The highly virulent Newcastle disease virus (NDV) isolates typically result in severe systemic pathological changes and high mortality in Newcastle disease (ND) illness, whereas avirulent or low-virulence NDV strains can cause subclinical disease with no morbidity and even asymptomatic infections in birds. However, understanding the host’s innate immune responses to infection with either a highly virulent strain or an avirulent strain, and how this response may contribute to severe pathological damages and even mortality upon infection with the highly virulent strain, remain limited. Therefore, the differences in epigenetic and pathogenesis mechanisms between the highly virulent and avirulent strains were explored, by transcriptional profiling of chicken embryonic visceral tissues (CEVT), infected with either the highly virulent NA-1 strain or the avirulent vaccine LaSota strain using RNA-seq. In our current paper, severe systemic pathological changes and high mortality were only observed in chicken embryos infected with the highly virulent NA-1 strains, although the propagation of viruses exhibited no differences between NA-1 and LaSota. Furthermore, virulent NA-1 infection caused intense innate immune responses and severe metabolic disorders in chicken EVT at 36 h post-infection (hpi), instead of 24 hpi, based on the bioinformatics analysis results for the differentially expressed genes (DEGs) between NA-1 and LaSota groups. Notably, an acute hyperinflammatory response, characterized by upregulated inflammatory cytokines, an uncontrolled host immune defense with dysregulated innate immune response-related signaling pathways, as well as severe metabolic disorders with the reorganization of host–cell metabolism were involved in the host defense response to the CEVT infected with the highly virulent NA-1 strain compared to the avirulent vaccine LaSota strain. Taken together, these results indicate that not only the host’s uncontrolled immune response itself, but also the metabolic disorders with viruses hijacking host cell metabolism, may contribute to the pathogenesis of the highly virulent strain in ovo.

We have characterized in this study 10 PPMV-1 isolated from domestic pigeons and one PPMV-1 isolated from a feral pigeon in the period 2007–2012, using both classical methods (HI test and ICPI test) and molecular methods (RT-qPCR, RT-PCR, and nucleotide sequencing). Using phylogenetic analysis of partial fusion gene sequences, these viruses clustered with recent European PPMV-1 isolates (EU/re) within the genotype VIb/1. All isolates possessed virulent cleavage site motifs with variable morbidity and mortality in pigeons. The intracerebral pathogenecity indices of the five isolates ranged from 0.59 to 1.53. The repetitive isolation of PPMV-1 viruses for several consecutive years led toward establishing enzootic presence of the disease in pigeons. A high nucleotide sequence homology between the Macedonian isolates and EU/re isolates was shown. Co-circulation of different isolates in the same holdings was detected. This is the first study to extensively describe the molecular epidemiology of PPMV-1 isolated in Macedonia. Caracterización y epidemiología de Paramyxovirus de paloma tipo 1 (PPMV-1) aislados en Macedonia. En este estudio se caracterizaron diez paramixovirus de paloma tipo 1 (con las siglas en inglés PPMV-1) aislados de palomas domésticas y un paramixovirus PPMV-1 aislado de una paloma silvestre en el período comprendido entre los años 2007-2012 utilizando métodos clásicos (prueba de inhibición de hemaglutinación y el índice de patogenicidad) y métodos moleculares (transcripción reversa y reacción en cadena de la polimerasa cuantitativa, transcripción reversa y reacción en cadena de la polimerasa y secuenciación de nucleótidos). Mediante el análisis filogenético de las secuencias parciales de los genes de fusión, estos virus se agruparon con los aislamientos europeos recientes de PPMV-1 (EU/re) dentro del genotipo VIb/1. Todos los aislamientos mostraron secuencias motivo del tipo virulento en el sitio de disociación con morbilidad y mortalidad variables en las palomas. Los índices de patogenia intracerebral de los cinco aislamientos variaron de 0.59 a 1.53. El aislamiento repetido de los virus PPMV-1 durante varios años consecutivos condujo a establecer la presencia enzoótica de la enfermedad en las palomas. Se demostró una alta similitud genética en las secuencia de nucleótidos entre los aislados macedonios y los aislados UE/re. Se detectó la co-circulación de diferentes aislamientos en las mismas explotaciones. Este es el primer estudio que describe ampliamente la epidemiología molecular de los paramixovirus de paloma tipo 1 aislados en Macedonia.

β-lactamases are a diverse class of enzymes produced by bacteria that present a major cause for resistance to β-lactams. In this study we analysed 159 fecal samples from dairy cows, for the presence of presumptive ESBL, AmpC, and carbapenemase-producing E. coli. Phylotyping was done using Clermont phylo-typing method, targeting arpA, ChuA, and YjaA genes, along with the DNA fragment TspE4.C2. Convetional PCR method was used to confirm the presence of bla genes among 39 phenotypically confirmed ESBL producing E. coli. The results showed presence of CTX-M, SHV, TEM and OXA1 bla genes in 28 (71.79%), 1 (2.56%), 29 (74.35%), 2 (5.12%) of isolates, respectively Twenty (51.28%) isolates showed presence of both blaCTX-M and TEM genes. The strain that carried the blaSHV gene was found to carry blaTEM gene as well, while one of the strains that carried blaOXA1 gene was also carrying blaCTX-M and TEM gene. The ration between isolates and phylo-groups was as follows: 9 (23.07%) strains were assigned to phyllo-group D; 14 (35.89%) to phyllo-group B; 16 (41.02%) to phyllo-group A. Out of the 39 strains where bla genes were identified, 29 (74.35%) were categorized as multi drug resistant.

Newcastle disease virus (NDV) continues to present a significant challenge for vaccination due to its rapid evolution and the emergence of new variants. Although molecular and sequence data are now quickly and inexpensively produced, genetic distance rarely serves as a good proxy for cross-protection, while experimental studies to assess antigenic differences are time consuming and resource intensive. In response to these challenges, this study explores and compares several machine learning (ML) methods to predict the antigenic distance between NDV strains as determined by hemagglutination-inhibition (HI) assays. By analyzing F and HN gene sequences alongside corresponding amino acid features, we developed predictive models aimed at estimating antigenic distances. Among the models evaluated, the random forest (RF) approach outperformed traditional linear models, achieving a predictive accuracy with an R² value of 0.723 compared to only 0.051 for linear models based on genetic distance alone. This significant improvement demonstrates the usefulness of applying flexible ML approaches as a rapid and reliable tool for vaccine selection, minimizing the need for labor-intensive experimental trials. Moreover, the flexibility of this ML framework holds promise for application to other infectious diseases in both animals and humans, particularly in scenarios where rapid response and ethical constraints limit conventional experimental approaches.

Mycoplasma hyopneumoniae (Mhyo) is primary pathogen involved in porcine respiratory diseases complex (PRDC). The objective of this study was to evaluate Mycoplasma hyopneumoniae (Mhyo) infection in five commercial pig farms by using serology and lung lesion scoring at slaughter. Five Macedonian pig herds with a history of respiratory diseases were included in the study. Blood samples were taken from pigs at 6, 10, 14, 18, and 22 weeks of age. Ten animals per age group from each farm were sampled and tested for antibodies to Mhyo. At abattoir, 50 lungs per farm were scored for lesions associated with enzootic pneumonia (EP). All farms were seropositive to Mhyo. Higher seroprevalence to Mhyo was observed in grower and finisher pigs, while significant difference (p10) were found among some of the farms (p<0.001). In conclusion, high seroprevalence to Mhyo in finishing pigs in most of the farms was most likely due to vaccination. Farms with higher seroprevalence to Mhyo obtained lower LLS. Serology monitoring of different pig categories and lung assessment at slaughterhouse is a practical tool for assessing vaccine efficacy of Mhyo in pig farms.

Influenza D virus (IDV), an emerging orthomyxovirus with zoonotic potential, infects diverse hosts, causes respiratory disease, and remains poorly characterized in China despite its global expansion. From October 2023 to January 2025, we collected 563 nasal swabs from cattle across 28 farms in Jilin Province, Northeast China, and identified seven IDV-positive samples (1.2%), recovering two viable isolates (JL/YB2024 and JL/CC2024). Full-genome sequencing revealed complete, stable seven-segment genomes with high nucleotide identity (up to 99.9%) to contemporary Chinese D/Yamagata/2019 strains and no evidence of reassortment. Maximum-likelihood and time-resolved Bayesian phylogenies of 231 global hemagglutinin-esterase-fusion (HEF) sequences placed the Jilin isolates within the East Asian D/Yamagata/2019 clade and traced their most recent common ancestor to approximately 2017 (95% highest posterior density: 2016–2018), suggesting a cross-border introduction likely associated with regional cattle movement. No IDV was detected in parallel surveillance of swine, underscoring cattle as the principal reservoir and amplifying host. Bayesian skyline analysis demonstrated a marked decline in global IDV genetic diversity during 2020–2022, coinciding with livestock-movement restrictions imposed during the COVID-19 pandemic. Collectively, these findings indicate that IDV circulation in China is sporadic and geographically localized, dominated by the D/Yamagata/2019 lineage, and shaped by multiple independent incursions rather than a single emergence. Both the incorporation of IDV diagnostics into routine bovine respiratory disease surveillance and cattle-import quarantine programs, and the adoption of a One Health framework to monitor potential human spillover and future viral evolution, were recommend.