The global rise in antimicrobial resistance (AMR) has intensified calls for responsible antimicrobial use in livestock farming, including the Australian pork industry. While stewardship efforts largely focus on husbandry and biosecurity, the routine inclusion of antimicrobials in chilled boar semen extenders used for artificial insemination remains relatively underexamined. Despite widespread use, international studies consistently report bacteriospermia in extended semen, raising concerns regarding the efficacy of current practices and their contribution to AMR development. Australia’s closed-herd system provides a unique opportunity to investigate bacterial dynamics within a contained environment; however, the seminal microbiota and associated AMR profiles remain poorly characterised. This review synthesises evidence from peer-reviewed literature, industry reports, and international guidelines to critically examine the composition of boar seminal microbiota, sources of bacterial contamination, and environmental influences on bacterial load. It explores the impacts of bacteriospermia on sperm quality and fertility, and it critically evaluates the rationale for antimicrobial inclusion in semen extenders, including commonly used agents such as gentamicin and neomycin and, in some cases, critically important antimicrobials like ceftiofur and enrofloxacin. Emerging non-antibiotic alternatives, including natural antimicrobials, nanoparticles, and probiotics, are discussed in the context of their feasibility and potential role in reducing AMR risk.

Parasitic helminths are a major constraint on livestock production worldwide, with significant implications for food security and animal and human health. As reliance on conventional anthelmintic drugs becomes increasingly unsustainable due to widespread anthelmintic resistance, chemical residues, and environmental concerns, there is an urgent need for innovative, biologically derived alternatives such as polyunsaturated fatty acids (PUFAs). This review evaluates PUFAs as biologically derived agents that could complement or partially replace conventional dewormers. We integrate molecular, cellular, and in vivo evidence showing that PUFAs exert dual actions: (i) direct effects on parasites, including membrane destabilization, redox dysregulation, and metabolic interference, and (ii) host-directed effects via immune modulation, resolution of inflammation, and tissue repair mediated by specialized pro-resolving lipid mediators. We examine dietary and feed-based sources, discuss the limitations of bioavailability and oxidative stability, and review emerging delivery technologies and bioengineering solutions. Framed within One Health, PUFA-based strategies could reduce chemical inputs, lower residues in food and the environment, and enhance resilience in production systems. Curren barriers include dosage optimization, understanding pharmacokinetics and mechanisms of actions, and generating robust field data. Overall, PUFA-based strategies represent a promising frontier in sustainable parasitology, offering a holistic approach to managing parasitic diseases across species and ecosystems.

Anthelmintic resistance (AR) in canine parasitology is rapidly emerging as a significant health challenge. Growing reports of multidrug resistance in the canine hookworm Ancylostoma caninum, as well as macrocyclic lactone resistance in the heartworm Dirofilaria immitis, and isolated cases in Dipylidium caninum, highlight the increasing importance of AR. Unlike livestock, AR in dogs develops under different dynamics, shaped by unique epidemiological and biological features, including lower treatment frequencies, smaller parasite populations, and distinct husbandry practices. Nevertheless, frequent prophylactic deworming, widespread use of fixed-dose combinations, and intense drug exposure in environments such as kennels create strong selection pressures that may accelerate resistance. Treatment failures in clinical settings, particularly among greyhounds and shelter dogs, suggest canine parasitology is entering the same ‘resistance crisis’ faced in production animals. This paper comprehensively reviews current evidence on AR in canine helminths, covering geographical distribution, mechanistic insights, and diagnostic methods. We highlight the applications and limitations of AR-detecting assays and discuss advances in molecular diagnostics, including polymerase chain reaction and next-generation sequencing. Overall, the evidence demonstrates that AR in canine parasitology is no longer anecdotal but an emerging issue, demanding improved diagnostics, targeted therapies, and judicious drug use to preserve treatment efficacy and mitigate broader health risks.

Antimicrobial resistance (AMR) is a global threat, and responsible antimicrobial use (AMU) in animals is crucial. However, AMR development is influenced by numerous factors. This scoping review aims to describe the association between AMR, AMU, and other risk factors in European livestock farms. Understanding the impact of different risk factors is essential for mitigating AMR. The results confirm that the AMR prevalence varies between livestock farms and that AMU affects this prevalence. At herd level, factors related to infection pressure and AMU have been predominantly studied and are often associated with AMR. Only a few other factors such as temperature and metals or disinfectants in the farm environment have been investigated. Overall, the associations between AMR and the studied farm level. Risk factors, including AMU, were variable and complex. The studies varied in their methodological approaches. Different AMR indicators were used, with phenotypic resistance in indicator Escherichia coli being most common, and resistome characterisation gaining interest in recent years. Some studies did not include AMU data or had insufficiently detailed data, while some calculated treatment incidences in different ways. Standardised measures for risk factors and outcome variables would facilitate comparisons between studies and meta-analyses. For deeper insights into resistance dynamics, resistome characterisation is preferable, whereas phenotypic characterisation of pathogenic bacteria is more appropriate for developing clinical guidelines, and resistance profiles in indicator bacteria are useful for monitoring. In conclusion, farm-level risk factors are complex and risk factor studies including AMU, using validated methods, sufficient sample sizes, and sound statistical analyses are still needed.

The adaptive evolution of influenza A virus is strongly influenced by the functional balance between its two major surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA). Although previous studies have demonstrated the importance of HA/NA interplay in receptor binding, virion release, cross-host transmission, and antiviral resistance, most have focused on individual proteins, specific residues, or discrete stages of infection. Consequently, how HA/NA functional balance responds to selective pressures and contributes to viral adaptive evolution remains incompletely understood. Here, we propose a dynamic ‘balance–imbalance–rebalance’ framework centred on the coordination between HA-mediated receptor binding and NA-mediated receptor cleavage. We systematically examine how HA/NA functional balance influences viral attachment, release, and transmission, cross-species adaptation, pathogenicity, immune escape, and antiviral resistance. We further discuss how changes in receptor availability, immune pressure, and antiviral selection may disrupt a pre-existing HA/NA balance and how coordinated changes in HA and NA may compensate for these perturbations to establish new adaptive states. Future studies integrating structural biology, virology, animal models, and large-scale evolutionary analyses will be essential for quantitatively defining the molecular principles and adaptive boundaries of HA/NA coevolution, thereby improving our ability to assess the evolutionary potential and cross-host transmission risk of emerging influenza viruses.

The North American bison is a keystone species of immense ecological, cultural, and economic importance, yet its long-term stability is increasingly threatened by infectious diseases such as mycoplasmosis caused by Mycoplasma bovis. First recognized in bison in the late 1990s, this disease differs substantially from its presentation in cattle, where M. bovis typically acts as a secondary opportunist. In bison, however, it has emerged as a primary pathogen, causing severe morbidity and mortality within herds, imposing significant economic losses on producers, and jeopardizing conservation and restoration efforts. Despite its profound impact on herd health and sustainability, progress in understanding M. bovis infection in bison has been steady but limited. Major gaps persist in epidemiology, pathogenesis, diagnostic capacity, and effective control strategies. This review synthesizes the current state of knowledge on bison mycoplasmosis, drawing from peer-reviewed literature, government reports, and field management experiences. It addresses epidemiology, clinical and pathological features, diagnostic approaches, and current management strategies. Finally, it highlights key knowledge gaps and outlines future research priorities. The overarching goal is to provide a comprehensive, evidence-based resource for researchers, veterinarians, wildlife managers, producers, and policymakers, while underscoring the urgent need for targeted research to mitigate the threat of M. bovis to North American bison.