Stacey R. Byers

Disseminated Bovine viral diarrhea virus in a persistently infected alpaca (Vicugna pacos) cria.

Bovine viral diarrhea virus (BVDV) is an emerging infectious pathogen of concern to the alpaca industry. A 4-month-old, intact, male alpaca cria was diagnosed as persistently infected with BVDV on the basis of repeated positive antemortem polymerase chain reaction (PCR) and virus isolation (VI) assays and negative serologic titers to BVDV. Immunohistochemistry, real-time reverse transcription PCR, and VI performed on tissues collected at necropsy demonstrated disseminated BVDV-1b infection. Virus was detected in multiple tissues, including parotid salivary gland, testes, prostate, kidneys, skin, and gastrointestinal tract. Demonstration of BVDV in previously unreported tissues suggests additional potential routes of BVDV transmission in alpacas.

Evaluation of a point-of-care glucose and β-hydroxybutyrate meter operated in various environmental conditions in prepartum and postpartum sheep.

OBJECTIVE To compare β-hydroxybutyrate (BHB) and glucose concentrations measured with a dual-purpose point-of-care (POC) meter designed for use in humans and a laboratory biochemical analyzer (LBA) to determine whether the POC meter would be reliable for on-farm measurement of blood glucose and BHB concentrations in sheep in various environmental conditions and nutritional states. ANIMALS 36 pregnant mixed-breed ewes involved in a maternal feed restriction study. PROCEDURES Blood samples were collected from each sheep at multiple points throughout gestation and lactation to allow for tracking of gradually increasing metabolic hardship. Whole blood glucose and BHB concentrations were measured with the POC meter and compared with serum results obtained with an LBA. RESULTS 464 samples were collected. Whole blood BHB concentrations measured with the POC meter compared well with LBA results, and error grid analysis showed the POC values were acceptable. Whole blood glucose concentrations measured with the POC meter had more variation, compared with LBA values, over the glucose ranges evaluated. Results of error grid analysis of POC-measured glucose concentrations were not acceptable, indicating errors likely to result in needless treatment with glucose or other supplemental energy sources in normoglycemic sheep. CONCLUSIONS AND CLINICAL RELEVANCE The POC meter was user-friendly and performed well across a wide range of conditions. The meter was adequate for detection of pregnancy toxemia in sheep via whole blood BHB concentration. Results should be interpreted with caution when the POC meter is used to measure blood glucose concentrations.

Neurological Causes of Diaphragmatic Paralysis in 11 Alpacas (Vicugna pacos)

Background: Diaphragmatic paralysis is a relatively uncommon medical condition in animals not reported in alpacas. Objectives: Describe the signalment, physical examination, diagnostic testing, clinical, and histopathologic findings related to diaphragmatic paralysis in alpacas. Animals: Eleven alpacas with spontaneous diaphragmatic paralysis. Methods: A retrospective study examined medical records from a 10‐year period and identified 11 alpacas with confirmed diaphragmatic paralysis admitted to Washington State University and Colorado State University Veterinary Teaching Hospitals between September 2003 and October 2009. Results: The 11 alpacas ranged in age from 2 to 12 months. Fluoroscopic imaging confirmed the presence of bilateral diaphragmatic paralysis in the 7 alpacas that were imaged. Arterial blood gas analyses showed hypercapnea, hypoxemia, and low oxygen saturation. Seven alpacas died or were euthanized between 2 and 60 days after onset of respiratory signs. Histopathologic examination of tissues found phrenic nerve degeneration in the 6 alpacas that were necropsied and additional long nerves examined demonstrated degeneration in 2 of these animals. Two animals had spinal cord lesions and 2 had diaphragm muscle abnormalities. No etiologic agent was identified in the alpacas. Conclusions and Clinical Importance: The etiology for diaphragmatic paralysis in these alpacas is unknown. A variety of medical treatments did not appear to alter the outcome.

Evaluation of a commercial bovine viral diarrhea virus vaccine in nonpregnant female alpacas (Vicugna pacos)

Bovine viral diarrhea virus (BVDV) is an emerging pathogen in alpacas and many questions still persist regarding disease mechanisms and control strategies. The purpose of this study was to evaluate a commercial BVDV vaccine for safety and efficacy in alpacas. Five nonpregnant alpacas were vaccinated with a modified-live BVDV vaccine and challenged 25 days post-immunization by nasal and ocular inoculation with a BVDV Type 1b strain isolated from a confirmed BVDV persistently infected alpaca. Two nonpregnant alpacas served as non-vaccinated controls and were similarly challenged. Results indicated that BVDV virus could not be detected from the vaccinated alpacas but was detected in the unvaccinated alpacas. Results suggest that administration of modified-live BVDV vaccine protected the alpacas in this study from experimental challenge and no adverse effects from the vaccine were observed.

Sodium Balance and the Dysnatremias

The dysnatremias are defined as abnormalities in serum sodium concentration. Depending on the magnitude and duration of the sodium abnormality and the nature of any concurrent or primary disease, hypernatremia and hypernatremia may result in no consequences, subclinical impairment of health and productivity, or severe clinical disease. Dysnatremias can be the sequelae to diseases or environmental conditions that promote fluid gain or loss from the body, as well as medical interventions that add excessive amounts of sodium or water to the extracellular fluid. Extreme, sustained dysnatremia may result in central nervous system dysfunction and death.

Evaluation of four point-of-care glucose meters in alpacas.

PURPOSE Hospitalized alpacas are often hyperglycemic requiring frequent blood glucose testing. OBJECTIVES To compare the performance of 4 brands of glucometers with a laboratory-based analyzer (LCA) over a range of glucose concentrations in alpacas. ANIMALS Four healthy male alpacas. METHODS A 2-treatment cross-over study was utilized. The alpacas were given 0.4 U/kg of regular insulin intravenously and then 500 mg/kg of dextrose intravenously with a 1 week washout period between treatments. Blood samples were collected from 10 minutes before until 6 hours after drug administration. Glucose concentrations were measured in whole blood and plasma samples on 4 glucometers, and serum glucose was measured on an LCA. RESULTS Glucometer performance varied depending on whether glucose concentrations were measured in plasma or whole blood. Based on error grid analysis, the Precision Xtra and One Touch Ultra 2 glucometers were clinically acceptable for testing whole blood samples, whereas the Accu-Chek Aviva and Nova StatStrip Xpress glucometers were clinically acceptable for testing plasma samples in comparison with serum glucose concentrations determined by the LCA. All glucometers had systematic and proportional biases that varied based on sample type. CONCLUSIONS AND CLINICAL IMPORTANCE Human-based glucometers in alpacas should be used cautiously, particularly at higher blood glucose concentrations. The blood sample type (plasma or whole blood) can alter meter performance when compared with serum glucose concentrations and potentially lead to errors in clinical decisions.

Retinal ganglion cell distribution and visual acuity in alpacas (Vicugna pacos).

OBJECTIVE To investigate the distribution of retinal ganglion cells (RGCs) and visual acuity in alpacas (Vicugna pacos) through Brn-3a immunofluorescent labeling. PROCEDURES Five eyes from four healthy alpacas with normal ophthalmic examination findings were included in the study. The axial length of the globes was measured before fixation. All five retinas were treated with Brn-3a antibodies to label RGCs. Images taken with a fluorescent microscope were used for RGC counting. RGC density maps were reconstructed by computer software. Visual acuity was estimated based on the results of peak RGC density and ocular anatomical parameters. RESULTS The reconstructed retinal maps from Brn-3a labeling showed a horizontal streak across the retinal meridian superior to the optic nerve head with a temporal, upward extension. The highest RGC densities were in the temporal retinas. The maximal visual acuity was located in the temporal retina and was estimated to range between 12.5 and 13.4 cycles per degree. CONCLUSIONS Alpacas have a horizontal streak across the retinal meridian superior to the optic disk with a temporal, upward extension based on the Brn-3a labeling of RGCs. The maximal visual acuity was located in the temporal retina. The reconstructed retinal maps indicate the RGC topography of alpacas is similar to that of other herbivores, but is different from that of dromedary camels.

Evaluation of the Efficacy of Disinfectant Footmats for the Reduction of Bacterial Contamination on Footwear in a Large Animal Veterinary Hospital

Background Infection control is critical to providing high‐quality patient care. Many veterinary teaching hospitals (VTHs) utilize footbaths or footmats at entrances and key control points throughout the facility to decrease trafficking of pathogenic microorganism on contaminated footwear. Hypothesis/Objectives To compare efficacy of 4 disinfectants used in footmats for decreasing bacterial contamination of footwear in a large animal hospital. Animals A single adult dairy cow was housed in a stall for 4 days to facilitate stall contamination with fecal material. Methods Overboots were experimentally contaminated with organic material in a standardized manner. Each boot was randomly assigned to 1 of 5 treatments (no treatment, or exposure to 1 of 4 disinfectants: an accelerated peroxygen [AHP], a peroxygen [VIRKON], a quaternary ammonium [QUAT], and a phenolic disinfectant [PHENOLIC]) by stepping on a soaked footmat and collecting samples from boot soles. Generalized linear modeling was used to analyze differences in bacterial counts. Results Reductions in colony‐forming units (CFUs) on treated boots ranged from no detectable reduction to 0.45 log10 and varied by disinfectant. Percentage reductions in total bacterial counts generally were larger (albeit still modest) for AHP and QUAT disinfectants (range 37–45%) and smallest for the PHENOLIC (no detectable reduction). Conclusions and Clinical Importance In general, use of disinfectant footmats was associated with significant reductions in viable bacteria on overboots—albeit with variable efficacy. Footmats may be useful adjuncts to cleaning and disinfection programs for decreasing trafficking of microorganisms throughout VTHs but should not be considered as a sole prevention method.

Evaluation of sample handling effects on serum vitamin e and cholesterol concentrations in alpacas.

Clinical cases of vitamin E deficiencies have been diagnosed in camelids and may indicate that these species are more sensitive to inadequate vitamin E in hay-based diets compared to other ruminant and equine species. In bovine, cholesterol has been reported to affect vitamin E concentrations. In order to evaluate vitamin E deficiencies in camelids, the effects of collection and storage of the blood samples prior to processing were necessary. Reports vary as to factors affecting vitamin E and cholesterol in blood samples, and diagnostic laboratories vary in instructions regarding sample handling. Blood was collected from healthy alpacas and processed under conditions including exposure to fluorescent light, serum and red blood cell contact, tube stopper contact, temperature, and hemolysis. Serum vitamin E and cholesterol concentrations were then measured. Statistical analyses found that the vitamin E concentrations decreased with prolonged contact with the tube stopper and with increasing hemolysis. Vitamin E concentration variations were seen with other factors but were not significant. Time prior to serum separation and individual animal variation was found to alter cholesterol concentrations within the sample, yet this finding was clinically unremarkable. No correlation was seen between vitamin E and cholesterol concentration, possibly due to lack of variation of cholesterol.

Infiltrative Cutaneous Hemangiolipoma in a Goat

An approximately 4-year-old castrated male, Saanen cross goat presented to the Colorado State University Veterinary Teaching Hospital for evaluation and removal of a 22 cm × 22 cm, dark red, thickened, and crusted cutaneous lesion along the left ventrolateral thorax. An initial incisional biopsy performed approximately 8 weeks earlier was suspicious for cutaneous hemangiosarcoma. Surgical excision was deemed to be the most appropriate treatment option for this goat. A complete physical exam, complete blood count, and chemistry profile were performed and results were within normal limits. Thoracic radiographs and abdominal ultrasound were performed to rule out metastatic disease and comorbid conditions; no metastatic lesions or other abnormalities were observed. En bloc surgical excision of the affected skin was performed and the entire tissue was submitted for histopathology. A final diagnosis of cutaneous hemangiolipoma was reached upon extensive sectioning and histologic examination of the larger tissue specimen. The goat recovered well from surgery and has had no further complications up to 9 months postoperatively. To our knowledge, this is the first case report of a hemangiolipoma in a goat and surgical excision for such lesions appears to be a viable treatment method.