Snapshot of the Phylogenetic Relationships among Avian Poxviruses Circulating in Portugal between 2017 and 2023

Simple Summary Avipoxvirus, the causative agent of avian pox disease, can infect more than 278 species of wild and domestic birds. It causes multiple negative consequences for both the economy and the ecosystem. These include reduced egg production, reduced mating success, growth retardation, and occasionally death. Several diagnostic methods are currently available, and prevention is mainly performed by implementing sanitary measures and vaccination. In order to evaluate and characterize the Avipoxviruses circulating in Portugal between 2017 and 2023, ten samples positive for this virus were analyzed. They were then compared with other isolates from other hosts, countries, and years of collection. As a result, it was possible to understand that certain variants of the virus continued to circulate over the years despite the introduction of new viruses.Abstract Avipoxvirus (APV), a linear dsDNA virus belonging to the subfamily Chordopoxvirinae of the family Poxviridae, infects more than 278 species of domestic and wild birds. It is responsible for causing avian pox disease, characterized by its cutaneous and diphtheric forms. With a high transmission capacity, it can cause high economic losses and damage to the ecosystem. Several diagnostic methods are available, and bird vaccination can be an effective preventive measure. Ten APV-positive samples were analyzed to update the molecular characterization and phylogenetic analysis of viruses isolated in Portugal between 2017 and 2023. A P4b gene fragment was amplified using a PCR, and the nucleotide sequence of the amplicons was determined using Sanger sequencing. The sequences obtained were aligned using ClustalW, and a maximum likelihood phylogenetic tree was constructed. With this study, it was possible to verify that the analyzed sequences are distributed in subclades A1, A2, B1, and B3. Since some of them are quite similar to others from different countries and obtained in different years, it is possible to conclude that there have been several viral introductions in Portugal. Finally, it was possible to successfully update the data on Avipoxviruses in Portugal.