The detection of Japanese encephalitis virus (JEV) in the Murray region, New South Wales: a public health investigation.

The detection of Japanese encephalitis virus (JEV) in pigs, at four piggeries in the Murray region in February 2022, prompted a public health investigation (PHI) by the New South Wales Department of Health (NSW Health) to identify people at greatest risk of infection. The PHI included three components: a vaccination clinic and accompanying clinic questionnaire; a serological investigation; and a cross-sectional study for consenting Australian-born participants who completed an extended questionnaire after receiving their serological results. The goals were to vaccinate a presumably naïve population to reduce associated risk and to understand the seroprevalence among Australian-born piggery workers.

The seroprevalence of antibodies to Japanese encephalitis virus in five New South Wales towns at high risk of infection, 2022: a cross-sectional serosurvey.

Objectives: To determine the proportion of people in New South Wales towns at high risk of Japanese encephalitis virus (JEV) infections during the 2022 outbreak; to identify risk factors for JEV infection.

Study Design: Cross-sectional serosurvey study of the seroprevalence of JEV-specific antibodies in NSW.

Setting, Participants: Convenience sample of people (all ages) from five regional NSW towns deemed to be at high risk of JEV infections after first outbreak of Japanese encephalitis in southeastern Australia in early 2022 (Balranald, Corowa, Dubbo, Griffith, Temora), 21 June - 22 July 2022.

Seroprevalence of Japanese encephalitis virus-specific antibodies in Australia following novel epidemic spread: protocol for a national cross-sectional study.

Introduction: Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus that causes encephalitis and other morbidity in Southeast Asia. Since February 2022, geographically dispersed JEV human, animal and vector detections occurred on the Australian mainland for the first time. This study will determine the prevalence of JEV-specific antibodies in human blood with a focus on populations at high risk of JEV exposure and determine risk factors associated with JEV seropositivity by location, age, occupation and other factors.

Characterizing the acute antibody response of monkeypox and MVA-BN vaccine following an Australian outbreak.

In response to the emergence of the monkeypox virus (MPXV) in Australia in May 2022, we developed and evaluated indirect immunofluorescence assays (IFA) for MPXV and Vaccinia virus (VACV) IgG and IgM antibodies using serum samples from patients with nucleic acid amplification test (NAAT)-confirmed mpox and uninfected unvaccinated controls. Additionally, 47 healthcare workers receiving two doses of the third-generation smallpox vaccine Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN) undertook serial serum collection to describe the serological response to vaccination. MPXV antibodies were detected in 16/18 individuals with NAAT-confirmed mpox (sensitivity 0.

New Detection of Locally Acquired Japanese Encephalitis Virus Using Clinical Metagenomics, New South Wales, Australia.

In the context of an emerging Japanese encephalitis outbreak within Australia, we describe a novel locally acquired case in New South Wales. A man in his 70s had rapidly progressive, fatal meningoencephalitis, diagnosed as caused by Japanese encephalitis virus by RNA-based metagenomic next-generation sequencing performed on postmortem brain tissue.

SARS-CoV-2 Seroprevalence in a Cohort of International Travellers Returning to Rural Australia: Enablers and Barriers to Containment of COVID-19.

Objective: To describe the effectiveness of the public health response to COVID-19 in our local region by documenting detection of SARS-CoV-2 infection by nucleic acid testing (NAT) positivity and seroprevalence.

Methods: In this prospective study (ACTRN12620000487910), symptomatic adult international travellers returning to regional Australia in March 2020 underwent SARS-CoV-2 NAT and SARS-CoV-2-specific serology.

Results: Ninety-nine eligible participants were included.

Improved Neutralisation of the SARS-CoV-2 Omicron Variant following a Booster Dose of Pfizer-BioNTech (BNT162b2) COVID-19 Vaccine.

In late November 2021, the World Health Organization declared the SARS-CoV-2 lineage B.1.1.

Emerging Genotype IV Japanese Encephalitis Virus Outbreak in New South Wales, Australia.

The detection of a new and unexpected Japanese encephalitis virus (JEV) outbreak in March 2022 in Australia, where JEV is not endemic, demanded the rapid development of a robust diagnostic framework to facilitate the testing of suspected patients across the state of New South Wales (NSW). This nascent but comprehensive JEV diagnostic service encompassed serological, molecular and metagenomics testing within a centralised reference laboratory. Over the first three months of the outbreak (4 March 2022 to 31 May 2022), 1,061 prospective samples were received from 878 NSW residents for JEV testing.

Emergence of Japanese encephalitis in Australia: a diagnostic perspective.

The unprecedented emergence of Japanese encephalitis (JE) in mainland Australia represents an outbreak of high clinical and public health significance. JE is a zoonosis spread by mosquitoes and is one of the most important causes of endemic viral encephalitis in South-East Asia and the Indian subcontinent. While occasional cases of human Japanese encephalitis virus (JEV) infection have occurred in far north Australia, its detection in pigs and the substantial number of locally acquired human cases across multiple jurisdictions in early 2022 prompted the declaration of this outbreak as a Communicable Disease Incident of National Significance.

Co-infection with SARS-CoV-2 Omicron and Delta variants revealed by genomic surveillance.

Co-infections with different variants of SARS-CoV-2 are a key precursor to recombination events that are likely to drive SARS-CoV-2 evolution. Rapid identification of such co-infections is required to determine their frequency in the community, particularly in populations at-risk of severe COVID-19, which have already been identified as incubators for punctuated evolutionary events. However, limited data and tools are currently available to detect and characterise the SARS-CoV-2 co-infections associated with recognised variants of concern.

Immunofluorescent Antibody Techniques in the Diagnosis of SARS-CoV-2 Infection in Humans.

Immunofluorescence (IF) is an important technique used in the diagnosis of many infectious diseases. In virology, it has proven to be particularly suited to detecting antibody directed against newly emerging viruses able to be cultivated in cell culture. It permits visualization of antibody and allows for antibody class to be determined which is critical to understanding the timing of infection.

Interleukin-17 contributes to Ross River virus-induced arthritis and myositis.

Arthritogenic alphaviruses are mosquito-borne viruses that are a major cause of infectious arthropathies worldwide, and recent outbreaks of chikungunya virus and Ross River virus (RRV) infections highlight the need for robust intervention strategies. Alphaviral arthritis can persist for months after the initial acute disease, and is mediated by cellular immune responses. A common strategy to limit inflammation and pathology is to dampen the overwhelming inflammatory responses by modulating proinflammatory cytokine pathways.

The utility of SARS-CoV-2-specific serology in COVID-19 diagnosis.

Introduction: In May 2020, The Communicable Diseases Network of Australia (CDNA) case definition introduced serological criteria to support the diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We present findings that support the utility of SARS-CoV-2-specific serology for public health investigations.

Methods: From 24 January to 31 July 2020, the following information was collected from individuals with positive SARS-CoV-2-specific immunofluorescence antibody tests: history of contact with COVID-19 cases; recent travel; symptoms consistent with COVID-19; and SARS-CoV-2 nucleic acid testing (NAT) results.

An evaluation of 4 commercial assays for the detection of SARS-CoV-2 antibodies in a predominantly mildly symptomatic low prevalence Australian population.

A total of 1080 individual patient samples (158 positive serology samples from confirmed, predominantly mildly symptomatic COVID-19 patients and 922 serology negative including 496 collected pre-COVID) from four states in Australia were analysed on four commercial SARS-CoV-2 serological assays targeting antibodies to different antigens (Roche Elecsys and Abbott Architect: nucleocapsid; Diasorin Liaison and Euroimmun: spike). A subset was compared to immunofluorescent antibody (IFA) and micro-neutralisation. Sensitivity and specificity of the Roche (n = 1033), Abbott (n = 806), Diasorin (n = 1034) and Euroimmun (n = 175) were 93.

Seroprevalence of SARS-CoV-2-specific antibodies in Sydney after the first epidemic wave of 2020.

Objectives: To estimate SARS-CoV-2-specific antibody seroprevalence after the first epidemic wave of coronavirus disease 2019 (COVID-19) in Sydney.

Setting, Participants: People of any age who had provided blood for testing at selected diagnostic pathology services (general pathology); pregnant women aged 20-39 years who had received routine antenatal screening; and Australian Red Cross Lifeblood plasmapheresis donors aged 20-69 years.

Design: Cross-sectional study; testing of de-identified residual blood specimens collected during 20 April - 2 June 2020.

Australian mumps serosurvey 2012-2013: any cause for concern?

Objectives: To determine population-level immunity to mumps in Australia.

Methods: We tested randomly selected specimens from people aged 1-49 years using the Enzygnost anti-parotitis IgG enzyme immunoassay from an opportunistically collected serum bank in 2012-2013. Weighted estimates of the proportion seropositive and equivocal for mumps-specific IgG antibody were determined by age group and compared with two previous national serosurveys conducted in 2007-2008 and 1997-1998.

Basic insights into Zika virus infection of neuroglial and brain endothelial cells.

Zika virus (ZIKV) has recently emerged as an important human pathogen due to the strong evidence that it causes disease of the central nervous system, particularly microcephaly and Guillain-Barré syndrome. The pathogenesis of disease, including mechanisms of neuroinvasion, may include both invasion via the blood-brain barrier and via peripheral (including cranial) nerves. Cellular responses to infection are also poorly understood.

Lower immunity to poliomyelitis viruses in Australian young adults not eligible for inactivated polio vaccine.

There are limited long-term data on seroprevalence of neutralising antibody (nAb) to the three poliovirus serotypes following the switch from oral polio vaccine (OPV) to inactivated polio vaccine (IPV). In Australia, combination vaccines containing IPV replaced OPV in late 2005. Using serum and plasma specimens collected during 2012 and 2013, we compared prevalence of nAb to poliovirus type 1 (PV1), type 2 (PV2) and type 3 (PV3) in birth cohorts with differing IPV and OPV eligibility from an Australian population-based sample.

Diphtheria Immunity in Australia: Should we be Concerned?

Objectives: We report the results of the 2007 national serological survey of immunity to diphtheria in Australia to assess the impact of recent schedule changes on diphtheria immunity, and the adequacy of current policy in the context of increased international travel of people and pathogens.

Methods: Residual sera (n =1656) collected opportunistically from Australian laboratories in 2007 were tested for diphtheria antibody levels using an enzyme immunoassay, with the protective threshold defined as ≥0.1 IU/mL.

Tetanus Immunity and Epidemiology in Australia, 1993-2010.

Background: This study evaluates trends in tetanus immunity and epidemiology over the last two decades in Australia, drawing on two national serological surveys and national tetanus morbidity data, to justify current Australian adult tetanus booster recommendations.

Methods: We compare tetanus immunity level between two national serosurveys, and examine incidence trends using the most accurate estimation of the true number of cases by correcting for under-ascertainment.

Results: Tetanus immunity in people aged <60 years is high, but the elderly, particularly the female elderly, may not be adequately protected.

Hepatitis B Seroepidemiology in Australia, One Decade After Universal Vaccination of Infants and Adolescents.

Background: This study assessed the impact of the staged introduction of universal infant and adolescent catch-up hepatitis B vaccination programs on the prevalence of immunity and past hepatitis B virus (HBV) infection in targeted cohorts over almost a decade in Australia.

Methods: We compared the prevalence of immunity in relevant cohorts of children and adolescents in repeated national serological surveys conducted in 1998-99, 2002 and 2007. Residual sera (n =2210) collected opportunistically from Australian laboratories in 2007 were tested for antibody to hepatitis B surface antigen (anti-HBs) indicating vaccine-induced immunity; sera from individuals aged 12-29 years with anti-HBs detected (n =386) were then tested for hepatitis B core antibody (anti-HBc) to identify past hepatitis B infection.