Detection of ovine respiratory syncytial virus in pneumonic lungs from apparently healthy sheep slaughtered at 5 abattoirs in Australia.

Respiratory disease is one of the main diseases of sheep in many regions globally. Respiratory syncytial virus (RSV) causes severe disease in humans and in calves, but little is known about the role of RSV in sheep. We studied the prevalence of ovine RSV in sheep processed at 5 abattoirs in southern Australia. Bronchial swab samples were collected from 182 consignments of lambs up to 12 months of age and 71 consignments of adult sheep; these were tested for the presence of the virus using a qPCR based on the F gene sequence. Six of the 253 abattoir consignments (2.4%) tested positive for ovine RSV. Four of the positive consignments were lambs and 2 were adult sheep. To our knowledge, this is the first report of the ovine strain of RSV in sheep with pneumonia from Australia. Further research is needed to clarify the role of RSV in pneumonia in sheep.

Les maladies respiratoires sont l'une des principales maladies des ovins dans de nombreuses régions du monde. Le virus respiratoire syncytial (VRS) provoque une maladie grave chez les humains et les veaux, mais on sait peu de choses sur le rôle du VRS chez les ovins. Nous avons étudié la prévalence du VRS ovin chez les moutons traités dans 5 abattoirs du sud de l'Australie. Des écouvillons bronchiques ont été prélevés sur 182 envois d'agneaux jusqu'à l'âge de 12 mois et 71 envois de moutons adultes; ceux-ci ont été testés pour la présence du virus à l'aide d'un qPCR basé sur la séquence du gène F. Six des 253 envois d'abattoirs (2,4 %) ont été testés positifs pour le VRS ovin. Quatre des envois positifs étaient des agneaux et 2 des ovins adultes. À notre connaissance, il s'agit du premier signalement de la souche ovine du VRS chez des moutons atteints de pneumonie en provenance d'Australie. Des recherches supplémentaires sont nécessaires pour clarifier le rôle du VRS dans la pneumonie chez le mouton.(Traduit par Docteur Serge Messier).

Diarrhoea associated with gastrointestinal parasites in grazing sheep.

Diarrhoea is a common, widespread and frustrating reality for sheep enterprises in most sheep producing regions globally and of particular concern in Australia as the major risk factor for breech flystrike. Parasitic disease has long been recognised as an important factor in diarrhoea in sheep, particularly the gastrointestinal nematodes (Trichostrongylus and Teladorsagia species). This review focuses on the role of parasitic infections in causing diarrhoea in sheep, with emphasis on the epidemiology of diarrhoea outbreaks related to worms and opportunities to manage the risk of diarrhoea outbreaks in sheep related to parasitic infections. Parasitic nematodes damage the gastrointestinal tract via a complex relationship between direct impacts from worms, such as physical changes to the gut mucosa, and indirect effects largely associated with the host response. Diarrhoea associated with large worm burdens is most efficiently managed through integrated parasite management programs. Despite some limitations, measuring faecal worm egg counts remains a mainstay for assessing the contribution of worms to outbreaks of diarrhoea in sheep. Larval hypersensitivity scouring is emerging as a significant cause of worm-related diarrhoea in sheep without large adult worm burdens in some geographic locations. The syndrome describes a heightened inflammatory response to the ingestion of trichostrongylid infective larvae seen in the gut of sheep with diarrhoea, and is most effectively addressed through selecting sheep for low breech soiling ('dag scores'), as worm resistant sheep may show an increased propensity for diarrhoea, even with low rates of larval challenge. Importantly, dag should be considered as a separate trait to WEC in breeding indexes. Outbreaks of diarrhoea in young sheep are often multifactorial, and co-infections with nematodes and other infectious agents associated with diarrhoea are common. This presents challenges for the field investigation of diarrhoea in grazing sheep.