title: Louping ill virus: an endemic tick-borne disease of Great Britain.
abstract: In Europe and Asia, Ixodid ticks transmit tick-borne encephalitis virus (TBEV), a flavivirus that causes severe encephalitis in humans but appears to show no virulence for livestock and wildlife. In the British Isles, where TBEV is absent, a closely related tick-borne flavivirus, named louping ill virus (LIV), is present. However, unlike TBEV, LIV causes a febrile illness in sheep, cattle, grouse and some other species, that can progress to fatal encephalitis. The disease is detected predominantly in animals from upland areas of the UK and Ireland. This distribution is closely associated with the presence of its arthropod vector, the hard tick Ixodes ricinus. The virus is a positive-strand RNA virus belonging to the genus Flavivirus, exhibiting a high degree of genetic homology to TBEV and other mammalian tick-borne viruses. In addition to causing acute encephalomyelitis in sheep, other mammals and some avian species, the virus is recognized as a zoonotic agent with occasional reports of seropositive individuals, particularly those whose occupation involves contact with sheep. Preventative vaccination in sheep is effective although there is no treatment for disease. Surveillance for LIV in Great Britain is limited despite an increased awareness of emerging arthropod-borne diseases and potential changes in distribution and epidemiology. This review provides an overview of LIV and highlights areas where further effort is needed to control this disease.
authors.affiliation: Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, Addlestone, Surrey KT15 3NB, UK.
authors.forename: C L
authors.initials: CL
authors.lastname: Jeffries
authors.affiliation: Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, Addlestone, Surrey KT15 3NB, UK.
authors.forename: K L
authors.initials: KL
authors.lastname: Mansfield
authors.affiliation: Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, Addlestone, Surrey KT15 3NB, UK.
authors.forename: L P
authors.initials: LP
authors.lastname: Phipps
authors.affiliation: Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, Addlestone, Surrey KT15 3NB, UK.
authors.forename: P R
authors.initials: PR
authors.lastname: Wakeley
authors.affiliation: Animal Health and Veterinary Laboratories Agency - Penrith, Merrythought, Calthwaite, Penrith CA11 9RR, UK.
authors.forename: R
authors.initials: R
authors.lastname: Mearns
authors.affiliation: Animal Health and Veterinary Laboratories Agency - Lasswade, Pentlands Science Park, Penicuik, Midlothian EH26 0PZ, UK.
authors.forename: A
authors.initials: A
authors.lastname: Schock
authors.affiliation: Animal Health and Veterinary Laboratories Agency -Shrewsbury Investigation Centre & Laboratory, Kendal Road, Harlscott, Shrewsbury, Shropshire SY1 4HD, UK.
authors.forename: S
authors.initials: S
authors.lastname: Bell
authors.affiliation: Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, Addlestone, Surrey KT15 3NB, UK.
authors.forename: A C
authors.initials: AC
authors.lastname: Breed
authors.affiliation: University of Liverpool, Department of Clinical Infection, Microbiology and Immunology, Liverpool, Merseyside L69 7BE, UK.|Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, Addlestone, Surrey KT15 3NB, UK.
authors.forename: A R
authors.initials: AR
authors.lastname: Fooks
authors.affiliation: Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, Addlestone, Surrey KT15 3NB, UK.
authors.forename: N
authors.initials: N
authors.lastname: Johnson
mesh_terms: D000818:Animals; D000829:Animals, Domestic; D004669:Encephalitis Viruses, Tick-Borne / Q000302:isolation & purification*; D004675:Encephalitis, Tick-Borne / Q000453:epidemiology* / Q000662:veterinary* / Q000821:virology; D019353:Endemic Diseases; D006801:Humans; D018884:Ixodes / Q000821:virology; D016273:Occupational Exposure; D006113:United Kingdom / Q000453:epidemiology; D015047:Zoonoses / Q000453:epidemiology* / Q000821:virology