Flock-prevalence of border disease virus infection in Basque dairy-sheep estimated by bulk-tank milk analysis

• Published in: Veterinary microbiology Vol. 118; no. 1; pp. 37 - 46
• Main Authors: Berriatua, E., Barandika, J.F., Aduriz, G., Hurtado, A., Estévez, L., Atxaerandio, R., García-Pérez, A.L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 26-11-2006; Elsevier Science
• Subjects: Animals; Antibodies, Viral - blood; antibody inhibition percentage; Antibody prevalence; Base Sequence; Biological and medical sciences; border disease; Border Disease - blood; Border Disease - epidemiology; Border Disease - virology; Border disease virus; Border disease virus - classification; Border disease virus - immunology; Border disease virus - isolation & purification; bulk milk; Bulk-tank milk; dairy animals; Dairy sheep; disease prevalence; Disease Reservoirs - veterinary; enzyme-linked immunosorbent assay; Enzyme-Linked Immunosorbent Assay - methods; Enzyme-Linked Immunosorbent Assay - veterinary; ewes; Female; Fundamental and applied biological sciences. Psychology; geographical variation; microbial genetics; Microbiology; Milk - virology; Miscellaneous; Molecular Sequence Data; nucleotide sequences; Pestivirus; Phylogeny; reverse transcriptase polymerase chain reaction; Reverse Transcriptase Polymerase Chain Reaction - methods; Reverse Transcriptase Polymerase Chain Reaction - veterinary; RT-PCR; Seroepidemiologic Studies; seroprevalence; Sheep; Spain; Spain - epidemiology; spatial distribution; Species Specificity; Virology; Spain; Europe; Border disease virus; Antibody prevalence; Bulk-tank milk; Dairy sheep; RT-PCR; Spain; Pestivirus; Farming animal; Prevalence; Microbiology; Antibody; Epidemiology; Virus; Vertebrata; Mammalia; Sheep; Artiodactyla; Flaviviridae; Veterinary; Reverse transcription polymerase chain reaction; Ungulata; Milk
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2006.06.013

Bulk-tank milk (BTM) samples from 154 sheep flocks were used to estimate BDV prevalence in the Basque Country in Spain using an ELISA and a RT-PCR test. The proportion of antibody-positive flocks was 68% but varied significantly between provinces and was 93% in Araba and 54–55% in Bizkaia and Gipuzkoa. Most ELISA-positive flocks had very low antibody inhibition percentage (AIP) indicating high seroprevalence and recent BDV exposure. However, only 9% flocks were PCR-positive suggesting few infected ewes were being milked at the time of sampling. Phylogenetic analysis of the 5′ NCR sequences of BDV from seven infected flocks showed that all except one clustered within the group formed by BDV type C strains from a previous study in the region, whereas the remaining isolate was closest to BDV type A. These results suggest that BDV strains in most Basque flocks have a common origin and differences in prevalence between provinces are associated to recent events affecting BDV spread such as use of communal pastures and sheep trading. The widespread distribution of BDV in the region, advocates for the implementation of BDV control strategies and highlights the potential risk of sheep as a pestivirus reservoir for other species.