Government vets have confirmed bluetongue disease is circulating in the UK and is now classed as an outbreak.
Symptoms of bluetongue are generally worst in sheep
What is bluetongue disease?
It is a non-contagious virus spread by a species of midge and is most commonly seen in the late summer and autumn.
All ruminants, such as cattle, goats, deer and sheep, are susceptible, although symptoms are generally most severe in sheep.
BLUETONGUE IN CATTLE
Swelling of the head and neck
Swelling of the mouth
However, in certain weather, midges can be carried much further, especially over water masses - up to 200km (124 miles).
Such distances vary according to local environmental, topographical and meteorological conditions, Defra says.
Will infected animals be culled?
Because bluetongue is spread by insects, Defra says compulsory slaughter of infected livestock would not normally be carried out.
However, the first five infected animals in Suffolk were killed and tests conducted to determine whether bluetongue had spread to other animals.
Government chief vet Fred Landeg had ruled out a cull because the disease cannot be passed from animal to animal and it would not help stamp it out.
Where has the disease been found?
Bluetongue was first discovered in South Africa but has since been found in most countries in the tropics and sub-tropics.
There are many species of the Culicoides midge, which is responsible for transmitting bluetongue disease
The species Culicoides imicola is active in Africa, the Middle East, south Asia and southern Europe
In central and northern Europe, including the UK, Culicoides obsoletus is the most common, but Culicoides pulicaris is also active
The Scottish highland midge is Culicoides impunctatus. There are no known natural cases of it passing on bluetongue
Since August 2006, the virus has been found in the Netherlands, Belgium, Luxembourg, Germany and northern France.
In late August 2008 two cases of bluetongue were found in rams near Lewes, East Sussex and Hemel Hempstead, Hertfordshire, both imported from Central France.
The disease was also found in eight imported cattle on premises near Tiverton, Devon which originated from Germany.
In September, 18 cattle imported from Germany were found to have the disease near Bishop Auckland, County Durham and another case was found on a premises near Yeovil, in Somerset, which originated from France.
There have also been outbreaks of different strains of the disease in Greece, Italy, Corsica and the Balearic Islands since 1998.
Cases have also occurred in Bulgaria, Croatia, Macedonia and Yugoslavia.
What restrictions are being placed on British farmers?
A 20km (12.4 miles) control zone is put in place around affected premises.
Ruminant animals can move within the zone, but not out of it, except to slaughter in the wider protection zone.
Farmers within the protection zone cannot transport livestock beyond the zone boundaries.
Can livestock be vaccinated against bluetongue?
Yes, a vaccine is available to all farmers in England and Wales with livestock inside the protection zone.
A voluntary programme is in operation.
Private vets are responsible for prescribing either the Intervet or Merial vaccine to sheep or cattle under their care following a clinical assessment, but need not administer it themselves.
Vaccinations will be compulsory in farms in Scotland for all seven million sheep and cattle from the start of the vector-free period which will begin in November, at the earliest, or possibly December.