Anna Salvaggiulo

Bluetongue virus serotype 5 (BTV-5) was detected in Sardinia in 2025, representing the first documented occurrence of this serotype in Europe. Following the initial identification and development of BTV-5-specific diagnostic tools, we examined its epidemiological trajectory through 2026. Molecular and serological data generated within Italian bluetongue surveillance were analysed together with outbreak-level information from Sardinia and compared with the historical trajectory of BTV-3 on the island. From October 2025 to September 2026, 1310 diagnostic samples were tested for BTV-5 at the National Reference Laboratory for Bluetongue; 169 samples from Sardinia were positive in 2025 and four in 2026, whereas no positives were detected among samples referred from the rest of Italy. The 2026 transmission season is still ongoing at the time of writing, and the 2026 figures should be therefore considered preliminary. Regional molecular surveillance in Sardinia detected BTV-5 in 114 BTV-positive samples in 2025 and three in 2026. In 2025, a total of 105 BTV-5 outbreaks affecting 33 municipalities were confirmed, followed by two outbreaks in 2026. These data document substantial local transmission in 2025 and further detection in 2026, with no evidence of broad geographical expansion. The previous non-linear course of BTV-3 in Sardinia cautions against interpreting low activity in a single season as evidence of disappearance and supports continued molecular, genomic, and epidemiological surveillance.

Bluetongue virus (BTV) is a segmented RNA virus capable of genome reassortment during co-infection. We characterized genome constellations recovered after co-infection of Vero cells with western BTV-1 and eastern BTV-16 strains followed by three serial passages. Of 157 plaques, 46 showed simultaneous detection of BTV-1 and BTV-16 Seg-2 and were excluded because a single parental background could not be established. Among 111 Seg-2-monotypic plaques, 20 were identified as reassortants, representing 18.0% of the evaluable plaques and 12.7% of all plaques collected. Across the 20 recovered reassortants, 111 of 200 segment assignments derived from BTV-1 and 89 from BTV-16. BTV-1-derived Seg-7 was observed in 18 of 20 plaques and BTV-16-derived Seg-3 in 14 of 20 plaques; 18 distinct genome constellations were observed. Because all plaques originated from a single co-infection and were sampled after three serial passages without parallel single-virus passage controls, the observed segment distributions integrate reassortment and post-reassortment selection and cannot separate these processes. These data demonstrate recovery of diverse BTV-1/BTV-16 reassortant genomes under the experimental conditions but do not establish the true reassortment frequency or reproducible segment-association patterns.

Historically considered accidental hosts of influenza A viruses, domestic cats (Felis catus) have gained attention during the global expansion of highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b. In addition to traditional exposure via predation on infected wild birds, recent outbreaks have highlighted novel transmission routes, including contaminated commercial raw poultry products and unpasteurised milk. The susceptibility of cats has been linked to the abundant distribution of α-2,3-linked sialic acid receptors in both the respiratory tract and the central nervous system, while adaptive mutations such as PB2-E627K may enhance viral replication efficiency in mammalian hosts. Clinical disease is characterised by severe respiratory, neurological, and ocular manifestations, including acute bilateral amaurosis, and is associated with high mortality rates. Recent documentation of feline-associated zoonotic transmission highlights the importance of surveillance and infection control measures in veterinary settings. Early recognition of compatible clinical syndromes, combined with rapid molecular diagnosis and appropriate biosafety measures, is essential for case management and risk mitigation. This review summarises current insights into the epidemiology, pathogenesis, clinical presentation, diagnosis, and One Health implications of H5N1 infection in domestic cats.

Antimicrobial resistance (AMR) represents a significant global concern, undermining the efficacy of treatments in both human and veterinary medicine. Livestock production plays a major role in the emergence and dissemination of AMR, primarily due to the extensive use of antibiotics for therapeutic, prophylactic, and metaphylactic purposes. Addressing this multifaceted issue necessitates a One Health approach. At the international level, regulatory frameworks are predominantly non-binding, relying on soft-law instruments developed by the World Health Organization (WHO), the Food and Agriculture Organization (FAO), and the World Organization for Animal Health (WOAH, formerly OIE), which advocate for harmonized guidelines and national action plans. In contrast, the European Union has implemented binding regulations, including Regulation (EU) 2019/6 and Regulation (EU) 2019/4, which restrict non-essential antimicrobial use (AMU) and reinforce veterinary accountability. Initiatives such as the Farm to Fork Strategy and platforms like ClassyFarm further advance antimicrobial stewardship by integrating animal welfare, sustainability, and access to EU funding. Achieving substantial reductions in AMR within livestock systems requires coordinated, cross-disciplinary, and multi-level governance efforts. The EU model illustrates how enforceable legal frameworks, combined with science-based monitoring and welfare incentives, can facilitate prudent antibiotic use and promote sustainable animal production. This review aims to provide an integrated overview of international and European strategies for regulating antibiotic use in food-producing animals, focusing on how scientific, veterinary and legal perspectives contribute to combating AMR and promoting animal welfare by emphasizing prevention, and a prudent and responsible AMU.

Group A rotaviruses (RVAs) are a major cause of acute dehydrating diarrhea in infants and young animals worldwide. In rabbits, RVAs are associated with enteric disease, likely in combination with other pathogens. We report the identification and characterization of a lapine RVA strain in an Italian rabbit breeding farm. Increased mortality rates associated with enteric symptoms were reported in the facility in post-weaning rabbits around 40 days of age. By quantitative RT-PCR, an RVA strain was identified in the intestinal contents of deceased rabbits. A PCR-based enrichment protocol coupled with Nanopore sequencing allowed the reconstruction of the nearly complete genome of a rabbit RVA strain, Rabbit-wt/ITA/36-9/2022/G3P[14], with a genotype constellation (G3-P[14]-I2-R2-C2-M3-A9-N2-T6-E5-H3) conserved among lapine RVAs. Each of the 11 gene segments displayed high nucleotide identity and phylogenetic clustering with lapine rotavirus strains, as well as two Belgian human G3P[14] strains, which had been shown to have a zoonotic (lapine) origin. However, the NSP2 gene of strain 36-9 clustered closer with a group of rare human G3P[9] strains, suggesting a common path during their evolution. Gathering sequence data on animal RVAs is pivotal to reconstructing the history of homologous and heterologous RVAs in various mammals, including humans.

Kobuviruses (KoVs) are a group of small, non-enveloped RNA viruses classified in the genus Kobuvirus within the Picornaviridae family, comprising Aichivirus species A to F. KoVs have been identified in humans and several mammals, including domestic ungulates. This study investigated the presence of KoVs in a collection of bovine stool samples (n = 38) obtained from animals with enteritis or without clinical signs. By RT-PCR screening, KoV RNA was detected in 10/38 animals (26.3%). Six of the ten positive animals had enteric signs. On sequence analysis of the amplicons, eight strains were related to species Aichivirus B, commonly identified in cattle. In contrast, two strains (ITA/2019/572-1 and ITA/2020/bovine/30-2), displayed the highest nt identity (up to 97.1%) to cattle, yak, and goat Aichivirus D strains. On whole genome analysis, strains ITA/2019/572-1 and ITA/2020/30-2 showed 88.9% nt identity to each other and 87.8–90.3% nt to the bovine kobuvirus strain CHN/2021/ON730709 identified in China. Interestingly these three Aichivirus D strains showed a recombinant makeup, clustering with D1 genotype in the capsid region and with D2 genotype in the non-structural genes. These findings suggest that Aichivirus D KoVs are common components of livestock virome. Understanding the genetic diversity of KoVs in animals will be useful to improve the diagnostics and gather epidemiological data.