No abstract

Porcine dermatitis and nephropathy syndrome (PDNS) is a sporadic, usually fatal disease of growing and finishing pigs that has been recognized in many pig-producing countries. Pasteurella multocida strains isolated from 15 pigs with PDNS and 51 pigs without PDNS were characterized by capsule and somatic antigen typing, random amplified polymorphic DNA (RAP-D) typing, and restriction analysis of genomic DNA using pulsedfield gel electrophoresis (PFGE). While capsular, somatic, and RAP-D typing did not discriminate PDNS isolates from non-PDNS isolates, all of the isolates from PDNS cases showed an identical ApaI PFGE restriction pattern. This pattern was also found in a high proportion (36%) of P. multocida strains isolated from non-PDNS cases. Isolation of a single variant of P. multocida from tissues of pigs with PDNS warrants further investigation into the possible role of these bacteria in the etiology of the disease.Porcine dermatitis and nephropathy syndrome (PDNS) is a disease of unknown etiology that has been recognized in many pig-producing countries. The disease most commonly affects pigs between 2 and 7 months of age, and cases can occur sporadically or as an outbreak within herds. There is a high mortality rate (approximately 80%) in clinically affected pigs. The pathological changes are consistent with an immune complex disorder resulting in severe glomerulonephritis. Vasculitis occurs in the kidneys, skin, and other tissues with deposits of immunoglobulins and complement in the areas of lesion development (1, 8, 14, 15). A number of potential causes have been suggested, including viral or bacterial infections and dietary factors (8, 13). However, no definitive link has yet been established with any specific factors. In a study on bacterial isolations from PDNS-affected pigs, Pasteurella multocida was isolated from one or more tissue sites in 16 out of 20 cases, and P. multocida-specific antigen was demonstrated in affected kidney tissue from 17 of these cases (16). Other potential bacterial pathogens were isolated from some of the PDNS cases, but their isolation rates were much lower and there was little consistency between cases, compared with results for P. multocida (16). Since these studies suggested a strong association with P. multocida, a strain typing study was undertaken with representative P. multocida isolates arising from these cases. The aim was first to compare the strain types between PDNS cases and second to compare the PDNS strain types with those isolated from a cohort of non-PDNS cases. This paper reports on the comparative strain typing studies. An abstract summarizing the results of this study has been published previously (J. R. Thomson, F. A. Lainson, N. Thomson, and W. Donachie, Proc. 15th Int. Pig Vet. Soc. Congr., vol. 3, p. 396, 1998). MATERIALS AND METHODS PDNS cases.Cases for this study were selected on the basis of their typical clinical histories and pathological lesions, the freshness of their carcasses, and because they each came from a different farm. The diagnostic...

This paper documents the salient clinical and pathological features of porcine dermatitis and nephropathy syndrome (PDNS) in 96 pigs submitted from 55 units in the UK from 1993 to 1998. This series of cases pre-dated the emergence of post-weaning multisystemic wasting syndrome (PMWS) in the UK. The morbidity during outbreaks was 1% or less. Affected pigs ranged from 14 to 70 kg in weight and most died after a short clinical illness. Fifty-five pigs had multifocal or coalescing erythematous skin lesions, some progressing to dermal necrosis. Biochemistry showed raised serum urea, creatinine and gamma globulin levels accompanied by proteinuria. All cases showed bilateral renal enlargement with petechiae throughout the cortices. Microscopically these renal lesions ranged in chronology from acute necrotizing glomerulitis and vasculitis with multiple hyaline casts in renal tubules to chronic glomerular sclerosis with interstitial inflammation and fibrosis. Haemorrhagic dermatitis when present was associated with necrotizing vasculitis in the dermal vessels. Vasculitis was sometimes detected in other tissues including subcutis, lymph nodes, spleen, liver, joint synovial membrane, gastric and intestinal submucosa or serosa and meninges but its frequency and distribution varied considerably in individual pigs. Immunostaining showed deposits of IgG and IgM in damaged glomeruli, renal casts and skin lesions. The aetiology and pathogenesis of the condition remain unknown but the histopathological and immunological findings suggest a systemic immune-complex disorder resulting in vasculitis with particular predilection for kidney and skin.

SummaryEpidermolysis bullosa (EB) was diagnosed in eight calves from four farms in the United Kingdom on the basis of clinical, histological and ultrastructural findings. In three affected herds, pedigree Simmental bulls had been mated with Simmental-cross cows. In a fourth herd two Holstein-Friesian calves were affected. Lesions included multifocal erosion and ulceration of the hard and soft palates, tongue, nares and gingiva, with onychomadesis (dysungulation). There was alopecia, erosion and crusting of the coronets, pasterns, fetlocks, carpi, hocks, flanks and axillae. Histopathological findings included segmental separation of full thickness epidermis from the dermis, with formation of large clefts containing eosinophilic fluid, extravasated red blood cells and small numbers of neutrophils. Follicular and interfollicular areas of skin were affected, with clefts extending around hair follicles and sometimes involving whole follicles. Ultrastructurally, there was evidence of vacuolar change within basal keratinocytes, corresponding to areas of histological clefting. Preliminary genetic screening of the candidate keratin genes (bKRT5 and bKRT14) has excluded mutations of these as the cause of this condition.Crown

Comprehensive bacterial cultures were made on samples from 20 pigs that had died of porcine dermatitis and nephropathy syndrome after a short clinical illness. Eleven species of porcine bacterial pathogens and a range of commensal organisms were isolated. Pasteurella multocida was isolated from 16 of the 20 cases but the other pathogens occurred much less commonly. P. multocida was isolated from between one and five sites per case and from the tonsils, retropharyngeal lymph node or lungs in 14 of the 16 cases. Immunohistochemical investigations of kidneys from 30 cases of the syndrome (including the 20 cases in the bacteriological study) revealed P. multocida-specific staining in 26 of the cases, primarily in the renal tubular epithelial cells of the proximal convoluted tubules, but also in the glomeruli, in lesions of renal vasculitis and in the cytoplasm of interstitial mononuclear cells.