Distribution of lesions in fetal brains following experimental infection of pregnant sheep with Toxoplasma gondii

Six ovine fetal brains were harvested 33 to 35 days postchallenge from 5 ewes, each of which was given 3000 Toxoplasma gondii oocysts on day 90 of pregnancy. Histopathologic examination of transverse sections taken at 13 levels in the fetal brains revealed the presence of toxoplasmosis-related lesions in all 6 brains. However, lesions were not randomly distributed (P = .007); they were most numerous at the level of the optic tract, the rostral margin of the pons, and 4 mm caudal to the ansate sulcus and were absent in all sections at the level of the caudal cerebellum. Lesion distribution may be due to hemodynamic factors, differences in the expression of endothelial surface receptor molecules at the level of the blood-brain barrier, or the presence of localized permissive/inhibitory factors within the brain. The results have implications for the selection of areas of brain from aborted ovine fetuses to be examined histopathologically for laboratory diagnosis.     

Investigation and control of an outbreak of salmonellosis caused by multidrug-resistant Salmonella typhimurium in a population of hospitalized horses

An outbreak of salmonellosis in a population of hospitalized horses resulted in the closure of a teaching hospital for a period of 10 weeks. Fecal samples were collected from suspected cases and cultured for Salmonella. Salmonella isolates were characterized using antimicrobial susceptibility testing, pulsed-field gel electrophoresis (PFGE) and phage typing. Thirty-three cases of infection by a multidrug-resistant strain of S. typhimurium were detected. The index case was admitted on 26 August 1999. Fifteen (45%) cases occurred between April and June 2000. PFGE results suggested that this strain of S. typhimurium might have been introduced into the hospital environment by a foal presenting with diarrhea. The hospital was closed on June 13, and intensive environmental cleaning and disinfection were completed. Enforcement of infectious disease control protocols in hospitals and environmental and patient surveillance is needed to prevent outbreaks of salmonellosis.     

Acute renal failure in dogs after the ingestion of grapes or raisins: a retrospective evaluation of 43 dogs (1992-2002)

A review of records from the AnTox database of the American Society for the Prevention of Cruelty to Animals Animal Poison Control Center identified 43 dogs that developed increased blood urea nitrogen concentration, serum creatinine concentration, or both as well as clinical signs after ingesting grapes, raisins, or both. Clinical findings, laboratory findings, histopathological findings, treatments performed, and outcome were evaluated. All dogs vomited, and lethargy, anorexia, and diarrhea were other common clinical signs. Decreased urine output, ataxia, or weakness were associated with a negative outcome. High calcium x phosphorus product (Ca x P), hyperphosphatemia, and hypercalcemia were present in 95%, 90%, and 62% of the dogs in which these variables were evaluated. Extremely high initial total calcium concentration, peak total calcium concentration, initial Ca x P, and peak Ca x P were negative prognostic indicators. Proximal renal tubular necrosis was the most consistent finding in dogs for which histopathology was evaluated. Fifty-three percent of the 43 dogs survived, with 15 of these 23 having a complete resolution of clinical signs and azotemia. Although the mechanism of renal injury from grapes and raisins remains unclear, the findings of this study contribute to an understanding of the clinical course of acute renal failure that can occur after ingestion of grapes or raisins in dogs.     

Stunted growth and mortality associated with sodium deficiency

We investigated reports of stunted growth and high mortality occurring among young poultry in 38 small privately owned flocks in Vermont and New Hampshire. Tests for infectious agents including avian influenza and Newcastle disease viruses were negative, as were toxicologic tests for mycotoxins, heavy metals, pesticides, and monensin in feed samples. Analysis of 6 samples of implicated feed revealed 330-870 ppm of sodium (median level 350 ppm), whereas the recommended minimum level for chick feed is 1200-2000 ppm. A case-control study included 38 affected and 23 unaffected flocks. Statistical analysis showed that affected flocks were 29 times more likely to have consumed a particular brand of poultry feed (odds ratio = 29.2, 95% confidence interval = 3.2-675.8) but did not show any association between clinical signs and hatchery, location of chick purchase, chick purchase date, or years of producer experience.     

Systemic inflammatory response syndrome, sepsis, and multiple organ dysfunction.

Companion animals with sepsis and multiple organ dysfunction can be the most challenging of all patients to treat. Current research in humans and laboratory models offers some exciting insights into the pathophysiology behind some of our most frustrating clinical challenges. This article applies several current concepts to a clinical case of pancreatitis and secondary sepsis to illustrate some of the cardiovascular, immune, and coagulation abnormalities commonly seen.     

Intercellular communication in mare endometrial epithelium isolated during estrus and diestrus

A primary culture system of equine uterine epithelial cells was developed to study interactions between these cells in vitro. Cultures were prepared by combined mechanical and collagenase separation of cells from endometrial biopsies taken from mares during estrus and diestrus. Cells were maintained in DME/F12 medium containing 10% fetal bovine serum. The purity of the epithelial cell population was estimated to be greater than 95% based upon the cobblestone morphology of cells and a uniform indirect immunofluorescence labelling of cells with an antibody directed against cytokeratin intermediate filament proteins. Radiating cytoplasmic cytokeratin filaments were characteristic of cells labelled after 3 days in culture. Preliminary analysis of the incidence and rate of cell-to-cell communication between epithelial cell populations was conducted using a fluorescence recovery after photobleaching assay. Recovery of carboxyfluorescein fluorescence in cells which were laser photobleached and in contact with other cells was monitored at one-minute intervals over 5 minutes. The incidence of communication among cells isolated during estrus and diestrus was 100%. The mean rates of fluorescence recovery at one minute (8.25% ± SEM 0.91 and 10.94% ± SEM 1.20 for cells obtained from estrous and diestrous mares, respectively) were not significantly different. These studies indicate that cells isolated from the endometrium of the mare are capable of intercellular diffusion of regulatory and informational molecules between cells in contact.