Neospora-like protozoan infection as a major cause of abortion in California dairy cattle

Ninety-five aborted bovine fetuses received from California dairies over a 4.5-year period had histologic lesions of focal encephalitis. Protozoa that reacted with Neospora caninum antiserum were detected in the brain of 88 of these fetuses and in the heart of 1 fetus. Sarcocystis spp schizonts were seen in the vascular endothelium of 1 fetus. It was concluded that a Neospora-like cyst-forming coccidian may be a major cause of abortion in California dairy cattle.     

Clinical observations on changes in concentrations of hormones in plasma of two stallions with thermally-induced testicular degeneration

To investigate effects of thermally-induced testicular degeneration on hormonal and seminal parameters in stallions, the scrotum was insulated for 36 hours in two mature (5-year-old mixed breed and 11-year-old Throughbred) stallions. Semen was collected daily for 10 days (DSO) prior to, and at intervals after, scrotal insulation. When DSO determinations were not being made, semen was collected 3 times weekly. Jugular blood samples were collected at 15-minute intervals for 6 hours from each stallion prior to, and at intervals after, scrotal insulation. A mouse interstitial cell testosterone assay was modified to quantify biologic activity of equine luteinizing hormone (BLH) in plasma samples. Immunoactive luteinizing hormone (ILH) and testosterone (T) concentrations were determined in plasma samples by routine RIA procedures. Percentages of progressively motile and morphologically normal spermatozoa began to decrease by 1 to 2 weeks postinsulation, reached nadir values at 3 to 3-1/2 weeks postinsulation, and returned to preinsulation values by 7 weeks postinsulation. Total number of spermatozoa and total number of progressively motile, morphologically normal spermatozoa in ejaculates at DSO returned to normal by 8 weeks postinsulation in stallion 2 and 12 weeks postinsulation in stallion 1. Concentrations of BLH and ILH increased, and while T concentrations decreased, immediately postinsulation. The increase in ILH concentrations was greater than the increase in BLH concentrations, resulting in a decrease in the BLH:ILH (B:I) ratio. Following the peak in LH secretion immediately postinsulation, LH concentrations gradually decreased while T concentrations increased. The B:I ratio was elevated from 1 to 13 weeks postinsulation compared to immediately postinsulation. In addition to changes in spermatozoal quality in ejaculates, stallion response to scrotal insulation included increased secretion of luteinizing hormone and impaired Leydig cell function (as determined by reduced testosterone concentration in circulating plasma). The proportion of biologically active LH secreted in response to thermal testicular injury increased during the recovery phase.     

Electron microscopic observation of the respiratory tract of SPF piglets inoculated with Mycoplasma hyopneumoniae.

Seven hysterectomy derived piglets were repeatedly challenged with Mycoplasma hyoneumoniae during the first week of life. Samples of trachea, bronchi and lung tissue collected 2–11 weeks post-inoculation (p.i.) were examined using light and electron microscopy. Autoradiography was used to study in more detail the site of M. hyopneumoniae multiplication. Gross lesions were observed in lung tissue and were characterized by hyperplasia of the epithelium and an increased mononuclear cell accumulation in perivascular and peribronchiolar areas. Mild lesions of the trachea and the bronchi, including epithelial hyperplasia and infiltration of the lamina propria by inflammatory cells, were noted.

Electron microscopy showed that, 2–6 weeks p.i., changes in the mid-trachea and bronchi surface consisted of the loss of cilia. Mycoplasmas covered tufts of cilia remaining on the epithelial cell surface. Scanning and transmission electron micrographs showed that they were predominantly found closely associated with the top of cilia. No specialized terminal structure could be seen and no mycoplasma cells were identified lying free in the lumen nor in close contact with the plasma membrane of cells of microvilli. Some fine fibrils radiating from one mycoplasma to another or to cilia were seen at higher magnification by scanning electron microscopy. Six to eleven weeks p.i., a disrupted epithelial surface lacking cilia was observed. Cells were desquamated and shed into the lumen with cellular remains containing droplets of mucus.

Autoradiography revealed that label corresponded to the observed mycoplasma distribution. At the top of cilia, a high density of labeling was visible in the zone of high mycoplasma concentration. Therefore, incorporation of the label in the mycoplasma is proof or their multiplication in the trachea.

The intimate association between the mycoplasma and cilia may be an important factor in the pathogenesis of the disease caused by M. hyopneumoniae (swine enzootic pneumonia).     

The development of methods for immunophenotypic and lymphocyte function analyzes for assessment of Southern sea otter (Enhydra lutris nereis) health

The Southern sea otter (Enhydra lutris nereis) is listed as threatened under the Endangered Species Act. The population began a pattern of slow decline in 1995. The decline was attributed to high adult mortality rates with infectious disease being the major cause of death. Multiple pathogens were implicated in these deaths including opportunistic pathogens such as Coccidiodes immitis and Toxoplasma sp. These findings suggested that the immunological health of mature animals in this population might be compromised. The primary goal of this study was to establish techniques for assessing phenotypic and functional baseline data for peripheral blood mononuclear cells (PBMC) in free-ranging sea otters. Standard total and differential white blood cell counts were augmented by emumeration of T and B lymphocyte subsets. Lymphocyte function was determined by both mitogen-induced proliferation and expression of IL-2 receptors. In addition to establishing normal ranges for adult animals, age-related changes were identified in B lymphocyte numbers and cell-surface density of major histocompatability complex class II (MHC II) proteins. The predominant lymphocyte subpopulation in Southern sea otters is the T lymphocyte. Substantial variation among individual animals was observed within the B lymphocyte population both in cell number and density of MHC II expression. Pups had greater numbers of T and B lymphocyte, as well as, greater MHC II expression on B lymphocytes than adults. Mitogen-induced proliferation of peripheral blood mononuclear cells (PBMC) was variable among individual animals with no significant difference in cell response between age class and gender. Concanavalin (ConA) was a more effective mitogen in stimulating proliferation and interleukin (IL)-2 receptor expression than pokeweed. This data can be used to augment routine hematology profiles and aid in the identification of animals with immunologic perturbations.     

Characterization of F21.A, a monoclonal antibody that recognize a leucocyte surface antigen for killer whale homologue to beta-2 integrin

The specificity of F21.A, a monoclonal antibody raised against bottlenose dolphin leucocytes, was characterized in killer whale on the basis of immunoprecipitation of a protein of 94 kDa, as well as flow cytometric analysis. While minimally expressed on resting cells, F21.A labeled a homologue to beta-2 integrin in 89-97% of PMA-activated neutrophils, 53-66% of activated monocytes, and activated B cells but not T cells. Activation of neutrophils reached its maximum 10 min after PMA stimulation. F21.A did not label intracellular stores as did both cross-reacting anti-canine CD11b and CD18, suggesting that an activation-induced conformational change would expose a neoepitope recognized by F21.A. F21.A labeling was largely inhibited by pre-incubation with plasma, suggesting a binding site closely related to that for fibrinogen. In vitro phagocytosis and respiratory burst were almost fully inhibited upon pre-incubation with F21.A, demonstrating its functional importance. This antibody is foreseen as a possible valuable diagnostic and research tool in cetacean immunology.     

Thermoregulation of the testicle in response to exercise and subsequent effects on semen characteristics of stallions

Stallions (n = 8) were implanted with a thermal sensory device in the muscle of the neck and the subcutaneous tissue of the scrotum and then assigned to either a nonexercise (Non-EX; n = 4) or exercise (EX; n = 4) group. A motorized equine exerciser was used to work EX stallions 30 min/d for 4 d/wk during a 12-wk period from July through October 2010. Temperatures (subcutaneous scrotal, intramuscular neck, and rectal) were recorded at 0, 22, and 30 min after the start of exercise, as well as 60 and 120 min post-exercise. Hourly ambient temperature and relative humidity data were also obtained. Semen was collected at 0, 4, 8, and 12 wk and analyzed for volume, sperm concentration, total sperm numbers, percentages of total and progressively motile sperm, sperm morphologic characteristics, and sperm DNA quality. No effect (P > 0.05) of exercise was observed on any of the measured semen variables. Implantation of thermal sensory devices had no demonstrable acute or chronic effects on the scrotal or neck tissue, indicating that the thermal sensory devices are a safe and effective way to measure subcutaneous scrotal and neck temperatures. At 22 and 30 min of exercise, rectal and neck temperatures increased (P < 0.0001) approximately 1.9 and 2.4°C, respectively, and scrotal temperatures simultaneously increased, although not significantly (P = 0.33), approximately 0.8°C. Correlations existed between scrotal, neck, rectal, and ambient temperatures, with the correlation between scrotal and rectal temperatures being greatest (r(s) = 0.76; P < 0.0001). Although moderate exercise for a short duration in extreme heat and humidity did significantly increase core body temperatures in stallions, scrotal temperatures did not significantly increase, and sperm parameters were unaffected.