{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,24]],"date-time":"2026-10-24T03:57:19Z","timestamp":1792814239360,"version":"4.5.0"},"reference-count":37,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,4,7]],"date-time":"2026-04-07T00:00:00Z","timestamp":1775520000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Vet. Sci."],"abstract":"<jats:p>\n                    Newcastle disease (ND) is a highly contagious and economically important viral disease of poultry, caused by virulent strains of\n                    <jats:italic>Orthoavulavirus javaense<\/jats:italic>\n                    (OAVJ). In Slovenia, vaccination is mandatory in commercial poultry and selected avian species, whereas backyard and free-range flock remain largely unregulated. In January and February 2025, two unrelated backyard and free-range flock of laying hens experienced acute outbreaks with severe clinical signs, increased mortality and distinct gross necropsy findings (haemorrhages in the mucosa of the gastrointestinal tract, multifocal pale foci in the liver, atrophy to enlarged hyperaemic spleen, oophoritis and salpingitis). OAVJ was detected in cloacal, oropharyngeal, and brain samples from both outbreaks using real-time RT-qPCR. Analysis of complete fusion (F) gene revealed identical nucleotide sequences in both outbreaks, with the cleavage site motif, characteristic of velogenic strains (amino acid sequence 112RRQKR116 at the C-terminus of the F2 protein and F at residue 117, the N-terminus of the F1 protein). Further phylogenetic analysis of the F gene demonstrated that both viruses belong to class II, sub-genotype VII.1.1, showing 99.6\u2013100% identity with strains recently detected in Poland. The hemagglutinin-neuraminidase (HN) glycoprotein comprised 571 amino acids, consistent with genotype VII viruses, with several amino acid substitutions previously associated with functional relevance. These results highlight that, despite the absence of ND in Slovenia for more than three decades, local poultry populations remain highly susceptible to the introduction of the virus, especially in backyard flocks where monitoring and disease control are difficult to implement. Although a virulent virus was confirmed in both outbreaks, no further spread to other poultry holdings was detected.\n                  <\/jats:p>","DOI":"10.3389\/fvets.2026.1803248","type":"journal-article","created":{"date-parts":[[2026,4,7]],"date-time":"2026-04-07T04:20:00Z","timestamp":1775535600000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":3,"title":["A Newcastle disease outbreak in backyard and free-range poultry in Slovenia"],"prefix":"10.3389","volume":"13","author":[{"given":"Zoran","family":"\u017dlabravec","sequence":"first","affiliation":[{"name":"Institute for Poultry, Birds, Small Mammals, and Reptiles, Veterinary Faculty\/National Veterinary Institute, University of Ljubljana","place":["Ljubljana, Slovenia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Brigita","family":"Slavec","sequence":"additional","affiliation":[{"name":"Institute for Poultry, Birds, Small Mammals, and Reptiles, Veterinary Faculty\/National Veterinary Institute, University of Ljubljana","place":["Ljubljana, Slovenia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alenka","family":"Dov\u010d","sequence":"additional","affiliation":[{"name":"Institute for Poultry, Birds, Small Mammals, and Reptiles, Veterinary Faculty\/National Veterinary Institute, University of Ljubljana","place":["Ljubljana, Slovenia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aleksandra","family":"Hari","sequence":"additional","affiliation":[{"name":"Animal Health and Welfare Division, Administration for Food Safety, Veterinary Sector and Plant Protection","place":["Ljubljana, Slovenia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jo\u0161ko","family":"Ra\u010dnik","sequence":"additional","affiliation":[{"name":"Institute for Poultry, Birds, Small Mammals, and Reptiles, Veterinary Faculty\/National Veterinary Institute, University of Ljubljana","place":["Ljubljana, Slovenia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jedrt Maurer","family":"Wernig","sequence":"additional","affiliation":[{"name":"Animal Health and Welfare Division, Administration for Food Safety, Veterinary Sector and Plant Protection","place":["Ljubljana, Slovenia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Edoardo","family":"Giussani","sequence":"additional","affiliation":[{"name":"European Reference Laboratory (EURL) for Avian Influenza and Newcastle Disease, Istituto Zooprofilattico Sperimentale Delle Venezie","place":["Padua, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elisa","family":"Palumbo","sequence":"additional","affiliation":[{"name":"European Reference Laboratory (EURL) for Avian Influenza and Newcastle Disease, Istituto Zooprofilattico Sperimentale Delle Venezie","place":["Padua, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria","family":"Varotto","sequence":"additional","affiliation":[{"name":"European Reference Laboratory (EURL) for Avian Influenza and Newcastle Disease, Istituto Zooprofilattico Sperimentale Delle Venezie","place":["Padua, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Isabella","family":"Monne","sequence":"additional","affiliation":[{"name":"European Reference Laboratory (EURL) for Avian Influenza and Newcastle Disease, Istituto Zooprofilattico Sperimentale Delle Venezie","place":["Padua, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Uro\u0161","family":"Krape\u017e","sequence":"additional","affiliation":[{"name":"Institute for Poultry, Birds, Small Mammals, and Reptiles, Veterinary Faculty\/National Veterinary Institute, University of Ljubljana","place":["Ljubljana, Slovenia"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,4,7]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"126","DOI":"10.1016\/j.vetmic.2016.12.019","article-title":"Newcastle disease vaccines \u2013 a solved problem or a continuous challenge?","volume":"206","author":"Dimitrov","year":"2017","journal-title":"Vet Microbiol"},{"key":"ref2","volume-title":"Manual of Diagnostic Tests and Vaccines for Terrestrial Animals","year":"2024"},{"key":"ref3","year":""},{"key":"ref4","doi-asserted-by":"publisher","first-page":"443","DOI":"10.20506\/rst.19.2.1231","article-title":"Newcastle disease and other avian paramyxoviruses","volume":"19","author":"Alexander","year":"2000","journal-title":"Rev Sci Tech Off Int Epizoot"},{"key":"ref5","doi-asserted-by":"publisher","first-page":"73","DOI":"10.1016\/S0005-2736(03)00164-0","article-title":"Structure and function of a paramyxovirus fusion 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