A 2.5-years-old female mongrel dog was routinely subcutaneously vaccinated. A few hours later mental dullness was noticed by the owner progressing into stupor the next day and resulting in a comatose state and death within 48 hours after vaccination. At post mortem examination, which was extended with histology and bacteriology, a necrotizing fasciitis and bacteremia caused by Streptococcus equi subsp. zooepidemicus were established. In the isolated Streptococcus strain four different superantigens were demonstrated that appeared to be able to produce exotoxins in vitro. Therefore, it is concluded that the minor skin trauma caused by vaccination enabled this strain to gain access to the subcutaneous tissue and to induce a necrotizing fasciitis. This process was complicated with a bacterial septicemia leading to death of the dog within 48 hours. The English text can be found in full on our website: https://www.knmvd.nl/ actueel/lTijdschrift-voor-Diergeneeskunde.
In December 2011, a previously unknown congenital syndrome of arthrogryposis and hydranencephaly in sheep and cattle appeared in the Netherlands as an emerging epizootic due to Schmallenberg virus (SBV). Gross lesions in 102 lambs and 204 calves included porencephaly, hydranencephaly, cerebellar dysplasia and dysplasia of the brainstem and spinal cord, a flattened skull with brachygnathia inferior, arthrogryposis, and vertebral column malformations. Microscopic lesions in the central nervous system showed rarefaction and cavitation in the white matter, as well as degeneration, necrosis, and loss of neurons in the gray matter. Brain and spinal cord lesions were more severe in lambs than in calves. Ovine and bovine cases examined early in the outbreak showed encephalomyelitis. SBV infection was confirmed by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) in brain samples in 46 of 102 lambs (45%) and in 32 of 204 calves (16%). Immunohistochemistry, performed on tissue samples from 18 RT-qPCR-positive lambs, confirmed the presence of bunyaviral antigen in neurons of the brain in 16 cases. SBV antibodies were detected by enzyme-linked immunosorbent assay in fetal blood in 56 of 61 sampled ovine cases (92%). In a virus neutralization test, all tested dams of affected newborns, 46 ewes and 190 cows, were seropositive. Compared with other teratogenic viral infections, the pathogenesis and lesions of SBV in sheep and cattle fetuses are similar to those of other ruminant orthobunyaviruses. However, the loss of spinal ventral motor neurons and their tracts, resulting in micromyelia, distinguishes SBV infection from other viral central nervous system lesions in newborn ruminants.
Schmallenberg virus (SBV), a novel orthobunyavirus that rapidly spread throughout north-western Europe in 2011, caused congenital malformations in lambs and goat kids (Van den Brom et al., 2012) and newborn calves (Hoffmann et al., 2012). The impact of the SBV epidemic seemed limited however, in terms of the number of affected herds with malformed offspring (European Food Safety Authority, 2012b). Nevertheless, little is known with regard to the overall within-herd impact of SBV infection. The objective of the current study was to quantify the impact of the 2011 SBV epidemic on the productivity of dairy cattle in the Netherlands and the district of Kleve, Germany.For the Netherlands, several multilevel multivariable statistical models were applied on eight productivity parameters regarding milk production, reproductive performance and mortality. All four fertility parameters analysed were slightly but significantly reduced between August 1st and November 1st 2011 compared to the reference period in 2009–2010. Between August 15th and September 19th 2011, the average loss in milk production per cow was −0.26 kg (95% CI: −0.30; −0.22) per day in dairy herds, compared to the reference period (p < 0.001). The total loss per cow in a subgroup of dairy herds that notified malformations in newborn calves during the mandatory notification period in the Netherlands was −0.43 kg (95% CI: −0.59; −0.28) per day (p < 0.001).For Germany, a study was carried out in the district of Kleve, situated in the state of North Rhine-Westphalia near the Dutch border. Data on milk yield, two fertility parameters and the number of rendered calves in this specific region were analysed. There was a small but significant increase in the number of secondary and third inseminations between August 1st and November 1st 2011, indicating reduced fertility. No significant change in calf mortality was observed in the assumed SBV period. Milk production at district level did not seem to be affected by SBV in August and September 2011.SBV had no or limited impact on mortality rates, which was as expected given the relatively mild expression of SBV in adult cows and the low incidence of notified malformations in newborn calves. Our results indicate that SBV had a limited impact on productivity of dairy cattle. However, the total economic impact of SBV on the ruminant industry not only consists of productivity caused losses; it is expected that international trade restrictions formed a larger part of the total economic impact.