Highly Virulent Newcastle Disease Virus in Eurasian Collared Doves in the North of Portugal.

Newcastle disease (ND), caused by avian orthoavulavirus 1 (AOAV-1), poses a global threat to poultry and wild birds. In early 2025, an outbreak of pigeon paramyxovirus type 1 (PPMV-1, genotype VI AOAV-1) was detected in a wildlife rehabilitation centre in northern Portugal, affecting Streptopelia decaocto, Streptopelia risoria, and Columba livia. Birds showed acute neurological signs and died rapidly. Necropsy revealed brain and pulmonary congestion, splenomegaly, and cloacal lesions, while histopathology demonstrated hepatocellular necrosis, hemorrhage, and eosinophilic intracytoplasmic inclusions in hepatocytes and renal tubular cells. Matrix (M) gene PCR using standard primers was negative, but metagenomic sequencing identified genotype VI as being closely related to strains from Iran and Cyprus. Partial fusion (F) gene analysis revealed the velogenic RRQKRF motif. These findings confirm the circulation of highly virulent PPMV-1 in Portugal, highlight that standard, recommended primers may fail to detect some genetically diverse strains, and emphasize the role of Columbidae as reservoirs with potential transmission to domestic poultry.