BVD-2 outbreak leads to high losses in cattle farms in Western Germany

Abstract

In November 2012, a dairy farmer in the district Kleve first observed a reduction in milk yield, respiratory symptoms, nasal discharge, fever, sporadic diarrhoea and sudden deaths in dairy cows and calves. In the following months, further farms were found infected with cattle showing similar clinical signs. An epidemiological investigation was carried out to identify the source of infection, the date of introduction, potential transmission pathways and to analyse the extent of the epidemic. Furthermore, laboratory analyses were conducted to characterise the causative agent. BVDV had been diagnosed in the index herd in December 2012, but due to the atypical clinical picture, the virus was not immediately recognised as the causative agent. Further laboratory analysis showed that this outbreak and subsequent infections in the area were caused by a BVD type 2c virus with a characteristic genome insertion, which seems to be associated with the occurrence of severe clinical symptoms in infected cattle.Epidemiological investigations showed that the probable date of introduction was in mid-October 2012. The high risk period was estimated as three months. A total of 21 affected farms with 5325 cattle were identified in two German Federal States. The virus was mainly transmitted by person contacts, but also by cattle trade and vehicles. The case-fatality rate was up to 60% and mortality in outbreak farms varied between 2.3 and 29.5%.The competent veterinary authorities imposed trade restrictions on affected farms. All persons who had been in contact with affected animals were advised to increase biosecurity measures (e.g. using farm-owned or disposable protective clothing). In some farms, affected animals were vaccinated against BVD to reduce clinical signs as an “emergency measure”. These measures stopped the further spread of the disease.

Bovine viral diarrhea virus (BVDV) genetic diversity in Spain: A review

“…However, in Portugal, the BVDV2a and 2b groups have been found in farms showing clinical signs of hemorrhagic disease (Barros et al, 2006). More recently, in 2012 and 2013, Germany, the Netherlands and Poland reported outbreaks of hemorrhagic syndrome with high mortality in calves and cows caused by an unusually virulent BVDV2c strain (Polak et al, 2014;Gethmann et al, 2015), which may have caused disease recurrence in 2014. In Belgium, a BVDV-2a strain was also isolated from cows showing high fever and severe watery diarrhea, sometimes with hemorrhagic aspect (Maris, 2016).…”

“…Both species show a similar range of disease manifestations except that certain BVDV-2 strains have been associated with severe hemorrhagic syndrome and high mortality (Carman et al, 1998;Gethmann et al, 2015).…”

“…While BVDV-2 is widespread in the USA and Canada (Pellerin et al, 1994;Fulton et al, 2005;Ridpath et al, 2011), it has been detected more sporadically in Europe, although, is increasingly being identified over the last years (Wakeley et al, 2004;Barros et al, 2006;Jackova et al, 2008;Letellier et al, 2010;Luzzago et al, 2012;Aduriz et al, 2015;Gethmann et al, 2015;Diéguez et al, 2016).…”

Genetic diversity of bovine viral diarrhea viruses from the Galicia region of Spain

“…Genetic and antigenic typing of BVDV isolates has led to the definition of two species, BVDV-1 and BVDV-2. Both cause acute and persistent infections and show a similar profile of disease manifestations, except that certain BVDV-2 strains have been associated with severe hemorrhagic syndrome and high mortality (Carman and others 1998, Gethmann and others 2015). …”

Analysis of bovine viral diarrhoea virus: Biobank and sequence database to support eradication in Scotland

“…While an extensive analysis of animal movements related to the samples within the database is now possible, it will also be important to consider all possible connections between premises in cases where the tracing of chains of infection is required. Recent publications suggest that additional factors such as over-the-fence contacts between contiguous premises, animal haulage, farm visitors (family, staff, veterinarians and others) and shared machinery may each contribute to spread in individual cases (Rossmanith and others 2014, Gethmann and others 2015, Stalder and others 2016). To provide livestock keepers and policy makers with appropriate evidence on which to base improvements to biosecurity measures and policies, we need to study chains of BVDV infection in greater depth and in a larger number of cases.…”