Probable transmission of hepatitis E virus (HEV) via transfusion in the United States.

BACKGROUND: Hepatitis E virus (HEV) can inapparently infect blood donors. To assess transfusion transmission of HEV in the United States, which has not been documented, a donor-recipient repository was evaluated. STUDY DESIGN AND METHODS: To identify donations that contained HEV RNA and were linked to patient-recipients with antibody evidence of HEV exposure, we assayed samples from the Retrovirus Epidemiology Donor Study (REDS) Allogeneic Donor and Recipient repository that represents 13,201 linked donations and 3384 transfused patients. Posttransfusion samples, determined to contain IgG anti-HEV by enzyme-linked immunosorbent assay, were reassayed along with corresponding pretransfusion samples for seroconversion (incident exposure) or at least fourfold IgG anti-HEV increase (reexposure). HEV-exposed patients were linked to donations in which HEV RNA was then detected by reverse-transcription quantitative polymerase chain reaction, confirmed by transcription-mediated amplification, and phylogenetically analyzed as subgenomic cDNA sequences. RESULTS: Among all patients, 19 of 1036 (1.8%) who had IgG anti-HEV before transfusion were reexposed; 40 of 2348 (1.7%) without pretransfusion IgG anti-HEV seroconverted. These 59 patients were linked to 257 donations, 1 of which was positive by reverse-transcription quantitative polymerase chain reaction and transcription-mediated amplification. Plasma from this donation contained 5.5 log IU/mL of HEV RNA that grouped with HEV genotype 3, clade 3abchij. The patient-recipient of RBCs from this donation had a greater than eightfold IgG increase; however, clinical data are unavailable. CONCLUSIONS: This is the first report of probable HEV transmission via transfusion in the United States, although it has been frequently observed in Europe and Japan. Additional data on the magnitude of the risk in the United States are needed.

Hepatitis E Virus Infection Among Solid Organ Transplant Recipients at a North American Transplant Center.

Background. Autochthonous hepatitis E virus (HEV) infection has been reported in over 200 solid organ transplant (SOT) recipients since 2006, yet little is known about the burden of HEV among SOT recipients in North America. We performed a retrospective, cross-sectional study to investigate the prevalence and risk factors associated with HEV infection among SOT recipients at our institution. Methods. Children and adults (n = 311) who received allografts between 1988 and 2012 at the Johns Hopkins Hospital were assessed for evidence of HEV infection by testing posttransplantation serum samples for HEV antibody by enzyme immunoassay and HEV RNA by reverse transcription quantitative polymerase chain reaction. Individuals with evidence of posttransplant HEV infection (presence of anti-HEV immunoglobulin [Ig]M antibody, anti-HEV IgG seroconversion, or HEV RNA) were compared with individuals without evidence of infection and assessed for risk factors associated with infection. Results. Twelve individuals (4%) developed posttransplant HEV infection. Posttransplant HEV infection was associated with an increased risk for graft rejection (odds ratio, 14.2; P = .03). No individuals developed chronic infection. Conclusions. Solid organ transplant recipients in the United States are at risk for posttransplant HEV infection. Further studies are needed to characterize environmental risk factors and the risk of HEV infection after SOT in North America.

Two Generations of "Gold Standards": The Impact of a Decade in Hepatitis E Virus Testing Innovation on Population Seroprevalence.

Hepatitis E virus (HEV) is a global pathogen responsible for approximately 20 million infections every year in developing countries, yet remains under-recognized. In this population-based cohort study, 1,025 randomly selected participants were enrolled from Matlab, Bangladesh (2004-2005). All participants were tested for HEV antibodies and total immunoglobulin (Ig), using an in-house enzyme immunoassay developed by Walter Reed Army Institute of Research (WRAIR). In 2014, we retested the banked sera of 1,009 of those participants using the Wantai anti-HEV IgG enzyme-linked immunosorbent assay (ELISA). The WRAIR assay estimated the overall population seroprevalence as 26.6% (95% confidence interval [CI]: 24.0, 29.5), whereas the Wantai assay produced significantly higher estimated seroprevalence, 46.7% (95% CI: 43.5-49.8) (P < 0.001). However, the two tests give nearly identical findings in those 5 years and under (N = 94) with a 98% agreement between the tests. Retesting populations with modern assays is necessary to establish better population-level estimates of disease burden.

Hepatitis e vaccine to prevent morbidity and mortality during epidemics.

Recurrent, large, waterborne epidemics of hepatitis E virus (HEV) occur regularly after monsoon rains contaminate water supplies in Asia or during humanitarian crises in Africa. These epidemics commonly affect thousands of persons, and it has a high mortality in pregnant women who become infected. Although a subunit HEV vaccine has been developed by Chinese investigators and was found to be highly effective and safe in a large clinical trial, this vaccine is only available in China. Until it is prequalified by the World Health Organization, the vaccine may not be available for use outside of China in low-income countries that lack national vaccine regulatory agencies. In this manuscript, we explore possible strategies for providing access to this potentially important vaccine for international use in responding to epidemics of HEV in low-resource countries.

Epidemiology and risk factors of incident hepatitis E virus infections in rural Bangladesh.

Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis in the world. Most of South Asia is HEV endemic, with frequent seasonal epidemics of hepatitis E and continuous sporadic cases. This author group's epidemiologic work and clinical reports suggest that Bangladesh is HEV endemic, but there have been few population-based studies of this country's HEV burden. The authors calculated HEV infection rates, over an 18-month interval between 2003 and 2005, by following a randomly selected cohort of 1,134 subjects between the ages of 1 and 88 years, representative of rural communities in southern Bangladesh. Baseline prevalence of antibody to hepatitis E virus (anti-HEV) was 22.5%. Seroincidence was 60.3 per 1,000 person-years during the first 12 months and 72.4 per 1,000 person-years from >12 to 18 months (during the monsoon season), peaking by age 50 years and with low rates during childhood. Few of the seroconverting subjects reported hepatitis-like illness. Overall incidence was calculated to be 64 per 1,000 person-years, with 1,172 person-years followed. No significant associations were found between anti-HEV incidence and demographic or socioeconomic factors for which data were available. This is the first study to document annual HEV infection rates among "healthy" and very young to elderly subjects in a rural Bangladeshi population.

Electronic medical record (EMR) utilization for public health surveillance.

INTRODUCTION: Public health surveillance systems need to be refined. We intend to use a generic approach for early identification of patients with severe influenza-like illness (ILI) by calculating a score that estimates a patients disease-severity. Accordingly, we built the Intelligent Severity Score Estimation Model (ISSEM), structured so that the inference process would reflect experts decision-making logic. Each patients disease-severity score is calculated from numbers of respiratory ICD9 encounters, and laboratory, radiologic, and prescription-therapeutic orders in the EMR. Other ISSEM components include chronic disease evidence, probability of immunodeficiency, and the providers general practice-behavior patterns. RESULTS: Sensitivity was determined from 200 randomly selected patients with upper- and lower-respiratory tract ILI; specificity, from 300 randomly selected patients with URI only. For different age groups, ISSEM sensitivity ranged between 90% and 95%; specificity was 72% to 84%. CONCLUSION: Our preliminary assessment of ISSEM performance demonstrated 93.5% sensitivity and 77.3% specificity across all age groups.

Outbreak management and implications of a nosocomial norovirus outbreak.

BACKGROUND: Noroviruses are enterically transmitted and are a frequent cause of gastroenteritis, affecting 23 million people annually in the United States. We describe a norovirus outbreak and its control in a tertiary care hospital during February-May 2004. METHODS: Patients and health care workers met the case definition if they had new onset of vomiting and/or diarrhea during the outbreak period. Selected stool samples were tested for norovirus RNA. We also determined outbreak costs, including the estimated lost revenue associated with unit closures, sick leave, and cleaning expenses. RESULTS: We identified 355 cases that affected 90 patients and 265 health care workers and that were clustered in the coronary care unit and psychiatry units. Attack rates were 5.3% (7 of 133) for patients and 29.9% (29 of 97) for health care workers in the coronary care unit and 16.7% (39 of 233) for patients and 38.0% (76 of 200) for health care workers in the psychiatry units. Thirteen affected health care workers (4.9%) required emergency department visits or hospitalization. Detected noroviruses had 98%-99% sequence identity with representatives of a new genogroup II.4 variant that emerged during 2002-2004 in the United States (e.g., Farmington Hills and other strains) and Europe. Aggressive infection-control measures, including closure of units and thorough disinfection using sodium hypochlorite, were required to terminate the outbreak. Costs associated with this outbreak were estimated to be $657,644. CONCLUSIONS: The significant disruption of patient care and cost of this single nosocomial outbreak support aggressive efforts to prevent transmission of noroviruses in health care settings.

Factors affecting serum concentrations of hepatitis C virus (HCV) RNA in HCV genotype 1-infected patients with chronic hepatitis.

The serum concentration of hepatitis C virus (HCV) RNA is usually stable (4 to 8 log(10) IU/ml) in untreated patients with chronic hepatitis C. While this baseline HCV RNA concentration ([HCV RNA](BL)) is predictive of a sustained virologic response to treatment, its determinants are only partially identified. We therefore analyzed the baseline characteristics of 2,472 HCV genotype 1-infected patients to identify correlations with gender, age, race, weight, body mass index (BMI), HCV acquisition mode, HCV subtype, alanine aminotransferase concentration, or histopathologic changes in the liver. After separation of the data according to four [HCV RNA](BL) groups (< or =5.0, >5.0 to 5.6, >5.6 to 5.9, and >5.9 log(10) IU/ml), we determined that increasing [HCV RNA](BL) correlated (P < 0.05) with increasing proportions of patients who were male, >40 years of age, or heavier (a weight of >85 kg or a BMI of >27 kg/m(2)). Histologic activity index (HAI) data were available for 1,304 of these patients: increasing [HCV RNA](BL) correlated with higher fibrosis and necrosis-inflammation scores. As a continuous variable, [HCV RNA](BL) correlated with age, gender, weight (continuous or < or =85 versus >85 kg), BMI (continuous or < or =27 versus >27 kg/m(2)), subtype, fibrosis score, and necrosis-inflammation score; however, multiple-regression analysis yielded P values of <0.1 only for age, gender, BMI (< or =27 versus >27 kg/m(2)), and fibrosis score. While our findings are suggestive of a role for these factors in maintenance of the pretreatment state of HCV infection, the multiple-regression model accounted for only < or =4.6% of the [HCV RNA](BL) differences between individuals (R(2) = 0.046 for 1,304 patients with HAI scores; 0.043 for all 2,472 patients).

Effective detection of toxigenic Clostridium difficile by a two-step algorithm including tests for antigen and cytotoxin.

We evaluated a two-step algorithm for detecting toxigenic Clostridium difficile: an enzyme immunoassay for glutamate dehydrogenase antigen (Ag-EIA) and then, for antigen-positive specimens, a concurrent cell culture cytotoxicity neutralization assay (CCNA). Antigen-negative results were > or = 99% predictive of CCNA negativity. Because the Ag-EIA reduced cell culture workload by approximately 75 to 80% and two-step testing was complete in < or = 3 days, we decided that this algorithm would be effective. Over 6 months, our laboratories' expenses were US dollar 143,000 less than if CCNA alone had been performed on all 5,887 specimens.

Severe community-onset pneumonia in healthy adults caused by methicillin-resistant Staphylococcus aureus carrying the Panton-Valentine leukocidin genes.

BACKGROUND: Recent worldwide reports of community-onset skin abscesses, outbreaks of furunculosis, and severe pneumonia associated with methicillin-resistant Staphylococcus aureus (MRSA) carrying Panton-Valentine leukocidin (PVL) genes and the staphylococcal cassette chromosome mec (SCCmec) type IV indicate that MRSA infections are evolving into a community-related problem. The majority of cases reported to date involve skin and soft-tissue infections, with severe pneumonia representing a relatively rare phenomenon. During a 2-month period in the winter of 2003-2004, four healthy adults presented to 1 of 2 Baltimore hospitals with severe necrotizing MRSA pneumonia in the absence of typical risk factors for MRSA infection. METHODS: Patients' MRSA isolates were characterized by strain typing with use of pulsed-field gel electrophoresis and SCCmec typing with use of a multiplex polymerase chain reaction (PCR) assay and detection of PVL genes by PCR. RESULTS: All 4 patients' MRSA isolates carried the PVL genes and the SCCmec type IV element and belonged to the USA300 pulsed-field type. These 3 findings are among the typical characteristics of community-onset MRSA strains. In addition, 2 of our patients had concomitant influenza A diagnosed, which likely contributed to the severity of their presentation. CONCLUSIONS: To our knowledge, these patients represent the first reported North American adults with severe community-onset MRSA pneumonia caused by strains carrying the PVL genes.

Accurate representation of the hepatitis C virus quasispecies in 5.2-kilobase amplicons.

Hepatitis C virus (HCV) exists as a swarm of genetically distinct but related variants, or a quasispecies, whose complexity and sequence evolution are critical to studies of viral pathogenesis. Because most studies of the HCV quasispecies have focused on a relatively small genomic segment, the first hypervariable region of the E2 gene, it is possible that viral complexity is occasionally underestimated (due to primer mismatch) and that sequence evolution is misperceived due to unrecognized covariation. This report describes a sensitive and reproducible method to amplify most of the HCV genome as a single 5.2-kb amplicon by using primers directed at relatively conserved genomic segments. Using 52 specimens obtained during acute infection over a range of viral RNA concentrations, the overall rate of successful amplification was 94% and varied in a concentration-dependent manner, with successful amplification in 26 of 26 (100%) specimens at greater than 10(5) IU/ml, 15 of 16 (94%) at 10(4) to 10(5) IU/ml, 6 of 7 (86%) at 10(3) to 10(4) IU/ml, and 2 of 3 (67%) at less than 10(3) IU/ml. Quasispecies complexity, determined by using this novel long-amplicon method followed by heteroduplex mobility assay combined with single-stranded conformational polymorphism (HDA+SSCP) analysis, was very high, even during acute HCV infection, when 10 to 21 (median, 16) different HDA+SSCP patterns were detected among 33 cDNA clones examined. Replicate analyses indicate that this diversity is not dominated by random errors generated during amplification. Therefore, the HCV quasispecies is highly complex even during acute infection and is accurately represented in amplicons representing more than half of the viral genome.

Hepatitis C virus (HCV) core antigen assay to detect ongoing HCV infection in thai injection drug users.

We evaluated a quantitative enzyme immunoassay (trak-C) for hepatitis C virus core antigen (HCV core Ag) by testing serum specimens from 820 injection drug users in Thailand with anti-HCV antibodies. The HCV genotypes in this population include genotypes 3 and 6, which have not been extensively tested with this assay. Among these specimens, 629 (76.7%) yielded positive results, with HCV core Ag concentrations predominantly spanning (35.7%) or above (58.2%) the measurable range of 1.5 to 100 pg/ml. To assess reproducibility, we retested 30 specimens representing six core Ag ranges; the mean coefficient of variation for each range was < or = 9.7% (highest for 1.5 to 25 pg/ml). We also tested 204 specimens of the 820-specimen set for HCV RNA: while 146 (71.6%) were core Ag positive, 168 (82.4%) had detectable HCV RNA, of which 96% were typeable as genotype 3 (39%), 1 (31%), or 6 (26%) by nested reverse transcription-PCR. Among RNA-positive specimens, 86.9% had core Ag; 94% of the RNA negatives were core Ag negative. While there was no apparent bias for detecting core Ag representing the tested genotypes, median quantified results were higher for types 1a and 6 than for genotype 3 (P = 0.01); similarly, the median core Ag concentration was higher in HCV-human immunodeficiency virus-coinfected subjects than in HCV-monoinfected subjects. Our results demonstrated a good correlation between core Ag and HCV RNA in this population with high frequencies of genotypes 3 and 6. Because most core Ag concentrations were greater than those in the measurable range, we recommend a 10-fold dilution of the specimen before quantification. Reproducibility, low technical requirements, and high throughput should make this assay useful for clinical or research monitoring of HCV levels during active infection.

NIST physical standards for DNA-based medical testing.

As DNA and RNA become major targets for clinical laboratory analysis, benchmark reagents will play an increasingly important role in standardization. Reliable national and international nucleic acid standards promote automation and third-party reimbursement for clinical testing. Furthermore, nucleic acid standards provide materials for quality assurance and quality control (QA/QC), and proficiency testing. Standard methods and training initially evolved from consensus guidelines endorsed by professional societies and governmental agencies. The National Institute of Standards and Technology (NIST), a nonregulatory agency of the U.S. Department of Commerce, develops and certifies physical and chemical standards in support of national commerce, manufacturing, and science. In its role supporting U.S. science and industry, the NIST responds to specific standards needs, most recently for medically and biologically important analytes. Broad-based consensus developed through interdisciplinary NIST workshops initiated development of NIST-certified DNA standards. Such materials serve the diagnostic community and help manufacturers benchmark a variety of DNA diagnostic testing platforms. Here we summarize the NIST experience and programs for development of national standards for DNA-based medical diagnostic testing.

Initial report of a hepatitis investigation in rural Belize

In spring 1991, Belizian health officials expressed concern about a possible hepatitis outbreak in a banana farming district. A study was designed to identify cases and to address the serological prevalence of hepatitis virus markers. Three populations were studied: (i) persons meeting a clinical case definition for hepatitis; (ii) designated banana workers; and (iii) people in a random sample of households in the community. Information was collected using questionnaires and sera were collected for laboratory testing. This report presents the preliminary results of a study conducted in June 1991. Among people who met the clinical case definition, 24 percent of 42 tested had immunoglobulin M antibody to hepatitis B virus (HBV) core antigen (anti-HBc IgM). In the worker and household survey populations, 248 and 280 people, respectively, were tested for anti-HBc IgM. In each group, 4 percent were positive. HBV surface antigen was found in 37 percent of 43 clinical cases, 18 percent of workers, and 13 percent of people in the household survey. Among the 3 study populations, the prevalence of HBV core antibody (anti-HBc) ranged from 73 percent to 81 percent. Almost all tested persons had evidence of prior infection with hepatitis viruses A and B was widespread, but an aetiology could not be established for most of the clinical cases. However, the prevalence of hepatitis B markers in this population was very high compared to other reports from the Caribbean (AU)

Initial report of a viral hepatitis investigation in rural Belize - abstract

In spring 1991, concern was expressed in Belize about a hepatitis outbreak. A cross-sectional study was designed to address hepatitis prevalence in a farming district. Three populations were identified: anyone meeting a case definition for hepatitis, any designated worker, and a random sample of the community by household. Survey information was collected on the farm, household, and individual. Sera were collected for laboratory study. This study reports on the current findings from 509 sera collected in June 1991. There had been widespread exposure to hepatitis A(98 percent). New hepatitis was primarily due to hepatitis B(24 percent of clinical cases, 4 percent of people in the random household sample, and 5 percent of workers). In our total, 16 percent had hepatitis B surface antigen and were potential carriers, while 73 percent had evidence of past hepatitis C by our detection method, and delta particle was not present in any of the tested cases. Hepatitis E antibody was detected in two cases. One risk revolved around perceptions of good medical care, using injectable medications. (AU)