Intestinal lesions in pigs affected with postweaning multisystemic wasting syndrome Lesões entéricas em suínos afetados por síndrome multissistêmica do definhamento dos suínos

Samples of mesenteric lymph nodes and intestines from 79 unthrifty 3- to 5-month-old postweaning pigs, confirmed as naturally affected with postweaning multisystemic wasting syndrome (PMWS), were studied. Pigs originated from 12 farms in southern Brazil and were selected on the basis of clinical signs and/or gross lesions suggestive of enteric disorder. Lymphohistiocytic infiltrates of varying intensity were associated with anti-porcine circovirus type 2 (anti-PCV2) immunostaining (IS) in samples of intestines and mesenteric lymph nodes from all pigs. Although most findings were similar to those described in PCV2-associated enteritis, anti-PCV2 IS in association with depletion of the goblet cell mucin stores (24 pigs), diffuse ileal villous atrophy and fusion (18 pigs), and dilatation of the lymphatic vessels (11 pigs) combined or not with lymphangitis were also observed. PCV2 antigen was immunohistochemically demonstrated in the cytoplasm and nuclei from intralesional epithelial cells, histiocytes, and endothelial-like cells in intestinal tissues. Together these findings imply an association with PCV2. The presence of co-infections by Lawsonia intracellularis, Brachyspira spp., Mycobacterium spp., Salmonella spp., rotavirus, parvovirus, coronavirus and enteric calicivirus with PCV2 in the intestinal lesions was investigated.<br>Amostras de linfonodos mesentéricos e intestinos de 79 leitões desmamados refugos, entre 3 e 5 meses de idade e confirmados como naturalmente afetados pela síndrome multissistêmica do definhamento foram estudadas. Os suínos eram oriundos de 12 criações no sul do país e foram selecionados em função dos sinais clínicos e/ou lesões macroscópicas sugestivos de doença entérica. Infiltrados linfoistiocíticos de intensidades variáveis foram associados com marcação positiva anti-circovirus suíno tipo 2 (anti-PCV2) em amostras de intestinos e linfonodos mesentéricos de todos os 79 animais. Embora a maioria dos achados fossem semelhantes aos descritos em enterite associada com PCV2, marcação imuno-histoquímica anti-PCV2 foi associada com depleção de células caliciformes (24 suínos), atrofia e fusão de vilosidades do íleo (18 suínos) e dilatação de vasos linfáticos (11 suínos) combinada ou não com linfangite. Antígenos de PCV2 foram demonstrados por imuno-histoquímica no citoplasma e núcleo de células epiteliais intralesionais, histiócitos e células tipo endotelial em tecidos intestinais. Em conjunto, esses resultados sugerem que as lesões estavam associadas com PCV2. A presença de co-infecções por Lawsonia intracellularis, Brachyspira spp., Mycobacterium spp., Salmonella spp., rotavírus, parvovírus, coronavírus e calicivírus entérico com PCV2 nas lesões intestinais foi investigada

Rectal stenosis in pigs associated with Salmonella Typhimurium and porcine circovirus type 2 (PCV2) infection

Rectal stricture is an acquired annular fibrous constriction of the rectum that results from a variety of chronic necrotizing enteric diseases. In pigs, it is in most cases a sequel of Salmonella infection. Porcine circovirus type 2 (PCV2) is a known pathogen causing immunosuppression in pigs worldwide. PCV2 infected pigs may be predisposed to salmonellosis. In this report, rectal stenosis was observed in 160 pigs from a herd that experienced an outbreak of enteric salmonellosis over a 4-month period. Distension of the abdominal wall and diarrhea were the main clinical signs observed. Five animals were analyzed showing annular cicatrization of the rectal wall 5.0-7.0 cm anterior to the anorectal junction and Salmonella-positive immunostaining in the large intestine. Salmonella Typhimurium was isolated from fragments of the large intestine. Porcine circovirus type 2 antigen was observed in the mesenteric lymph-node in 4 pigs and in the large intestine in 3 pigs