Clinical symptoms caused by the bluetongue virus serotype 8: experiences from the outbreak in Belgium

The present paper describes our clinical experiences with the outbreak of Blue Tongue Virus (BTV) serotype 8 in Belgium since 2006. Especially in 2007 the spread of the infection was very rapid and caused by Culicoides vectors which are also present in countries like UK. Although the outbreak of this infectious although not contagious disease was especially catastrophic in sheep, severe clinical symptoms were also seen in cattle. The most prominent clinical Symptoms in cattle were: crusts/lesions of nasal mucous membranes, salivation, fever, conjunctivitis, dysphagia, serous nasal discharge, apathy and/or tiredness, hyperaemic/purple coloration, lesions of teats, lameness and coronitis. Until now, it is not fully clear yet what the effects of this viral infection may be in the long term. Furthermore, the present paper shortly describes some basic knowledge of the virus and the pathogenesis of the disease, and more comprehensively points up the clinical symptoms of BTV-serotype 8 infections based on our experiences with the outbreaks of 2006 and 2007 in Belgium. Paramount aim of the paper is to help practitioners to recognise and report the disease promptly in the event of an outbreak in another country. As the serotype 8 outbreak was characterized by some specific clinical features different from the well described symptoms accompanying infections caused by more regularly occurring serotypes, the main emphasis will go to these specific features