Phylogenetic analysis and spatial distribution of bovine viral diarrhea virus (BVDV) in dairy cattle from Galicia (NW Spain)

Aim of study: To examine the frequency and diversity of bovine viral diarrhea viruses infecting dairy cattle Area of study: The study was carried out in Galicia (NW Spain), the main dairy cattle area of Spain Material and methods: A total of 157 BVDV isolates (from 140 dairy herds) were typed. Typing was based on a 288-bp sequence from the 5' untranslated region of viral RNA genome. Subsequently, to investigate whether the presence of herds diagnosed with a particular strain was higher in some areas or during some specific time period, data were tested using a Bernouille approach Main results: Of the 157 isolates, 137 (87.3%) were typed as BVDV-1b, 10 (6.4%%) as 1d, 7 (4.4%) as 1e and 2 (1.3%) as 1f. One isolate was assigned to type 1p. Three of the strains found in the study (the three belonging to type 1b) showed significant spatial clustering. Research highlights: This report indicates that BVDV-1b was the predominant species, although there was an important genetic diversity in the study population. Spatial analysis indicated important drawbacks in the application of biosecurity measures, especially as regards purchase of cattle or after the reintroduction of animals from cattle concentration points.