Schmallenberg Virus

1Schmallenberg Virus is a new emerging disease of livestock. It was named after the German town where it was first noticed. So far the virus has been detected in Belgium, France, Germany, the Netherlands, Italy and the UK. As it is new, there isn’t much know yet but it is in the Simbu serogroup of the Orthobunyavirus group in Bunyaviridae family.

It seems to be similar to e.g. Akabane and Shamonda viruses. These are vector transmitted, such as by midges, mosquitoes and ticks. At this point it is unclear whether there is a potential for direct contact transmission.

The virus is not thought to be zoonotic but investigations are being made to confirm this.

Differential diagnosis : Bovine viral diarrhoea, malignant catarrhal fever, infectious bovine rhinotracheitis, bluetongue, coccidiosis, foot and mouth disease, vesicular and necrotic stomatitis and bovine papular stomatitis. Vesicular diseases do not have accompanying haemorrhage and blisters should be differentiated from erosions (ulcers) seen at RP.

Adult cattle tend to show mild to moderate disease of short duration. Milk drop, diarrhoea and pyrexia may be noticed. Adult sheep seem to show less to no signs. On the other hand signs in adult sheep seemed to be missed more due to less intense supervision as in dairy cattle.

There may be abortion in the later stages of pregnancy or defects in newborn calves, lambs or kids. These defects could be exhibited as brain, limb or spinal cord malformations or nervous system damage such as ataxia, blindness, inability to nurse or stand and occasional convulsions. Arthrogryposis is an SBV associated deformation. Due to some malformation of the newborns, the mother animal can suffer from extensive birthcanal damage.

Diagnosis

Schmallenberg virus is not a notifiable disease, however, farmers are encouraged to contact their veterinarians in cases of stillbirths or fetal malformations or nervous system signs. Veterinarians in turn should contact their laboratory if they suspect Schmallenberg virus infection.

Histopathological and virological examinations are available and will be used but PCR on tissues is needed to confirm the diagnosis. Blood test for the virus are available.