Influence of Communal Alpine Pasturing on the Spread of Pestiviruses among Sheep and Goats in Austria: First Identification of Border Disease Virus in Austria

Abstract

The purpose of this investigation was to determine the influence of communal Alpine pasturing on the spread of pestivirus infections among sheep and goats. The study included 481 sheep from 23 farms and 131 goats from 26 farms pastured on separated Alpine meadows in the western part of Austria. At the starting of pasturing on the sheep meadow, 325 (67.6%) animals were seropositive, on the goat meadows in 16 (12.2%) samples antibodies to pestiviruses were detected. At the end of pasturing, 74 seronegative sheep and two seronegative goats had seroconverted. Between the beginning and the end of pasturing the seroprevalence in sheep increased significantly from 67.6% to 83% (P<0.05). Moreover, in the peripheral blood mononuclear cells of four sheep, pestivirus-specific RNA was detected before as well as after pasturing; these animals remained serologically negative throughout the investigation. They were, therefore, identified as persistently infected. Sequence analysis in the N(pro) region revealed that the detected pestiviruses were the same at genetic level and they were grouped into the Border disease virus (BDV)-3 genotype. No pestivirus RNA was found in goat samples. The results of this survey indicate that communal Alpine pasturing does play a key role in the spread of BDV. Moreover, BDV has been identified and characterized for the first time in sheep in Austria, which until then had been regarded as being free from BD.

Comparative Investigation of Border Disease Virus Infection in Sheep Flocks with Abortion Problems in Konya Province

“…Pestiviruses infect sheep, cattle, and pigs, and cause significant economic losses worldwide [1,2]. Border disease virus (BDV) belongs to the genus Pestivirus within the family Flaviviridae.…”

BVDV control program in Austria - is a monitoring of the BDV status in sheep in Austria necessary?

“…Particularly in the mountainous regions, were communal alpine pasturing is a century old farming practice high seroprevalence levels in sheep were found in a survey carried out between and 2003(KrametterFroetscher et al, 2007b. The first cases of sheep persistently infected with Border disease virus in Austria were found in the alpine region of Vorarlberg in 2003 (Krametter-Froetscher et al, 2007a). The animals described were clinically healthy and persistently infected with a BDV-3 strain closely related to BDV-3 type species Gifhorn.…”

“…This study and previous studies (Krametter-Froetscher et al, 2007a,b, 2008bHornberg et al, 2009) make clear that in Austria particular in regions with communal alpine pasturing and on farms with close contact of cattle and sheep a high risk factor for reintroduction of pestiviruses in BVDV free cattle herds exists, associated with expensive financial penalties to the farmers. However, in consideration of the fact that large sheep breeding countries like UK or New Zealand have only voluntary BVDV eradication programs among cattle and they also use vaccines against BVDV in cattle (Reichel et al, 2008;Heffernan et al, 2009), sheep persistently infected with BDV are inconsiderable for the pestivirus epidemiology there and an investigation of the sheep population for BDV in those countries would be uneconomic.…”

“…In contrast BDV in cattle has only been described in a cattle orginating from Tyrol, a Federal state of Austria (Hornberg et al, 2009) and in five cases orginating from England and Wales (Cranwell et al, 2007;Strong et al, 2009). The BDV isolate described by Hornberg et al (2009) showed a high similarity at the nucleotide level to the BDV strains detected by Krametter-Froetscher et al (2007a) in sheep in Vorarlberg a neighbour state of Tyrol.…”

“…RT-PCR was carried out on lysed PBMCs (peripheral blood mononuclear cell pellets) of all sheep blood samples, on the blood sample drawn four weeks after birth and organ samples of the calf (lung, kidney, spleen and liver) available after culling (Krametter-Froetscher et al, 2007a). The primers 324 and 326 (Vilcek et al, 1994) amplify a conserved domain at the 5'-end of the viral genome of 288 bp in length.…”