November 4, 2012

Schmallenberg Disease

Schmallenberg Virus Spreading West (February 2018)

Date published: 13 February 2018

Area of Expertise:   Animal Health and Welfare

Schmallenberg virus (SBV) was first identified in Germany in late 2011 as a cause of malformations in newborn calves and lambs. This virus can cause a temporary dip in production, such as milk output. However, the greatest economic impact comes from abortions, stillbirths and birth defects that can result when pregnant animals are affected.

AFBI has recently detected SBV in eight ovine abortion cases in Counties Fermanagh and Tyrone. In all of these cases the lambs submitted have had evidence of arthrogryposis (hyperflexion of the joints) of the hind limbs and fore limbs. Torticollis (wry neck) has also been observed. Further diagnostic testing has revealed the presence of Schmallenberg virus in the brain, lung and spinal cord sampled from seven of the cases. Whilst in one of the cases no virus was detected in the samples tested, antibodies to SVB were detected in foetal fluid indicating exposure to the virus by the lamb whilst in the womb. These are first virus positive cases confirmed by AFBI in the west of the province. The Department of Agriculture, Food and the Marine in the Republic of Ireland have also recently reported suspected cases in counties Sligo, Cavan and Leitrim. Antibody has also recently been detected in blood samples from ewes in Armagh, Antrim and Fermanagh, indicating exposure to the virus or vaccination.

Schmallenberg virus was first detected in Northern Ireland in a cattle herd in County Down in October 2012. Three further cases were confirmed the following spring in County Down in two cattle herds and one sheep flock. In 2017, the virus reappeared and was detected in one ovine abortion in County Down. Last year AFBI also detected positive tests for antibodies to Schmallenberg in two calves born with skeletal deformities and a cow from a herd experiencing abortions and calf abnormalities, providing evidence that the virus was circulating again in Northern Ireland.

Schmallenberg virus is transmitted to livestock by Culicoides biting midges.  These midges are very effective at transmitting SBV and are very difficult to control, or prevent from spreading the virus.  Although they are less active during the colder winter months, temperatures last winter were not low enough across the British Isles to kill all infected midges.

Problems with malformed calves and lambs arise when pregnant cows and sheep are exposed to the virus during a critical time window in early to mid-pregnancy.  Following infection, exposed animals may give birth to malformed progeny but are likely to develop a strong immunity to subsequent infection.  They are therefore unlikely to suffer any ill-effects if exposed to the same virus in subsequent years.  Commercial vaccines against the Schmallenberg virus are also available for use in cattle and sheep.

Farmers who suspect problems caused by SBV in their flocks or herds, should seek advice from their private veterinary surgeons on the most appropriate action, including on the submission of samples to AFBI’s veterinary laboratories at Omagh and Stormont.

There is no evidence of any risk to humans from SBV infection.

Schmallenberg Virus (SBV) Key Facts:

  • Caused by a new orthobunyavirus, a group of viruses not found in northern Europe until 2011
  • Vectored by insects from the genus Culicoides, which are indigenous to NI and active during April to early December
  • At the time of infection the virus can cause transient fever, diarrhoea and milk-drop in cows
  • More significant clinical picture is of:
  • an increase in lambs, calves & kids born dead or weak, at or near their due date
  • lambs, calves & kids born with varying degrees of fused or stiff limb joints, twisted spines, or abnormal skulls or jaws
  • Affects ruminants but no evidence to date that it causes disease in humans, or non-ruminant species such as horses or pigs
  • Highest risk period is when mother is infected in early-mid pregnancy
  • Commercial vaccines for Schmallenberg virus are available
  • Schmallenberg is not a notifiable disease
  • DAERA does not impose any restrictions on infected holdings

 

Merial launch new Schmallenberg Vaccine – March 2014

A new Schmallenberg vaccine – SBVvax – is now available from Merial Animal Health after receiving approval for use in sheep and cattle in the UK.  SBVvax is the only vaccine licensed for the prevention of viraemia in both cattle and sheep.

Findlay MacBean, Merial’s Head of Large Animal Business, said: “SBVvax will provide a cost-effective solution for those producers who want to protect their flocks pre-tupping over the coming months. We also believe that it will be a useful tool for beef or dairy farmers bringing replacements into their herds and vaccinating cows prior to bulling.”

Protection from Schmallenberg with SBVvax is provided by a single low-volume dose for sheep and two low-volume doses, three weeks apart for cattle. The vaccine is licensed for use in non-pregnant animals from 2.5 months of age and onset of immunity has been demonstrated 3 weeks after the primary vaccination course.

The impact of the virus is most evident in new born animals, where malformation or still birth is common. Death of ewes and cattle after birth and reduction in fertility through abortions and early reabsorption has also been observed.

Farmers should consult their vet for information about vaccinating their flock or herd with SBVvax.

 

Report – January 2013

SBV has caused a major problem for Charollais flocks lambing to date. The office was first alerted by flocks lambing in early December that they were losing lambs with signs of SBV. A number of flocks had these early lambs tested and this confirmed the existence of SBV.

It was then crucial that we obtained a clear picture of the severity and spread of the disease, so we asked breeders to let us know if and how bad the losses had been in their flocks.  The disease is not a notifiable disease and animal health offices were not particularly interested in cases from farms in counties, where the disease had already been recorded.  Farmers would be required to pay for the test – so what was there for them to gain?  For this reason the reporting of the disease and the official statistics are woefully understated.

To date we have been informed of SBV in 62 flocks.  The geographical spread of these has been from North Yorkshire on the east side of the country to Staffordshire/Cheshire on the west and all counties south of these two points in England.  In Wales the problem does not seem to have spread further north than Brecon.  We have also had reports from Southern Ireland of the disease. No cases of the disease have been reported in Scotland or Northern Ireland.

The majority of flocks have lost between 25 – 50% of their lambs.  A few flocks have been lucky where losses have been small; either they seem to be on the ‘edge’ of the infected area or as in the case of Norfolk/Kent/Essex sheep were probably infected last year and have gained immunity.

Although it does seem that immunity in subsequent years may be strong, we took the viewpoint that the industry needed a reliable and tested solution to combat this disease.  Not only will the financial losses for the infected flocks be great, but the distress of dealing with deformed lambs that are often difficult to deliver, has been huge.  We have had a number of breeders state they will not go through this again and will either sell or not mate their sheep this year unless a suitable vaccine is available to use.

The problem is in no way restricted to our breed.  Other early lambing flocks such as Hampshires, Dorsets and Suffolks were similarly affected.  As the lambing season continues other breeds and commercial flocks are now seeing the problem.  It would also seem that the spread is going further north as the season continues and also losses in January lambing sheep have increased in regions only minimally hit in December.  This does not bode well for the main commercial lambing season.  In Norfolk last year cases of SBV were seen from January until May.

The development of a vaccine is well underway by MSD.  It is currently awaiting approval by the VMD – but this situation seems to have been the case for some time now.  We do not have a delivery date for vaccine.  The Chief Vet has not endeared himself to our breeders by stating that the disease is a ‘low impact disease’.  This is patently not the case for those flocks which have been affected.

We have been successful in getting our message over via the media.  We had coverage on Radio 4 Farming Today programme around Christmas – Jonathan was on 3 times in the week before Christmas and also had a slot on Boxing Day.  Carroll has just recorded a further piece on SBV to go out wk beginning 28/01/2013.  We have been reported in Farmers Weekly, Farmers Guardian and Scottish Farmer.  Charles Sercombe has been busy both in his role as Livestock Chairman NFU and sheep farmer with an infected flock with pieces in the farming press and an excellent spot on BBC 1’s Countryfile.  This is worth catching up on Iplayer if you have not already seen it.

We will keep the pressure on NSA, NFU and other bodies to lobby for the arrival of the vaccine in good time for our next mating season.

Schmallenberg Virus is a new emerging livestock disease that has been detected in Belgium, Germany, the Netherlands and the UK.

It is similar to some other animal disease pathogens, such as Akabane and Shamonda viruses, which are transmitted by vectors, such as midges, mosquitoes and ticks.

The virus has been associated with brief mild/moderate disease (milk drop, pyrexia, diarrhoea) in adult cattle and late abortion or birth defects in newborn cattle, sheep and goats.

All the evidence currently suggests that the disease was brought into the UK from infected midges blown across the Channel.  We have seen no evidence to suggest that it was from imported livestock. We are closely tracking the disease and will continue to work with partners across Europe and the UK to develop our knowledge of the disease.

Schmallenberg Virus is not a notifiable disease but farmers are asked to contact their veterinary surgeon if they encounter cases of ruminant neonates or fetuses which are stillborn, show malformations or are showing nervous disease.

 

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