Around 4500 Ross River virus (RRV) human cases are reported in Australia annually. To date, there is no registered nor licenced vaccine to protect against RRV disease. Identifying and substituting preferred with less-preferred codons and dinucleotides is a recognised strategy to attenuate viruses and may prove useful to vaccine development efforts for RRV and other related viruses. Here, we used bioinformatic approaches aimed at assessing evidence of codon usage and dinucleotide bias in 55 RRV whole genomes sampled from humans (Homo sapiens), macropods (Notomacropus agilis), and the Aedes vigilax mosquito. Our results indicate that RRV undergoes positive and negative codon usage bias with natural selection as the major force driving RRV codon usage patterns. RRV displays a bias towards codons with an A or C at the 3rd position while H. sapiens displays a G or C and N. agilis and Ae. vigilax both show bias towards codons with an A or U at the same 3rd position. RRVs codon usage patterns are coincidental to those displayed by common vertebrate hosts and antagonistic to patterns of Ae. vigilax. The coincidental bias identified suggests vertebrate host gene expression greatly influences RRV evolution. In addition, we show that the UG dinucleotides in RRV are overrepresented at all three codon sites, while CA dinucleotides are only overrepresented at codon sites 1-2 and 2-3. These over and under-representations can be exploited to develop attenuated RRV RNA vaccines. The approach utilised here could also be used to develop vaccines for other alphaviruses of global importance.

The Sunshine Coast Public Health Unit (SCPHU) identified a measles case in a childcare educator (CE) with secondary vaccine failure (SVF). The CE had been exposed to a confirmed measles case in a hospital emergency department and later developed symptoms including fever, cough, malaise, and a rash. Diagnostic tests confirmed measles virus infection. Sunshine Coast Public Health Unit (SCPHU) mplemented control measures including contact tracing, vaccination, post-exposure prophylaxis, and quarantine for susceptible contacts. Out of 372 identified contacts, 72 were identified as susceptible, all of whom were infants and children. Despite the CE having close contact to all susceptible infants and children, no onward transmission occurred. This suggests that SVF cases pose a lower risk of spreading measles compared to immunologically na & iuml;ve individuals. This report highlights the importance of prioritising immunologically na & iuml;ve cases in outbreak responses.

Sindbis virus (SINV) is a widely dispersed mosquito-borne alphavirus. Reports of Sindbis disease are largely restricted to northern Europe and South Africa. SINV is frequently sampled in Australian mosquito-based arbovirus surveillance programs, but human disease has rarely been reported. Molecular epidemiological studies have characterized six SINV genotypes (G1–G6) based on E2 gene phylogenies, mostly comprising viruses derived from the African–European zoogeographical region and with limited representation of Australasian SINV. In this study, we conducted whole genome sequencing of 66 SINV isolates sampled between 1960 and 2014 from countries of the Australasian region: Australia, Malaysia, and Papua New Guinea. G2 viruses were the most frequently and widely sampled, with three distinct sub-lineages defined. No new G6 SINV were identified, confirming geographic restriction of these viruses to south-western Australia. Comparison with global SINV characterized large-scale nucleotide and amino acid sequence divergence between African–European G1 viruses and viruses that circulate in Australasia (G2 and G3) of up to 26.83% and 14.55%, respectively, divergence that is sufficient for G2/G3 species demarcation. We propose G2 and G3 are collectively a single distinct alphavirus species that we name Argyle virus, supported by the inapparent or mild disease phenotype and the higher evolutionary rate compared with G1. Similarly, we propose G6, with 24.7% and 12.61% nucleotide and amino acid sequence divergence, is a distinct alphavirus species that we name Thomson’s Lake virus.

Ross River virus (RRV) and Barmah Forest virus (BFV) are arthritogenic arthropod-borne viruses (arboviruses) that exhibit generalist host associations and share distributions in Australia and Papua New Guinea (PNG). Using stochastic mapping and discrete-trait phylogenetic analyses, we profiled the independent evolution of RRV and BFV signature mutations. Analysis of 186 RRV and 88 BFV genomes demonstrated their viral evolution trajectories have involved repeated selection of mutations, particularly in the nonstructural protein 1 (nsP1) and envelope 3 (E3) genes suggesting convergent evolution. Convergent mutations in the nsP1 genes of RRV (residues 248 and 441) and BFV (residues 297 and 447) may be involved with catalytic enzyme mechanisms and host membrane interactions during viral RNA replication and capping. Convergent E3 mutations (RRV site 59 and BFV site 57) may be associated with enzymatic furin activity and cleavage of E3 from protein precursors assisting viral maturation and infectivity. Given their requirement to replicate in disparate insect and vertebrate hosts, convergent evolution in RRV and BFV may represent a dynamic link between their requirement to selectively 'fine-tune' intracellular host interactions and viral replicative enzymatic processes. Despite evidence of evolutionary convergence, selection pressure analyses did not reveal any RRV or BFV amino acid sites under strong positive selection and only weak positive selection for nonstructural protein sites. These findings may indicate that their alphavirus ancestors were subject to positive selection events which predisposed ongoing pervasive convergent evolution, and this largely supports continued purifying selection in RRV and BFV populations during their replication in mosquito and vertebrate hosts.

Introduction: Widespread transmission of Japanese encephalitis virus (JEV) genotype four (GIV) occurred across mainland Australia in 2022. This resulted in forty-five human cases, including seven deaths, and the identification of JEV infection in over 80 commercial piggeries.Materials and Methods: We collected mosquitoes which were trapped using CO2-baited light traps deployed near piggeries reporting disease or in regions linked to human cases in the Wide Bay region in the state of Queensland. Mosquitoes from four traps yielded JEV RNA by real-time RT-PCR. Pools containing RNA positive mosquitoes were inoculated onto mosquito cell monolayers.Discussion: A single isolate of JEV was obtained from a pool of mixed mosquito species. Near whole genome sequencing and phylogenetic analysis of the JEV isolate demonstrated its high genomic relatedness with JEV GIV pig sequences sampled from Queensland and the state of New South Wales in 2022.Conclusion: We report the first isolation of JEV GIV from mosquitoes collected in Australia. With only a few JEV GIV isolates available globally, the isolate we report will be essential for future research of JEV host interactions, evolution and disease markers, and development of effective therapies, vaccines, diagnostic assays, and mosquito control strategies.

Pteropine orthoreoviruses (PRVs) are an emerging group of fusogenic, bat-borne viruses from the Orthoreovirus genus. Since the isolation of PRV from a patient with acute respiratory tract infections in 2006, the zoonotic potential of PRV has been further highlighted following subsequent isolation of PRV species from patients in Malaysia, Hong Kong and Indonesia. However, the entry mechanism of PRV is currently unknown. In this study, we investigated the role of previously identified mammalian orthoreovirus (MRV) receptors, sialic acid and junctional adhesion molecule-1 for PRV infection. However, none of these receptors played a significant role in PRV infection, suggesting PRV uses a distinct entry receptor from MRV. Given its broad tissue tropism, we hypothesized that PRV may use a receptor that is widely expressed in all cell types, heparan sulphate (HS). Enzymatic removal of cell surface HS by heparinase treatment and genetic ablation of HS biosynthesis genes, SLC35B2, exostosin-1, N-deacetylase/N-sulfotransferase I and beta-1,3-glucuronyltransferase 3, significantly reduced infection with multiple genetically distinct PRV species. Replication kinetic of PRV3M in HS knockout cells revealed that HS plays a crucial role in the early phase of PRV infection. Mechanistic studies demonstrated that HS is an essential host-factor for PRV attachment and internalization into cells. To our knowledge, this is the first report on the use of HS as an attachment receptor by PRVs.

A man in his thirties presented immediately on return from a one-month trip to Europe with widespread pustular lesions, tender lymphadenopathy, fever, and headache. Initial contact was with his general practitioner, who notified the local Public Health Unit and the Infectious Diseases Unit. He identified as a man who has sex with men. He had a background of human immunodeficiency virus (HIV) infection, which was well controlled (CD4+ cells, 1190 cells/mm3 [reference interval (RI), 560–1580 cells/mm3]; HIV viral load not detected [limit of quantitation, 20 RNA copies/mL]) with bictegravir 50 mg, emtricitabine 200 mg, and tenofovir alafenamide 25 mg daily. He first noticed a lesion resembling a pimple on the forehead while still overseas, which progressed over the six days before his return (Box 1) followed by a clustering of similar lesions over his right buttock, but no mucosal lesions. More lesions then developed over his thigh and hand. He reported intermittent rectal paraesthesia and spasm, in addition to fever and mild generalised headache. Tender inguinal and cervical lymphadenopathy became established, along with fatigue and malaise. He did not report sore throat, cough, diarrhoea, dysuria, or neck stiffness. He had had sexual contact with known cases of mpox (formerly monkeypox) in Europe. He was admitted to hospital in a single negative pressure room, with contact and airborne precautions. Full blood count and chemistry were normal, and C-reactive protein was 17 mg/L (RI, < 5 mg/L). Testing for Chlamydia trachomatis and Neisseria gonorrhoeae was negative. Swabs were taken from the perianal lesion and sent for National Association of Testing Authorities (NATA)-accredited in-house Orthopoxvirus group real-time polymerase chain reaction (PCR) test targeting the OPG105 gene. Positive by real-time PCR, monkeypox virus (MPXV) DNA from both the perianal lesion and throat specimens was subsequently confirmed using two additional conventional PCR tests targeting the OPG105 and OPG185 genes. Whole genome sequencing and phylogenetic analyses (Supporting Information) of a genome sequence obtained from the perianal specimen (MPXV_QLD_MX00001_2022, GenBank accession number OP235282) demonstrated placement within the human MPXV (hMPXV) sublineage B.1 of clade IIb and was most closely related to other recent 2022 MPXV sequences from the United States, Europe, Australia and Canada (Box 2). Additional laboratory methods are included in the Supporting Information. * Alignments were trimmed to remove the 5’ inverted terminal repeat (ITR) sequence and mask several repetitive regions. The newly classified MPXV phylogenetic clades I (formally Central African), IIa and IIb (formally West African) are highlighted, and the human MPXV (h) sublineages A, A.1, A.1.1 and B.1 are named at key nodes and are correspondingly denoted with coloured branches. Clade I includes a collapsed grouping of 34 sequences. The recent Queensland 2022 MPXV sequence (MPXV_QLD_OP235282_2022) is highlighted in bold blue font. No antiviral therapy was initiated, and his systemic symptoms improved rapidly over 24 hours, at which time he was discharged home to self-isolate under the care of the coronavirus disease 2019 (COVID-19) virtual ward. He lived alone and was instructed to stay at home except for essential activities, such as buying groceries or solo outdoor exercise, and to avoid high risk settings and physical and intimate contact with others until all skin lesions had scabbed over. Mpox is caused by MPXV, a double-stranded DNA virus of the genus Orthopoxvirus in the family Poxviridae.1 The incubation period is five to 21 days, and most clinical infections are self-limiting. Symptoms include rash, fever, lethargy and lymphadenopathy, usually lasting two to four weeks.1 By 5 January 2023, in the current global mpox outbreak, 110 countries have reported cases, including 144 laboratory-confirmed cases in Australia.2 An international case series reported that 95% of patients presented with a rash (almost two-thirds having fewer than ten lesions), 62% reported fever, and 56% lymphadenopathy.3 Ninety-eight per cent of infected individuals were found to be gay or bisexual men, 41% had HIV infection, and MPXV was detected in 91% (29/32) of seminal fluid specimens tested. Concomitant sexually transmissible infections were reported in 29% of cases. Although MPXV was thought to be mainly transmitted via respiratory droplets and close contact with skin lesions, the current global outbreak is notable for spreading primarily during sexual contact. Fomites (eg, towels, sex toys) may be also involved in MPXV transmission. Public health interventions including case and close contact management should be provided as per the mpox guidelines from the Communicable Diseases Network Australia (CDNA).4 We were able to repurpose the existing virtual ward and public health capacity developed originally for the COVID-19 pandemic response, demonstrating the legacy of a stronger public health system able to deal with emerging infectious diseases outbreaks. There are no antiviral therapies for mpox approved by the Therapeutic Goods Administration (TGA). However, the antiviral agent tecovirimat, which inhibits the MPXV envelope wrapping protein, is held in the National Medication Stockpile for the treatment of severe disease and for patients at risk of complications, such as severely immunosuppressed individuals and children less than eight years old.5 Vaccinia immune globulin may be an alternative therapy in pregnancy. Management is generally supportive, with careful attention to analgesia for anogenital and oropharyngeal lesions. The replication-incompetent live virus vaccine modified vaccinia Ankara–Bavarian Nordic (MVA-BN, Jynneos [Bavarian Nordic]) prevents mpox infection, although occasional breakthrough cases are described. In these cases, it may reduce the severity of mpox.6 The vaccine is not registered for use in Australia but is available via a special emergency pathway. Genetic classification of MPXV was recently revised, with new naming conventions comprising of clade I (formerly Central African) and clade II (formerly West African, further divided into IIa and IIb).7 The current 2022 human outbreak is caused by the hMPXV sublineage B.1 of clade IIb, which might cause less severe disease. Open access publishing facilitated by The University of Queensland, as part of the Wiley - The University of Queensland agreement via the Council of Australian University Librarians. Krispin Hajkowicz has received speaking fees, honoraria, advisory board fees, and a research grant from Gilead Sciences, and support from Moderna to attend an educational meeting. Adam Stewart has received speaking fees and honoraria from Gilead Sciences, and support from Pfizer for travel and meeting expenses. Not commissioned; externally peer reviewed. Supporting Information. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Lymphocytic choriomeningitis virus (LCMV) is a zoonotic virus that can cause clinically significant illnesses in humans. Although cases of LCMV infection are well described globally, and there is evidence that the virus is present in Australian rodent populations, there has been only one case of domestically acquired LCMV infection published previously. Here, we describe a cluster of LCMV infections in South-East Queensland identified in early 2021, and the diagnostic testing processes implemented. This identifies LCMV as an under-recognised human pathogen in Australia.

The current COVID-19 pandemic is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We demonstrate that despite the large size of the viral RNA genome (~30 kb), infectious full-length cDNA is readily assembled in vitro by a circular polymerase extension reaction (CPER) methodology without the need for technically demanding intermediate steps. Overlapping cDNA fragments are generated from viral RNA and assembled together with a linker fragment containing CMV promoter into a circular full-length viral cDNA in a single reaction. Transfection of the circular cDNA into mammalian cells results in the recovery of infectious SARS-CoV-2 virus that exhibits properties comparable to the parental virus in vitro and in vivo. CPER is also used to generate insect-specific Casuarina virus with ~20 kb genome and the human pathogens Ross River virus (Alphavirus) and Norovirus (Calicivirus), with the latter from a clinical sample. Additionally, reporter and mutant viruses are generated and employed to study virus replication and virus-receptor interactions.

Objective(s): To describe an autochthonous dengue virus type 2 (DENV-2) outbreak in Central Queensland from May 2019 and subsequent public health actions. Design and setting: Public health outbreak investigation of locally acquired DENV-2 cases in Rockhampton, Central Queensland. This included laboratory investigations, associated mosquito vector surveillance, and control measures implemented in response to the outbreak. Results: Twenty-one locally-acquired DENV-2 cases were identified during the Rockhampton outbreak (from 23 May to 7 October 2019): 13 laboratory-confirmed and eight probable cases. Clinical symptoms included lethargy (100%); fever (95%); headache (95%); and aches and pains (90%). Inspections of premises demonstrated that Aedes aegypti was present in 9.5% of those investigated which was more than half of the premises identified as containing mosquitoes. Nucleotide sequencing of a DENV-2 isolate recovered from the first confirmed case and DENV-2 RNA from an additional 5 patients indicated a single DENV-2 strain was responsible for the outbreak which was most closely related to DENV-2 strains from Southeast Asia. Conclusions: The 2019 DENV-2 outbreak in Rockhampton, Central Queensland, Australia, likely resulted from the importation of a strain, most closely related to DENV-2 strains from Southeast Asia and is the first reported outbreak in the region specifically implicating DENV-2. Given the presence of Aedes aegypti in Rockhampton, appropriate medical and mosquito avoidance advice; ongoing surveillance; and deployment of mosquito control strategies for the prevention of dengue and other mosquito-borne diseases should be priorities for this region.

The principal vector of dengue, Zika and chikungunya viruses is the mosquito Aedes aegypti, with its ability to transmit pathogens influenced by ambient temperature. We use chikungunya virus (CHIKV) to understand how the mosquito transcriptome responds to arbovirus infection at different ambient temperatures. We exposed CHIKV-infected mosquitoes to 18, 28 and 32°C, and found that higher temperature correlated with higher virus levels, particularly at 3 days post infection, but lower temperature resulted in reduced virus levels. RNAseq analysis indicated significantly altered gene expression levels in CHIKV infection. The highest number of significantly differentially expressed genes was observed at 28°C, with a more muted effect at the other temperatures. At the higher temperature, the expression of many classical immune genes, including Dicer-2, was not substantially altered in response to CHIKV. The upregulation of Toll, IMD and JAK-STAT pathways was only observed at 28°C. Functional annotations suggested that genes in immune response and metabolic pathways related to energy supply and DNA replication were involved in temperature-dependent changes. Time post infection also led to substantially different gene expression profiles, and this varied with temperature. In conclusion, temperature significantly modulates mosquito gene expression in response to infection, potentially leading to impairment of immune defences at higher temperatures.

On 23 May 2019, the Central Queensland Public Health Unit received a confirmed laboratory notification of a dengue virus serotype-2 (DENV-2) infection in a Rockhampton resident. On 5 May, a 71-year-old man without a history of travel overseas or to Far North Queensland had developed symptoms consistent with a zoonotic disease, and presented later that month to his general practitioner because his symptoms had not abated. Between 23 May and 7 October 2019, 21 locally acquired cases of DENV-2 were identified in Rockhampton: 13 laboratory-confirmed cases and eight probable cases detected by active surveillance. This was the first outbreak of locally acquired dengue in Central Queensland for 65 years.1 In 14 cases (67%), the infected persons sought medical attention; two required hospitalisation. A formal outbreak response was initiated by the Central Queensland Public Health Unit on 23 May 2019, including extensive mosquito surveillance and active and passive human surveillance within 200 metres of the residences of each identified infected person. Particular attention was directed to surveying locations that might facilitate increased dengue transmission in the community (such as schools, a plant nursery, and aged care facilities) for artificial and natural containers that could serve as breeding areas for infected mosquitoes (Aedes aegypti). Such containers were either removed or emptied of residual water and treated with pellets of the insect growth regulator (S)-methoprene, and the premises and buildings were sprayed inside and out with the residual insecticide Temprid 75 (Bayer; includes imidacloprid and β-cyfluthrin). In addition to the house-to-house human surveillance, a novel “lure and kill” approach was adopted for vector control: lethal ovitraps were deployed within 200 metres of the residence of any person with a probable or confirmed infection. Ae. aegypti was found in 105 of 1107 inspected residential premises (9.5%), or more than half of the 205 premises found to contain mosquitoes. Enhanced serological surveillance was undertaken to detect patients with viraemia early, enabling prompt public health and mosquito control interventions. The complete DENV-2 genome sequence (GenBank accession number, MN982899.1) indicated that the implicated virus was most closely related to Southeast Asian strains of DENV-2. Given the presence of Ae. aegypti in Central Queensland and the increasing numbers of travellers and visitors returning from countries in which dengue is endemic, it is important that Rockhampton be recognised as a dengue-receptive area. As locally acquired cases of dengue are being reported outside Far North Queensland, the state map of dengue-receptive areas2 should be updated; specifically, the broad geographic area from Townsville south to Rockhampton should be considered dengue-receptive. We acknowledge the assistance of Fred Moore (Public Health Virology Laboratory, Forensic and Scientific Services, Coopers Plains); Nicolas Smoll, Odewumi Adeqbija, Arifuzzaman Khan, Rashidul Hasan (Central Queensland Public Health Unit, Central Queensland Hospital and Health Service); and Heidi Carroll (Communicable Disease Branch, Queensland Health, Brisbane). We also thank staff from the Queensland Health Communicable Disease Branch and other Queensland Public Health Units, scientists from the Queensland Health Forensic and Scientific Services Laboratory, medical entomologists, Queensland Health media, and the Rockhampton Regional Council, who together formed our Incident Management Team. No relevant disclosures.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of COVID-19, is a readily transmissible and potentially deadly pathogen which is currently re-defining human susceptibility to pandemic viruses in the modern world. The recent emergence of several genetically distinct descendants known as variants of concern (VOCs) is further challenging public health disease management, due to increased rates of virus transmission and potential constraints on vaccine effectiveness. We report the isolation of SARS-CoV-2 VOCs imported into Australia belonging to the B.1.351 lineage, first described in the Republic of South Africa (RSA), and the B.1.1.7 lineage originally reported in the United Kingdom, and directly compare the replication kinetics of these two VOCs in Vero E6 cells. In this analysis, we also investigated a B.1.1.7 VOC (QLD1516/2021) carrying a 7-nucleotide deletion in the open reading frame 7a (ORF7a) gene, likely truncating and rendering the ORF7a protein of this virus defective. We demonstrate that the replication of the B.1.351 VOC (QLD1520/2020) in Vero E6 cells can be detected earlier than the B.1.1.7 VOCs (QLD1516/2021 and QLD1517/2021), before peaking at 48 h post infection (p.i.), with significantly higher levels of virus progeny. Whilst replication of the ORF7a defective isolate QLD1516/2021 was delayed longer than the other viruses, slightly more viral progeny was produced by the mutant compared to the unmutated isolate QLD1517/2021 at 72 h p.i. Collectively, these findings contribute to our understanding of SARS-CoV-2 replication and evolutionary dynamics, which have important implications in the development of future vaccination, antiviral therapies, and epidemiological control strategies for COVID-19.

The dengue viruses (DENVs) occur throughout tropical and subtropical regions of the world where they infect 100s of millions of people annually. In Australia, the dengue receptive zone is confined to the northern state of Queensland where the principal vector Aedes aegypti (L.) is present. In the current study, two populations of Ae. aegypti from north Queensland were exposed to two urban outbreak strains and one sylvatic strain of dengue virus type 2 (DENV-2). The titer of virus required to infect 50% of mosquitoes was between 105 and 106 50% tissue culture infectious dose (TCID)50/ml and was influenced by the combination of the origin of Ae. aegypti population and virus strain. When exposed to infectious bloodmeal titers > 106 TCID50/ml, infection and dissemination rates were all > 50% and were significantly affected by the origin of the mosquito population but not by the strain of DENV-2. Replication of DENV-2 was also significantly affected by the mosquito population and the titer of the infectious bloodmeal that mosquitoes were exposed to. The results of this study are discussed in the context of DENV transmission dynamics in northern Australia and the relative fitness of the sylvatic virus strain in urban Ae. aegypti populations.

Middle Point orbivirus (MPOV) is an Australian arbovirus, belongs to the Yunnan orbivirus species found in China. First detected and reported from Beatrice Hill, Northern Territory (NT), MPOV has to date, only been exclusively reported from the NT, Australia. Whilst genetic characterization of MPOV has been previously described, only restricted to sequence information for segments 2 and 3 coding core protein VP2 and outer capsid protein VP3, respectively. This study presents for the first time nearly full-length genome sequences of MPOV, which represent 24 isolates collected over a span of more than 20 years from 1997 to 2018. Whilst the majority of isolates were sampled at Beatrice Hill, NT where MPOV is most frequently isolated, this report also describes the first two isolations of MPOV from Queensland (QLD), Australia. One of which is the first non-bovine isolate obtained from the mosquito vector Aedes vittiger. We further compared these MPOV sequences with known sequences of the Yunnan orbivirus and other known orbivirus sequences of mosquito origin found in Australia. The phylogenetic analyses indicate the Australian MPOV sequences are more closely related to each other than other known sequences of Yunnan orbivirus. Furthermore, MPOV sequences are closely related to sequences from the Indonesian isolate JKT-8650. The clustering of Australian sequences in the phylogenetic tree suggests the monophyletic lineage of MPOV circulating in Australia. Further, ongoing surveillance is required to assess the existence and prevalence of this or other yet undetected lineages of MPOV and other orbiviruses in Australia.

The Australian backyard mosquito, Aedes notoscriptus, is a highly urbanised pest species that has invaded New Zealand and the USA. Importantly, Ae. notoscriptus has been implicated as a vector of Ross River virus, a common and arthritogenic arbovirus in Australia, and is a laboratory vector of numerous other pathogenic viruses, including West Nile, yellow fever, and Zika viruses. To further explore live viruses harboured by field populations of Ae. notoscriptus and, more specifically, assess the genetic diversity of its virome, we processed 495 pools, comprising a total of 6,674 female Ae. notoscriptus collected across fifteen suburbs in Brisbane, Australia, between January 2018 and May 2019. Nine virus isolates were recovered and characterised by metagenomic sequencing and phylogenetics. The principal viral family represented was Flaviviridae. Known viruses belonging to the genera Flavivirus, Orbivirus, Mesonivirus, and Nelorpivirus were identified together with two novel virus species, including a divergent Thogoto-like orthomyxovirus and an insect-specific flavivirus. Among these, we recovered three Stratford virus (STRV) isolates and an isolate of Wongorr virus (WGRV), which for these viral species is unprecedented for the geographical area of Brisbane. Thus, the documented geographical distribution of STRV and WGRV, both known for their respective medical and veterinary importance, has now been expanded to include this major urban centre. Phylogenies of the remaining five viruses, namely, Casuarina, Ngewotan, the novel Thogoto-like virus, and two new flavivirus species, suggested they are insect-specific viruses. None of these viruses have been previously associated with Ae. notoscriptus or been reported in Brisbane. These findings exemplify the rich genetic diversity and viral abundance within the Ae. notoscriptus virome and further highlight this species as a vector of concern with the potential to transmit viruses impacting human or animal health. Considering it is a common pest and vector in residential areas and is expanding its global distribution, ongoing surveillance, and ecological study of Ae. notoscriptus, together with mapping of its virome and phenotypic characterisation of isolated viruses, is clearly warranted. Immanently, these initiatives are essential for future understanding of both the mosquito virome and the evolution of individual viral species.

In this letter, we report the ability of the nanostructured aluminum Al 6063 alloy surfaces to inactivate the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There was no recoverable viable virus after 6 h of exposure to the nanostructured surface, elucidating a 5-log reduction compared to a flat Al 6063 surface. The nanostructured surfaces were fabricated using wet-etching techniques which generated nanotextured, randomly aligned ridges approximately 23 nm wide on the Al 6063 alloy surfaces. In addition to the excellent mechanical resilience properties previously shown, the etched surfaces have also demonstrated superior corrosion resistance compared to the control surfaces. Such nanostructured surfaces have the potential to be used in healthcare environment such as hospitals and public spaces to reduce the surface transmission of SARS-CoV-2 and combat COVID-19.

When a mosquito feeds on a host, it ingests not only its blood meal but also an assortment of microorganisms that are present in the blood, thus acting as an environmental sampler. By using specific tests, it is possible to detect arthropod-borne viruses (arboviruses) like dengue and West Nile viruses in mosquito excreta. Here, we explored the use of next-generation sequencing (NGS) for unbiased detection of RNA viruses present in excreta from experimentally infected and field-collected mosquitoes. We have demonstrated that mosquito excreta provide a suitable template for NGS and that it is possible to recover and assemble near-full-length genomes of both arboviruses and insect-borne viruses, including potentially novel ones. These results importantly show the direct practicality of the use of mosquito excreta for NGS, which in the future could be used for virus discovery, environmental virome sampling, and arbovirus surveillance.

We sequenced the genomes of two chikungunya virus isolates obtained from viremic patients who had traveled to Australia. The first patient acquired the infection in Bangladesh in 2017, and the second was infected in Thailand in 2019. Phylogenetic sequence analysis demonstrated that both isolates belonged to the East/Central/South African genotype.

A severe case of Japanese encephalitis virus (JEV) infection, resulting in fatality, occurred in an unvaccinated Australian male traveler from Bali, Indonesia, in 2019. During hospitalisation in Australia, patient cerebrospinal fluid (CSF) yielded JEV-specific IgM antibodies and RNA, and an isolate of the virus. Ongoing transmission of JEV in Bali underscores this pathogen as a public health risk and the importance of appropriate health, vaccination and mosquito avoidance advice to prospective travelers to the region.