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 Virus surveillance unit:
protecting livestock and wildlife
The Virus Surveillance Unit (VSU) at Moredun contributes to two important aspects of the Scottish rural economy. The first of these is the control of endemic disease in domestic livestock and the second is through the effect of viruses on the biodiversity of wildlife. In addition, the resources at Moredun and the experience of the staff are invaluable for advising on the diagnosis of any new animal disease that may emerge. The identification of new diseases also relies heavily on Moredun’s Pathology Unit which is integrated with the VSU
Monitoring endemic disease through surveillance
The VSU provides specialist virological support to the laboratories of the Scottish Agricultural College Veterinary Services (SACVS).
The main viruses detected are
- Bovine viral diarrhoea virus (BVDV), a pestivirus which principally causes reproductive loss but which is also the cause of mucosal disease and can be involved in other disease syndromes. Since 2000, the VSU and SACVS have typed all BVDV viruses isolated in Scotland by real time RT-PCR – to November 2008 all of the Scottish BVDV isolates have belonged to the BVDV-1 group which has been recorded in Scotland since 1956.
- Border disease virus (BDV), another pestivirus which mainly infects sheep causing reproductive disease and the birth of weak lambs known as ‘hairy shakers’. Typing of isolates from border disease outbreaks show that 80% are caused by BDV while 20% are caused by BVDV-1 suggesting cross-infection from cattle.
- Cattle respiratory viruses, bovine herpesvirus type 1 (BoHV-1), bovine respiratory syncytial virus (BRSV), and Bovine parainfluenza virus 3. These viruses cause respiratory disease; BoHV-1 causes infectious bovine rhintotracheitis (IBR) and the other 2 viruses are involved in calf pneumonia. In addition to the classical presentation of IBR, BoHV-1 continues to cause atypical outbreaks of disease which have recently included severe milk drop and abortion in dairy cattle. The VSU has a PhD student investigating the virus genetics of these usual presentations.
- Orf virus, which causes severe mouth problems in lambs and udder problems in ewes. See the orf research group pages for further information
- Louping ill (LIV), a tick borne disease of many species, most often sheep, cattle and red grouse, though many species including horses, goats, dogs and (rarely) humans can be affected. This virus affects the brain and causes signs such as fever, inco-ordination and difficulty walking. which can progress to coma and death.
- Malignant catarrhal fever (MCF), a sporadic disease of cattle, caused in the UK by ovine herpesvirus 2. See the malignant catarrhal fever research group pages for further information.
By building up banks of virus isolates it is possible to monitor changes occurring in viruses under field conditions especially after the introduction of new vaccines. In addition, any newly introduced virus can be quickly and reliably identified.
The platform technology of real time polymerase chain reaction (PCR) has being used to develop a new generation of highly sensitive, quantitative tests to detect and identify ruminant pestiviruses, louping-ill virus, bovine respiratory syncytial virus, ruminant herpesviruses and orf virus.
the effect of viruses on the biodiversity of wildlife
A spin-off from Moredun’s expertise on orf virus of sheep has been our ability to characterise a squirrel pox virus (SQPV) associated with deaths in red squirrels. The development of an assay to measure antibody to SQPV in squirrel serum showed that grey squirrels in England had a high prevalence of antibody while those in Scotland were free of antibody. Also, healthy red squirrels never had antibody but those dying of the poxvirus disease did have antibody. This has led to the hypothesis that grey squirrels carry SQPV without suffering any disease but that the virus is lethal to red squirrels. In 2005 Moredun scientists demonstrated that grey squirrels with antibody to SQPV had crossed the border from England and were now threatening the large population of red squirrels in the Scottish Borders. The situation is being monitored in collaboration with the Red Squirrels in South Scotland Project.
Louping ill virus (LIV) is a tick transmitted disease of many domestic animals, wildlife and man. Moredun is the sole UK resource for the diagnosis of louping ill and plays a crucial role in surveillance of the virus in wildlife and the diagnosis of new manifestations of disease. In addition, it has a pivotal input into research projects on the lethal effects of LIV in red grouse and the ecology of LIV in upland areas. Each year, several thousand LIV tests are undertaken with infection being recorded in sheep, cattle, red grouse, red deer, roe deer, mountain hares, dogs and horses. Approximately 60% of all tests were done to investigate the prevalence of LIV on moorland estates through the auspices of the Game Conservancy Trust. Such testing makes a useful contribution to understanding the role of disease on biodiversity in Scotland’s upland habitat
 list of viruses for which diagnostic tests are available at Moredun
- Bovine virus diarrhoea virus (BVDV)
- Border disease virus (BDV)
- Louping ill virus (LIV)
- Bovine herpesvirus types 1, 2, 4 and 5 (BoHV-1, 2, 4, 5)
- Ovine herpesvirus 2 (OvHV-2)
- Alcelaphine herpesvirus 1 (AlHV-1)
- Cervid herpesvirus 1 and 2 (CvHV-1, 2)
- Caprine herpesvirus 1 and 2 (CpHV-1, 2)
- Orf Virus
- Pseudocowpox Virus
- Red squirrel poxvirus
- Bovine parainfluenza virus 3
- Ovine parainfluenza virus 3
- Bovine respiratory syncytial virus (BRSV)
- Other agents can be detected on request.
Some diagnostic testing for other clients can also be performed by individual arrangement. For further information please contact Dr Kim Willoughby.
The Virus Surveillance Unit is funded by the Scottish Government.
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