Promotion of Hendra virus replication by microRNA 146a

Hendra virus is a highly pathogenic zoonotic paramyxovirus in the genus Henipavirus. Thirty-nine outbreaks of Hendra virus have been reported since its initial identification in Queensland, Australia, resulting in seven human infections and four fatalities. Little is known about cellular host factors impacting Hendra virus replication. In this work, we demonstrate that Hendra virus makes use of a microRNA (miRNA) designated miR-146a, an NF-κB-responsive miRNA upregulated by several innate immune ligands, to favor its replication. miR-146a is elevated in the blood of ferrets and horses infected with Hendra virus and is upregulated by Hendra virus in human cells in vitro. Blocking miR-146a reduces Hendra virus replication in vitro, suggesting a role for this miRNA in Hendra virus replication. In silico analysis of miR-146a targets identified ring finger protein (RNF)11, a member of the A20 ubiquitin editing complex that negatively regulates NF-κB activity, as a novel component of Hendra virus replication. RNA interference-mediated silencing of RNF11 promotes Hendra virus replication in vitro, suggesting that increased NF-κB activity aids Hendra virus replication. Furthermore, overexpression of the IκB superrepressor inhibits Hendra virus replication. These studies are the first to demonstrate a host miRNA response to Hendra virus infection and suggest an important role for host miRNAs in Hendra virus disease.

Methodological considerations in the measurement of institutional and structural forms of HIV discrimination

The systematic measurement of HIV/AIDS-related discrimination is imperative within the current rhetoric that holds discrimination as one of the two ‘biggest' barriers to HIV/AIDS pandemic intervention. This paper provides a methodological critique of the UNAIDS (2000b) Protocol for the Identification of Discrimination against People Living with HIV (the Protocol) . Specifically, the paper focuses on the Protocol's capacity to accurately identify and measure institutional levels of HIV-related discrimination that allows data that are reliable and comparable across time and contexts. Conceptual issues including the Protocol's objective as an indicator versus a direct measure of discrimination and the role of the Protocol as a tool of research versus a tool of advocacy are explored. Design issues such as the operationalization of discrimination, appropriateness of indicator content, sampling and data collection strategies and issues of scoring are also evaluated. It is hoped that the matters outlined will provide readers with ways of critically reflecting and evaluating the findings of the research papers presented in this Special Issue, as well as pointing to ways of improving research design.

Quantitative microbial risk assessment models for consumption of raw vegetables irrigated with reclaimed water

Quantitative microbial risk assessment models for estimating the annual risk of enteric virus infection associated with consuming raw vegetables that have been overhead irrigated with nondisinfected secondary treated reclaimed water were constructed. We ran models for several different scenarios of crop type, viral concentration in effluent, and time since last irrigation event. The mean annual risk of infection was always less for cucumber than for broccoli, cabbage, or lettuce. Across the various crops, effluent qualities, and viral decay rates considered, the annual risk of infection ranged from 10–3 to 10–1 when reclaimed-water irrigation ceased 1 day before harvest and from 10–9 to 10–3 when it ceased 2 weeks before harvest. Two previously published decay coefficients were used to describe the die-off of viruses in the environment. For all combinations of crop type and effluent quality, application of the more aggressive decay coefficient led to annual risks of infection that satisfied the commonly propounded benchmark of ≤10–4, i.e., one infection or less per 10,000 people per year, providing that 14 days had elapsed since irrigation with reclaimed water. Conversely, this benchmark was not attained for any combination of crop and water quality when this withholding period was 1 day. The lower decay rate conferred markedly less protection, with broccoli and cucumber being the only crops satisfying the 10–4 standard for all water qualities after a 14-day withholding period. Sensitivity analyses on the models revealed that in nearly all cases, variation in the amount of produce consumed had the most significant effect on the total uncertainty surrounding the estimate of annual infection risk. The models presented cover what would generally be considered to be worst-case scenarios: overhead irrigation and consumption of vegetables raw. Practices such as subsurface, furrow, or drip irrigation and postharvest washing/disinfection and food preparation could substantially lower risks and need to be considered in future models, particularly for developed nations where these extra risk reduction measures are more common.

Disentangling the stigma of HIV/AIDS from the stigmas of drugs use, commercial sex and commercial blood donation - a factorial survey of medical students in China

Background
HIV/AIDS related stigma interferes with the provision of appropriate care and support for people living with HIV/AIDS. Currently, programs to address the stigma approach it as if it occurs in isolation, separate from the co-stigmas related to the various modes of disease transmission including injection drug use (IDU) and commercial sex (CS). In order to develop better programs to address HIV/AIDS related stigma, the inter-relationship (or 'layering') between HIV/AIDS stigma and the co-stigmas needs to be better understood. This paper describes an experimental study for disentangling the layering of HIV/AIDS related stigmas.

Methods
The study used a factorial survey design. 352 medical students from Guangzhou were presented with four random vignettes each describing a hypothetical male. The vignettes were identical except for the presence of a disease diagnosis (AIDS, leukaemia, or no disease) and a co-characteristic (IDU, CS, commercial blood donation (CBD), blood transfusion or no co-characteristic). After reading each vignette, participants completed a measure of social distance that assessed the level of stigmatising attitudes.

Results
Bivariate and multivariable analyses revealed statistically significant levels of stigma associated with AIDS, IDU, CS and CBD. The layering of stigma was explored using a recently developed technique. Strong interactions between the stigmas of AIDS and the co-characteristics were also found. AIDS was significantly less stigmatising than IDU or CS. Critically, the stigma of AIDS in combination with either the stigmas of IDU or CS was significantly less than the stigma of IDU alone or CS alone.

Conclusion
The findings pose several surprising challenges to conventional beliefs about HIV/AIDS related stigma and stigma interventions that have focused exclusively on the disease stigma. Contrary to the belief that having a co-stigma would add to the intensity of stigma attached to people with HIV/AIDS, the findings indicate the presence of an illness might have a moderating effect on the stigma of certain co-characteristics like IDU. The strong interdependence between the stigmas of HIV/AIDS and the co-stigmas of IDU and CS suggest that reducing the co-stigmas should be an integral part of HIV/AIDS stigma intervention within this context.

Deterministic versus stochastic quantitative microbial Risk Assessment models for wastewater irrigation of food crops

Reuse of wastewater to irrigate food crops is being practiced in many parts of the world and is becoming more commonplace as the competition for, and stresses on, freshwater resources intensify. But there are risks associated with wastewater irrigation, including the possibility of transmission of pathogens causing infectious disease, to both workers in the field and to consumers buying and eating produce irrigated with wastewater. To manage these risks appropriately we need objective and quantitative estimates of them. This is typically achieved through one of two modelling approaches: deterministic or stochastic. Each parameter in a deterministic model is represented by a single value, whereas in stochastic models probability functions are used. Stochastic models are theoretically superior because they account for variability and uncertainty, but they are computationally demanding and not readily accessible to water resource and public health managers. We constructed models to estimate risk of enteric virus infection arising from the consumption of wastewater-irrigated horticultural crops (broccoli, cucumber and lettuce), and compared the resultant levels of risk between the deterministic and stochastic approaches. Several scenarios were tested for each crop, accounting for different concentrations of enteric viruses and different lengths of environmental exposure (i.e. the time between the last irrigation event and harvest, when the viruses are liable to decay or inactivation). In most situations modelled the two approaches yielded similar estimates of risk (within 1 order-of-magnitude). The two methods diverged most markedly, up to around 2 orders-of-magnitude, when there was large uncertainty associated with the estimate of virus concentration and the exposure period was short (1 day). Therefore, in some circumstances deterministic modelling may offer water resource managers a pragmatic alternative to stochastic modelling, but its usefulness as a surrogate will depend upon the level of uncertainty in the model parameters.

The cost of community-managed viral respiratory illnesses in a cohort of healthy preschool-aged children

Background : Acute respiratory illnesses (ARIs) during childhood are often caused by respiratory viruses, result in significant morbidity, and have associated costs for families and society. Despite their ubiquity, there is a lack of interdisciplinary epidemiologic and economic research that has collected primary impact data, particularly associated with indirect costs, from families during ARIs in children.
Methods : We conducted a 12-month cohort study in 234 preschool children with impact diary recording and PCR testing of nose-throat swabs for viruses during an ARI. We used applied values to estimate a virus-specific mean cost of ARIs.
Results : Impact diaries were available for 72% (523/725) of community-managed illnesses between January 2003 and January 2004. The mean cost of ARIs was AU$309 (95% confidence interval $263 to $354). Influenza illnesses had a mean cost of $904, compared with RSV, $304, the next most expensive single-virus illness, although confidence intervals overlapped. Mean carer time away from usual activity per day was two hours for influenza ARIs and between 30 and 45 minutes for all other ARI categories.
Conclusion : From a societal perspective, community-managed ARIs are a significant cost burden on families and society. The point estimate of the mean cost of community-managed influenza illnesses in healthy preschool aged children is three times greater than those illnesses caused by RSV and other respiratory viruses. Indirect costs, particularly carer time away from usual activity, are the key cost drivers for ARIs in children. The use of parent-collected specimens may enhance ARI surveillance and reduce any potential Hawthorne effect caused by compliance with study procedures. These findings reinforce the need for further integrated epidemiologic and economic research of ARIs in children to allow for comprehensive cost-effectiveness assessments of preventive and therapeutic options.

Location rather than CD62L phenotype is critical in the early establishment of influenza-specific T cell memory

The rapid recall of influenza virus-specific CD8+ T cell effector function is protective, although our understanding of T cell memory remains incomplete. Recent debate has focused particularly on the CD62L lymph node homing receptor. The present analysis shows that although functional memory can be established from both CD62Lhi and CD62Llo CD8+ T cell subsets soon after initial encounter between naive precursors and antigen, the optimal precursors are CD8+CD44hiCD25lo immune lymphocytes isolated from draining lymph nodes on day 3.5 after influenza virus infection. Analysis of primed T cells at different times after challenge indicates that the capacity to transfer memory is diminished at the peak of the primary cytotoxic T lymphocyte response, challenging speculations that the transition to memory first requires full differentiation to effector status. It seems that location rather than CD62Lhi/lo phenotype may be the more profitable focus for further dissection of the early establishment of T cell memory.

Why the tuberculosis incidence rate is not falling in New Zealand

Aims To assess the role of migration from high-incidence countries, HIV/AIDS infection, and prevalence of multi-drug resistant organisms as contributors to tuberculosis (TB) incidence in New Zealand (NZ) relative to ongoing local transmission and reactivation of disease.

Methods TB notification data and laboratory data for the period 1995 to 2004 and population data from the 1996 and 2001 Census were used to calculate incidence rates of TB by age and ethnicity, country of birth (distinguishing high and low -incidence countries), and interval between migration and onset of disease. Published reports of multi-drug-resistant TB for the period 1995 to 2004 were reviewed. Anonymous HIV surveillance data held by AIDS Epidemiology Group were matched with coded and anonymised TB surveillance data to measure the extent of HIV/AIDS coinfection in notified TB cases.

Results Migration of people from high-TB incidence countries is the main source of TB in NZ. Of those who develop TB, a quarter does so within a year of migration, and a quarter of this group (mainly refugees) probably enter the country with pre-existing disease. Rates of local TB transmission and reactivation of old disease are declining steadily for NZ-born populations, except for NZ-born Māori and Pacific people under 40. HIV/AIDS and multi-drug-resistant organisms are not significant contributors to TB incidence in NZ and there is no indication that their role is increasing.

Conclusion TB incidence is not decreasing in NZ mainly due to migration of TB infected people from high-incidence countries and subsequent development of active disease in some of them in NZ. This finding emphasises the importance of regional and global TB control initiatives. Refugees and migrants are not acting as an important source of TB for most NZ-born populations. Those caring for them should have a high level of clinical suspicion for TB.

Labeling of multiple HIV-1 proteins with the biarsenical-tetracysteine system

Due to its small size and versatility, the biarsenical-tetracysteine system is an attractive way to label viral proteins for live cell imaging. This study describes the genetic labeling of the human immunodeficiency virus type 1 (HIV-1) structural proteins (matrix, capsid and nucleocapsid), enzymes (protease, reverse transcriptase, RNAse H and integrase) and envelope glycoprotein 120 with a tetracysteine tag in the context of a full-length virus. We measure the impact of these modifications on the natural virus infection and, most importantly, present the first infectious HIV-1 construct containing a fluorescently-labeled nucleocapsid protein. Furthermore, due to the high background levels normally associated with the labeling of tetracysteine-tagged proteins we have also optimized a metabolic labeling system that produces infectious virus containing the natural envelope glycoproteins and specifically labeled tetracysteine-tagged proteins that can easily be detected after virus infection of T-lymphocytes. This approach can be adapted to other viral systems for the visualization of the interplay between virus and host cell during infection.

RNA interference : more than a research tool in the vertebrates' adaptive immunity

In recent years, RNA silencing, usage of small double stranded RNAs of ~21 – 25 base pairs to regulate gene expression, has emerged as a powerful research tool to dissect the role of unknown host cell factors in this 'post-genomic' era. While the molecular mechanism of RNA silencing has not been precisely defined, the revelation that small RNA molecules are equipped with this regulatory function has transformed our thinking on the role of RNA in many facets of biology, illustrating the complexity and the dynamic interplay of cellular regulation. As plants and invertebrates lack the protein-based adaptive immunity that are found in jawed vertebrates, the ability of RNA silencing to shut down gene expression in a sequence-specific manner offers an explanation of how these organisms counteract pathogen invasions into host cells. It has been proposed that this type of RNA-mediated defence mechanism is an ancient form of immunity to offset the transgene-, transposon- and virus-mediated attack. However, whether 1) RNA silencing is a natural immune response in vertebrates to suppress pathogen invasion; or 2) vertebrate cells have evolved to counteract invasion in a 'RNA silencing' independent manner remains to be determined. A number of recent reports have provided tantalizing clues to support the view that RNA silencing functions as a physiological response to regulate viral infection in vertebrate cells. Amongst these, two manuscripts that are published in recent issues of Science and Immunity, respectively, have provided some of the first direct evidences that RNA silencing is an important component of antiviral defence in vertebrate cells. In addition to demonstrating RNA silencing to be critical to vertebrate innate immunity, these studies also highlight the potential of utilising virus-infection systems as models to refine our understanding on the molecular determinants of RNA silencing in vertebrate cells.

Chronic hepatitis C

Chronic hepatitis C is a major public health issue. Of acutely affected people with hepatitis C virus infection, about 80% will eventually develop chronic infection.

Inhibition of reactive oxygen species production ameliorates inflammation induced by influenza A viruses via upregulation of SOCS1 and SOCS3.

Highly pathogenic avian influenza virus infection is associated with severe mortality in both humans and poultry. The mechanisms of disease pathogenesis and immunity are poorly understood although recent evidence suggests that cytokine/chemokine dysregulation contributes to disease severity following H5N1 infection. Influenza A virus infection causes a rapid influx of inflammatory cells, resulting in increased reactive oxygen species production, cytokine expression, and acute lung injury. Proinflammatory stimuli are known to induce intracellular reactive oxygen species by activating NADPH oxidase activity. We therefore hypothesized that inhibition of this activity would restore host cytokine homeostasis following avian influenza virus infection. A panel of airway epithelial and immune cells from mammalian and avian species were infected with A/Puerto Rico/8/1934 H1N1 virus, low-pathogenicity avian influenza H5N3 virus (A/duck/Victoria/0305-2/2012), highly pathogenic avian influenza H5N1 virus (A/chicken/Vietnam/0008/2004), or low-pathogenicity avian influenza H7N9 virus (A/Anhui/1/2013). Quantitative real-time reverse transcriptase PCR showed that H5N1 and H7N9 viruses significantly stimulated cytokine (interleukin-6, beta interferon, CXCL10, and CCL5) production. Among the influenza-induced cytokines, CCL5 was identified as a potential marker for overactive immunity. Apocynin, a Nox2 inhibitor, inhibited influenza-induced cytokines and reactive oxygen species production, although viral replication was not significantly altered in vitro. Interestingly, apocynin treatment significantly increased influenza virus-induced mRNA and protein expression of SOCS1 and SOCS3, enhancing negative regulation of cytokine signaling. These findings suggest that apocynin or its derivatives (targeting host responses) could be used in combination with antiviral strategies (targeting viruses) as therapeutic agents to ameliorate disease severity in susceptible species.

Australian women`s experiences of living with hepatitis C virus: results from a cross-sectional survey

Background: Of the estimated 160 000 Australians currently infected with the hepatitis C virus (HCV), over one-third are women and very few have received clinical treatment, with most managing their illness in non-specialist settings. Little is known about the experiences of women living with HCV in the general community. The present study provides the results from the first comprehensive social survey of Australian women's experiences of living with HCV.

Methods: In 2000, a questionnaire was administered to a largely non-clinical sample of women with HCV (n = 462) living in the state of Victoria and the Australian Capital Territory, Australia. The questionnaire was self-administered with a return rate of 75%. The mean age was 35 years and 83% were 'current' or 'past' injecting drug users. The mean time since diagnosis was 4.6 years (SD = 4.0) and the mean time since infection was 10.5 years (SD = 8.2).

Results: Fifty-eight percent of women reported experiencing symptoms related to their HCV, the most common being tiredness (78%) and nausea (44%). Of the sample, 56% currently saw a doctor for their HCV, and while 52% had ever been referred to a specialist, only 17% of the total sample had ever begun interferon-based combination or monotherapy. Forty-eight percent of women reported experiencing less favorable treatment by a health professional because of their HCV. Age-related self-assessed health status was significantly lower than Australian norms, as were SF-12 physical and mental health scores. The SF-12 physical and mental health scores were highly correlated, indicating a significant physical and mental health burden associated with HCV.

Conclusion: The social, physical and mental health needs of women living with HCV are considerable. Most women had not accessed specialist treatment and the response of the primary health care system to HCV-related women's health issues requires improvement.

A theoretical discussion of the impact of stigma on psychological adjustment to having a sexually transmissible infection

This paper provides a discussion of the utility of stigma theory as a conceptual framework for the interpretation and analysis of the psychological impact of contracting a sexually transmissible infection (STI). Most particularly, it focuses on those viral infections that cannot be medically cured, such as genital herpes and genital human papilloma virus. Recent research in the area of STIs suggests that the stigma associated with these conditions can hinder psychosocial and sexual adjustment post-diagnosis, and provides support for the use of stigma theory as a conceptual framework with which to analyse these experiences. This paper defines the concept of stigma and presents a theoretical overview of the process of stigmatisation. Three dimensions of stigma relevant to the experience of having a STI are then presented: the degree of concealability of the condition including the social consequences of concealing a condition; the origin of the condition; and the degree of peril presented by the condition. An overview of the way in which the presence of a stigmatising condition such as a STI may affect a person’s feelings of self and his/her intimate relationships is then presented. Finally, the implications of stigma theory as a conceptual framework for guiding future research in the area of personal and interpersonal reactions to STIs is discussed.