Abstract
To study Schmallenberg virus (SBV) excretion in bovine semen after experimental infection, two bulls were inoculated subcutaneously with a SBV isolate (1 ml Vero cell culture 106 TCID50). After inoculation (at day 0), semen was collected daily from both animals for 21 days and samples were tested for SBV by qRT-PCR assay. At 24 days post-inoculation both animals were subjected to necropsy and the genital organs and lymph nodes draining these organs were also tested for SBV RNA (qRT-PCR). After SBV infection both animals in the study showed viraemia (qRT-PCR) with fever and diarrhoea. SBV RNA could be detected in semen from both animals. The highest SBV RNA concentrations in semen were found in the first week (days 4-7 post-inoculation) but concentrations were relatively low (Ct values 30-39). Viable SBV was only isolated from blood samples and not from semen or genital tissues.
Highlights
During 2011 and 2012 Europe experienced the emergence of a new arbovirus of domesticated ruminants, namely Schmallenberg virus (SBV) [1]
As of October 2012, about 6000 holdings with confirmed cases of SBV were reported by the European Food Safety Authority (EFSA) in Europe [5]
Scattered low concentration positives were found in weeks 2 and 3 after inoculation in single amplification runs. qRT–PCR inhibitory conditions were observed in a few undiluted test samples as the internal control (β-actin) was not detected or showed a relatively high Ct value
Summary
During 2011 and 2012 Europe experienced the emergence of a new arbovirus of domesticated ruminants, namely Schmallenberg virus (SBV) [1]. Infection of susceptible pregnant animals can be associated with abortions, and musculoskeletal and central nervous system malformations in stillborn or newborn lambs and calves. The first acute infections associated with SBV were reported in August 2011, while the first malformations in stillborn animals caused by this virus were detected in The Netherlands in December 2011 [3, 4]. In May 2012, eight European Union countries (Belgium, France, Germany, Italy, Luxembourg, The Netherlands, Spain, UK) had reported cases of SBV. In the summer of 2012 SBV-confirmed cases were reported by Denmark, Finland, Poland, Sweden and Switzerland and in new areas in France, UK and Germany [5]. As of October 2012, about 6000 holdings with confirmed cases of SBV were reported by the European Food Safety Authority (EFSA) in Europe [5]. A study in 363 flocks in France showed that 15% of lambs were born dead or died within
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