Louping ill virus: an endemic tick-borne disease of Great Britain.

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.

Laminin 332 deposition is diminished in irradiated skin in an animal model of combined radiation and wound skin injury.

Skin exposure to ionizing radiation affects the normal wound healing process and greatly impacts the prognosis of affected individuals. We investigated the effect of ionizing radiation on wound healing in a rat model of combined radiation and wound skin injury. Using a soft X-ray beam, a single dose of ionizing radiation (10-40 Gy) was delivered to the skin without significant exposure to internal organs. At 1 h postirradiation, two skin wounds were made on the back of each rat. Control and experimental animals were euthanized at 3, 7, 14, 21 and 30 days postirradiation. The wound areas were measured, and tissue samples were evaluated for laminin 332 and matrix metalloproteinase (MMP) 2 expression. Our results clearly demonstrate that radiation exposure significantly delayed wound healing in a dose-related manner. Evaluation of irradiated and wounded skin showed decreased deposition of laminin 332 protein in the epidermal basement membrane together with an elevated expression of all three laminin 332 genes within 3 days postirradiation. The elevated laminin 332 gene expression was paralleled by an elevated gene and protein expression of MMP2, suggesting that the reduced amount of laminin 332 in irradiated skin is due to an imbalance between laminin 332 secretion and its accelerated processing by elevated tissue metalloproteinases. Western blot analysis of cultured rat keratinocytes showed decreased laminin 332 deposition by irradiated cells, and incubation of irradiated keratinocytes with MMP inhibitor significantly increased the amount of deposited laminin 332. Furthermore, irradiated keratinocytes exhibited a longer time to close an artificial wound, and this delay was partially corrected by seeding keratinocytes on laminin 332-coated plates. These data strongly suggest that laminin 332 deposition is inhibited by ionizing radiation and, in combination with slower keratinocyte migration, can contribute to the delayed wound healing of irradiated skin.

Pericardial myxoid liposarcoma in a common eland (Taurotragus oryx).

A pericardial myxoid liposarcoma was diagnosed in a common eland (Taurotragus oryx) based on gross, microscopical and immunohistochemical findings. The pericardial and epicardial tissues were soft and uniformly thickened. Microscopically, the neoplastic mass consisted of stellate cells embedded in a myxoid matrix. These cells contained cytoplasmic vacuoles stained by oil red O. Immunohistochemical analysis showed the neoplastic cells to express vimentin and S-100.

Obstructive jaundice and photosensitization in a lamb secondary to diaphragmatic hernia.

Obstructive jaundice and photosensitization occurred in a 9-month-old lamb as a sequela to a diaphragmatic hernia. A loop of proximal duodenum was displaced, resulting in occlusion of the common bile duct, cholecystitis and necrotizing hepatitis.

Outbreak of tuberculosis caused by Mycobacterium bovis in golden Guernsey goats in Great Britain.

An outbreak of caprine tuberculosis caused by Mycobacterium bovis was disclosed in June 2008, affecting goats of the golden Guernsey breed kept on 10 separate smallholdings in south-west Wales and the west of England. Following the initial diagnosis at postmortem examination, 30 goats that reacted positively to the single intradermal comparative cervical tuberculin (SICCT) test, together with five in-contact animals, were euthanased and subjected to postmortem examination and mycobacterial culture. Spoligotyping and variable number tandem repeat analysis of isolates showed that they were all of the same genotype, endemic to south-west Wales. Retrospective movement tracings identified a goat herd in south-west Wales, by then completely dispersed, as the probable common source of infection. There was a perfect correlation between the SICCT test and culture results in all slaughtered goats. Grossly visible tubercular lesions were observed at postmortem examination in all but one reactor.

Cerebral segmental polyarteritis of unknown aetiology in sheep.

Vasculitis affecting the meningeal elastic arteries was identified in six sheep of various breeds during routine diagnostic investigation. The lesions consisted of multifocal intimal proliferation, thickening of the tunica media, multifocal infiltration of the media by inflammatory cells and more extensive perivascular accumulation of lymphocytes and plasma cells within the tunica adventitia. Fibrinoid necrosis affected an intergyral artery in one sheep. Immunohistochemistry failed to demonstrate pestivirus antigen associated with the lesions and no alternative aetiology was defined. Possible causes of meningeal segmental polyarteritis in sheep are discussed.

Outbreak of sarcoptic mange in alpacas (Vicugna pacos) and control with repeated subcutaneous ivermectin injections.

An outbreak of sarcoptic mange was investigated in an alpaca herd. Clinical disease occurred 2 months after the introduction of four alpacas with dry seborrhoeic skin lesions, the cause of which was not investigated. Initially a group of females was affected, despite repeated topical treatment with ivermectin at a dose of 0.5mg/kg bodyweight. One female died and post-mortem examination indicated sarcoptic mange as the cause of death. Infection with Sarcoptes scabiei was also demonstrated on microscopic examination of skin scrapes taken from clinically affected cohorts. Later in the outbreak, a separate group of male alpacas was also affected. Treatment using subcutaneous ivermectin injections at a dose of 0.2mg/kg, administered at 14-day intervals, was evaluated. During this course of treatment, another female died. A successful response in the other alpacas was eventually reached following 12 treatments of the female group and 8 treatments of the male group.