Fatal Human Neurologic Infection Caused by Pigeon Avian Paramyxovirus-1, Australia.

Avian paramyxovirus type 1 (APMV-1) is a virus of birds that results in a range of outcomes, from asymptomatic infections to outbreaks of systemic respiratory and neurologic disease, depending on the virus strain and the avian species affected. Humans are rarely affected; those who are predominantly experience mild conjunctivitis. We report a fatal case of neurologic disease in a 2-year-old immunocompromised child in Australia. Metagenomic sequencing and histopathology identified the causative agent as the pigeon variant of APMV-1. This diagnosis should be considered in neurologic conditions of undefined etiologies. Agnostic metagenomic sequencing methods are useful in such settings to direct diagnostic and therapeutic efforts.

A meta-analytic investigation of the potential for plant volatiles and sex pheromones to enhance detection and management of Lepidopteran pests.

Effective early detection, monitoring and management methods are critical for reducing the impacts of insect pests in agriculture and forestry. Combining host plant volatiles with sex pheromones could enhance trapping methodologies, whilst the use of non-host volatiles could improve the effectiveness of pest management through repellency effects. In this meta-analysis approach, we analysed 51 studies that used electroantennograms (EAG), wind tunnels and/or field traps to evaluate the antennal and behavioural responses of Lepidoptera to sex pheromones combined with attractant or repellent plant volatiles. Proposed attractant plant volatiles had a positive association with female Lepidoptera responses to sex pheromone, but effects on males were highly variable, with unexpected repellency reported in some studies. Proposed repellent plant volatiles were significantly or near-significantly negatively associated with male attraction to sex pheromones but were scarcely studied. Sub-group analysis identified that male responses to sex pheromone were reduced when the dose of attractant plant volatile relative to sex pheromone was increased. Green-leaf volatiles were associated with the strongest positive effects for males in field traps. Multiple-compound attractant plant volatile blends were less effective than single compounds in field studies. Our analysis demonstrates, (i) the potential value of combining host plant volatiles with sex pheromones to capture females rather than only males, (ii) the importance of identifying appropriate host plant volatiles and optimal relative doses, and (iii) the potential for non-host plant volatile use in pest management strategies.

Novel Hendra Virus Variant Detected by Sentinel Surveillance of Horses in Australia.

We identified and isolated a novel Hendra virus (HeV) variant not detected by routine testing from a horse in Queensland, Australia, that died from acute illness with signs consistent with HeV infection. Using whole-genome sequencing and phylogenetic analysis, we determined the variant had ≈83% nt identity with prototypic HeV. In silico and in vitro comparisons of the receptor-binding protein with prototypic HeV support that the human monoclonal antibody m102.4 used for postexposure prophylaxis and current equine vaccine will be effective against this variant. An updated quantitative PCR developed for routine surveillance resulted in subsequent case detection. Genetic sequence consistency with virus detected in grey-headed flying foxes suggests the variant circulates at least among this species. Studies are needed to determine infection kinetics, pathogenicity, reservoir-species associations, viral-host coevolution, and spillover dynamics for this virus. Surveillance and biosecurity practices should be updated to acknowledge HeV spillover risk across all regions frequented by flying foxes.

Bluetongue virus serotype 12 enters Australia - a further incursion of novel western lineage genome segments.

Bluetongue virus (BTV) is an arbovirus (genus: Orbivirus) that occurs worldwide. It infects domestic and wild ruminant species and can cause disease in livestock, producing high economic impact. Recently, it gained extra prominence throughout Europe, with disease occurring in regions traditionally free of BTV. BTV enters Australia from Southeast Asia via wind-borne infected Culicoides spp. The first Australian isolation was 1975 (BTV-20) and further serotypes were isolated between 1979-86 (BTV-1, -3, -9, -15, -16, -21, -23). Despite increased, more sensitive, monitoring, no more were detected in over two decades, implying a stable BTV episystem of eastern ancestry. Isolations of BTV-2, -7 and -5 then occurred between 2007-15, with the latter two possessing genome segments with high sequence identity to western isolates. We report on the first isolation and genomic characterization of BTV-12, which revealed that three more novel western topotype gene segments have entered northern Australia.

A new Hendra virus genotype found in Australian flying foxes.

BACKGROUND: Hendra virus (HeV) has caused lethal disease outbreaks in humans and horses in Australia. Flying foxes are the wildlife reservoir from which the virus was first isolated in 1996. Following a heat stress mortality event in Australian flying foxes in 2013, a novel HeV variant was discovered. This study describes the subsequent surveillance of Australian flying foxes for this novel virus over a nine year period using qRT-PCR testing of tissues from flying foxes submitted primarily for Australian bat lyssavirus diagnosis. Genome sequencing and characterisation of the novel HeV variant was also undertaken. METHODS: Spleen and kidney samples harvested from flying fox carcasses were initially screened with two real-time qRT-PCR assays specific for the prototype HeV. Two additional qRT-PCR assays were developed specific for the HeV variant first detected in samples from a flying fox in 2013. Next-generation sequencing and virus isolation was attempted from selected samples to further characterise the new virus. RESULTS: Since 2013, 98 flying foxes were tested and 11 were positive for the new HeV variant. No samples were positive for the original HeV. Ten of the positive samples were from grey-headed flying foxes (GHFF, Pteropus poliocephalus), however this species was over-represented in the opportunistic sampling (83% of bats tested were GHFF). The positive GHFF samples were collected from Victoria and South Australia and one positive Little red flying fox (LRFF, Pteropus scapulatus) was collected from Western Australia. Immunohistochemistry confirmed the presence of henipavirus antigen, associated with an inflammatory lesion in cardiac blood vessels of one GHFF. Positive samples were sequenced and the complete genome was obtained from three samples. When compared to published HeV genomes, there was 84% sequence identity at the nucleotide level. Based on phylogenetic analyses, the newly detected HeV belongs to the HeV species but occupies a distinct lineage. We have therefore designated this virus HeV genotype 2 (HeV-g2). Attempts to isolate virus from PCR positive samples have not been successful. CONCLUSIONS: A novel HeV genotype (HeV-g2) has been identified in two flying fox species submitted from three states in Australia, indicating that the level of genetic diversity for HeV is broader than first recognised. Given its high genetic relatedness to HeV, HeV-g2 is a zoonotic pathogen.

Antarctic Penguins as Reservoirs of Diversity for Avian Avulaviruses.

Wild birds harbor a huge diversity of avian avulaviruses (formerly avian paramyxoviruses). Antarctic penguin species have been screened for avian avulaviruses since the 1980s and, as such, are known hosts of these viruses. In this study, we screened three penguin species from the South Shetland Islands and the Antarctic Peninsula for avian avulaviruses. We show that Adelie penguins (Pygoscelis adeliae) are hosts for four different avian avulavirus species, the recently described avian avulaviruses 17 to 19 and avian avulavirus 10-like, never before isolated in Antarctica. A total of 24 viruses were isolated and sequenced; avian avulavirus 17 was the most common, and phylogenetic analysis demonstrated patterns of occurrence, with different genetic clusters corresponding to penguin age and location. Following infection in specific-pathogen-free (SPF) chickens, all four avian avulavirus species were shed from the oral cavity for up to 7 days postinfection. There was limited shedding from the cloaca in a proportion of infected chickens, and all but one bird seroconverted by day 21. No clinical signs were observed. Taken together, we propose that penguin species, including Antarctic penguins, may be the central reservoir for a diversity of avian avulavirus species and that these viruses have the potential to infect other avian hosts.IMPORTANCE Approximately 99% of all viruses are still to be described, and in our changing world, any one of these unknown viruses could potentially expand their host range and cause epidemic disease in wildlife, agricultural animals, or humans. Avian avulavirus 1 causes outbreaks in wild birds and poultry and is thus well described. However, for many avulavirus species, only a single specimen has been described, and their viral ecology and epidemiology are unknown. Through the detection of avian avulaviruses in penguins from Antarctica, we have been able to expand upon our understanding of three avian avulavirus species (avian avulaviruses 17 to 19) and report a potentially novel avulavirus species. Importantly, we show that penguins appear to play a key role in the epidemiology of avian avulaviruses, and we encourage additional sampling of this avian group.

Crimean-Congo Hemorrhagic Fever, Herat Province, Afghanistan, 2017.

We studied the clinical and epidemiologic features of an outbreak of Crimean-Congo hemorrhagic fever in Herat Province, Afghanistan. The study comprised 63 patients hospitalized in 2017. The overall case-fatality rate was 22.2%; fatal outcome was significantly associated with a negative IgM test result, longer prothrombin time, and nausea.

Divergent Human-Origin Influenza Viruses Detected in Australian Swine Populations.

Global swine populations infected with influenza A viruses pose a persistent pandemic risk. With the exception of a few countries, our understanding of the genetic diversity of swine influenza viruses is limited, hampering control measures and pandemic risk assessment. Here we report the genomic characteristics and evolutionary history of influenza A viruses isolated in Australia from 2012 to 2016 from two geographically isolated swine populations in the states of Queensland and Western Australia. Phylogenetic analysis with an expansive human and swine influenza virus data set comprising >40,000 sequences sampled globally revealed evidence of the pervasive introduction and long-term establishment of gene segments derived from several human influenza viruses of past seasons, including the H1N1/1977, H1N1/1995, H3N2/1968, and H3N2/2003, and the H1N1 2009 pandemic (H1N1pdm09) influenza A viruses, and a genotype that contained gene segments derived from the past three pandemics (1968, reemerged 1977, and 2009). Of the six human-derived gene lineages, only one, comprising two viruses isolated in Queensland during 2012, was closely related to swine viruses detected from other regions, indicating a previously undetected circulation of Australian swine lineages for approximately 3 to 44 years. Although the date of introduction of these lineages into Australian swine populations could not be accurately ascertained, we found evidence of sustained transmission of two lineages in swine from 2012 to 2016. The continued detection of human-origin influenza virus lineages in swine over several decades with little or unpredictable antigenic drift indicates that isolated swine populations can act as antigenic archives of human influenza viruses, raising the risk of reemergence in humans when sufficient susceptible populations arise.IMPORTANCE We describe the evolutionary origins and antigenic properties of influenza A viruses isolated from two separate Australian swine populations from 2012 to 2016, showing that these viruses are distinct from each other and from those isolated from swine globally. Whole-genome sequencing of virus isolates revealed a high genotypic diversity that had been generated exclusively through the introduction and establishment of human influenza viruses that circulated in past seasons. We detected six reassortants with gene segments derived from human H1N1/H1N1pdm09 and various human H3N2 viruses that circulated during various periods since 1968. We also found that these swine viruses were not related to swine viruses collected elsewhere, indicating independent circulation. The detection of unique lineages and genotypes in Australia suggests that isolated swine populations that are sufficiently large can sustain influenza virus for extensive periods; we show direct evidence of a sustained transmission for at least 4 years between 2012 and 2016.

Evaluation of an African swine fever (ASF) vaccine strategy incorporating priming with an alphavirus-expressed antigen followed by boosting with attenuated ASF virus.

In this study, an alphavirus vector platform was used to deliver replicon particles (RPs) expressing African swine fever virus (ASFV) antigens to swine. Alphavirus RPs expressing ASFV p30 (RP-30), p54 (RP-54) or pHA-72 (RP-sHA-p72) antigens were constructed and tested for expression in Vero cells and for immunogenicity in pigs. RP-30 showed the highest expression in Vero cells and was the most immunogenic in pigs, followed by RP-54 and RP-sHA-p72. Pigs primed with two doses of the RP-30 construct were then boosted with a naturally attenuated ASFV isolate, OURT88/3. Mapping of p30 identified an immunodominant region within the amino acid residues 111-130. However, the principal effect of the prime-boost was enhanced recognition of an epitope covered by the peptide sequence 61-110. The results suggest that a strategy incorporating priming with a vector-expressed antigen followed by boosting with an attenuated live virus may broaden the recognition of ASFV epitopes.

Characterization of Fitzroy River Virus and Serologic Evidence of Human and Animal Infection.

In northern Western Australia in 2011 and 2012, surveillance detected a novel arbovirus in mosquitoes. Genetic and phenotypic analyses confirmed that the new flavivirus, named Fitzroy River virus, is related to Sepik virus and Wesselsbron virus, in the yellow fever virus group. Most (81%) isolates came from Aedes normanensis mosquitoes, providing circumstantial evidence of the probable vector. In cell culture, Fitzroy River virus replicated in mosquito (C6/36), mammalian (Vero, PSEK, and BSR), and avian (DF-1) cells. It also infected intraperitoneally inoculated weanling mice and caused mild clinical disease in 3 intracranially inoculated mice. Specific neutralizing antibodies were detected in sentinel horses (12.6%), cattle (6.6%), and chickens (0.5%) in the Northern Territory of Australia and in a subset of humans (0.8%) from northern Western Australia.

Virulence and Evolution of West Nile Virus, Australia, 1960-2012.

Worldwide, West Nile virus (WNV) causes encephalitis in humans, horses, and birds. The Kunjin strain of WNV (WNVKUN) is endemic to northern Australia, but infections are usually asymptomatic. In 2011, an unprecedented outbreak of equine encephalitis occurred in southeastern Australia; most of the ≈900 reported cases were attributed to a newly emerged WNVKUN strain. To investigate the origins of this virus, we performed genetic analysis and in vitro and in vivo studies of 13 WNVKUN isolates collected from different regions of Australia during 1960-2012. Although no disease was recorded for 1984, 2000, or 2012, isolates collected during those years (from Victoria, Queensland, and New South Wales, respectively) exhibited levels of virulence in mice similar to that of the 2011 outbreak strain. Thus, virulent strains of WNVKUN have circulated in Australia for >30 years, and the first extensive outbreak of equine disease in Australia probably resulted from a combination of specific ecologic and epidemiologic conditions.

Reassortant highly pathogenic influenza A(H5N6) virus in Laos.

In March 2014, avian influenza in poultry in Laos was caused by an emergent influenza A(H5N6) virus. Genetic analysis indicated that the virus had originated from reassortment of influenza A(H5N1) clade 2.3.2.1b, variant clade 2.3.4, and influenza A(H6N6) viruses that circulate broadly in duck populations in southern and eastern China.

Acute meningoencephalitis associated with echovirus 9 infection in Sri Lanka, 2009.

The aetiology of acute meningoencephalitis in Sri Lankan children and adults is poorly understood. This study was carried out to determine pathogens responsible for meningoencephalitis in Sri Lanka. A hospital-based cross-sectional study was performed using cerebrospinal fluid samples (22 adult and 17 pediatric) collected from August to December 2009 from patients clinically diagnosed with acute meningoencephalitis at two tertiary care hospitals in Sri Lanka. Routine microbiology for bacterial pathogens together with in-house RT-PCR and PCR assays for the detection of dengue viruses, Japanese encephalitis virus, West Nile virus, chikungunya virus, enteroviruses, mumps virus, measles virus, herpes simplex viruses types 1 and 2, and varicella zoster virus were performed. Bacterial pathogens were not isolated from any patient specimens. However, from nine of the paediatric patients aged 1 month to 10 years (mean age 5.2 years) echovirus 9 (E-9; family Picornaviridae, genus Enterovirus,species Enterovirus B ) was detected by RT-PCR. All nine patients presented with fever, six had headache, and seven had vomiting. Neck stiffness indicating meningitis was present in six of the patients. Phylogenetic analysis of partial VP1 and VP4-VP2 genes showed these E-9 strains to be most closely related to E-9 strains detected in CSF from Korea and France in 2005 and 2006. The remaining patients were negative for all other viruses tested. E-9 was the most common cause of acute meningoencephalitis in the tested paediatric population from Sri Lanka in 2009, which likely reflects circulation of this E-9 strain between Europe and Asia over several years.

Leveraging wastewater surveillance to detect viral diseases in livestock settings.

Wastewater surveillance has evolved into a powerful tool for monitoring public health-relevant analytes. Recent applications in tracking severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection highlight its potential. Beyond humans, it can be extended to livestock settings where there is increasing demand for livestock products, posing risks of disease emergence. Wastewater surveillance may offer non-invasive, cost-effective means to detect potential outbreaks among animals. This approach aligns with the "One Health" paradigm, emphasizing the interconnectedness of animal, human, and ecosystem health. By monitoring viruses in livestock wastewater, early detection, prevention, and control strategies can be employed, safeguarding both animal and human health, economic stability, and international trade. This integrated "One Health" approach enhances collaboration and a comprehensive understanding of disease dynamics, supporting proactive measures in the Anthropocene era where animal and human diseases are on the rise.

Genetic divergence among members of the Kokobera group of flaviviruses supports their separation into distinct species.

The Kokobera virus group comprises mosquito-borne flaviviruses that cluster together phylogenetically. These viruses are unique to Australia and Papua New Guinea, and have been associated with a mild polyarticular disease in humans. Recent isolation of genetically diverse viruses within this group has prompted analysis of their genetic and phenotypic relationships. Phylogenetic analysis based on complete ORF, the envelope gene or the NS5/3' untranslated region supported the separation of the group into distinct species: Kokobera virus (KOKV), Stratford virus, New Mapoon virus, MK7979 and TS5273. Virulence studies in 3-week-old mice also provided the first evidence that a member of the KOKV group (MK7979) was neuroinvasive after intraperitoneal inoculation. In this context, our recent detection of KOKV group-specific antibodies in horses in the field suggests that these viruses should be considered in the epidemiology of flavivirus encephalitis in Australia.

Comparison of Different Mosquito Traps for Zoonotic Arbovirus Vectors in Papua New Guinea.

Vector surveillance is important to control mosquito-borne diseases. We compared the efficacies of three mosquito-trapping devices: the CDC light trap with incandescent light (CDC_I), the CDC light trap with ultraviolet light (CDC_UV), and the Biogents-sentinel (BG) trap, to identify a suitable and cost-effective surveillance tool for key vectors of neglected zoonotic arboviral diseases in Papua New Guinea (PNG). Of 13,788 female mosquitoes, CDC_I caught 7.9%, BG caught 14.5%, and CDC_UV caught 77.6%. Culex was the most predominant genus caught in all the traps. Centers for Disease Control light trap with ultraviolet light trap captured the highest abundance, highest species richness of mosquitoes and exhibited the highest overall Culex mosquito capture rates compared with BG and CDC_l. This study represents the first assessment of trapping devices for zoonotic arbovirus vectors in PNG. We recommend the CDC _UV trap for future monitoring and surveillance of infectious arboviral vector programs in PNG.

Analysis of acidified feed components containing African swine fever virus.

Mitigation of African swine fever (ASF) virus in contaminated feed materials would assist control activities. Various finely-ground pig feed ingredients (5 cereals, 4 plant proteins, 2 animal proteins, 1 oil, 1 compound) were sprayed and mixed thoroughly with a buffered formic acid formulation (0, 1 or 2% vol/vol) to produce a consistent and durable level of formate (1% or 2%) with consistent acidification of cereal ingredients to less than pH 4. No such acidification was noted in other ingredients. Selected representative feed ingredients were further mixed with infectious ASF virus (106 TCID50) or media alone and incubated for 0, 6, 12, 24, 48, 72 or 168 h. The residual ASF virus at each timepoint was quantified using qPCR and a cell culture based TCID50 assay to determine survivability. Maize, rice bran and compound feed (with or without formate) all reduced infectious ASF virus to levels below the detection threshold of the cell culture assay (101.3 TCID50/mL). A consistent reduction in ASF virus DNA levels was observed by qPCR assay when maize containing ASF virus was mixed with 1% or 2% buffered formic acid. This reduction in viral DNA corresponded to the acidifying pH effect measured. No such reduction in ASF virus DNA levels was noted in non-cereal ingredients containing ASF virus, in which the pH had not been lowered below pH 4 following treatment. Interestingly, residual ASF virus levels in spiked meat/bone meal were greater than control levels, suggesting a buffering effect of that feed ingredient.

Comparative genomic analysis of the first Ehrlichia canis detections in Australia.

Ehrlichia canis (Rickettsiales; Anaplasmataceae) is one of the most prevalent tick-borne pathogens of dogs globally. The bacterium infects monocytes and is the aetiological agent of canine monocytic ehrlichiosis. For many decades Australia was thought to be free of the pathogen, but this abruptly changed in May 2020 when E. canis was detected in several dogs from Kununurra, Western Australia. Subsequent surveillance activities found unexpectedly large scale spread of E. canis throughout much of northern Australia. To gain insight into the genetic relationships of the Australian strain and its potential origin, we undertook a genomic analysis of E. canis positive domestic dog and tick (Rhipicephalus linnaei) samples from the north of Western Australia, the far north of South Australia and the Northern Territory, covering thousands of square kilometres. We obtained complete E. canis genomes from each of the three states, plus an additional 16 partial genomes, substantially increasing publicly available E. canis genetic resources. The Australian E. canis genomes were highly conserved across large geographic distances. Outside of Australia, the genomes were most similar to E. canis YZ-1 from China, although few reference sequences were available. We analysed the variable trp36 gene to obtain greater phylogenetic signal, which demonstrated that the Australian E. canis belonged to the Taiwan genotype, comprised of samples from Taiwan, China, Thailand and Turkey. Taken together, our findings suggest that E. canis in Australia may have originated from Asia or the Middle East and spread throughout northern and central Australia following its introduction.

Japanese Encephalitis Virus: The Emergence of Genotype IV in Australia and Its Potential Endemicity.

A fatal case of Japanese encephalitis (JE) occurred in northern Australia in early 2021. Sequence studies showed that the virus belonged to genotype IV (GIV), a genotype previously believed to be restricted to the Indonesian archipelago. This was the first locally acquired case of Japanese encephalitis virus (JEV) GIV to occur outside Indonesia, and the second confirmed fatal human case caused by a GIV virus. A closely related GIV JEV strain subsequently caused a widespread outbreak in eastern Australia in 2022 that was first detected by fetal death and abnormalities in commercial piggeries. Forty-two human cases also occurred with seven fatalities. This has been the first major outbreak of JEV in mainland Australia, and geographically the largest virgin soil outbreak recorded for JEV. This outbreak provides an opportunity to discuss and document the factors involved in the virus' spread and its ecology in a novel ecological milieu in which other flaviviruses, including members of the JE serological complex, also occur. The probable vertebrate hosts and mosquito vectors are discussed with respect to virus spread and its possible endemicity in Australia, and the need to develop a One Health approach to develop improved surveillance methods to rapidly detect future outbreak activity across a large geographical area containing a sparse human population. Understanding the spread of JEV in a novel ecological environment is relevant to the possible threat that JEV may pose in the future to other receptive geographic areas, such as the west coast of the United States, southern Europe or Africa.