An estimated 65 million people globally suffer from post-acute sequelae of COVID-19 (PASC), with many experiencing cardiovascular symptoms (PASC-CVS) like chest pain and heart palpitations. This study examines the role of chronic inflammation in PASC-CVS, particularly in individuals with symptoms persisting over a year after infection. Blood samples from three groups—recovered individuals, those with prolonged PASC-CVS and SARS-CoV-2-negative individuals—revealed that those with PASC-CVS had a blood signature linked to inflammation. Trace-level pro-inflammatory cytokines were detected in the plasma from donors with PASC-CVS 18 months post infection using nanotechnology. Importantly, these trace-level cytokines affected the function of primary human cardiomyocytes. Plasma proteomics also demonstrated higher levels of complement and coagulation proteins in the plasma from patients with PASC-CVS. This study highlights chronic inflammation’s role in the symptoms of PASC-CVS.

Highly pathogenic avian influenza viruses (HPAIVs) in gallinaceous poultry are associated with viral infection of the endothelium, the induction of a ‘cytokine storm, and severe disease. In contrast, in Pekin ducks, HPAIVs are rarely endothelial tropic, and a cytokine storm is not observed. To date, understanding these species-dependent differences in pathogenesis has been hampered by the absence of a pure culture of duck and chicken endothelial cells. Here, we use our recently established in vitro cultures of duck and chicken aortic endothelial cells to investigate species-dependent differences in the response of endothelial cells to HPAIV H5N1 infection. We demonstrate that chicken and duck endothelial cells display a different transcriptional response to HPAI H5N1 infection in vitro—with chickens displaying a more pro-inflammatory response to infection. As similar observations were recorded following in vitro stimulation with the viral mimetic polyI:C, these findings were not specific to an HPAIV H5N1 infection. However, similar species-dependent differences in the transcriptional response to polyI:C were not observed in avian fibroblasts. Taken together, these data demonstrate that chicken and duck endothelial cells display a different response to HPAIV H5N1 infection, and this may help account for the species-dependent differences observed in inflammation in vivo.

Influenza virus has a high mutation rate, such that within one host different viral variants can emerge. Evidence suggests that influenza virus variants are more prevalent in pregnant and/or obese individuals due to their impaired interferon response. We have recently shown that the non-allergic, paucigranulocytic subtype of asthma is associated with impaired type I interferon production. Here, we seek to address if this is associated with an increased emergence of influenza virus variants. Compared to controls, mice with paucigranulocytic asthma had increased disease severity and an increased emergence of influenza virus variants. Specifically, PB1 mutations exclusively detected in asthmatic mice were associated with increased polymerase activity. Furthermore, asthmatic host-derived virus led to increased disease severity in wild-type mice. Taken together, these data suggest that at least a subset of patients with asthma may be more susceptible to severe influenza and may be a possible source of new influenza virus variants.

Toxocara pteropodis, an intestinal nematode, occurs in several captive and free-ranging pteropid bat species. We report infection in free-ranging Indian flying foxes (Pteropus medius) in Sri Lanka and contribute to our understanding of parasites in free-ranging P. medius .

Borrelia are tick-borne spirochetes that include important pathogens that cause Lyme borreliosis and relapsing fevers. While multiple Borrelia species have been identified in Australia, further research is needed to understand their ecological roles and potential zoonotic risks. This study aimed to isolate and characterise two Australian Borrelia species-Borrelia tachyglossi and Borrelia sp. HB-through in vitro culture, genomic sequencing, and molecular surveys of ticks and vertebrate hosts. Despite extensive efforts, Borrelia sp. HB could not be cultured from Haemaphysalis bancrofti ticks, and its prevalence in questing ticks was low (0.14 %). Additionally, molecular screening of 504 wildlife hosts found no evidence of Borrelia sp. HB infection, suggesting a cryptic or highly restricted enzootic cycle. In contrast, B. tachyglossi was successfully cultured from Bothriocroton concolor ticks collected from echidnas (Tachyglossus aculeatus), enabling complete genome sequencing. Complement-mediated bactericidal assays demonstrated that B. tachyglossi is highly susceptible to human innate immunity, indicating it is unlikely to be pathogenic. Molecular surveys of wildlife-associated ticks revealed a broad diversity of reptile-associated Borrelia species in monitor lizards and snakes, reinforcing the hypothesis that Australian Borrelia persist in host-specific enzootic cycles. Our findings confirm that Borrelia species in Australia belong exclusively to the relapsing fever and reptile-associated clades, with no evidence of B. burgdorferi sensu lato. These results improve our understanding of Borrelia diversity in Australia and highlight the need for further research into their ecology, vector competence, and evolutionary history.

Biting midges (Culicoides spp.) are important vectors of several insect borne arboviruses but are underrepresented in terms of availability of high-resolution genomic resources. We assembled and annotated complete mitochondrial genomes for two Culicoides species, namely C. brevitarsis and C. imicola which are proven vectors for Bluetongue Virus (BTV). We used both long read and short read sequencing technologies to assemble the circular genomes. The genome sizes are 17,100 bp and 17,031 bp, respectively, all comprising 37 genes, including 13 protein, 22 tRNA, two rRNA coding genes, and one non-coding AT rich control region. The gene organizations and orientations are comparable to other available Culicoides mitogenomes, except for a translocation of ND2 and six tRNA genes in both C. brevitarsis and C. imicola. Eleven protein-coding genes encode a full TAA stop codon, while two (ND5, COX3) are completed by mRNA polyadenylation. Phylogenetic analysis of the mitogenomes showed C. brevitarsis and C. imicola form a monophyletic group. The sequences of these mitogenomes contribute to a baseline of molecular tools for diagnostics and surveillance for use by World Organisation for Animal Health (WOAH) reference laboratories for monitoring vectors of emerging diseases.