Culicoides biting midges in Spain: A brief overview

BackgroundDespite the importance of some species of Culex (Melanoconion) (Diptera: Culicidae) as vectors of several arboviruses that cause diseases in humans and other animals, there are few taxonomic studies focusing on species of the subgenus, especially providing morphological keys for species identification.ResultsThirteen species of the Atratus Group of Culex (Melanoconion) were reviewed, five new species are described, and two taxonomic changes are proposed: Cx. (Mel.) exedrus Root, 1927 and Cx. (Mel.) loturus Dyar, 1925 are resurrected from synonymy with Cx. (Mel.) dunni Dyar, 1918 and Cx. (Mel.) zeteki Dyar, 1918, respectively. The Atratus Group now includes fourteen species: Cx. (Mel.) atratus Theobald, 1901; Cx. (Mel.) caribeanus Galindo & Blanton, 1954; Cx. (Mel.) columnaris Sá & Hutchings n. sp.; Cx. (Mel.) commevynensis Bonne-Wepster & Bonne, 1919; Cx. (Mel.) comptus Sá & Sallum n. sp.; Cx. (Mel.) dunni; Cx. (Mel.) ensiformis Bonne-Wepster & Bonne, 1919; Cx. (Mel.) exedrus; Cx. (Mel.) longisetosus Sá & Sallum n. sp.; Cx. (Mel.) longistylus Sá & Sallum n. sp.; Cx. (Mel.) loturus; Cx. (Mel.) spinifer Sá & Sallum n. sp.; Cx. (Mel.) trigeminatus Clastrier, 1970; and Cx. (Mel.) zeteki. Keys, descriptions and illustrations for the identification of the male, female, pupal and fourth-instar larval stages of each species are provided. The treatment of each species includes a complete synonymy, descriptions of available life stages, a taxonomic discussion, updated bionomics and geographical distribution, and a list of material examined.ConclusionsThe taxonomy of the Atratus Group of Culex (Melanoconion) is updated, including descriptions of five new species. The number of valid species is greater than the number recognized in the previous taxonomic study of the group, increasing from seven to 14 species. Distributional and bionomical data are updated. Morphology-based identification keys for females, males, fourth-instar larvae and pupae provided in this study will facilitate species identification.

Bluetongue (BT) and Epizootich Emorrhagic Disease (EHD) are two vector-borne infectious diseases that are clinically very similar. They are transmitted by insects of the genus Culicoides spp. and are caused by two RNA viruses belonging to the genus Orbivirus: the Bluetongue virus (BTV) and the epizootich emorrhagic disease virus (EHDV). These pathogens mainly affect domestic ruminants but can also infect wild ruminants, which may contribute to the spread and persistence of the infections. Although they are not zoonoses, BT and EHD have a significant impact from a sanitary, environmental, and economic perspective, representing a major risk to animal health and international trade. Infections manifest with a wide spectrum of clinical signs and lesions, which vary depending on the affected species and the viral strain. BTV and EHDV show a marked affinity for the erythrocyte membrane, a characteristic that allows them to persist for long periods in the host, actingas reservoirs with important epidemiological implications. Climate change, the increase in wild ungulate density, and the growing interaction between domestic and wildlife animals make it necessary to further investigate the transmission mechanisms and routes of spread of BTV and EHDV in order to implement early detection and control strategies. Due to its geographical position, Sicily is particularly exposed to the introduction of arboviruses from North Africa, representing one of the main gateways to the European continent. In Sicily, the main wild ruminant species is the fallow deer, present mainly in the Madonie Park (Palermo) and the Peloritani Mountains (Messina). Following the identification in 2024 of a case of BTV-8 in a fallow deer from the province of Messina, confirmed by the National Reference Centre for Exotic Animal Diseases at IZS Abruzzo and Molise, surveillance activities for BTV and EHDV were intensified during 2024–2025 in wildlife. Targeted sampling of fallow deer, wascarried out, oftenwithincullingcampaigns, in areas of the province of Messina and in the Madonie Park. Overall, 165 organ samples including lung, trachea, spleen, and lymphnodes, were collected from 65 fallow deer. Samples underwent RNA extraction and amplification by specific real-time RT-PCR for BTV and EHDV [2]. None of the analyzed samples tested positive for BTV or EHDV, suggesting that fallow deer did not represent the main reservoir of the two orbiviruses in Sicily during the period considered. These results contributed to expanding epidemiological knowledge on the circulation of BTV and EHDV in wildlife in relation to the environmental and territorial characteristics of the island, improving the understanding of virus maintenance cycles and the complex interactions among pathogens, hosts, and vectors in ecosystems with high biodiversity. This work was funded by the project GR-2021-12373930 and the project RC IZS SI 02/23.

Bluetongue (BT) is a non-contagious animal disease transmitted by midges of the Culicoides genus. The etiological agent is the BT virus (BTV) that induces a variety of clinical signs in wild or domestic ruminants. BT is included in the notifiable diseases list of the World Organization for Animal Health (OIE) due to its health impact on domestic ruminants. A total of 27 BTV serotypes have been described and additional serotypes have recently been identified. Since the 2000s, the distribution of BTV has changed in Europe and in the Mediterranean Basin, with continuous BTV incursions involving various BTV serotypes and strains. These BTV strains, depending on their origin, have emerged and spread through various routes in the Mediterranean Basin and/or in Europe. Consequently, control measures have been put in place in France to eradicate the virus or circumscribe its spread. These measures mainly consist of assessing virus movements and the vaccination of domestic ruminants. Many vaccination campaigns were first carried out in Europe using attenuated vaccines and, in a second period, using exclusively inactivated vaccines. This review focuses on the history of the various BTV strain incursions in France since the 2000s, describing strain characteristics, their origins, and the different routes of spread in Europe and/or in the Mediterranean Basin. The control measures implemented to address this disease are also discussed. Finally, we explain the circumstances leading to the change in the BTV status of France from BTV-free in 2000 to an enzootic status since 2018.