After five animals were confirmed to be infected with the Bluetongue virus the UK government has declared an outbreak. This is the first time bluetongue has appeared in the United Kingdom. An official from Defra (Department for the Environment, Foods and Rural Affairs) said the disease is now circulating among the local animal and midge population.

The five confirmed infected animals were in Suffolk, eastern England. Authorities say that the animals have been culled.

Nobody knows how the disease arrived in the UK. It has been suggested that generally warmer weather may be a factor. Authorities are said to be hoping for a cold winter, which should eradicate the disease. Since July this year there have been almost 3,000 cases of bluetongue in Northwestern Europe.

A 20km Control Zone has been set up around the area where the five cases were identified. According to Defra, ruminant animals will be able to move around inside the Bluetongue Control Zone, but not out of it. A 150km Bluetongue Protection Zone which covers parts of the counties from Lincolnshire to Sussex will also be in place – ruminant animals will be able to move around inside that area, but not out of it. Defra informs that these Bluetongue zones will replace the Bluetongue Temporary Control Area which was set up on September 25th.

What is Bluetongue?

Bluetongue is a disease which affects all ruminant animals, such as cattle, deer, sheep, goats and camlids – humans and horses are not affected. Sheep are more severely affected than other animals. Cattle are the main mammalian reservoir of the virus.

The virus spreads through certain types of biting midges.

History of the disease

We are not sure how long it has been around. It was first described in South Africa, and is now recognized in most tropical and sub-tropical countries. Widespread outbreaks have occurred in the following countries since 1999: Greece, Italy, France (Corsica), Spain (Balearic Islands). There have also been cases in Bulgaria, Croatia, Macedonia, Yugoslavia and Kosovo – it normally does not reach as far north as these countries, but seems to have made its way there via North Africa and Turkey. In 2007 outbreaks were confirmed in Germany, Belgium, France, The Netherlands and Luxembourg – indicating the virus survived these countries’ winters successfully.

Clinical Signs of Bluetongue (How to spot it)

Depending on the species, clinical signs can vary. Although symptoms are more severe in sheep, occasionally cattle can show signs of the disease.

Sheep – Clinical Signs

— Eye, nasal discharge
— Drooling resulting from ulcerations in the mouth
— Fever
— Swelling of the neck, head and mouth
— The animal has a limp (lameness)
— Hemorrhages into or under the skin
— Inflammation at the coronary band (junction of the skin and the horn of the foot)
— Difficulty breathing
— Sheep mortality in a flock may reach 70%. Surviving animals might lose condition, resulting in a reduction in wool production and meat

Cattle – Clinical Signs
It is not uncommon for cattle to show no signs. With cattle the disease cannot be diagnosed on clinical grounds, laboratory testing is required.

— Nasal discharge
— Swelling around the neck and the head
— Runny eyes (conjunctivitis)
— Swelling of the mouth
— Ulceration in the mouth
— Swollen teats
— Lethargy, fatigue
— Drooling

Cause of Bluetongue

It is caused by a virus of the Orbivirus genus of the family Reorvirades. There are 24 known serotypes.

Biting midges (Culicoides) transmit the virus. One animal cannot directly infect another animal. When the midge bites an infected animal, the virus passes to the midge in the blood meal – the virus then multiplies in the midge. When the midge bites another animal, it infects that animal.

— How to spot the disease (PDF)
— Photos of clinical signs
— Photo of a midge (culicoides)
— Guidance on the disease vector and potential mitigation measures (PDF)
— http://www.defra.gov.uk

Written by: Christian Nordqvist