The Emergence of Bluetongue Virus Serotype 3 in Portugal (2024)

In September 2024, bluetongue virus serotype 3 (BTV-3) was first identified in Portugal, specifi-cally in the Alentejo region (Évora District), using molecular diagnostic methods. The initial case involved a sheep exhibiting severe clinical symptoms, including head oedema, prostration, nasal discharge, and significant respiratory distress. A subsequent case was documented in another sheep from a different farm within the same district, which presented with high fever (41.5°C), nasal discharge, and arthritis, ultimately resulting in mortality. Within one month of these initial detections, additional cases in both sheep and cattle were reported in neighboring districts, indi-cating the virus rapid spread within the region. In response to this emerging threat, extensive monitoring efforts are being undertaken to delineate the distribution of BTV-3, and vaccination campaigns targeting this serotype have been initiated. These measures aim to mitigate the impact of the virus on livestock health and prevent further transmission.