Detection of epizootic hemorrhagic disease virus in Culicoides captured in Idanha-a-Nova, Castelo Branco, Portugal

Resumo

Epizootic hemorrhagic disease (EHD), transmitted to domestic and wild ruminants by female Culicoides midges, is associated with high morbidity, mortality, and significant economic losses. In 2022, the disease was detected in Europe for the first time, in Italy and southern Spain. During an outbreak in Portugal (September-November 2023), Culicoides midges were collected in Idanha-a-Nova, Castelo Branco district, to evaluate the presence of the EHD virus in these vectors. The virus was detected in 13 of the 19 pools of biting midges analyzed (68.42%), indicating a high prevalence. Intra-herd morbidity ranged from 0.60% and 51.42%, with a mean value of 11.34%, while mortality reached a maximum of 3.75%, with a mean value of 1.05%, which is in agreement with the frequencies observed in other European countries. Eight of the 21 inquired producers (38.10%) used insecticides until two months prior to the appearance of the first clinical signs. These results highlight the importance of systematic monitoring of Culicoides midges in epidemiological surveillance, contributing to the early detection and control of EHD.