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BACKGROUND: As a primary vector of bluetongue virus (BTV) in the US, seasonal abundance and diel flight activity of Culicoides sonorensis has been documented, but few studies have examined how time of host-seeking activity is impacted by environmental factors. This knowledge is essential for interpreting surveillance data and modeling pathogen transmission risk. METHODS: The diel host-seeking activity of C. sonorensis was studied on a California dairy over 3 years using a time-segregated trap baited with CO2. The relationship between environmental variables and diel host-seeking activity (start, peak, and duration of activity) of C. sonorensis was evaluated using multiple linear regression. Fishers exact test and paired-sample z-test were used to evaluate the seasonal difference and parity difference on diel host-seeking activity. RESULTS: Host-seeking by C. sonorensis began and reached an activity peak before sunset at a higher frequency during colder months relative to warmer months. The time that host-seeking activity occurred was associated low and high daily temperature as well as wind speed at sunset. Colder temperatures and a greater diurnal temperature range were associated with an earlier peak in host-seeking. Higher wind speeds at sunset were associated with a delayed peak in host-seeking and a shortened duration of host-seeking. Parous midges reached peak host-seeking activity slightly later than nulliparous midges, possibly because of the need for oviposition by gravid females before returning to host-seeking. CONCLUSIONS: This study demonstrates that during colder months C. sonorensis initiates host-seeking and reaches peak host-seeking activity earlier relative to sunset, often even before sunset, compared to warmer months. Therefore, the commonly used UV light-baited traps are ineffective for midge surveillance before sunset. Based on this study, surveillance methods that do not rely on light trapping would provide a more accurate estimate of hos

Background: Antananarivo, the capital city of Madagascar, is experiencing a steady increase in population growth. Due to the abundance of mosquito vectors in this locality, the population exposed to mosquito-borne diseases is therefore also increasing, as is the risk of epidemic episodes. The aim of the present study was to assess, in a resource-limited setting, the information on mosquito population dynamics and disease transmission risk that can be provided through a longitudinal entomological study carried out in a multi-host single site. Methods: Mosquitoes were collected every 15 days over 16 months (from January 2017 to April 2018) using six CDC-light traps in a peri-urban area of Antananarivo. Multivariable generalised linear models were developed using indoor and outdoor densities of the predominant mosquito species as response variables and moon illumination, environmental data and climatic data as the explanatory variables. Results: Overall, 46,737 mosquitoes belonging to at least 20 species were collected, of which Culex antennatus (68.9%), Culex quinquefasciatus (19.8%), Culex poicilipes (3.7%) and Anopheles gambiae sensu lato (2.3%) were the most abundant species. Mosquito densities were observed to be driven by moon illumination and climatic factors interacting at different lag periods. The outdoor models demonstrated biweekly and seasonal patterns of mosquito densities, while the indoor models demonstrated only a seasonal pattern. Conclusions: An important diversity of mosquitoes exists in the peri-urban area of Antananarivo. Some well-known vector species, such as Cx. antennatus, a major vector of West Nile virus (WNV) and Rift-Valley fever virus (RVFV), Cx. quinquefasciatus, a major vector of WNV, Cx. poicilipes, a candidate vector of RVFV and An. gambiae sensu lato, a major vector of Plasmodium spp., are abundant. Importantly, these four mosquito species are present all year round, even though their abundance declines during the cold dry season, wi

Epizootic hemorrhagic disease (EHD) virus serotype 8 (EHDV-8) emerged in Spain in autumn 2022. In this study, we aimed to (1) characterize the clinical and lesional presentation of EHDV infection in European red deer (Cervus elaphus), and (2) study the spatial spread of the virus in wild ruminants in Spain after its introduction, in 2022/2023. We confirmed EHDV infection in two clinically compatible sick red deer by PCR and detection of anti-EHDV specific antibodies. EHDV infection occurred in red deer with hyperacute to acute clinical signs and lesions associated to vascular changes leading to death of the animals. Partial sequences of variable segment 2 (VP2) and segment 5 (NS1) genes of the detected viruses had >99% nucleotide identity with EHDV-8 sequences from Tunisia and Italy. In a cross-sectional serological study of EHDV in 592 wild ruminants, mainly red deer (n=578), in southwestern Spain, we detected anti-EHDV antibodies in 37 of 592 samples (6.3%; 95% confidence interval: 4.3–8.2), all from red deer and from the localities where clinical cases of EHD were confirmed in red deer. We conclude that EHDV-8 infection causes severe EHD in European red deer. The serosurvey revealed a limited spread of EHDV-8 in Spanish wild ruminant populations in the first year of virus detection in Spain.

Dataset of the scientific article "Nestling sex and behaviour determine the host preference of insect vectors in avian nests".

Op vrijdag 8 september jongstleden is de Kamer geïnformeerd over de stand van zaken van besmettingen met blauwtongvirus (BTV) in Nederland. Met deze brief wordt de Kamer geinformeerd over de huidige situatie, de bevestiging van serotype 3, het tweede advies van de deskundigengroep dierziekten, de aanpassingen in het beleid en het vervolg.

Blauwtong (BT) is een niet-besmettelijke virusziekte bij schapen en andere herkauwers zoals runderen en geiten. De belangrijkste besmettingsroute is de beet van vliegjes (knutten) die besmet zijn met het blauwtongvirus (BTV). Zieke dieren kunnen elkaar niet direct besmetten en de ziekte is niet overdraagbaar naar de mens. Wageningen Bioveterinary Research (WBVR) verricht onderzoek naar deze ziekte.

Culicoides (Diptera: Ceratopogonidae) biting midge is a genus of small hematophagous flies that can transmit multiple disease-causing pathogens to animals and humans. In southern California, Culicoides sonorensis is the only known vector of the bluetongue virus, which is of great concern worldwide due to its rapid spread and high morbidity/mortality in ruminant animals. Investigating the diel host-seeking activity of C. sonorensis as a function of environmental conditions and exploring the overwintering mechanism of BTV will increase our knowledge of BTV transmission. It is observed that the host-seeking activity pattern of C. sonorensis varies among days and most activity starts near sunset though sometimes it starts before sunset during winter periods. The host-seeking activity pattern is influenced by weather, moon, and seasons. The relatively mild winter in southern California allows C. sonorensis to be active throughout the year, but virogenesis requires a certain temperature. Therefore, it remains unclear which mechanisms BTV is utilized for overwintering and needs further investigation. While C. sonorensis is recognized as the main vector of BTV in the southern California dairies, other Culicoides species may be important vectors of BTV to wild ruminants (e.g., bighorn sheep) in the desert regions of California. However, correct identification of these species becomes an obstacle for investigating Culicoides species-related topics in the desert area. Therefore, I develop molecular techniques combined with traditional morphological methods to identify Culicoides species in the southern California desert, which contributes to the global Culicoides taxonomy and biology. Moreover, studying the Culicoides diversity and their host preferences in the inland desert area of southern California may shed light on the relationship between Culicoides species and hemorrhagic diseases among wild ruminants and will facilitate studies of the epizootiology of hemorrhagic disea

Culicoides (Diptera: Ceratopogonidae) biting midge is a genus of small hematophagous flies that can transmit multiple disease-causing pathogens to animals and humans. In southern California, Culicoides sonorensis is the only known vector of the bluetongue virus, which is of great concern worldwide due to its rapid spread and high morbidity/mortality in ruminant animals. Investigating the diel host-seeking activity of C. sonorensis as a function of environmental conditions and exploring the overwintering mechanism of BTV will increase our knowledge of BTV transmission. It is observed that the host-seeking activity pattern of C. sonorensis varies among days and most activity starts near sunset though sometimes it starts before sunset during winter periods. The host-seeking activity pattern is influenced by weather, moon, and seasons. The relatively mild winter in southern California allows C. sonorensis to be active throughout the year, but virogenesis requires a certain temperature. Therefore, it remains unclear which mechanisms BTV is utilized for overwintering and needs further investigation. While C. sonorensis is recognized as the main vector of BTV in the southern California dairies, other Culicoides species may be important vectors of BTV to wild ruminants (e.g., bighorn sheep) in the desert regions of California. However, correct identification of these species becomes an obstacle for investigating Culicoides species-related topics in the desert area. Therefore, I develop molecular techniques combined with traditional morphological methods to identify Culicoides species in the southern California desert, which contributes to the global Culicoides taxonomy and biology. Moreover, studying the Culicoides diversity and their host preferences in the inland desert area of southern California may shed light on the relationship between Culicoides species and hemorrhagic diseases among wild ruminants and will facilitate studies of the epizootiology of hemorrhagic disea

Bacteria are part of the insect gut system and influence many physiological traits of their host. Gut bacteria may even reduce or block the transmission of arboviruses in several species of arthropod vectors. Culicoides biting midges are important arboviral vectors of several livestock and wildlife diseases, yet limited information is available on their gut bacterial communities. Addressing this gap will help inform how these communities can be manipulated and ultimately used as novel tools to control pathogens. To assess how bacterial communities change during the life stages of lab-reared C. nubeculosus and C. sonorensis, endosymbiotic bacteria were identified using Illumina sequencing of 16S rRNA and taxonomically characterised. Analyses were conducted to determine how gut bacterial communities in adults are influenced by species identity and geographic distance among biting midge populations. Communities of the two lab-reared Culicoides species significantly changed after pupation and with maturation into 6-day-old adults. Pseudomonas, Burkholderiaceae and Leucobacter bacteria were part of a core community that was trans-stadially transmitted and found throughout their life cycle. Among field-collected biting midges, the bacterial communities were unique for almost each species. Cardinium, Rickettsia and Wolbachia were some of the most abundant bacteria in midges collected from wetlands. Only Pseudomonas was present in high relative abundance in all field-collected species. In this study, species identity, as well as geographic distance, influenced the gut bacterial communities and may partly explain known inter- and intra-species variability in vector competence. Additionally, stably associated bacterial species could be candidates for paratransgenic strategies to control vector-borne pathogens.

Depuis la réémergence du sérotype 8 de la fièvre catarrhale ovine (FCO) en France continentale en 2015, une surveillance entomologique des populations de Culicoides a été redéployée à l'échelle de la métropole entre novembre 2015 et avril 2018, complétant le réseau de piégeages déjà en place en Corse depuis 2002. Pour la saison hivernale 2017-2018, cette surveillance aura permis de déclarer 16 départements en zone saisonnièrement indemne sur des durées variables. Suite à l'arrêt de la surveillance en France continentale en avril 2018, le réseau a continué de fonctionner en Corse et au port de Sète. De plus, des missions ponctuelles de surveillance de l'espèce d'origine afrotropicale Culicoides imicola, vectrice majeure du virus de la FCO, ont eu lieu en alternance une année sur deux, dans les Pyrénées-Orientales, où l'espèce n'est plus capturée depuis 2012, et dans le Var et les Alpes-Maritimes où l'on observe une stabilité de la distribution géographique et des abondances des populations depuis l'installation de l'espèce détectée en 2003. Les données d'abondance et de distribution relevée sur le long terme dans cette zone suggèrent que cette espèce exotique pourrait avoir atteint sa limite géographique nord dans le bassin méditerranéen.

Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are the biological vectors of arboviruses of global importance in animal health. We characterized the physicochemical parameters that determine the density and composition of the main Culicoides species of veterinary interest in larval habitats of the Niayes region of Senegal. For this purpose, we combined larval and substrate sampling in the field in different habitat types with adult emergence and physicochemical analyses in the laboratory. Three major habitat types were identified, conditioning the predominant species of Culicoides and pH and the amount of organic matter were positively correlated with the abundance of larvae and emerging Culicoides, as opposed to salinity. The diversity of emerging Culicoides was positively correlated with pH while it was negatively correlated with salinity. Culicoides distinctipennis was the predominant species in the larval habitat group of freshwater lake edges. In the larval habitat group of pond and puddle edges, C. oxystoma and C. nivosus were predominant; both species were again most abundant in the larval habitat group of saltwater lake edges. These variabilities in physicochemical parameters support the distribution of different Culicoides species in different habitat groups. These results make it possible to implement effective, selective and environmental-friendly control measures but also to improve current models for estimating the abundance of adult vector populations at a local scale.

Les moucherons du genre Culicoides Latreille, sont de petits diptères nématocères et hématophages, responsables de la transmission de plusieurs agents pathogènes tels que des filaires, des protozoaires et des virus. Parmi ces virus, on trouve le virus de la fièvre catarrhale des ovins ou bluetongue (FCO ou BTV) et la maladie hémorragique épizootique (EHDV), qui touchent les ruminants domestiques et sauvages. Ainsi, les Culicoides sont considérés comme des espèces d'intérêt vétérinaire. Ces moucherons piqueurs se trouvent dans le monde entier à l'exception de l'Antarctique. En Algérie, peu d'étude aborde ces insectes ; la majorité se sont intéressées aux recensements et à l'identification des espèces. Les inventaires des espèces de Culicoides ne sont pour l'instant pas complets et la liste des espèces d'Algérie demeure par conséquent loin d'être exhaustive. En revanche, l'écologie, la chorologie et la dynamique de ces espèces restent qu'exceptionnellement étudiées en Algérie. A la lumière de ce contexte, l'objectif de cette étude est, dans un premier temps, de décrire la diversité des Culicoides dans la région du Nord-ouest algérien (Wilaya de Tiaret) et de préciser leur bioécologie. Dans un second temps, de déterminer et d'identifier la chorologie et la dynamique des populations et enfin de contribuer à modéliser et prédire la dynamique et l'abondance des espèces les plus abondantes dans la région de Tiaret, et ce, à partir des variables environnementales et climatiques. Pour ce faire, des prospections ont été menées sur neuf sites de captures à savoir : le centre équestre de Tiaret (Haras National Chaouchaoua) et des fermes agricoles d'élevages mixtes. Les captures ont été effectuées à l'aide des pièges lumineux ultra-violet placés à l'intérieur des différents bâtiments d'élevage. L'identification, à l'espèce, des spécimens capturés a été réalisée grâce à l'utilisation des clés d'identification des espèces de la région paléarctique. Les données de ce travail ont ét

Background: Reunion Island regularly faces outbreaks of bluetongue and epizootic hemorrhagic diseases, two insect borne orbiviral diseases of ruminants. Hematophagous midges of the genus Culicoides (Diptera: Ceratopogo nidae) are the vectors of bluetongue (BTV ) and epizootic hemorrhagic disease (EHDV ) viruses. In a previous study, statistical models based on environmental and meteorological data were developed for the five Culicoides species present in the island to provide a better understanding of their ecology and predict their presence and abundance. The purpose of this study was to couple these statistical models with a Geographic Information System (GIS) to pro duce dynamic maps of the distribution of Culicoides throughout the island. Methods: Based on meteorological data from ground weather stations and satellite derived environmental data, the abundance of each of the five Culicoides species was estimated for the 2214 husbandry locations on the island for the period ranging from February 2016 to June 2018. A large scale Culicoides sampling campaign including 100 farms was carried out in March 2018 to validate the model.Results:According to the model predictions, no husbandry location was free of Culicoides throughout the study period. The five Culicoides species were present on average in 57.0% of the husbandry locations for C.bolitinosMeiswinkel, 40.7% for C.enderleini Cornet & Brunhes, 26.5% for C.grahamii Austen, 87.1% for C.imicola Kieffer and 91.8% for C.kibatiensis Goetghebuer. The models also showed high seasonal variations in their distribution. During the validation process, predictions were acceptable for C.bolitinos, C.enderleini and C.kibatiensis, with normalized root mean square errors (NRMSE) of 15.4%, 13.6% and 16.5%, respectively. The NRMSE was 27.4% for C.grahamii. For C.imicola, the NRMSE was acceptable (11.9%) considering all husbandry locations except in two specific areas, the Cirque de Salazie—an inner mountainous part of the island—a

Background: Culicoides imicola (Diptera: Ceratopogonidae) is an important Afrotropical and Palearctic vector of disease, transmitting viruses of animal health and economic significance including African horse sickness and bluetongue viruses. Maternally inherited symbiotic bacteria (endosymbionts) of arthropods can alter the frequency of COI (cytochrome c oxidase subunit I) mitochondrial haplotypes (mitotypes) in a population, masking the true patterns of host movement and gene flow. Thus, this study aimed to assess the mtDNA structure of C. imicola in relation to infection with Candidatus Cardinum hertigii (Bacteroides), a common endosymbiont of Culicoides spp. Methods: Using haplotype network analysis, COI Sanger sequences from Cardinium-infected and -uninfected C. imicola individuals were first compared in a population from South Africa. The network was then extended to include mitotypes from a geographic range where Cardinium infection has previously been investigated. Results: The mitotype network of the South African population demonstrated the presence of two broad mitotype groups. All Cardinium-infected specimens fell into one group (Fisher's exact test, P = 0.00071) demonstrating a linkage disequilibrium between endosymbiont and mitochondria. Furthermore, by extending this haplotype network to include other C. imicola populations from the Mediterranean basin, we revealed mitotype variation between the Eastern and Western Mediterranean basins (EMB and WMB) mirrored Cardinium-infection heterogeneity. Conclusions: These observations suggest that the linkage disequilibrium of Cardinium and mitochondria reflects endosymbiont gene flow within the Mediterranean basin but may not assist in elucidating host gene flow. Subsequently, we urge caution on the single usage of the COI marker to determine population structure and movement in C. imicola and instead suggest the complementary utilisation of additional molecular markers.

Background: In the last two decades, recurrent epizootics of bluetongue virus and Schmallenberg virus have been reported in the western Palearctic region. These viruses affect domestic cattle, sheep, goats and wild ruminants and are transmitted by native hematophagous midges of the genus Culicoides (Diptera: Ceratopogonidae). Culicoides dispersal is known to be stratified, i.e. due to a combination of dispersal processes occurring actively at short distances and passively or semi-actively at long distances, allowing individuals to jump hundreds of kilometers. Methods: Here, we aim to identify the environmental factors that promote or limit gene flow of Culicoides obsoletus, an abundant and widespread vector species in Europe, using an innovative framework integrating spatial, population genetics and statistical approaches. A total of 348 individuals were sampled in 46 sites in France and were genotyped using 13 newly designed microsatellite markers. Results: We found low genetic differentiation and a weak population structure for C. obsoletus across the country. Using three complementary inter-individual genetic distances, we did not detect any significant isolation by distance, but did detect significant anisotropic isolation by distance on a north-south axis. We employed a multiple regression on distance matrices approach to investigate the correlation between genetic and environmental distances. Among all the environmental factors that were tested, only cattle density seems to have an impact on C. obsoletus gene flow. Conclusions: The high dispersal capacity of C. obsoletus over land found in the present study calls for a re-evaluation of the impact of Culicoides on virus dispersal, and highlights the urgent need to better integrate molecular, spatial and statistical information to guide vector-borne disease control.

Genome segmentation is mainly thought to facilitate reassortment. Here, we show that segmentation can also allow differences in segment abundance in populations of bluetongue virus (BTV). BTV has a genome consisting in 10 segments, and its cycle primarily involves periodic alternation between ruminants and Culicoides biting midges. We have developed a reverse transcription-quantitative PCR (RT-qPCR) approach to quantify each segment in wild BTV populations sampled in both ruminants and midges during an epizootic. Segment frequencies deviated from equimolarity in all hosts. Interestingly, segment frequencies were reproducible and distinct between ruminants and biting midges. Beyond a putative regulatory role in virus expression, this phenomenon could lead to different evolution rates between segments. IMPORTANCE The variation in viral gene frequencies remains a largely unexplored aspect of within-host genetics. This phenomenon is often considered to be specific to multipartite viruses. Multipartite viruses have segmented genomes, but in contrast to segmented viruses, their segments are each encapsidated alone in a virion. A main hypothesis explaining the evolution of multipartism is that, compared to segmented viruses, it facilitates the regulation of segment abundancy, and the genes the segments carry, within a host. These differences in gene frequencies could allow for expression regulation. Here, we show that wild populations of a segmented virus, bluetongue virus (BTV), also present unequal segment frequencies. BTV cycles between ruminants and Culicoides biting midges. As expected from a role in expression regulation, segment frequencies tended to show specific values that differed between ruminants and midges. Our results expand previous knowledge on gene frequency variation and call for studies on its role and conservation beyond multipartite viruses.

Bacteria are part of the insect gut system and influence many physiological traits oftheir host. Gut bacteria may even reduce or block the transmission of arboviruses in several species of arthropod vectors. Culicoides biting midges are important arboviral vectors of several livestock and wildlife diseases, yet limited information is available on their gut bacterial communities. Addressing this gap will help inform how these communities can be manipulated and ultimately used as novel tools to control pathogens. To assess how bacterial communities change during the life stages of lab-reared C. nubeculosus and C. sonorensis , endosymbiotic bacteria were identified using Illumina sequencing of 16S rRNA and taxonomically characterized. Analyses were conducted to determine how gut bacterial communities in adults are influenced by species identity and geographic distance among biting midge populations. Communities of the two lab-reared Culicoides species significantly changed after pupation and with maturation into six-day-old adults. Pseudomonas, Burkholderiaceae and Leucobacter bacteria were part of a core community that was trans-stadially transmitted and found throughout their life cycle. Among field-collected biting midges, the bacterial communities were unique for almost each species. Cardinium, Rickettsia and Wolbachia were some of the most abundant bacteria in midges collected from wetlands. Only Pseudomonas was present in high relative abundance in all field-collected species. In this study, species identity, as well as geographic distance, influenced the gut bacterial communities and may partly explain known inter- and intra-species variability in vector competence. Additionally, stably associated bacterial species could be candidates for paratransgenic strategies to control vector-borne pathogens, Bacteria are part of the insect gut system and influence many physiological traits oftheir host. Gut bacteria may even reduce or block the transmission of arboviruses in several species of arthropod vectors. Culicoides biting midges are important arboviral vectors of several livestock and wildlife diseases, yet limited information is available on their gut bacterial communities. Addressing this gap will help inform how these communities can be manipulated and ultimately used as novel tools to control pathogens. To assess how bacterial communities change during the life stages of lab-reared C. nubeculosus and C. sonorensis , endosymbiotic bacteria were identified using Illumina sequencing of 16S rRNA and taxonomically characterized. Analyses were conducted to determine how gut bacterial communities in adults are influenced by species identity and geographic distance among biting midge populations. Communities of the two lab-reared Culicoides species significantly changed after pupation and with maturation into six-day-old adults. Pseudomonas, Burkholderiaceae and Leucobacter bacteria were part of a core community that was trans-stadially transmitted and found throughout their life cycle. Among field-collected biting midges, the bacterial communities were unique for almost each species. Cardinium, Rickettsia and Wolbachia were some of the most abundant bacteria in midges collected from wetlands. Only Pseudomonas was present in high relative abundance in all field-collected species. In this study, species identity, as well as geographic distance, influenced the gut bacterial communities and may partly explain known inter- and intra-species variability in vector competence. Additionally, stably associated bacterial species could be candidates for paratransgenic strategies to control vector-borne pathogens

Depuis la réémergence du sérotype 8 de la fièvre catarrhale ovine (FCO) en France continentale en 2015, une surveillance entomologique des populations de Culicoides a été redéployée à l'échelle de la métropole entre novembre 2015 et avril 2018, complétant le réseau de piégeages déjà en place en Corse depuis 2002. Pour la saison hivernale 2017-2018, cette surveillance aura permis de déclarer 16 départements en zone saisonnièrement indemne sur des durées variables. Suite à l'arrêt de la surveillance en France continentale en avril 2018, le réseau a continué de fonctionner en Corse et au port de Sète. De plus, des missions ponctuelles de surveillance de l'espèce d'origine afrotropicale Culicoides imicola, vectrice majeure du virus de la FCO, ont eu lieu en alternance une année sur deux, dans les Pyrénées-Orientales, où l'espèce n'est plus capturée depuis 2012, et dans le Var et les Alpes-Maritimes où l'on observe une stabilité de la distribution géographique et des abondances des populations depuis l'installation de l'espèce détectée en 2003. Les données d'abondance et de distribution relevée sur le long terme dans cette zone suggèrent que cette espèce exotique pourrait avoir atteint sa limite géographique nord dans le bassin méditerranéen.

Les moucherons du genre Culicoides Latreille, sont de petits diptères nématocères et hématophages, responsables de la transmission de plusieurs agents pathogènes tels que des filaires, des protozoaires et des virus. Parmi ces virus, on trouve le virus de la fièvre catarrhale des ovins ou bluetongue (FCO ou BTV) et la maladie hémorragique épizootique (EHDV), qui touchent les ruminants domestiques et sauvages. Ainsi, les Culicoides sont considérés comme des espèces d'intérêt vétérinaire. Ces moucherons piqueurs se trouvent dans le monde entier à l'exception de l'Antarctique. En Algérie, peu d'étude aborde ces insectes ; la majorité se sont intéressées aux recensements et à l'identification des espèces. Les inventaires des espèces de Culicoides ne sont pour l'instant pas complets et la liste des espèces d'Algérie demeure par conséquent loin d'être exhaustive. En revanche, l'écologie, la chorologie et la dynamique de ces espèces restent qu'exceptionnellement étudiées en Algérie. A la lumière de ce contexte, l'objectif de cette étude est, dans un premier temps, de décrire la diversité des Culicoides dans la région du Nord-ouest algérien (Wilaya de Tiaret) et de préciser leur bioécologie. Dans un second temps, de déterminer et d'identifier la chorologie et la dynamique des populations et enfin de contribuer à modéliser et prédire la dynamique et l'abondance des espèces les plus abondantes dans la région de Tiaret, et ce, à partir des variables environnementales et climatiques. Pour ce faire, des prospections ont été menées sur neuf sites de captures à savoir : le centre équestre de Tiaret (Haras National Chaouchaoua) et des fermes agricoles d'élevages mixtes. Les captures ont été effectuées à l'aide des pièges lumineux ultra-violet placés à l'intérieur des différents bâtiments d'élevage. L'identification, à l'espèce, des spécimens capturés a été réalisée grâce à l'utilisation des clés d'identification des espèces de la région paléarctique. Les données de ce travail ont ét

Background: Reunion Island regularly faces outbreaks of bluetongue and epizootic hemorrhagic diseases, two insect borne orbiviral diseases of ruminants. Hematophagous midges of the genus Culicoides (Diptera: Ceratopogo nidae) are the vectors of bluetongue (BTV ) and epizootic hemorrhagic disease (EHDV ) viruses. In a previous study, statistical models based on environmental and meteorological data were developed for the five Culicoides species present in the island to provide a better understanding of their ecology and predict their presence and abundance. The purpose of this study was to couple these statistical models with a Geographic Information System (GIS) to pro duce dynamic maps of the distribution of Culicoides throughout the island. Methods: Based on meteorological data from ground weather stations and satellite derived environmental data, the abundance of each of the five Culicoides species was estimated for the 2214 husbandry locations on the island for the period ranging from February 2016 to June 2018. A large scale Culicoides sampling campaign including 100 farms was carried out in March 2018 to validate the model.Results:According to the model predictions, no husbandry location was free of Culicoides throughout the study period. The five Culicoides species were present on average in 57.0% of the husbandry locations for C.bolitinosMeiswinkel, 40.7% for C.enderleini Cornet & Brunhes, 26.5% for C.grahamii Austen, 87.1% for C.imicola Kieffer and 91.8% for C.kibatiensis Goetghebuer. The models also showed high seasonal variations in their distribution. During the validation process, predictions were acceptable for C.bolitinos, C.enderleini and C.kibatiensis, with normalized root mean square errors (NRMSE) of 15.4%, 13.6% and 16.5%, respectively. The NRMSE was 27.4% for C.grahamii. For C.imicola, the NRMSE was acceptable (11.9%) considering all husbandry locations except in two specific areas, the Cirque de Salazie—an inner mountainous part of the island—a

Background: Culicoides imicola (Diptera: Ceratopogonidae) is an important Afrotropical and Palearctic vector of disease, transmitting viruses of animal health and economic significance including African horse sickness and bluetongue viruses. Maternally inherited symbiotic bacteria (endosymbionts) of arthropods can alter the frequency of COI (cytochrome c oxidase subunit I) mitochondrial haplotypes (mitotypes) in a population, masking the true patterns of host movement and gene flow. Thus, this study aimed to assess the mtDNA structure of C. imicola in relation to infection with Candidatus Cardinum hertigii (Bacteroides), a common endosymbiont of Culicoides spp. Methods: Using haplotype network analysis, COI Sanger sequences from Cardinium-infected and -uninfected C. imicola individuals were first compared in a population from South Africa. The network was then extended to include mitotypes from a geographic range where Cardinium infection has previously been investigated. Results: The mitotype network of the South African population demonstrated the presence of two broad mitotype groups. All Cardinium-infected specimens fell into one group (Fisher's exact test, P = 0.00071) demonstrating a linkage disequilibrium between endosymbiont and mitochondria. Furthermore, by extending this haplotype network to include other C. imicola populations from the Mediterranean basin, we revealed mitotype variation between the Eastern and Western Mediterranean basins (EMB and WMB) mirrored Cardinium-infection heterogeneity. Conclusions: These observations suggest that the linkage disequilibrium of Cardinium and mitochondria reflects endosymbiont gene flow within the Mediterranean basin but may not assist in elucidating host gene flow. Subsequently, we urge caution on the single usage of the COI marker to determine population structure and movement in C. imicola and instead suggest the complementary utilisation of additional molecular markers.

Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are the biological vectors of arboviruses of global importance in animal health. We characterized the physicochemical parameters that determine the density and composition of the main Culicoides species of veterinary interest in larval habitats of the Niayes region of Senegal. For this purpose, we combined larval and substrate sampling in the field in different habitat types with adult emergence and physicochemical analyses in the laboratory. Three major habitat types were identified, conditioning the predominant species of Culicoides and pH and the amount of organic matter were positively correlated with the abundance of larvae and emerging Culicoides, as opposed to salinity. The diversity of emerging Culicoides was positively correlated with pH while it was negatively correlated with salinity. Culicoides distinctipennis was the predominant species in the larval habitat group of freshwater lake edges. In the larval habitat group of pond and puddle edges, C. oxystoma and C. nivosus were predominant; both species were again most abundant in the larval habitat group of saltwater lake edges. These variabilities in physicochemical parameters support the distribution of different Culicoides species in different habitat groups. These results make it possible to implement effective, selective and environmental-friendly control measures but also to improve current models for estimating the abundance of adult vector populations at a local scale.

Genome segmentation is mainly thought to facilitate reassortment. Here, we show that segmentation can also allow differences in segment abundance in populations of bluetongue virus (BTV). BTV has a genome consisting in 10 segments, and its cycle primarily involves periodic alternation between ruminants and Culicoides biting midges. We have developed a reverse transcription-quantitative PCR (RT-qPCR) approach to quantify each segment in wild BTV populations sampled in both ruminants and midges during an epizootic. Segment frequencies deviated from equimolarity in all hosts. Interestingly, segment frequencies were reproducible and distinct between ruminants and biting midges. Beyond a putative regulatory role in virus expression, this phenomenon could lead to different evolution rates between segments. IMPORTANCE The variation in viral gene frequencies remains a largely unexplored aspect of within-host genetics. This phenomenon is often considered to be specific to multipartite viruses. Multipartite viruses have segmented genomes, but in contrast to segmented viruses, their segments are each encapsidated alone in a virion. A main hypothesis explaining the evolution of multipartism is that, compared to segmented viruses, it facilitates the regulation of segment abundancy, and the genes the segments carry, within a host. These differences in gene frequencies could allow for expression regulation. Here, we show that wild populations of a segmented virus, bluetongue virus (BTV), also present unequal segment frequencies. BTV cycles between ruminants and Culicoides biting midges. As expected from a role in expression regulation, segment frequencies tended to show specific values that differed between ruminants and midges. Our results expand previous knowledge on gene frequency variation and call for studies on its role and conservation beyond multipartite viruses.

Background: In the last two decades, recurrent epizootics of bluetongue virus and Schmallenberg virus have been reported in the western Palearctic region. These viruses affect domestic cattle, sheep, goats and wild ruminants and are transmitted by native hematophagous midges of the genus Culicoides (Diptera: Ceratopogonidae). Culicoides dispersal is known to be stratified, i.e. due to a combination of dispersal processes occurring actively at short distances and passively or semi-actively at long distances, allowing individuals to jump hundreds of kilometers. Methods: Here, we aim to identify the environmental factors that promote or limit gene flow of Culicoides obsoletus, an abundant and widespread vector species in Europe, using an innovative framework integrating spatial, population genetics and statistical approaches. A total of 348 individuals were sampled in 46 sites in France and were genotyped using 13 newly designed microsatellite markers. Results: We found low genetic differentiation and a weak population structure for C. obsoletus across the country. Using three complementary inter-individual genetic distances, we did not detect any significant isolation by distance, but did detect significant anisotropic isolation by distance on a north-south axis. We employed a multiple regression on distance matrices approach to investigate the correlation between genetic and environmental distances. Among all the environmental factors that were tested, only cattle density seems to have an impact on C. obsoletus gene flow. Conclusions: The high dispersal capacity of C. obsoletus over land found in the present study calls for a re-evaluation of the impact of Culicoides on virus dispersal, and highlights the urgent need to better integrate molecular, spatial and statistical information to guide vector-borne disease control.

Los ceratopogónidos son dípteros nematóceros muy numerosos y ampliamente distribuidos por todo el mundo. Estos nematóceros presentan una importante relevancia en la propagación de enfermedades tanto en humanos como en animales, y a pesar de ello es una familia de insectos que no ha suscitado demasiado interés entre los entomólogos. Son capaces de transmitir enfermedades como la mansonelosis en humanos y el virus de la lengua azul en animales. La mansonelosis, provocada principalmente por Mansonella ozzardi, es una enfermedad que prácticamente se va a desarrollar solo en zonas endémicas y, actualmente, no existen demasiados trabajos al respecto, a pesar de las grandes discapacidades que produce. No ocurre lo mismo con el virus de la lengua azul, cuya enfermedad afecta a los animales y está clasificada entre las enfermedades de la categoría “A”, notificables a la Organización Mundial de Sanidad Animal (OIE). Conocer el ciclo biológico de estos nematóceros, así como las manifestaciones clínicas y síntomas que presentan las enfermedades que transmiten y/o producen, serán esenciales para un diagnóstico precoz y para su prevención y control, pudiendo así actuar más rápidamente y evitar mayores complicaciones. En la actualidad, los factores climáticos y los cambios que producen sus efectos, afectan a la distribución de muchos artrópodos vectores, como las especies del género Culicoides de la familia Ceratopogonidae, vector del virus de la lengua azul que ya se ha distribuido prácticamente por todo el mundo. Esto se debe principalmente a que se han creado zonas favorables para el desarrollo de este género, el que tiene una mayor capacidad vectorial, dentro de los ceratopogónidos. La investigación sobre estos determinantes ambientales, que favorecen el desarrollo y la actividad de estos insectos, será clave para prevenir y controlar el virus de la lengua azul y otras enfermedades transmitidas por especies de Culicoides. En este trabajo se contemplan estos factores para preve

Comme suite à la réémergence du sérotype 8 de la fièvre catarrhale ovine (FCO)ovine en septembre 2015, un nouveau dispositif de surveillance entomologique des populations de Culicoides a été déployé en France continentale à l'automne-hiver 2016-2017, pour la deuxième année consécutive. Cette surveillance entomologique a permis de déterminer avec succès les périodes d'inactivité vectorielle relatives aux 24 zones de piégeage définies sur le territoire continental. Les informations issues de ce dispositif couplées à une surveillance de la circulation virale ont permis de déclarer jusqu'à seize départements de la zone réglementée en zones saisonnièrement indemnes (ZSI) sur des durées variables.

Background: Culicoides biting midges are vectors involved in the biological transmission cycle of important animal diseases such as bluetongue and African horse sickness. In Romania, the first outbreaks of bluetongue were reported in 2014, leading to increased activities within the existing entomological surveillance network. The main goals of the surveillance activities were the establishment of the vector free period in relation to animal trade and the identification of Culicoides species involved in the transmission of the pathogen. This study was conducted on the composition and relative abundance of the species belonging to the genus Culicoides (Diptera: Ceratopogonidae) in certain regions of Romania and provided the opportunity to update the existing checklist of Culicoides species of this country. Methods: The study was conducted in 33 of the 42 administrative units (counties), including a total of 659 catches, in 102 locations. The collections were carried out with UV blacklight suction traps (OVI type). The collected insects were preserved in 70% ethanol. Morphological insect identification was carried out using a stereomicroscope, according to established identification keys. In ten localities the relative abundance of the cryptic species of the Obsoletus complex was determined by multiplex PCR assay based on the ITS2 segment. The identification of the Culicoides chiopterus (Meigen) species by morphological examination was confirmed by PCR assay based on the ITS1 segment. Results: Eleven species were identified using morphological and PCR tools. The rest of the individuals were separated into five taxa. The species of the Obsoletus complex (grouping Culicoides obsoletus (Meigen) and Culicoides scoticus Downes & Kettle) were the most abundant, accounting for 59% of the total number of captured Culicoides spp. Three of the identified species are mentioned, according to our knowledge, for the first time in Romania: Culicoides newsteadi Austen, Culicoides flav

This is the third in a planned series of data papers presenting modelled vector distributions produced during the ECDC and EFSA funded VectorNet project. The data package presented here includes those Culicoides vectors species first modelled in 2015 as part of the VectorNet gap analysis work namely C. imicola, C. obsoletus, C. scoticus, C. dewulfi, C. chiopterus, C. pulicaris, C. lupicaris, C. punctatus, and C. newsteadi. The known distributions of these species within the Project area (Europe, the Mediterranean Basin, North Africa, and Eurasia) are currently incomplete to a greater or lesser degree. The models are designed to fill the gaps with predicted distributions, to provide a) first indication of vector species distributions across the project geographical extent, and b) assistance in targeting surveys to collect distribution data for those areas with no field validated information. The models are based on input data from light trap surveillance of adult Culicoides across continental Europe and surrounding regions (71.8°N –33.5°S, – 11.2°W – 62°E), concentrated in Western countries, supplemented by transect samples in eastern and northern Europe. Data from central EU are relatively sparse.

Background: The Culicoides fauna of Algeria has been historically investigated, leading to the description of many new species by Kieffer in the 1920s, Clastrier in the 1950s or Callot in the 1960s and to a comprehensive inventory by Szadziewski in the 1980s. The emergence of bluetongue in the late 1990s enhanced Culicoides collections made in the country over the last two decades, but information remained mostly unpublished. The aim of this study is therefore to provide a comprehensive and updated checklist of Culicoides biting midge species in Algeria. Methods: The literature (published and grey, in French and in English) from 1920 to date on Culicoides collections in Algeria was collected and analyzed in the light of the current taxonomic and systematic knowledge and methods. Fresh Culicoides material was also analyzed using light/suction trap collections carried out from November 2015 to September 2018 in nine localities of the 'wilayah' of Tiaret (northwestern Algeria). Slide mounted specimens were identified morphologically using the interactive identification key IIKC and original descriptions. Specimens were then compared with non-type material originating from different countries and partly with type material. Results: A total of 13,709 Culicoides, belonging to at least 36 species within 10 subgenera, were examined leading to 10 new records in Algeria, including C. chiopterus, C. dewulfi, C. navaiae, C. grisescens, C. paradoxalis, C. shaklawensis, C. simulator, C. univittatus, C. achrayi and C. picturatus. These new records and all previous records provided by the literature review were discussed. Conclusions: We propose a Culicoides checklist for the Algerian fauna of 59 valid species, including species mainly with a large Palaearctic distribution and a specific Mediterranean distribution, and only a few species from the Afrotropical region. Among them, several species, mainly of the subgenera Avaritia and Culicoides, are confirmed or probable vectors of a

Background: Culicoides obsoletus is an abundant and widely distributed Holarctic biting midge species, involved in the transmission of bluetongue virus (BTV) and Schmallenberg virus (SBV) to wild and domestic ruminants. Females of this vector species are often reported jointly with two morphologically very close species, C. scoticus and C. montanus, forming the Obsoletus/Scoticus Complex. Recently, cryptic diversity within C. obsoletus was reported in geographically distant sites. Clear delineation of species and characterization of genetic variability is mandatory to revise their taxonomic status and assess the vector role of each taxonomic entity. Our objectives were to characterize and map the cryptic diversity within the Obsoletus/Scoticus Complex. Methods: Portion of the cox1 mitochondrial gene of 3763 individuals belonging to the Obsoletus/Scoticus Complex was sequenced. Populations from 20 countries along a Palaearctic Mediterranean transect covering Scandinavia to Canary islands (North to South) and Canary islands to Turkey (West to East) were included. Genetic diversity based on cox1 barcoding was supported by 16S rDNA mitochondrial gene sequences and a gene coding for ribosomal 28S rDNA. Species delimitation using a multi-marker methodology was used to revise the current taxonomic scheme of the Obsoletus/Scoticus Complex. Results: Our analysis showed the existence of three phylogenetic clades (C. obsoletus clade O2, C. obsoletus clade dark and one not yet named and identified) within C. obsoletus. These analyses also revealed two intra-specific clades within C. scoticus and raised questions about the taxonomic status of C. montanus. Conclusions: To our knowledge, our study provides the first genetic characterization of the Obsoletus/Scoticus Complex on a large geographical scale and allows a revision of the current taxonomic classification for an important group of vector species of livestock viruses in the Palaearctic region.

Background: Culicoides biting midges transmit viruses resulting in disease in ruminants and equids such as bluetongue, Schmallenberg disease and African horse sickness. In the past decades, these diseases have led to important economic losses for farmers in Europe. Vector abundance is a key factor in determining the risk of vector-borne disease spread and it is, therefore, important to predict the abundance of Culicoides species involved in the transmission of these pathogens. The objectives of this study were to model and map the monthly abundances of Culicoides in Europe. Methods: We obtained entomological data from 904 farms in nine European countries (Spain, France, Germany, Switzerland, Austria, Poland, Denmark, Sweden and Norway) from 2007 to 2013. Using environmental and climatic predictors from satellite imagery and the machine learning technique Random Forests, we predicted the monthly average abundance at a 1 km2 resolution. We used independent test sets for validation and to assess model performance. Results: The predictive power of the resulting models varied according to month and the Culicoides species/ensembles predicted. Model performance was lower for winter months. Performance was higher for the Obsoletus ensemble, followed by the Pulicaris ensemble, while the model for Culicoides imicola showed a poor performance. Distribution and abundance patterns corresponded well with the known distributions in Europe. The Random Forests model approach was able to distinguish differences in abundance between countries but was not able to predict vector abundance at individual farm level. Conclusions: The models and maps presented here represent an initial attempt to capture large scale geographical and temporal variations in Culicoides abundance. The models are a first step towards producing abundance inputs for R0 modelling of Culicoides-borne infections at a continental scale.

Morocco has suffered several outbreaks of Culicoides-borne viruses in recent decades and most studies have focused on Culicoidesimicola, considered for a long time as the only important vector. The change in bluetongue (BT) epidemiol-ogy in the Mediterranean Basin and Europe over the past two decades has high-lighted the role of other Culicoides species in BT virus transmission. The objective of this study was to provide new insights on the Culicoides species composition and seasonality in three different host environments (a horse-riding center, a goat farm and a cattle farm) around Rabat, the capital of Morocco, where BT has been endemic since 2004. Light / suction trap collections were carried out on two con-secutive nights at fortnight intervals from May 2016 to May 2017. Culicoides were identified morphologically at the species level when possible. Multivariate anal-yses were used to compare the impact of the site / vertebrate species, and the collection month on the species communities. In addition, statistical modelingwas used to identify environmental drivers of the Culicoides seasonality. A total of 12,460 Culicoides individuals belonging to at least 15 different species were col-lected during the survey. Culicoides imicola was by far the most abundant species (71.4% of total catches). The site location, and thus the vertebrate species, did not influence the species composition, which was mainly impacted by the month of collection. Surprisingly, the atmospheric pressure was the environmental param-eter the most frequently selected in seasonal models. The potential impact of this meteorological parameter along with the other selected variables is discussed. Identifying the environmental parameters driving Culicoides seasonal abundance is the first step to implementing robust Culicoides dynamic models that could later be used in transmission risk modeling.

Background: Within the genus Culicoides (Diptera: Ceratopogonidae), the subgenus Avaritia is of particular interest as it contains a significant number of economically important vector species. Disagreements about the systematic classification of species within this subgenus have resulted in a taxonomic imbroglio. Methods: A molecular phylogeny of the subgenus Avaritia was conducted to test the existing systematic classification, which is based on phenetic assessment of morphological characters. Three nuclear ribosomal markers, internal transcribed spacer 1 and 2 (ITS1, ITS2), 5.8S, and three mitochondrial markers, cytochrome c oxidase subunit 1 and 2, and cytochrome b (cox1, cox2 and cytb), were obtained for 37 species of the subgenus Avaritia from all six biogeographical regions. Phylogenetic reconstructions using these genes independently and in combination were implemented using Bayesian inference analysis and maximum likelihood methods. Results: Phylogenetic reconstructions gave strong support to several monophyletic groups within the subgenus Avaritia. Both C. actoni and C. pusillus formed a single clade with C. grahamii so their respective groups, the Actoni and Pusillus groups, have been merged with the Grahamii group. Some support was provided for the Boophagus and Jacobsoni groups. A group of species currently placed into the Orientalis group clustered in a clade with poor support. The Obsoletus group was defined as a sister clade to all other Avaritia groups. The clade including the Imicola group was well supported based on phylogenetic criteria. Conclusions: This phylogenetic study combining five distinct molecular markers has provided meaningful insights into the systematic relationships of Culicoides (Avaritia) and highlighted future directions to continue the study of this subgenus. While the cox2 marker appeared to be useful to investigate closely related species, the 5.8S marker was highly conserved and uninformative. Further investigations includin

Bluetongue is a vector-borne, viral disease of ruminants that can cause substantial losses in productivity in farmed livestock. It is transmitted by Culicoides midges (Diptera: Ceratopogonidae) which means that the geographic distribution of disease is restricted to those regions where these vectors are present. In 2006 a virulent serotype of bluetongue (BTV-8) was detected in Northern Europe causing losses of livestock with knock-on economic and welfare effects. Bluetongue virus is endemic in Northern Australia, but clinical signs of disease have not been reported in either cattle or sheep. The risk of incursion of a virulent strain of bluetongue into Australia represents a constant threat, particularly the risk imposed by infected Culicoides midges blown from Indonesia to the northern borders of the Northern Territory. This thesis reports the results of a series of studies designed to enhance Australia’s preparedness for an incursion of a virulent serotype of bluetongue. This objective was achieved by design and implementation of facilities to allow the Australian Animal Disease Simulation model (AADIS) to simulate the spread of vector-borne diseases. In Chapter 3 we developed a model to allow the spatial and temporal distribution of Culicoides spp. across Australia to be estimated as a function of ambient temperature, prevailing wind conditions and the presence of cattle. In Chapter 4 a model of bluetongue virus vector-host transmission was developed, using the simulated midge population from Chapter 3 for the source population of insect vectors and details from the National Livestock Identification Scheme for the cattle host population at risk. A novel approach in Chapter 4 was the separation of host and vector populations into two ‘layers’ of different spatial format: a raster layer for the insect vector population and a spatial vector layer (i.e. points) to represent the cattle herd population at risk. This allowed our model to be readily adapted for other ins

Bluetongue is a non-contagious viral disease affecting small ruminants and cattle that can cause severe economic losses in the livestock sector. The virus is transmitted by certain species of the genus Culicoides and consequently, understanding their distribution is essential to enable the identification of high-risk transmission areas. In this work we use bioclimatic and environmental variables to predict vector abundance, and estimate spatial variations in the basic reproductive ratio

Comme suite à la réémergence du sérotype 8 de la fièvre catarrhale ovine (FCO)ovine en septembre 2015, un nouveau dispositif de surveillance entomologique des populations de Culicoides a été déployé en France continentale à l'automne-hiver 2016-2017, pour la deuxième année consécutive. Cette surveillance entomologique a permis de déterminer avec succès les périodes d'inactivité vectorielle relatives aux 24 zones de piégeage définies sur le territoire continental. Les informations issues de ce dispositif couplées à une surveillance de la circulation virale ont permis de déclarer jusqu'à seize départements de la zone réglementée en zones saisonnièrement indemnes (ZSI) sur des durées variables.

Background: The Culicoides fauna of Algeria has been historically investigated, leading to the description of many new species by Kieffer in the 1920s, Clastrier in the 1950s or Callot in the 1960s and to a comprehensive inventory by Szadziewski in the 1980s. The emergence of bluetongue in the late 1990s enhanced Culicoides collections made in the country over the last two decades, but information remained mostly unpublished. The aim of this study is therefore to provide a comprehensive and updated checklist of Culicoides biting midge species in Algeria. Methods: The literature (published and grey, in French and in English) from 1920 to date on Culicoides collections in Algeria was collected and analyzed in the light of the current taxonomic and systematic knowledge and methods. Fresh Culicoides material was also analyzed using light/suction trap collections carried out from November 2015 to September 2018 in nine localities of the 'wilayah' of Tiaret (northwestern Algeria). Slide mounted specimens were identified morphologically using the interactive identification key IIKC and original descriptions. Specimens were then compared with non-type material originating from different countries and partly with type material. Results: A total of 13,709 Culicoides, belonging to at least 36 species within 10 subgenera, were examined leading to 10 new records in Algeria, including C. chiopterus, C. dewulfi, C. navaiae, C. grisescens, C. paradoxalis, C. shaklawensis, C. simulator, C. univittatus, C. achrayi and C. picturatus. These new records and all previous records provided by the literature review were discussed. Conclusions: We propose a Culicoides checklist for the Algerian fauna of 59 valid species, including species mainly with a large Palaearctic distribution and a specific Mediterranean distribution, and only a few species from the Afrotropical region. Among them, several species, mainly of the subgenera Avaritia and Culicoides, are confirmed or probable vectors of a

This is the third in a planned series of data papers presenting modelled vector distributions produced during the ECDC and EFSA funded VectorNet project. The data package presented here includes those Culicoides vectors species first modelled in 2015 as part of the VectorNet gap analysis work namely C. imicola, C. obsoletus, C. scoticus, C. dewulfi, C. chiopterus, C. pulicaris, C. lupicaris, C. punctatus, and C. newsteadi. The known distributions of these species within the Project area (Europe, the Mediterranean Basin, North Africa, and Eurasia) are currently incomplete to a greater or lesser degree. The models are designed to fill the gaps with predicted distributions, to provide a) first indication of vector species distributions across the project geographical extent, and b) assistance in targeting surveys to collect distribution data for those areas with no field validated information. The models are based on input data from light trap surveillance of adult Culicoides across continental Europe and surrounding regions (71.8°N –33.5°S, – 11.2°W – 62°E), concentrated in Western countries, supplemented by transect samples in eastern and northern Europe. Data from central EU are relatively sparse.

Background: Culicoides biting midges are vectors involved in the biological transmission cycle of important animal diseases such as bluetongue and African horse sickness. In Romania, the first outbreaks of bluetongue were reported in 2014, leading to increased activities within the existing entomological surveillance network. The main goals of the surveillance activities were the establishment of the vector free period in relation to animal trade and the identification of Culicoides species involved in the transmission of the pathogen. This study was conducted on the composition and relative abundance of the species belonging to the genus Culicoides (Diptera: Ceratopogonidae) in certain regions of Romania and provided the opportunity to update the existing checklist of Culicoides species of this country. Methods: The study was conducted in 33 of the 42 administrative units (counties), including a total of 659 catches, in 102 locations. The collections were carried out with UV blacklight suction traps (OVI type). The collected insects were preserved in 70% ethanol. Morphological insect identification was carried out using a stereomicroscope, according to established identification keys. In ten localities the relative abundance of the cryptic species of the Obsoletus complex was determined by multiplex PCR assay based on the ITS2 segment. The identification of the Culicoides chiopterus (Meigen) species by morphological examination was confirmed by PCR assay based on the ITS1 segment. Results: Eleven species were identified using morphological and PCR tools. The rest of the individuals were separated into five taxa. The species of the Obsoletus complex (grouping Culicoides obsoletus (Meigen) and Culicoides scoticus Downes & Kettle) were the most abundant, accounting for 59% of the total number of captured Culicoides spp. Three of the identified species are mentioned, according to our knowledge, for the first time in Romania: Culicoides newsteadi Austen, Culicoides flav

Background: Culicoides obsoletus is an abundant and widely distributed Holarctic biting midge species, involved in the transmission of bluetongue virus (BTV) and Schmallenberg virus (SBV) to wild and domestic ruminants. Females of this vector species are often reported jointly with two morphologically very close species, C. scoticus and C. montanus, forming the Obsoletus/Scoticus Complex. Recently, cryptic diversity within C. obsoletus was reported in geographically distant sites. Clear delineation of species and characterization of genetic variability is mandatory to revise their taxonomic status and assess the vector role of each taxonomic entity. Our objectives were to characterize and map the cryptic diversity within the Obsoletus/Scoticus Complex. Methods: Portion of the cox1 mitochondrial gene of 3763 individuals belonging to the Obsoletus/Scoticus Complex was sequenced. Populations from 20 countries along a Palaearctic Mediterranean transect covering Scandinavia to Canary islands (North to South) and Canary islands to Turkey (West to East) were included. Genetic diversity based on cox1 barcoding was supported by 16S rDNA mitochondrial gene sequences and a gene coding for ribosomal 28S rDNA. Species delimitation using a multi-marker methodology was used to revise the current taxonomic scheme of the Obsoletus/Scoticus Complex. Results: Our analysis showed the existence of three phylogenetic clades (C. obsoletus clade O2, C. obsoletus clade dark and one not yet named and identified) within C. obsoletus. These analyses also revealed two intra-specific clades within C. scoticus and raised questions about the taxonomic status of C. montanus. Conclusions: To our knowledge, our study provides the first genetic characterization of the Obsoletus/Scoticus Complex on a large geographical scale and allows a revision of the current taxonomic classification for an important group of vector species of livestock viruses in the Palaearctic region.

Background: Within the genus Culicoides (Diptera: Ceratopogonidae), the subgenus Avaritia is of particular interest as it contains a significant number of economically important vector species. Disagreements about the systematic classification of species within this subgenus have resulted in a taxonomic imbroglio. Methods: A molecular phylogeny of the subgenus Avaritia was conducted to test the existing systematic classification, which is based on phenetic assessment of morphological characters. Three nuclear ribosomal markers, internal transcribed spacer 1 and 2 (ITS1, ITS2), 5.8S, and three mitochondrial markers, cytochrome c oxidase subunit 1 and 2, and cytochrome b (cox1, cox2 and cytb), were obtained for 37 species of the subgenus Avaritia from all six biogeographical regions. Phylogenetic reconstructions using these genes independently and in combination were implemented using Bayesian inference analysis and maximum likelihood methods. Results: Phylogenetic reconstructions gave strong support to several monophyletic groups within the subgenus Avaritia. Both C. actoni and C. pusillus formed a single clade with C. grahamii so their respective groups, the Actoni and Pusillus groups, have been merged with the Grahamii group. Some support was provided for the Boophagus and Jacobsoni groups. A group of species currently placed into the Orientalis group clustered in a clade with poor support. The Obsoletus group was defined as a sister clade to all other Avaritia groups. The clade including the Imicola group was well supported based on phylogenetic criteria. Conclusions: This phylogenetic study combining five distinct molecular markers has provided meaningful insights into the systematic relationships of Culicoides (Avaritia) and highlighted future directions to continue the study of this subgenus. While the cox2 marker appeared to be useful to investigate closely related species, the 5.8S marker was highly conserved and uninformative. Further investigations includin

Morocco has suffered several outbreaks of Culicoides-borne viruses in recent decades and most studies have focused on Culicoidesimicola, considered for a long time as the only important vector. The change in bluetongue (BT) epidemiol-ogy in the Mediterranean Basin and Europe over the past two decades has high-lighted the role of other Culicoides species in BT virus transmission. The objective of this study was to provide new insights on the Culicoides species composition and seasonality in three different host environments (a horse-riding center, a goat farm and a cattle farm) around Rabat, the capital of Morocco, where BT has been endemic since 2004. Light / suction trap collections were carried out on two con-secutive nights at fortnight intervals from May 2016 to May 2017. Culicoides were identified morphologically at the species level when possible. Multivariate anal-yses were used to compare the impact of the site / vertebrate species, and the collection month on the species communities. In addition, statistical modelingwas used to identify environmental drivers of the Culicoides seasonality. A total of 12,460 Culicoides individuals belonging to at least 15 different species were col-lected during the survey. Culicoides imicola was by far the most abundant species (71.4% of total catches). The site location, and thus the vertebrate species, did not influence the species composition, which was mainly impacted by the month of collection. Surprisingly, the atmospheric pressure was the environmental param-eter the most frequently selected in seasonal models. The potential impact of this meteorological parameter along with the other selected variables is discussed. Identifying the environmental parameters driving Culicoides seasonal abundance is the first step to implementing robust Culicoides dynamic models that could later be used in transmission risk modeling.

Background: Culicoides biting midges transmit viruses resulting in disease in ruminants and equids such as bluetongue, Schmallenberg disease and African horse sickness. In the past decades, these diseases have led to important economic losses for farmers in Europe. Vector abundance is a key factor in determining the risk of vector-borne disease spread and it is, therefore, important to predict the abundance of Culicoides species involved in the transmission of these pathogens. The objectives of this study were to model and map the monthly abundances of Culicoides in Europe. Methods: We obtained entomological data from 904 farms in nine European countries (Spain, France, Germany, Switzerland, Austria, Poland, Denmark, Sweden and Norway) from 2007 to 2013. Using environmental and climatic predictors from satellite imagery and the machine learning technique Random Forests, we predicted the monthly average abundance at a 1 km2 resolution. We used independent test sets for validation and to assess model performance. Results: The predictive power of the resulting models varied according to month and the Culicoides species/ensembles predicted. Model performance was lower for winter months. Performance was higher for the Obsoletus ensemble, followed by the Pulicaris ensemble, while the model for Culicoides imicola showed a poor performance. Distribution and abundance patterns corresponded well with the known distributions in Europe. The Random Forests model approach was able to distinguish differences in abundance between countries but was not able to predict vector abundance at individual farm level. Conclusions: The models and maps presented here represent an initial attempt to capture large scale geographical and temporal variations in Culicoides abundance. The models are a first step towards producing abundance inputs for R0 modelling of Culicoides-borne infections at a continental scale.

Bolest plavog jezika (BPJ) je virusno nekontagiozno oboljenje domaćih i divljih preţivara, koje se preteţno javlja kod ovaca, izazvano RNK virusom iz roda Orbivirus i familije Reoviridae. Virus plavog jezika (BTV) se prenosi hematofagnim insektima iz roda Culicoides. Dinamika i širenje bolesti uslovljeno je klimatskim faktorima, meĊusobnom interakcijom virusa sa populacijom vektora i prijemĉivom populacijom domaćina. BPJ se javlja sezonski u kasnim letnjim mesecima obiĉno, kada je populacija vektora najbrojnija. Virus se u prirodi odrţava infekcijom vektora i prijemĉivih domaćina, kao što su preţivari i glodari. Virus plavog jezka (BTV) u Repulici Srbiji je kontrolisan vakcinacijom kao i u većini zemalja evropske unije (EU). Strategija borbe protiv BTV se bazira na depopulaciji obolelih ţivotinja u zaraţenim podruĉjima, najĉešće u kombinaciji sa vakcinacijom i uvoĊenjem visokih biosigurnosnih mera na farmama i u objektima u kojima se drţe ţivotinje. Primenom ovakvih mera moţe se obezbediti odsustvo bolesti većih razmera. Zbog znaĉajnog uticaja klimatskih faktora na pojavljivenje i širenje vektora bolesti, kao i samog naĉina drţanja prijemĉivih ţivotinja, ne postoji univerzalni obrazac kontrole BTV. Cilj ovog istraţivanja je da se prikaţe celokupna epizootiološka situacija u R Srbiji, nastala kao posledica pojave BPJ i da se izvrši analiza ekonomskih šteta. Osnovni cilj je razvijanje i primena stohastiĉkog modela, koji meĊusobno povezuje klimatske faktore, populaciju vektora, prijemĉive domaćine i mere intervencije, odnosno mere kontrole BPJ. Model simulira dnevno prenošenje bolesti vektorima kroz prijemĉivu populaciju, a sam intenzitet prenošenja, odnosno brojnost i vektorski kapacitet uslovljeni su klimatskim faktorima, odnosno dnevnim promenama proseĉne temperature. Za ceo ispitivani period obolelo je ukupno 2.786 ovaca, 271 grlo goveda i 25 grla koza. Od ukupnog broja obolelih uginulo je 1.272 ovce, 41 grlo goveda i 11 koza..., Bluetongue disease (BTD) is a viral, non contagious disease of domestic and wild ruminants, mainly present in sheep, caused by the RNK virus of the genus Orbivirus, family Reoviridae. Bluetongue virus (BTV) is transmitted by hematophagous insects from the genus Culicoides. The dynamics and spreading of the disease depend upon climatic factors, the interaction of the virus with the vector population and the susceptible host population. BTD is a seasonal disease, appearing mainly during the late summer months when the vector population is usually numerous. In its natural environment the virus cycle is maintained through infection of the vectors such are ruminants and rodents. BTV in the Republic of Serbia is controlled by means of vaccination, same as in the EU countries. The strategy against BTV is based upon the depopulation of the diseased animals in the infected area, most often in combination with vaccination and strict biosecurity measures on the farms and premises where the animals are housed. By applying such measures, the presence of the disease on a larger scale can be avoided. Due to the significant influence that climatic conditions have upon the vectors, and the way in which the susceptible animals are kept, there is no universal mode for BTV control. The aim of this study was to describe the complete epizootiological situation for BTD in R. Serbia, as well as to determine the economic losses. The main target was to develop and implement a stochastic model which would integrate the climate conditions, vector population, susceptible hosts and BTD control measures. The model simulates the daily disease transmission by vectors through the susceptible population, and the intensity of the transmission, as the number and vector capacity are conditioned by climate conditions i.e. daily average temperature variations...

Les élevages bovins de La Réunion connaissent régulièrement des foyers de "bavites", appellation locale des maladies causées par les virus de la fièvre catarrhale ovine (bluetongue virus, BTV) et de la maladie hémorragique épizootique (epizootic hemorragic disease virus, EHDV), deux orbivirus transmis par des moucherons hématophages du genre Culicoides (Diptera : Ceratopogonidae). Plusieurs sérotypes de ces deux orbivirus circulent sur l'île et sont responsables de pertes économiques et de dégradations de l'état sanitaire du cheptel bovin. Parmi les 5 espèces de Culicoides décrites à La Réunion, Culicoides imicola, Culicoides bolitinos, Culicoides enderleini, Culicoides grahamii, et Culicoides kibatiensis, au moins les deux premières sont vectrices du BTV et de l'EHDV aux ruminants. Dans ce contexte, il paraît important de caractériser l'écologie et de préciser le rôle vectoriel des Culicoides à La Réunion. Ce travail vise à i) déterminer les facteurs environnementaux et climatiques qui gouvernent la présence et l'abondance de chaque espèce de Culicoides dans l'île ; ii) modéliser leurs dynamiques temporelles et spatio-temporelles ; iii) identifier les espèces potentiellement impliquées dans la transmission des deux orbivirus et caractériser la circulation de ces deux virus dans les populations locales de Culicoides. Un suivi longitudinal reposant sur des collectes bimensuelles de moucherons réalisées dans 11 sites durant 26 mois a permis de caractériser puis d'analyser avec des modèles statistiques de haie les dynamiques temporelles des différentes espèces de Culicoides afin d'identifier les paramètres environnementaux et climatiques qui les gouvernent. Ces modèles de dynamique ont ensuite été spatialisés en utilisant le logiciel Ocelet et validés en s'appuyant sur les données issues d'une large campagne de captures dans 101 sites répartis sur toute l'île. Enfin, la recherche de BTV et d'EHDV, effectuée par PCR (réaction en chaîne par polymérase) dans 1500 pools mo

Bluetongue disease (BTD) is a viral, non contagious disease of domestic and wild ruminants, mainly present in sheep, caused by the RNK virus of the genus Orbivirus, family Reoviridae. Bluetongue virus (BTV) is transmitted by hematophagous insects from the genus Culicoides. The dynamics and spreading of the disease depend upon climatic factors, the interaction of the virus with the vector population and the susceptible host population. BTD is a seasonal disease, appearing mainly during the late summer months when the vector population is usually numerous. In its natural environment the virus cycle is maintained through infection of the vectors such are ruminants and rodents. BTV in the Republic of Serbia is controlled by means of vaccination, same as in the EU countries. The strategy against BTV is based upon the depopulation of the diseased animals in the infected area, most often in combination with vaccination and strict biosecurity measures on the farms and premises where the animals are housed. By applying such measures, the presence of the disease on a larger scale can be avoided. Due to the significant influence that climatic conditions have upon the vectors, and the way in which the susceptible animals are kept, there is no universal mode for BTV control. The aim of this study was to describe the complete epizootiological situation for BTD in R. Serbia, as well as to determine the economic losses. The main target was to develop and implement a stochastic model which would integrate the climate conditions, vector population, susceptible hosts and BTD control measures. The model simulates the daily disease transmission by vectors through the susceptible population, and the intensity of the transmission, as the number and vector capacity are conditioned by climate conditions i.e. daily average temperature variations..., Bolest plavog jezika (BPJ) je virusno nekontagiozno oboljenje domaćih i divljih preţivara, koje se preteţno javlja kod ovaca, izazvano RNK virusom iz roda Orbivirus i familije Reoviridae. Virus plavog jezika (BTV) se prenosi hematofagnim insektima iz roda Culicoides. Dinamika i širenje bolesti uslovljeno je klimatskim faktorima, meĊusobnom interakcijom virusa sa populacijom vektora i prijemĉivom populacijom domaćina. BPJ se javlja sezonski u kasnim letnjim mesecima obiĉno, kada je populacija vektora najbrojnija. Virus se u prirodi odrţava infekcijom vektora i prijemĉivih domaćina, kao što su preţivari i glodari. Virus plavog jezka (BTV) u Repulici Srbiji je kontrolisan vakcinacijom kao i u većini zemalja evropske unije (EU). Strategija borbe protiv BTV se bazira na depopulaciji obolelih ţivotinja u zaraţenim podruĉjima, najĉešće u kombinaciji sa vakcinacijom i uvoĊenjem visokih biosigurnosnih mera na farmama i u objektima u kojima se drţe ţivotinje. Primenom ovakvih mera moţe se obezbediti odsustvo bolesti većih razmera. Zbog znaĉajnog uticaja klimatskih faktora na pojavljivenje i širenje vektora bolesti, kao i samog naĉina drţanja prijemĉivih ţivotinja, ne postoji univerzalni obrazac kontrole BTV. Cilj ovog istraţivanja je da se prikaţe celokupna epizootiološka situacija u R Srbiji, nastala kao posledica pojave BPJ i da se izvrši analiza ekonomskih šteta. Osnovni cilj je razvijanje i primena stohastiĉkog modela, koji meĊusobno povezuje klimatske faktore, populaciju vektora, prijemĉive domaćine i mere intervencije, odnosno mere kontrole BPJ. Model simulira dnevno prenošenje bolesti vektorima kroz prijemĉivu populaciju, a sam intenzitet prenošenja, odnosno brojnost i vektorski kapacitet uslovljeni su klimatskim faktorima, odnosno dnevnim promenama proseĉne temperature. Za ceo ispitivani period obolelo je ukupno 2.786 ovaca, 271 grlo goveda i 25 grla koza. Od ukupnog broja obolelih uginulo je 1.272 ovce, 41 grlo goveda i 11 koza...

Background: Investigations of Culicoides fauna, including inventories, were carried out in Morocco at different periods after the country had faced major bluetongue and African horse sickness outbreaks. However, no comprehensive reference publication has provided a clear overview of the Culicoides species diversity. This study reviewed available data on Culicoides biting midge species in Morocco from 1968 to 2015 (published and grey literature in French and English) in order to revise the current checklist, in light of state of the art taxonomic and systematic knowledge, and confirmed the checklist with morphological and molecular identifications of specimens collected from the region of Rabat. Methods: Literature related to Culicoides collections in Morocco was collated. Authors were contacted to obtain raw data and additional information for the collections. Fresh Culicoides material was collected and examined from two sites around Rabat, the capital of Morocco. Each collected individual was examined and morphologically identified, if possible, to the species level. In addition, molecular identification was performed to separate closely related species, to confirm difficult morphological identifications and to confirm new species records. Results: A total of 6121 individuals of Culicoides spp. were collected and analyzed and at least 17 species were identified: C. cataneii/C. gejgelensis, C. circumscriptus, C. fagineus, C. festivipennis, C. imicola, C. jumineri, C. kingi, C. longipennis, C. montanus, C. newsteadi, C. obsoletus, C. paolae, C. parotti, C. puncticollis, C. sahariensis, C. scoticus and C. subfagineus. Seven species were confirmed using phylogenetic analyses. Two new species records for Morocco are reported: C. paolae and C. subfagineus. Conclusions: The Moroccan fauna of Culicoides now includes 54 valid species. Further work would certainly increase this total, as one of the clades we identified was not affiliated to any described and valid species.

Bluetongue virus (BTV) is a Culicoides-borne pathogen infecting both domestic and wild ruminants. In Europe, the Red Deer (Cervus elaphus) (RD) is considered a potential BTV reservoir, but persistent sylvatic cycle has not yet been demonstrated. In this paper, we explored the dynamics of BTV1 and BTV8 serotypes in the RD in France, and the potential role of that species in the re-emergence of BTV8 in livestock by 2015 (i.e., 5 years after the former last domestic cases). We performed 8 years of longitudinal monitoring (2008–2015) among 15 RD populations and 3065 individuals. We compared Culicoides communities and feeding habits within domestic and wild animal environments (51,380 samples). Culicoides diversity (>30 species) varied between them, but bridge-species able to feed on both wild and domestic hosts were abundant in both situations. Despite the presence of competent vectors in natural environments, BTV1 and BTV8 strains never spread in RD along the green corridors out of the domestic outbreak range. Decreasing antibody trends with no PCR results two years after the last domestic outbreak suggests that seropositive young RD were not recently infected but carried maternal antibodies. We conclude that RD did not play a role in spreading or maintaining BTV in France

Background: Reunion Island regularly faces outbreaks of epizootic haemorrhagic disease (EHD) and bluetongue (BT), two viral diseases transmitted by haematophagous midges of the genus Culicoides (Diptera: Ceratopogonidae) to ruminants. To date, five species of Culicoides are recorded in Reunion Island in which the first two are proven vector species: Culicoides bolitinos, C. imicola, C. enderleini, C. grahamii and C. kibatiensis. Meteorological and environmental factors can severely constrain Culicoides populations and activities and thereby affect dispersion and intensity of transmission of Culicoides-borne viruses. The aim of this study was to describe and predict the temporal dynamics of all Culicoides species present in Reunion Island. Methods: Between 2016 and 2018, 55 biweekly Culicoides catches using Onderstepoort Veterinary Institute traps were set up in 11 sites. A hurdle model (i.e. a presence/absence model combined with an abundance model) was developed for each species in order to determine meteorological and environmental drivers of presence and abundance of Culicoides. Results: Abundance displayed very strong heterogeneity between sites. Average Culicoides catch per site per night ranged from 4 to 45,875 individuals. Culicoides imicola was dominant at low altitude and C. kibatiensis at high altitude. A marked seasonality was observed for the three other species with annual variations. Twelve groups of variables were tested. It was found that presence and/or abundance of all five Culicoides species were driven by common parameters: rain, temperature, vegetation index, forested environment and host density. Other parameters such as wind speed and farm building opening size governed abundance level of some species. In addition, Culicoides populations were also affected by meteorological parameters and/or vegetation index with different lags of time, suggesting an impact on immature stages. Taking into account all the parameters for the final hurdle model

Background: Vector-borne diseases are among the leading causes of morbidity and mortality in humans and animals. In the Afrotropical region, some are transmitted by Culicoides, such as Akabane, bluetongue, epizootic haemorrhagic fever and African horse sickness viruses. Bluetongue virus infection has an enormous impact on ruminant production, due to its high morbidity and mortality rates. Methods: A nationwide Culicoides trapping campaign was organized at the end of the 2012 rainy season in Senegal. A Maximum Entropy approach (MaxEnt), Boosted Regression Tree (BRT) method and Ecological Niche Factor Analysis (ENFA) were used to develop a predictive spatial model for the distribution of Culicoides, using bio-climatic variables, livestock densities and altitude. Results: The altitude, maximum temperature of the warmest month, precipitation of the warmest quarter, mean temperature of the wettest quarter, temperature seasonality, precipitation of the wettest quarter and livestock density were among the most important factors to predict suitable habitats of Culicoides. Culicoides occurrences were, in most of the cases, positively correlated to precipitation variables and livestock densities; and negatively correlated to the altitude and temperature indices. The Niayes area and the Groundnut basin were the most suitable habitats predicted. Conclusion: We present ecological niche models for different Culicoides species, namely C. imicola, C. oxystoma, C. enderleini and C. miombo, potential vectors of bluetongue virus, on a nationwide scale in Senegal. Through our modelling approach, we were able to determine the effect of bioclimatic variables on Culicoides habitats and were able to generate maps for the occurrence of Culicoides species. This information will be helpful in developing risk maps for disease outbreaks.