Histopathologic lesions in conventional pigs experimentally infected with Haemophilus parasuis serovar 5.

OBJECTIVE: In the present study various tissues of pigs were investigated for the presence of histopathologic lesions after an experimental infection with Haemophilus (H.) parasuis serovar 5. MATERIAL AND METHODS: Conventional pigs (n = 36) were divided into a control group B (n = 9) and a challenge group A (n = 27), which was infected intratracheally. Pigs that did not die prior to study termination were euthanized on day 14 post inoculation. Postmortem samples of the lung, heart, liver, kidney, spleen, left tarsal joint capsule and brain were collected. RESULTS: All but one pig with detectable histopathologic lesions (n = 11) showed typical macroscopic changes. Histopathologic examination of all tissue samples identified pyelitis (n = 10), synovitis (n = 7) and meningitis (n = 7) and all those animals were euthanized prior to study termination. No histopathologic lesions were found in pigs of the control group. The correlations between pyelitis and meningitis, pyelitis and synovitis and synovitis and meningitis were significant (p < 0.001). No significant correlation could be observed between the histopathologic and the clinical examination of the joints. The investigation of samples from the joints by PCR was not significantly correlated with the observed synovitis. The clinical observation of neurologic signs was significantly correlated with meningitis (p = 0.03). A significant correlation (p < 0.001) could be detected between meningitis and the detection of H. parasuis by PCR in brain samples. CONCLUSIONS: H. parasuis constantly causes clinical signs and pathologic lesions as soon as it infects the brain while it can infect the joints without causing histopathologic lesions. Pigs with histopathologic lesions do not always show typical clinical signs. Only few studies described the finding of kidney lesions in pigs with Glässer's disease and this is the first study to describe a pyelitis in pigs experimentally infected with H. parasuis. The observed pyelitis mainly occurred in acute cases.

[Evaluation of the efficacy of a combination therapy of an antibiotic and a NSAID following an experimental Haemophilus parasuis infection in nursery piglets]. / Wirksamkeitsbeurteilung einer Kombinationstherapie aus Antibiose und NSAID nach experimenteller Haemophilus-parasuis-Infektion bei Absetzferkeln.

OBJECTIVE: The aim of the present study was to evaluate the combination therapy of an antibiotic (enrofloxacine-arginine, Baytril® RSi) and a non-steroidal anti-inflammatory drug (NSAID, ketoprofen, Dinalgen® 60 mg/ml) against a Haemophilus parasuis (HPS) infection in nursery piglets. MATERIAL AND METHODS: Forty-eight 3-week-old pigs were divided into four groups (group 1: non-infected controls; group 2: HPS infection; group 3: HPS infection/Baytril® RSi; group 4: HPS infection/Baytril® RSi/Dinalgen®) and housed within the isolation facility. After an acclimatization period of 10 days, the piglets in groups 2-4 were intratracheally infected with 1 x 107 colony forming units (CFU) HPS serovar 5, whereas animals of group 1 received physiological saline. Total clinical scores and joint scores were calculated daily after clinical examination. Seven days after the infection, piglets were humanely euthanized. At necropsy, pathological findings on serosal surfaces were scored according to severity and extension. RESULTS: Group 1 had the lowest clinical and pathological scores, followed by groups 4, 3 and 2. Piglets treated with the combination of an antibiotic and an NSAID showed the lowest body temperatures (significant). The average daily weight gain (ADWG) was not significantly different between the groups, but piglets of group 4 tended to reach a higher mean ADWG (340.5 g/d) than animals of the non-infected group 1 (323.8 g/d), the Baytril® RSi-treated group 3 (278.0 g/d) and the positive control group 2 (247.0 g/d). Piglets of the positive control group (group 2) achieved the highest values in the clinical, joint and serositis scores. CONCLUSION: The study demonstrated that a simultaneous treatment with enrofloxacine-arginine (Baytril® RSi) and ketoprofen had a superior therapeutic effect compared to a single antibiotic treatment with Baytril® RSi in nursery piglets experimentally infected with HPS.

Immunohistochemical characterization of type II pneumocyte proliferation after challenge with type I porcine reproductive and respiratory syndrome virus.

The aim of this study was to characterize histologically and immunohistochemically the lung lesions developing in growing pigs, 10 and 21 days after experimental challenge with a field strain of porcine reproductive and respiratory syndrome virus (PRRSV). Lung lesions were scored for (1) pneumocyte hypertrophy and hyperplasia, (2) septal mononuclear infiltration, (3) intra-alveolar necrotic debris, (4) intra-alveolar inflammatory cell accumulation and (5) perivascular inflammatory cell accumulation. Immunohistochemistry was performed using antibodies specific for cytokeratin, Ki67, thyroid transcription factor (TTF)-1, the myelomonocytic marker MAC387 and PRRSV. Anti-TTF-1 identified type II pneumocytes and there was marked proliferation of these cells compared with control lung (P <0.05). Anti-cytokeratin labelled type I and II pneumocytes as well as bronchial epithelial cells; however, this labelling was not suitable for cell counting purposes. There was a correlation between lesion severity and the number of cells expressing Ki67 (P <0.05).

Long-term results of subtotal colectomy for acquired hypertrophic megacolon in eight dogs.

OBJECTIVES: To evaluate the long-term results of subtotal colectomy for acquired hypertrophic megacolon in the dog. METHODS: Eight dogs with acquired hypertrophic megacolon underwent subtotal colectomy with preservation of the ileocolic junction. Long-term follow-up was obtained by clinical records and telephone interviews with the owners. RESULTS: Eight large-breed dogs (age range: 6 to 12 years; mean age: 10.75 years) were enrolled. The use of bone meal, low levels of exercise, chronic constipation with dyschesia and tenesmus refractory to medical management were factors predisposing dogs to acquired hypertrophic megacolon. The diagnosis was confirmed in all animals by abdominal palpation, plain radiography and postoperative histopathological findings. There were no intraoperative complications. One dog died as a result of septic peritonitis. The clinical conditions (that is, resolution of obstipation and stool consistency) of the remaining seven dogs were improved at discharge; all animals returned to normal defecation in five to 10 weeks (mean: 7.3 weeks) and were alive 11 to 48 months (mean: 40.5 months) after surgery. CLINICAL SIGNIFICANCE: Predominantly bony diet and/or low levels of physical activity may predispose dogs to acquired hypertrophic megacolon. Our results emphasise the long-term effectiveness of subtotal colectomy with preservation of the ileocolic junction in this condition.