Browsing by Subject "POTENTIAL VECTORS"

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  • EFSA Panel Anim Hlth Welf EFSA AHA; Nielsen, Soren Saxmose; Sihvonen, Liisa Helena (2020)
    Effectiveness of surveillance and control measures against Rift Valley Fever (RVF) in Mayotte (overseas France) and in continental EU were assessed using mathematical models. Surveillance for early detection of RVF virus circulation implies very low design prevalence values and thus sampling a high number of animals, so feasibility issues may rise. Passive surveillance based on notified abortions in ruminants is key for early warning and at present the only feasible surveillance option. The assessment of vaccination and culling against RVF in Mayotte suggests that vaccination is more effective when quickly implemented throughout the population, e.g. at a rate of 200 or 2,000 animals vaccinated per day. Test and cull is not an option for RVF control in Mayotte given the high number of animals that would need to be tested. If the risk of RVFV introduction into the continental EU increases, ruminant establishments close to possible points of disease incursion should be included in the surveillance. An enhanced surveillance on reproductive disorders should be applied during summer in risk areas. Serosurveillance targets of 0.3% animals should be at least considered. RVF control measures possibly applied in the continental EU have been assessed in the Netherlands, as an example. Culling animals on farms within a 20 km radius of detected farms appears as the most effective measure to control RVF spread, although too many animals should be culled. Alternative measures are vaccination in a 50 km radius around detection, ring vaccination between 20 and 50 km and culling of detected farms. The assessment of zoning showed that, following RVFV introduction and considering an R-0 = 2, a mean vector dispersal of 10 km and 10 farms initially detected, RVFV would spread beyond a radius of up to 100 km or 50 km from the infected area with 10% or 55% probability, respectively. (C) 2020 European Food Safety Authority. EFSA Journal published by John Wiley and Sons Ltd on behalf of European Food Safety Authority.
  • Mignotte, Antoine; Garros, Claire; Gardes, Laetitia; Balenghien, Thomas; Duhayon, Maxime; Rakotoarivony, Ignace; Tabourin, Laura; Poujol, Lea; Mathieu, Bruno; Ibanez-Justicia, Adolfo; Deniz, Ahmet; Cvetkovikj, Aleksandar; Purse, Bethan; Ramilo, David W.; Stougiou, Despoina; Werner, Doreen; Pudar, Dubravka; Petric, Dusan; Veronesi, Eva; Jacobs, Frans; Kampen, Helge; da Fonseca, Isabel Pereira; Lucientes, Javier; Navarro, Javier; de la Puente, Josue Martinez; Stefanovska, Jovana; Searle, Kate R.; Khallaayoune, Khalid; Culverwell, C. Lorna; Larska, Magdalena; Bourquia, Maria; Goffredo, Maria; Bisia, Marina; England, Marion; Robin, Matthew; Quaglia, Michela; Miranda-Chueca, Miguel Angel; Bodker, Rene; Estrada-Pena, Rosa; Carpenter, Simon; Tchakarova, Simona; Boutsini, Sofia; Sviland, Stale; Schafer, Stefanie M.; Ozolina, Zanda; Seglina, Zanda; Vatansever, Zati; Huber, Karine (2020)
    BackgroundCulicoides 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.MethodsPortion 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.ResultsOur 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.ConclusionsTo 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.