Dysentery caused by Escherichia coli (S102-9) in calves: natural and experimental disease

A dysentery syndrome was recognized among the Institute's calves at 18 to 21 days of age. It was reproduced experimentally in gnotobiotic calves with an atypical Escherichia coli (S102-9) isolated from the affected calves. In both natural and experimental disease the calves passed copious bright red blood in the feces and developed diarrhea. Walls of the colon and rectum were thickened, and the mucosa was reddened and covered by an exudate that contained mucus and blood clots. Bacteria were seen closely adherent to the luminal surfaces of enterocytes, often in cup-shaped depressions or on cytoplasmic pedestals. Microvilli were distorted, disorientated or absent. There was exfoliation of infected enterocytes and a mild acute inflammation of the underlying lamina. In two of five calves with natural disease, the adherent bacteria did not stain by the immunoperoxidase method with antisera raised against E. coli (S102-9). This indicated that there was possibly more than one bacterial cause of the syndrome. Lesions in experimentally infected calves were indistinguishable from those produced by some E. coli which are enteropathogenic for man, rabbits, and pigs.     

Comparison of suture materials and suture patterns for inverting intestinal anastomosis of the jejunum in the horse

In 7 horses, 4 anastomoses were done in the small intestine in each, using the combinations of synthetic absorbable monofilament and multifilament suture materials with continuous- and interrupted-suture patterns in the serosubmucosal layer of a 2-layer inverting-suture technique. Horses were evaluated 30 days after the operation for adhesion formation, lumen diameter, evidence of chronic obstruction, and suture tract inflammation at the anastomosis. Postoperative obstruction occurred in 5 of the 7 horses, and 6 horses survived. One horse was euthanatized on postoperative day 6 after 48 hours of ileus and obstruction; necropsy revealed a partial intussusception involving the anastomosis done with continuous multifilament-suture material. Two other horses that became obstructed between postoperative days 3 and 5 had protracted ileus and gastric reflux up to 48 hours' duration, but survived. Horses that had obstruction after the 6th postoperative day recovered within 4 hours of onset. The continuous inverting-suture pattern in the serosubmucosal layer resulted in significantly (P less than 0.05) fewer adhesions than did the interrupted pattern, and suture material had no effect on adhesion formation. There was no significant difference in the percentage of reduction of lumen diameter between the variations of the 2-layer technique, and there was no evidence of chronic obstruction related to any of the anastomoses. Suture tract inflammation was moderate in the anastomoses, using continuous-multifilament suture, with neutrophils being the predominant cell type. The anastomoses with continuous-monofilament suture had mild inflammation with focal accumulations of neutrophils. Minimal inflammation was associated with both types of suture in the interrupted pattern.     

Tumors of the alimentary tract

Neoplasms of the canine and feline alimentary tract represent diagnostic and therapeutic challenges for the veterinarian in practice. Careful attention to historical details and thorough and repeated examination are of paramount importance in evaluating animals with chronic digestive disturbances. By judicious use of ancillary studies such as plain and contrast radiography, endoscopy, and exploratory surgery, the clinician may arrive at a diagnosis earlier in the course of a neoplasm. This in turn may facilitate more efficacious treatment. A particularly interesting aspect of tumors of the gastrointestinal tract is their frequent association with environmental carcinogens. By being aware of these relationships, veterinarians stand a better chance of reaching the ultimate goal of cancer therapists--the prevention of malignant disease.     

Gold-induced immune thrombocytopenia in the dog

In two seven-year studies with gold compounds in dogs of both sexes, thrombocytopenia was observed after 45 to 72 months of dosing in three of 14 and two of 14 dogs in high-dose groups that received 2.4 to 3.6 mg/kg of auranofin per day orally or 0.5 to 2.0 mg/kg of gold sodium thiomalate intramuscularly once every three days, respectively. An immune basis for the disorder was suggested by the apparent consumptive nature of the thrombocytopenia (increased bone marrow megakaryocytes and large peripheral blood platelets), the response to corticosteroid therapy and the demonstration of increased platelet-associated immunoglobulin. The latter was demonstrated with a solid phase radioimmunoassay and by electron microscopy using a staphylococcal protein A-colloidal gold conjugate. Platelet-associated immunoglobulin decreased as the platelet counts rose, and in one dog monitored over periods of steroid-induced remissions and subsequent relapses, the amount of platelet-associated immunoglobulin G correlated inversely with the platelet count (r = 0.82). These findings suggest that the long-term administration of gold compounds in dogs is associated with a dose-dependent incidence of thrombocytopenia, which is immune-mediated and similar to that associated with parenteral chrysotherapy in man. The application of tests for platelet-associated immunoglobulin to canine patients with immune thrombocytopenia should be useful in the diagnosis of the disorder in clinical practice.     

Trypanosoma evansi infection in buffaloes in north-east Thailand. I. Field investigations

Clinical, parasitological and serological findings of Trypanosoma evansi infections in buffaloes (Bubalis bubalis) from north-eastern Thailand are reported. The overall infection rate was found to be around 20% with a distinct peak of acute infections during the rainy season. The disease is aggravated by normally well tolerated concomitant infections such as liver fluke infestations and by other stress factors.