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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.

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Pasteurella multocida serogroup A is commonly isolated from nasal swabs of clinically healthy calves and also from diseased lung tissue in bovine pneumonia. Here, we report the draft genome sequence of the virulent strain P. multocida 671/90, which has been characterized previously in experimental infections of calves and mice.

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Pasteurella multocida is a major pathogen of farm animals and has worldwide distribution. Here we report the draft genome sequences of four strains that were isolated from animals in the United Kingdom and the United States and represent pathogenic and commensal presentation of the bacterium.

Current epidemiological data (VIDA UK) relating to bovine pneumonic pasteurellosis, a disease of welfare and economic significance worldwide, indicate that Pasteurella multocida serotype A has overtaken Mannheimia haemolytica as the leading cause of disease. Iron acquisition mechanisms in P. multocida, as with the majority of bacteria, are an essential element for survival and proliferation and a major virulence factor, although the detailed processes involved are not defined. A mathematical approach described here has constructed a reaction network representing iron acquisition from host transferrin, suggested target genes for quantitative RT-PCR (qRT-PCR) and provided data for initial theoretical modelling. Primers were designed for qRT-PCR study of 8 iron acquisition genes: fur, tbpA, tonB, exbB, exbD, fbpA, fbpB and fbpC and applied to the analysis of total RNA extracted from P. multocida A:3 grown in vitro in iron replete and iron restricted conditions in a 4 x 1L benchtop fermenter (B. Braun Biotech); 3 vessels iron restricted (αα-dipyridyl), 1 control. Growth rates were measured from hourly sequential samples by estimated and live viable counts. Results for qRT-PCR revealed differences in expression of iron restricted outer membrane protein (IROMP) genes in iron replete and iron restricted conditions. In replete conditions, all genes showed a similar transcription pattern with a steady increase from 0-4 hours, followed by a plateau from 4-8 hours. Under iron restriction, all genes with the exception of fur exhibited a faster initial phase of transcription from 0-2 hours followed by a drop at 2 hours and a subsequent recovery at 6-8 hours. The transcription pattern for fur showed an initial drop from 0-2 hours followed by a steady increase in expression tending to plateau between 6-8 hours. The differing transcription pattern of fur is expected due to its role as a transcriptional repressor of IROMP expression. Surprisingly, bacterial growth rate was not suppressed by iron restriction using 200 µM αα-dipyridyl, suggesting that IROMP expression under these conditions was sufficient to provide the necessary iron. The subsequent drop in transcription may represent a period wherein acquired iron is metabolised after which a recovery in transcription is triggered by the need to replenish intracellular iron levels. Results suggest that the initial period of growth from 0-3 hours should be studied in greater depth.