Prevalence of genotypes 1 and 2 of bovine viral diarrhea virus in Lower Saxony, Germany

The aim of this study was to find whether an antigenic drift had occurred i n Lower Saxony in the past 40 years. For this, the genetic diversity of bov ine viral diarrhea virus (BVDV) isolates mainly from Lower Saxony was estim ated by RT-PCR and sequencing of a 420 bp fragment of the E2 glycoprotein g ene. Sixty-one field virus isolates collected during routine diagnostics be tween 1960 and 2000 in Lower Saxony, Northern Germany, were analyzed. Phylo genetic analysis allowed discrimination of genotypes BVDV 1 and 2. Exceptin g two isolates, which were of BVDV type 2, most of the isolates were classi fied as BVDV type 1. This group could be further subdivided into four subgr oups and one disparate isolate. Independent of the year of isolation and ge ographical localization, 54 isolates clustered in two subtypes (BVDV subtyp es Ib and Id). Only one isolate was classified as BVDV type la, thus being similar to the North American NADL strain, and to the vaccine strain Oregon C24V, which was extensively used for vaccination in Germany. The remaining isolates belonged to new clusters tentatively designated as BVDV subtypes Ig and If. To compare the cluster designation with that of other studies, p hylogenetic analysis of representatives of each of the subgroups based on t he 5' untranslated region (5'UTR) was performed. It grouped the viruses sim ilarly. The results indicate that the BVDV population seems to be relativel y stable over 40 years in Lower Saxony. (C) 2001 Elsevier Science B.V. All rights reserved.