From the start of the study in May 2013 to the present, 1,410 bovine samples have been received by the laboratory. Of these, 684 (48%) were serum samples, 445 (32%) were EDTA whole blood samples, 64 (5%) ear biopsy samples, 17 (1%) tank milk samples and 200 (14%) organ samples obtained through necropsy of dead animals. 52% (975) of samples came from dairy cattle, 22% (256) came from extensive herds and 26% (179) came from feedlot calves.
With the exception of the RT-PCR used for serotyping, which was employed specifically for this project, the techniques used to analyse the samples were no different to those used in regular laboratory practice:
- BVD virus antigen detection: Capture ELISA (Erns) (IDEXX). Samples: Ear tissue biopsies, EDTA blood, blood serum and plasma.
- Detection of antibodies to the BVDV p80 protein: Blocking ELISA (Pourquier-IDEXX). Samples: Blood serum or plasma.
- BVD virus detection: Real-time RT-PCR (Hofmann et al., 2006). Samples: Tank milk, tissue, EDTA blood, blood serum and plasma.
- Virus typing (BVDV1 and BVDV2): Real-time RT-PCR (Baxi et al., 2006). Samples: positive RT-PCR detection samples (milk or tissue). Directly on EDTA blood and blood serum and plasma samples.
The data collected to date reveal that, of a total of 239 sample submissions, 50.20% have resulted in the isolation of BVDV. Of a total of 1,410 samples analysed to date (this study remains ongoing), 120 samples have been found to be positive for the BVD virus. Of them, 63 (52.5%) came from dairy cattle, 31 (25.83%) came from feedlot herds and 26 (21.67%) came from extensive cattle. All were found to belong to genotype 1.
To complement the surveillance network, 47 BVDV-positive samples were simultaneously genotyped from NEIKER's repository of specimens obtained between 2012 and 2013, as well as 96 samples from the Galicia Animal Health and Production Laboratory (LASAPAGA), released by the laboratory for this study. All samples belonging to the LASAPAGA were genotyped as BVDV genotype 1.
However, two of the samples from the NEIKER specimen repository were identified by PCR as BVDV genotype 2 and confirmed by sequencing (Aduriz et al., 2014). This is extremely significant as this is the first time that BVDV2 has been identified in Spain.
Read the whole study here.
- Manuel Cerviño (1), Gorka Aduriz (2), Carmen Eiras (3), Juan Manuel Loste (4) and Susana Astiz (5)
- (1) Boehringer-Ingelheim España S.A. email@example.com; (2) NEIKER-TECNALIA; (3) Animal Health and Production Laboratory, Galician Regional Government; (4) Albaikide S.A.; (5) Dept. of Animal Reproduction (INIA).