Bluetongue

Bluetongue viruses (BTV) cause diseases that have serious economic consequences in ruminants (sheep, cattle) in many parts of the world. The incidence of bluetongue disease affects the international movement of animals and germ plasm. Although the etiological agent of the disease was isolated in 1900 and preliminary biochemical characterizations were pub lished as early as in 1969, most of the current understanding of the molecular biology, biochemistry, and genetics of BTV has evolved only recently. Triggered by the modern techniques of molecular biology, genetics, and immunology, BTV research has experienced an information explosion in the past 10 years. However, much of this information is scattered throughout an extensive literature. It is therefore an appropriate time to meld this together into a reference book. This book includes compre hensive information on BTV research provided in articles contributed by researchers from around the world. It covers what is known about the molecular structure of the virus and the current understanding of its biology, evolution, and relationships with its invertebrate and vertebrate hosts (infection, immunity, and pathogenicity).

The third volume in the Institute of Animal Health (IAH) Biology of Animal Infections Series, Bluetongue discusses one of the most economically important diseases of domesticated livestock. Affecting primarily sheep particularly the improved mutton and wool breeds, it is now endemic in Africa, India, the Middle and Far East, Australia and the Americas, and over the last six years has caused a series of outbreaks throughout the Mediterranean region and central Europe. Bluetongue represent a paradigm not only for the other orbiviruses (such as African horse sickness virus, which shares the same vector species) but also for other insect transmitted diseases, including those of humans. The only single definitive work that provides both historical and up to date data on the disease Describes the latest developments in epidemiological modelling, molecular epidemiology and vaccine development, as well as explaining the current global epidemiology of the disease Outlines the importance and possible mechanisms of overwintering, and the impact of global warming on the vectors and virus distribution

Bluetongue, African Horse Sickness, and Related Orbiviruses: Proceedings of the Second International Symposium provides the latest scientific information about this group of Orbiviruses, which are transmitted by species of Culicoides (biting midges) and are important causes of disease in domestic livestock and wildlife. Originally presented at the Second International Symposium on the Orbivirus held in Paris, France in June 1991, the book reviews the history and latest data on epizootiology; clinical syndromes and host responses; vector biology, competence, genetics, and capacity; molecular virology and genetics; and diagnostic procedures. The book covers regulatory issues associated with bluetongue, epizootic hemmorrhagic disease, African horse sickness, Ibaraki disease, and equine encephalosis. It also addresses the latest orbiviral diagnostic procedures including ELISA and the polymerase chain reaction; the latest cloning, sequencing, and genetics information of these viruses, and the genetics of oral susceptibility of the vector. Bluetongue, African Horse Sickness, and Related Orbiviruses: Proceedings of the Second International Symposium is an excellent reference source for researchers in arbovirology, veterinary regulatory officials, foreign animal disease diagnosticians, and veterinary students.

Bluetongue may be described as an acute insect borne disease of ruminants, manifested clinically in sheep by a catarrhal inflammation of the mucous mem branes of the digestive and respiratory systems and associated with degenerative changes in the skeletal musculature. The profound emaciation and weakness which follow the acute disease are responsible for a protracted convalescence and for serious economic losses due to diminished productivity. II. Historical During the early colonisation of Africa, susceptible Merino and other European breeds of sheep were introduced into the Cape, at first by the Dutch East India Company between 1652 and 1785 and again later in 1870. A report of the Cattle and Sheep Diseases Commission (1876) records the appearance of a serious febrile disease amongst these imported sheep in which both morbidity and mortality was high (cited by HENNING, 1949). HuTCHEON (1881) gave this disease the name of "Fever" or "Epizootic Catarrh", in order to distinguish it from other clinical conditions of a similar nature encountered amongst sheep. In the first com prehensive description of this clinical syndrome and its epizootiology HuTCHEON (1902) referred to it as "Malarial Catarrhal Fever of Sheep", a designation which was obviously influenced by the mistaken belief that an intracorpuscular parasite was the primary cause of the disease. More systematic studies were conducted by SPREULL (1902; 1905), who endeavoured to immunize sheep by the simultaneous inoculation of immune serum and infective blood.

Bluetongue (BT) is an infectious, viral and vector-borne disease of improved breeds of sheep and some species of deer that is of major international importance. The infection is usually unapparent in cattle, which acts as reservoir for the virus. However, some serotypes such as serotype 8 (BTV-8), which recently caused a severe epizootic of BT in northern Europe, exhibit a more important virulence in cattle. Consequently, the redaction of a scientific booklet describing Bluetongue is of great utility for veterinarians and animal health professionals in the framework of an early detection of Bluetongue and other emerging diseases.