Migration and Histologic Effects of Visible Implant Elastomer (VIE) and Passive Integrated Transponder (PIT) Tags in the Marine Toad (Rhinella marina).

Passive integrated transponder (PIT) and visible implant elastomer (VIE) tags are commonly used to identify reptiles, amphibians, and fish. Despite reports of good retention rates and little to no negative effect on survival time, migration remains a concern and histologic changes have not been widely evaluated. Fifty-six wild-caught marine toads (Rhinella marina) were marked with a PIT tag in the left caudal thigh and a VIE tag over the right gastrocnemius muscle prior to transport to the North Carolina Zoo. Fourteen toads were then humanely euthanized on day 9, 15, 32, and 62 for postmortem examination and histopathology which were compared to 10 control toads with no tags. All PIT tags were functional and 95% remained at the insertion site with minimal to no histologic changes. Externally, 48% of VIE tags were visible through the skin at the original site of injection under fluorescent or UV light. Upon gross examination of the tissues, VIE tags had an overall retention rate of 62% at the injection site, with similar retention rates across time points. Migrated VIE material was visible grossly and histologically in the kidneys of 98% of toads and along the right leg, proximally and distally, in 25% of toads. VIE material was also found sporadically in mesentery, colon, and free in the coelomic cavity. Histologically, VIE material in the skin was surrounded by minimal to mild granulomatous inflammation while in the kidney it was associated with dilation of the small vessels, edema, and granulomatous nephritis that progressed in severity over time. Based on these findings, the authors recommend the use of PIT tags over VIE tags for identification of adult anurans, when feasible.

Effects of intravenous administration of lidocaine and buprenorphine on gastrointestinal tract motility and signs of pain in New Zealand White rabbits after ovariohysterectomy.

OBJECTIVE To compare analgesic and gastrointestinal effects of lidocaine and buprenorphine administered to rabbits undergoing ovariohysterectomy. ANIMALS Fourteen 12-month-old female New Zealand White rabbits. PROCEDURES Rabbits were assigned to 2 treatment groups (7 rabbits/group). One group received buprenorphine (0.06 mg/kg, IV, q 8 h for 2 days), and the other received lidocaine (continuous rate infusion [CRI] at 100 µg/kg/min for 2 days). Variables, including food and water consumption, fecal output, glucose and cortisol concentrations, and behaviors while in exercise pens, were recorded. RESULTS Rabbits receiving a lidocaine CRI had significantly higher gastrointestinal motility, food intake, and fecal output and significantly lower glucose concentrations, compared with results for rabbits receiving buprenorphine. Rabbits receiving lidocaine also had a higher number of normal behaviors (eg, sprawling, traveling, and frolicking) after surgery, compared with behaviors such as crouching and sitting that were seen more commonly in rabbits receiving buprenorphine. Both groups had significant weight loss after surgery. Pain scores did not differ significantly between treatment groups. Significant decreases in heart rate and respiratory rate were observed on the day of surgery, compared with values before and after surgery. Rabbits in the lidocaine group had significantly overall lower heart rates than did rabbits in the buprenorphine group. CONCLUSIONS AND CLINICAL RELEVANCE A CRI of lidocaine to rabbits provided better postoperative outcomes with respect to fecal output, food intake, and glucose concentrations. Thus, lidocaine appeared to be a suitable alternative to buprenorphine for alleviating postoperative pain with minimal risk of anorexia and gastrointestinal ileus.

Ameloblastoma in a wild black rat snake (Pantherophis alleghaniensis).

Reports of neoplasia in captive reptiles are becoming more frequent; however, there is still scarce knowledge of the occurrence of neoplasia in wild reptiles. A wild black rat snake (Pantherophis alleghaniensis) was presented to the Zoological Medicine service of the University of Georgia's Veterinary Teaching Hospital with a 3 cm in diameter solid mandibular mass that was partially ulcerated. Radiographically, the mass was radiopaque with small bone spicules and partial osteolysis of the adjacent mandible. Histologic examination of the mass revealed a neoplasm composed of cuboidal to polygonal cells arranged in islands, anastomosing cords, and trabeculae of pseudostratified epithelium with a palisading peripheral layer of densely packed columnar cells with cytoplasmic clearing. The neoplastic tissue was separated from the mesenchyme by a prominent band of fine collagen. Neoplastic cells were positive for cytokeratin and negative for smooth muscle actin. Electron microscopy highlighted the presence of tonofilaments and microvilli. These findings led to the diagnosis of ameloblastoma, an odontogenic epithelial tumor known to occur in humans and most veterinary species.

Effects of lidocaine administration via continuous rate infusion on the minimum alveolar concentration of isoflurane in New Zealand White rabbits (Oryctolagus cuniculus).

OBJECTIVE: To evaluate the effect of a continuous rate infusion (CRI) of lidocaine on the minimum alveolar concentration (MAC) of isoflurane in rabbits. ANIMALS: Five 12-month-old female New Zealand White rabbits (Oryctolagus cuniculus). PROCEDURES: Rabbits were anesthetized with isoflurane. Baseline isoflurane MAC was determined by use of the tail clamp technique. A loading dose of lidocaine (2.0 mg/kg, IV) was administered followed by a CRI of lidocaine at 50 µg/kg/min. After 30 minutes, isoflurane MAC was determined. Another loading dose was administered, and the lidocaine CRI then was increased to 100 µg/kg/min. After 30 minutes, isoflurane MAC was determined again. Plasma samples were obtained for lidocaine analysis after each MAC determination. RESULTS: Baseline isoflurane MAC was 2.09%, which was similar to previously reported values in this species. Lidocaine CRI at 50 and 100 µg/kg/min induced significant reductions in MAC. The 50 µg/kg/min CRI resulted in a mean plasma lidocaine concentration of 0.654 µg/mL and reduction of MAC by 10.5%. The 100 µg/kg/min CRI of lidocaine resulted in a mean plasma concentration of 1.578 µg/mL and reduction of MAC by 21.7%. Lidocaine also induced significant decreases in arterial blood pressure and heart rate. All cardiopulmonary variables were within reference ranges for rabbits anesthetized with inhalation anesthetics. No adverse effects were detected; all rabbits had an uncomplicated recovery from anesthesia. CONCLUSIONS AND CLINICAL RELEVANCE: Lidocaine administered as a CRI at 50 and 100 µg/kg/min decreased isoflurane MAC in rabbits. The IV administration of lidocaine may be a useful adjunct in anesthesia of rabbits.

Avian simuliotoxicosis: outbreak in Louisiana.

From April 20 to May 10, 2010, multiple species of birds were seen at the Louisiana State University (LSU) Zoological Medicine Department for a disease syndrome characterized by acute lethargy, generalized subcutaneous petechiae, vasculitis, and death caused by a black fly identified as Simulium meridionale. Twenty psittacine birds presented with severe depression and multifocal subcutaneous hemorrhages over the body and especially noted in the featherless areas of the head and neck. Ten out of 20 clinical cases seen survived on a treatment regimen consisting of intravenous fluid therapy, anti-inflammatories, antihistaminic medications, and supportive care. The 10 other birds likely died of cardiopulmonary collapse and anaphylactoid reactions. In all post mortem examinations multifocal to coalescing dermal hemorrhage, eosinophilic dermatitis, severe edema, and vasculitis were observed. The LSU School of Animal Science conducted a brief survey that included 34 of the 64 Louisiana parishes and showed that 17 parishes, at least, were affected by this outbreak. A total of at least 225 poultry bird deaths could be attributed to black fly strikes. Simuliotoxicosis outbreaks have previously been reported in North America, and this report documents the clinical and post mortem findings, treatment response, and extent of such an outbreak in pet and farm birds in Louisiana.

Effects of dopamine and dobutamine on isoflurane-induced hypotension in Hispaniolan Amazon parrots (Amazona ventralis).

OBJECTIVE: To assess the effects of dopamine and dobutamine on the blood pressure of isoflurane-anesthetized Hispaniolan Amazon parrots (Amazona ventralis). ANIMALS: 8 Hispaniolan Amazon parrots. PROCEDURES: A randomized crossover study was conducted. Each bird was anesthetized (anesthesia maintained by administration of 2.5% isoflurane in oxygen) and received 3 doses of each drug during a treatment period of 20 min/dose. Treatments were constant rate infusions (CRIs) of dobutamine (5, 10, and 15 µg/kg/min) and dopamine (5, 7, and 10 µg/kg/min). Direct systolic, diastolic, and mean arterial pressure measurements, heart rate, esophageal temperature, and end-tidal partial pressure of CO(2) were recorded throughout the treatment periods. RESULTS: Mean ± SD of the systolic, mean, and diastolic arterial blood pressures at time 0 (initiation of a CRI) were 132.9 ± 22.1 mm Hg, 116.9 ± 20.5 mm Hg, and 101.9 ± 22.0 mm Hg, respectively. Dopamine resulted in significantly higher values than did dobutamine for the measured variables, except for end-tidal partial pressure of CO(2). Post hoc multiple comparisons revealed that the changes in arterial blood pressure were significantly different 4 to 7 minutes after initiation of a CRI. Overall, dopamine at rates of 7 and 10 µg/kg/min and dobutamine at a rate of 15 µg/kg/min caused the greatest increases in arterial blood pressure. CONCLUSIONS AND CLINICAL RELEVANCE: Dobutamine CRI at 5, 10, and 15 µg/kg/min and dopamine CRI at 5, 7, and 10 µg/kg/min may be useful in correcting severe hypotension in Hispaniolan Amazon parrots caused by anesthesia maintained with 2.5% isoflurane.