, Color, and Bioactive Compounds Enhancement on Raspberries during Frozen Storage after Decontamination Using New Formula Sanitizer Washing or Pulsed Light

Berries are normally washed before they are frozen. Washing with sanitizer and treatment with pulsed light (PL) were studied for their effectiveness to inactivate foodborne pathogens on raspberries during frozen storage, while maintaining or enhancing major quality parameters. Raspberries were inoculated with Salmonella or Escherichia coli O157:H7 and then underwent a washing treatment with citric acid plus sodium dodecyl sulfate (CA+SDS) or citric acid plus thymol (CA+THY) or treatment with PL (dry PL, water-assisted [wet] PL, and PL-SDS). Pathogen survival was determined immediately after treatments and during frozen storage at -20°C for 3 months. Washing with CA+SDS or CA+THY significantly reduced Salmonella (by 3.6 and 3.2 log CFU/g, respectively) and E. coli O157:H7 (by 4.1 and 3.7 log CFU/g, respectively). At the end of storage, washing with CA+SDS reduced Salmonella to 0.6 log CFU/g and E. coli O157:H7 to 0.5 log CFU/g; washing with CA+THY reduced Salmonella to 0.9 log CFU/g and E. coli O157:H7 to 0.5 log CFU/g. PL-SDS showed decontamination efficacy on raspberries, with 0.7 log CFU/g Salmonella and 0.9 log CFU/g E. coli O157:H7 surviving at the end of storage; in comparison, in the control, 1.6 log CFU/g Salmonella and 1.5 log CFU/g E. coli O157:H7 survived. Pathogen survival in raspberries that had been washed or treated with PL-SDS was significantly lower than in untreated raspberries. Major quality parameters, including color, total phenolic content, total anthocyanin content, total bacterial count, and total yeast and mold counts, were evaluated on raspberries immediately after treatments and during frozen storage. Redness increased in PL-treated raspberries. At the end of storage, PL-treated raspberries had significantly higher total phenolic content and total anthocyanin content compared with control samples. Washing with sanitizers and treatment with PL decreased the total bacterial count and total yeast and mold counts on raspberries and maintained the low counts. Our findings suggest that washing with a sanitizer or treatment with PL could be used to process frozen raspberries for enhanced food safety and quality.

Nucleic acid-based biotechnologies for food-borne pathogen detection using routine time-intensive culture-based methods and fast molecular diagnostics

Diseases caused by food-borne pathogens constitute a major burden to consumers, food business operators, and national governments. Bacterial and viral pathogens are the major biotic factors influencing food safety. A vast array of culture dependent analytical methods and protocols have been developed. Recently, nucleic acid-based methods have begun to replace or complement culture-based methods for routine use in food control laboratories. Basic advantages provided by nucleic acid-based technologies are faster speed and more information, such as sub-species identification, antibiotic resistance, and food microbiology. In particular, PCR and alternative methods have been developed to a stage that provides good speed, sensitivity, specificity, and reproducibility with minimized risk of carryover contamination. This review briefly summarizes currently available and developing molecular technologies that may be candidates for involvement in microbiological molecular diagnostic methods in the next decade.

Evaluation of high hydrostatic pressure inactivation of human norovirus on strawberries, blueberries, raspberries and in their purees

Human norovirus (HuNoV) has been an increasing concern of foodborne illness related to fresh and frozen berries. In this study, high hydrostatic pressure (HHP) inactivation of HuNoV on fresh strawberries, blueberries, and raspberries and in their purees was investigated. Porcine gastric mucin (PGM)-conjugated magnetic beads (PGM-MBs) and real-time reverse transcriptional polymerase chain reaction (RT-qPCR) were utilized for infectious HuNoV discrimination and quantification. Strawberry puree inoculated with HuNoV genogroup I.1 (GI.1) strain was HHP-treated at 450, 500 and 550 MPa for 2 min each at initial sample temperatures of 0, 4 and 20 °C. HuNoV GI.1 strain became more sensitive to HHP treatment as the temperature decreased from 20 to 0 °C. HuNoV GI.1 or genogroup II.4 (GII.4) strains were inoculated into three types of berries and their purees and treated at pressure levels from 250 to 650 MPa for 2 min at initial sample temperature of 0 °C. For the purees, the HHP condition needed to achieve >2.9 log reduction of HuNoV GI.1 strain and >4.0 log reduction of HuNoV GII.4 strain was found to be ≥ 550 MPa for 2 min at 0 °C. HHP treatment showed better inactivation effect of HuNoV on blueberries than on strawberry quarters and raspberries. HuNoV GI.1 strain was more resistant to HHP treatment than HuNoV GII.4 strain under different temperatures and environment. The physical properties and sensory qualities of HHP-treated and untreated blueberries and the three types of berry purees were evaluated. Color, pH and viscosity of blueberries and three berry purees showed no or slight changes after HHP treatment. Sensory evaluation demonstrated that HHP treatment of 550 MPa for 2 min at 0 °C did not significantly reduced the sensory qualities of three berry purees. The results demonstrated that the HHP treatment of 550 MPa for 2 min at 0 °C could be a potential nonthermal intervention for HuNoV in berry purees without adversely affecting their sensory qualities and physical properties.

Viral Contamination of Food

A review of the relevant foodborne viruses is presented. Published data from scientific journals as well as the data presented in official reports and published on the Internet were used for this review. In the review, information is given for the main foodborne viruses, implicated virus species, and food matrices involved, some history data are given, as well as modes of transmission, and sources of the virus presence in food. Results of surveys on the presence of viruses in different kind of foods commodities (fresh produces and shellfish) and in some cases connections to caused outbreaks are presented. Also, possible zoonotic infection and implicated viruses that could be transmitted through food are given. Human Norovirus followed by hepatitis A virus are the most common foodborne viruses, which are transmitted by food consumed raw, such as shellfish, fresh vegetables, and berry fruit. In developed countries, hepatitis E virus is increasingly being recognized as an emerging viral foodborne pathogen that includes zoonotic transmission via pork products. The existing knowledge gaps and the major future expectations in the detection and surveillance of foodborne viruses are mentioned.

Trends in disease and complications of hepatitis A virus infection in the United States, 1999-2011: a new concern for adults

BACKGROUND

In recent years, few US adults have had exposure and resultant immunity to hepatitis A virus (HAV). Further, persons with liver disease have an increased risk of adverse consequences if they are infected with HAV.

METHODS

This study used 1999-2011 National Notifiable Diseases Surveillance System and Multiple Cause of Death data to assess trends in the incidence of HAV infection, HAV-related hospitalization, and HAV-related mortality.

RESULTS

During 1999-2011, the incidence of HAV infection declined from 6.0 cases/100 000 to 0.4 cases/100 000. Similar declines were seen by sex and age, but persons aged ≥80 years had the highest incidence of HAV infection in 2011 (0.8 cases/100 000). HAV-related hospitalizations increased from 7.3% in 1999 to 24.5% in 2011. The mean age of hospitalized cases increased from 36.0 years in 1999 to 45.1 years in 2011. While HAV-related mortality declined, the mean age at death among decedents with HAV infection increased from 48.0 years in 1999 to 76.2 years in 2011. The median age range of decedents who had HAV infection and a liver-related condition was 51.0 to 68.0 years.

CONCLUSIONS

Although vaccine-preventable, HAV-related hospitalizations increased greatly, mostly among adults, and liver-related conditions were frequently reported among HAV-infected individuals who died. Public health efforts should focus on the need to assess protection from hepatitis A among adults, including those with liver disease.

Survival of Salmonella and Escherichia coli O157:H7 on strawberries, basil, and other leafy greens during storage

The survival of Salmonella and Escherichia coli O157:H7 on strawberries, basil leaves, and other leafy greens (spinach leaves, lamb and butterhead lettuce leaves, baby leaves, and fresh-cut iceberg lettuce) was assessed at cold (<7 °C) and ambient temperatures. All commodities were spot inoculated with E. coli O157:H7 or Salmonella to obtain an initial inoculum of 5 to 6 log and 4 to 5 log CFU/g for strawberries and leafy greens, respectively. Samples were air packed. Strawberries were stored at 4, 10, 15, and 22 °C and basil leaves and other leafy greens at 7, 15, and 22 °C for up to 7 days (or less if spoiled before). Both Salmonella and E. coli O157:H7 showed a gradual decrease in numbers if inoculated on strawberries, with a similar reduction observed at 4, 10, and 15 °C (2 to 3 log after 5 days). However, at 15 °C (and 10 °C for E. coli O157:H7), the survival experiment stopped before day 7, as die-off of both pathogens below the lower limit of detection was achieved or spoilage occurred. At 22 °C, strawberries were moldy after 2 or 4 days. At that time, a 1- to 2-log reduction of both pathogens had occurred. A restricted die-off (on average 1.0 log) and increase (on average , 0.5 log) of both pathogens on basil leaves occurred after 7 days of storage at 7 and 22 °C, respectively. On leafy greens, a comparable decrease as on basil was observed after 3 days at 7 °C. At 22 °C, both pathogens increased to higher numbers on fresh-cut iceberg and butterhead lettuce leaves (on average 1.0 log), probably due to the presence of exudates. However, by using spot inoculation, the increase was rather limited, probably due to minimized contact between the inoculum and cell exudates. Avoiding contamination, in particular, at cultivation (and harvest or postharvest) is important, as both pathogens survive during storage, and strawberries, basil, and other leafy green leaves are consumed without inactivation treatment.

HAV Immunity in Iranian Medical Students

BACKGROUND

Hepatitis A, a fecal-oral transmitted disease, which has been considered endemic in developing countries, seems to change its pattern in developing countries because of their improved socioeconomic status.

OBJECTIVES

In the present study, we aimed to determine the need of vaccination in 270 students at AJA University of Medical Sciences.

MATERIALS AND METHODS

The serum level of anti-HAV antibody was checked in 270 students of AJA University of medical students, and effect of different factors, including age, gender, pre-university entrance exam region, familial education, familial income, clean water availability, and previous history of jaundice were tested.

RESULTS

Of total 270 students, 30 were female. Their age ranged between 18 and 30 years old with the mean age of 20.58 years and just 34% of students had positive level of anti-HAV antibody. Age and sex had no role in positive serum level of anti-HAV antibody. According to analyzed data, lack of clean water availability, pre-university entrance exam region, lower family education, and poor health status estimation increased statistically the risk of HAV infection.

CONCLUSIONS

Because 66% of students were anti-HAV antibody negative and they will work as health care workers in future, our study suggest vaccinating all students accepted at AJA University of Medical Sciences.