BLUETONGUE

In July-August 1999, bluetongue was reported in Bulgaria where serotype 9 was isolated by the OIE Reference Laboratory, Institute of Animal Health, Pirbright (see EMPRES Bulletin No. 11).

More recently, in December 1999, an outbreak of bluetongue was reported in Tunisia for the first time after detection of antibodies and the observation of clinical signs in sheep. The outbreaks were located in seven districts (Ouardanine, Jemmel, Bembla, Zeramdine, El Djem, Sousse and Sfax south) in the governorates of Monastir, Mahdia and Sfax (see map) and involved 8 924 small ruminants. A total of 829 cases were seen, of which 325 animals died.

A thorough epidemiological investigation will be necessary to determine the full extent of the outbreak, its origin and the distribution of the vector responsible for the transmission of the disease. Furthermore, the serotype responsible for the disease must be identified before considering the implementation of any vaccination campaign. So far, the following control measures have been taken.

In the outbreaks:

• Imposition of quarantine in the affected farms;
• Identification of animals by ear-tagging;
• Burial of carcasses;
• Cleansing and disinfection;
• Insecticide applied on animals and premises.

Around the outbreaks:

• Clinical surveillance of the farms;
• Periodical inspection of flocks;
• Clinical examination of animals.

BLUETONGUE Bluetongue is an arthropod-borne viral disease of ruminants. The disease is of variable clinical severity and is characterized by catarrhal inflammation of mucous membranes with widespread haemorrhaging and oedema. All ruminants are susceptible (sheep, goats, cattle, buffaloes, antelopes and deer), but among domestic animals sheep are the most severely affected. In acute cases, the lips and tongue become very swollen and oedema may extend over the face to include the ears and the intermandibular space. The clinical feature that gives the disease its name - a deeply cyanotic tongue - occurs only in a small percentage of cases.