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The Gram-negative bacterium Pasteurella multocida causes pneumonic and systemic pasteurellosis in bovids for which vaccines are either unavailable or inadequate. The work assessed whether an intranasal P. multocida challenge in mice might provide a model of infection for future vaccine development work. Clinical, pathological and biochemical responses were compared in seven strains of mice challenged with a virulent bovine pneumonic isolate of P. multocida A:3. Six mouse strains (Porton, CD-1, BALB/c, VM, C57BL/10 and C57BL/6) developed clinical signs of pneumonic disease and variable pneumonic lesions 41-70 h post-infection. In contrast, mouse strain RIII became septicaemic within 36 h post-infection. Concentrations of plasma acute phase proteins and serum lipopolysaccharide increased in all mice after infection, and the main or interaction effect of mouse strain and infection status was statistically significant (P < 0.05). Responses in C57BL/10 mice showed close similarity to bovine pneumonic and in RIII mice to bovine systemic pasteurellosis. [ABSTRACT FROM AUTHOR]

The native red squirrel Sciurus vulgaris population in Britain has been on the decline for many years. A poxvirus associated with the introduced American grey squirrel S. carolinensis has been recognized as having a major role in the reduction of red squirrel numbers by causing a deleterious disease, known as squirrelpox, from which they seldom recover. In Ireland, red squirrel numbers have also been reducing while the grey squirrel population, first introduced in 1911, has been expanding. Until now, no poxvirus-associated disease had been found in Irish red squirrels and therefore, the role of squirrelpox in the displacement of red squirrels by grey squirrels in Ireland has been questioned. Here we report, for the first time, confirmed squirrelpox disease in two populations of red squirrels in Northern Ireland. In addition, we present serological evidence of the extent of poxvirus infection in the grey squirrels from both the Republic of Ireland and Northern Ireland, including an apparent increase in the seroprevalence of antibodies against the virus in grey squirrels over the period of the study, and discuss the implications of our findings for the conservation tactics employed to protect red squirrels. [ABSTRACT FROM AUTHOR]

The possible cause of disease and mortality in corvids on an outdoor pig unit in the north of England between August 2007 and March 2008 was investigated. Nine carrion crows (Corvus corone corone) and nine rooks (Corvus frugilegus), comprising five live-caught birds with clinical signs of respiratory disease, one live-caught bird without respiratory disease, and 12 birds submitted dead were examined. Clinical signs, gross and histopathological examination, microbiology and toxicology indicated that Pasteurella multocida infection was the cause of disease. Molecular and serotyping analyses showed that P. multocida isolates (obtained from live-caught birds with clinical respiratory disease) were all capsular type F with a mix of somatic serotypes 3, 4 and 7. Immunohistochemistry increased the diagnostic sensitivity of the analysis and detected P. multocida within the pulmonary lesions of all affected live-caught birds and 10 of 12 birds found dead. These findings suggest that wild corvids in the UK can suffer from lung pathology associated with P. multocida and, as potential vectors of P. multocida, may pose a risk to domestic poultry. [ABSTRACT FROM AUTHOR]

The objectives of this study were to investigate the early stages of experimental infection of the ovine mammary gland with Mannheimia haemolytica and to identify the lymphocyte subsets accumulating at the teat duct. M. haemolytica was inoculated into one teat of each of 25 ewes and clinical, bacteriological, cytological, haematological, physicochemical, gross pathological, histopathological and immunohistochemical examinations were carried out. Clinical signs of inflammation were evident by 8 h but had subsided 2 days after challenge. Polymorphonuclear neutrophils (PMN) predominated in milk films up to 1 day following challenge, but the proportion of lymphocytes and macrophages progressively increased thereafter. Total blood leucocyte counts decreased immediately after challenge and then rose until 1 day after challenge with immature PMNs comprising >3% of the total. The pH of the mammary secretions from the challenged side was increased (>7.0). Focal lymphoid accumulations were observed in the lamina propria at the junction of the teat duct and cistern, including CD79+, CD3+ and γδ T cells, CD68+ and MHC-II+ cells with a particular increase in the numbers of CD8+ T cells from days 3 to 5 after challenge. The findings suggest that these organised lymphoid structures are inducible and contribute to the defence of the infected teat when the PMN-macrophage response is overwhelmed. [ABSTRACT FROM AUTHOR]

Squirrelpox, caused by a poxvirus, is a major threat to the remaining UK red squirrel population. The spread of antibody-positive grey squirrels has been monitored in the UK for the past decade. In 2005 grey squirrels that had been exposed to the virus appeared in the south of Scotland for the first time, followed approximately two years later by the appearance of squirrelpox disease in the local red squirrels. Four squirrels were examined. They all had gross external lesions and histological lesions typical of squirrelpox disease, but no significant internal lesions. The diagnosis was confirmed by PCR, electron microscopy and serology. [ABSTRACT FROM AUTHOR]

Cardiovascular disease is the leading cause of human mortality and disability worldwide, primarily due to myocardial infarction (MI) and the resultant heart failure. To address this, animal models of MI have been developed to better understand the pathophysiological process and to enable the discovery and development of new therapies. The most commonly used small and large mammal models of MI accurately reproduce histopathologically the four characteristic post-MI phases: cardiac cell death, inflammation, myocardial repair and remodelling. However, differences between the time of onset of each characteristic phase and the kinetics of various cellular reactions between human MI and animal models, and between animal models, require careful consideration when defining the variables to be analysed and the timepoints of assessment in experimental studies. Typically, the progression of the different phases post-MI occur more rapidly in rodent models compared with large-animal models and man, suggesting the use of large-animal models is more translational for studying human MI. This review provides an overview of the main anatomopathological features of small and large animal models of MI and discusses the key species-specific histopathological similarities and differences., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

European moles (Talpa europaea) are a common species in the UK, but there are few published data on the causes of mortality in these animals. An opportunistic post-mortem study was carried out on 44 moles found dead or dying in Cornwall, UK. Assessment of muscle condition and fat reserves, where possible, indicated that most (27 of 37, 73%) were in good nutritive condition. The majority had died of trauma (n = 40, 91%), the principal cause of which was predation (n = 36, 81.8%) by foxes and domestic cats and dogs. The carcases were in a variable state of preservation, but 28 cases were suitable for histopathological examination. This revealed lesions in the lungs of 92.8 % (26 of 28) of the animals. The commonest lesions comprised localized infiltration of the parenchyma by macrophages and eosinophils and in most cases the lesions were unlikely to have been of clinical significance; in two cases they were associated with infection by a parasitic nematode. One mole showed severe pneumonitis and hepatitis caused by infection with Toxoplasma gondii. Adiaspiromycosis was diagnosed in two moles, one by direct microscopical examination of the lung and one by histopathology; the lesions were not considered to be of clinical significance. Severe pleurisy and pericarditis caused by infection with Streptobacillus moniliformis was seen in a mole that had suffered bite wounds to a foot previously. Cholangitis due to infection by a protozoal parasite, provisionally identified as Cyclospora talpae, was a common histopathological finding (11 of 28, 39.3%); infection by the parasite did not appear to affect body condition adversely. Miscellaneous conditions identified were ulcerative dermatitis associated with gram-positive cocci (n = 1), extra medullary haemopoiesis in spleens (six of 12, 50%) and mineralized foci in pulmonary blood vessels (three of 28, 10.7%). No significant pathology was seen in the kidneys. This study suggests that the health status of moles in Cornwall is generally good and predation is a common cause of mortality. Pulmonary disease, associated in some cases with nematode infections, is also prevalent, but probably of little clinical significance. There is a high prevalence of cholangitis due to infection with a protozoan parasite believed to be C. talpae. Other diseases identified include adiaspiromycosis, streptobacillosis and toxoplasmosis., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Louping-ill (LI), caused by louping-ill virus (LIV), results in a frequently fatal encephalitis primarily affecting sheep and red grouse (Lagopus lagopus scotica), but it does occur in other species. An adult male Border collie dog was definitively diagnosed with fatal LI and the lesion profile, LIV antigen distribution and full genome sequence of the LIV responsible were investigated to determine if this differed significantly from sheep-derived LIV. No gross lesions were present. The histological lesions were confined to the central nervous system and comprised of lymphocytic perivascular cuffs, glial foci, neuronal necrosis and neuronophagia. Immunolocalization of viral antigen showed small amounts present in neurons only. These histological and immunohistochemical findings were similar to those reported in affected sheep. Compared with published full genome sequences of sheep-derived LIV, only very minor differences were present and phylogenetically the virus clustered individually between a subclade containing Scottish strains, LIV 369/T2 and G and another subclade containing an English isolate LIV A. The LIV isolated from the dog shares a common progenitor with LIV A. These findings suggest there is no canine-specific LIV strain, dogs are susceptible to sheep-associated strains of LI and with the increase in tick prevalence, and therefore exposure to LIV, a safe, effective vaccine for dogs may be required., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Gill disorders have become a significant problem during the marine phase of farming Atlantic salmon (Salmo salar L.). The term complex gill disease (CGD) includes a wide range of clinical gill disease presentations generally occurring from the end of summer to early winter on marine Atlantic salmon farms. The gross and histological lesions observed are the resultant culmination of exposure to a mixture of environmental insults, pathogenic organisms and farm management practices. None of the three principal agents purportedly associated with CGD (Desmozoon lepeophtherii, salmon gill poxvirus or Candidatus Branchiomonas cysticola) have been cultured successfully in-vitro, so individual in-vivo challenge studies to identify their pathogenesis have not been possible. Studies of cohabitation of single pathogen-infected fish with naïve fish, and epidemiological investigations are required urgently to elucidate the roles of these pathogens and other factors in CGD., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The Gough moorhen (Gallinula comeri) is native to Gough Island, Tristan da Cunha, and listed as Vulnerable by the International Union for Conservation of Nature due to its restricted range and susceptibility to introduced predators. A planned ecosystem restoration by eradication of introduced house mice (Mus musculus) via aerially delivered rodenticide requires a reproductively balanced population of Gough moorhens to be held in captivity to avoid primary and secondary poisoning. To aid disease detection during the period of captivity, Gough moorhens (n = 43; 25 adult females and 18 adult males) were captured, measured and sampled to determine ease of sexing by morphometrics, to establish reference ranges for routine haematological and biochemical parameters and to identify any intestinal and haemoparasites as well as determine which faecal bacteria were present. Male Gough moorhens had significantly greater mean body mass (P = 0.019) and head and bill length (P = 0.001) compared with females, but the overlapping ranges showed genetic identification of sex was required for accurate determination. Plasma globulin and total protein concentrations were significantly greater in female compared with male birds (P = 0.032 and P = 0.012, respectively) and probably related to egg yolk production. No haemoparasites or gastrointestinal parasites were found in any bird and there were no sex-related differences in the haematology. Multiple bacterial taxa were isolated from the faeces of all birds including Enterococcus spp. (n = 42), Klebsiella spp. (n = 40), Staphylococcus aureus (n = 33), Staphylococcus intermedius (n = 16), Escherichia coli (n = 41) and Pseudomonas spp. (n = 7). No clinical or subclinical disease was found in any of the birds examined, suggesting they are suitable for short-term captivity but rapid on-island genetic-based sex determination will be essential to ensure a reproductively balanced population., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Spanish goat encephalitis virus (SGEV) is a recently described member of the genus Flavivirus belonging to the tick-borne encephalitis group of viruses, and is closely related to louping ill virus (LIV). Naturally acquired disease in goats results in severe, acute encephalitis and 100% mortality. Eighteen goats were challenged subcutaneously with SGEV; nine were vaccinated previously against LIV and nine were not. None of the vaccinated goats showed any clinical signs of disease or histological lesions, but all of the non-vaccinated goats developed pyrexia and 5/9 developed neurological clinical signs, primarily tremors in the neck and ataxia. All non-vaccinated animals developed histological lesions restricted to the central nervous system and consistent with a lymphocytic meningomyeloencephalitis. Vaccinated goats had significantly (P <0.003) greater concentrations of serum IgG and lower levels of IgM (P <0.0001) compared with unvaccinated animals. SGEV RNA levels were below detectable limits in the vaccinated goats throughout the experiment, but increased rapidly and were significantly (P <0.0001) greater 2-10 days post challenge in the non-vaccinated group. In conclusion, vaccination of goats against LIV confers highly effective protection against SGEV; this is probably mediated by IgG and prevents an increase in viral RNA load in serum such that vaccinated animals would not be an effective reservoir of the virus., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Spanish goat encephalitis virus (SGEV) is a member of the genus Flavivirus, family Flaviviridae, and causes encephalomyelitis in goats. The aim of this study was to determine whether sheep are susceptible to experimental challenge with SGEV by two different routes. The results show that SGEV can infect sheep by both the subcutaneous and intravenous routes, resulting in neurological clinical disease with extensive and severe histological lesions in the central nervous system. Lambs challenged subcutaneously developed more severe lesions on the ipsilateral side of the brain, but the lesion morphology was similar irrespective of the route of challenge. The clinical presentation, pathogenesis, lesion morphology and distribution shows that SGEV is very similar to louping ill virus (LIV) and therefore any disease control plan must take into account any host species and SGEV vectors as potential reservoirs. Furthermore, discriminatory diagnostics need to be applied to any sheep or goat suspected of disease due to any flavivirus in areas where SGEV and LIV co-exist., (Copyright © 2017 Elsevier Ltd. All rights reserved.)