Detecting new diseases such as Schmallenberg Virus infections (SBV) Guda van der Burgt, Veterinary Investigation Officer AHVLA Luddington 1
SURVEILLANCE WHAT DOES IT NEED TO DO? Detect at an early stage a new disease, infection or intoxication. Rapidly detect pathogens or diseases which are currently absent from the UK. To monitor trends in existing diseases. 2
Veterinary Laboratories Agency A network of 16 regional laboratories in England and Wales 3
PYRAMID OF SCRUTINY VLA Regional Laboratory Private veterinary Surgeon Livestock Producer 4
Main Programmes Emerging Disease and Welfare (END) Food and Environmental Safety (FES) Statutory and Exotic Bacteria (SEB) Statutory and Exotic Viruses (SEV) Transmissible Spongiform Encephalopathies (TSE) 5
VSD RL activities PVS Diagnostic submissions Necropsy Advisory / surveillance visits Emerging disease investigations Scanning Surveillance Welfare advice, farm visits, prosecutions Zoonosis advice, farm visits, human outbreaks Notifiable disease eg TSEs, Tb, Exotic disease Planned projects (Targeted surveillance) 13
Update on Schmallenberg Virus (a new and emerging disease of ruminants)
What is SBV New virus Similar to Akabane virus Orthobunya virus
Deductions Similar viruses have been identified in Asia, Australia and Africa Rarely associated with clinical disease BUT can induce congenital defects if dam first infected when pregnant Not contagious Transmitted by insect vectors
Clinical signs of disease Dairy cattle Diarrhoea Pyrexia Milk drop Sheep None? Increased return to oestrus rate
Transmission Thought to be spread by insect vectors High transmission efficiency Spread by wind across channel then spread within a region in the UK Culicoides obseletus and C dewulfi Both are found in UK C obseletus was the main vector for BTV 8 spread
Where did it start? Disease in Netherlands in dairy cattle (1 st Sept) Fever Production loss (up to 20%) Diarrhoea (up to 70% of herd affected) Housed and grazed cattle Disease in dairy cattle in Germany (mid October) Thought to have been widespread in Europe during Sept/Oct 2011
German Work Cases of pyrexia + milk drop Diarrhoea less of a feature Tested for BTV, BVDV, FMD, BHV-1, MCF Exotic viruses Rift Valley fever and bovine ephemeral fever New virus identified Experimental infection in cattle (end of Dec)
December Reports from Netherlands of 5 cases of deformed lambs First report of disease in Belgium Enhanced surveillance commenced within VLA and SAC Case definition Standard protocol re collection of tissues for examination
January 2012 Report on 5 th Belgium 11 sheep farms with deformed lambs which were virus positive Netherlands 160 farms with affected lambs, calves and kids 40 of the 92 sheep farms are virus positive 1 of the 3 goat farms None of the 62 cattle farms are virus positive
Predominately two types of gross pathological lesions With Akabane virus different pathology depending on stage of gestation 76-104 days hydraencephaly 103-173 arthrogryposis >173 poliomyelitis Can get both in same calf as dates not exact Risk time for sheep 2 nd and 3 rd month
Arthrogryphosis Non progressive Congenital contractures that develop before birth and are present at birth Reduced mobility of multiple joints. If sever can include rotation and abduction of limbs, scoliosis, kyphosis and torticollis Often concurrent muscle wastage
Hydraencephaly Cerebral hemispheres largely absent and replaced with fluid filled sacs within a normal skull compartment Porencephaly Cysts/ cavities within brain tissue
Cerebellar dysgenesis Hydranencephaly
Differential Diagnosis BVD/Border disease Manganese deficiency Lupin or Sorghum ingestion during pregnancy Inherited defects Blue tongue virus Akabane CVM
25 th Jan 2012 4 farms positive Norfolk E Sussex Suffolk
Diagnosis Clinical and post mortem findings Viral PCR on brain tissue Histopathology Foetal fluid serology Maternal serology
Current UK Situation 32 Confirmed cattle cases Sampled 251 cattle farms 217 Confirmed sheep cases From 617 sheep farms Also tested goats, alpacas, deer, oryx, dogs and a horse- all negative
Was it in UK cattle last autumn? No apparent increase in DNR for diarrhoea in cattle Clinical signs vague But dramatic numbers affected We were unaware of disease Not reported by farmers to vets, or not reported by vets to VLA?
Cattle
January 2013
Countries include- Trade Restrictions United States, Canada, Mexico, Peru, Argentina, Brazil, Algeria, Morocco, Egypt, Lebanon, Jordan, Ukraine, Bosnia-Herzegovina, Belarus, Kazakhstan, India and Japan Mainly genetic material Live exports, including pigs are restricted by Russia
Future impact in UK Will it become endemic? If so less risk as exposure pre pregnancy Vector is widespread in UK Will we see clinical disease in dairy cattle? Will there be any dummy calves Will it become reportable/ notifiable?
Positives Good collaboration with European vets Makes AHVLA (VLA) look good at time of uncertainty Devised a new recording system which if needed could be used in a notifiable disease outbreak Increased awareness of the risks of importing new diseases from other countries
Future Developments Vaccination Movement restrictions?? Exact definition Industry support
What we don t know LOTS Are normal appearing co-twins infectious? How to best control insect vectors Is there any potential for spread within a flock/herd without going via an insect? Will apparently normal co twins survive till adult/ fatten as normal Any effect on rams if infected at tupping time