RESUMEN
Bluetongue (BT) is a vector-borne viral disease caused by the Bluetongue virus (BTV), an Orbivirus from the Reoviridae family, affecting domestic and wild ruminants. BTV circulation in Brazil was first reported in 1978, and several serological surveys indicate that the virus is widespread, although with varied prevalence. In 2014, BT outbreaks affected sheep flocks in Rio Grande do Sul state, causing significant mortality (18.4%; 91/495) in BTV-infected sheep. In total, seven farms were monitored, and one or two sheep from each farm that died due to clinical signs of BT were necropsied. Apathy, pyrexia, anorexia, tachycardia, respiratory, and digestive disorders were noted. Additionally, an abortion was recorded in one of the monitored farms. The main gross lesions observed were pulmonary edema, anterior-ventral pulmonary consolidation, muscular necrosis in the esophagus and in the ventral serratus muscle, and hemorrhagic lesions in the heart. The blood and tissue samples were tested for BTV RNA detection by RT-qPCR targeting the segment 10. Positive samples were used for viral isolation. The isolated BTVs were typed by conventional RT-PCR targeting the segment 2 of the 26 BTV serotypes, followed by sequencing analysis. BTV-1, BTV-4 and BTV-17 were identified in the analyzed samples. Double or triple BTV co-infections with these serotypes were detected. We report the occurrence of BT outbreaks related to BTV-1, BTV-4 and BTV-17 infections and co-infections causing clinical signs in sheep flocks in Southern Brazil, with significant mortality and lethality rates.
Asunto(s)
Virus de la Lengua Azul/genética , Lengua Azul/epidemiología , Coinfección/epidemiología , Brotes de Enfermedades/veterinaria , Enfermedades de las Ovejas/epidemiología , Animales , Lengua Azul/patología , Lengua Azul/virología , Virus de la Lengua Azul/clasificación , Brasil/epidemiología , Coinfección/patología , Coinfección/virología , Serogrupo , Ovinos , Enfermedades de las Ovejas/patología , Enfermedades de las Ovejas/virologíaRESUMEN
The complete genome sequence of Bluetongue virus (BTV) serotype 17 strain 17/BRA/2014/73, isolated from a sheep in Brazil in 2014, is reported here. All segments clustered with western topotype strains and indicated reassortment events with other BTV from the Americas. The strain 17/BRA/2014/73 represents a novel reference strain for BTV-17 from South America.