R. Scott Larsen

Differential mortality of male spectacled eiders (Somateria fischeri) and king eiders (Somateria spectabilis) subsequent to anesthesia with propofol,bupivacaine, and ketoprofen

Abstract Twenty free-ranging spectacled eiders (Somateria fischeri; 10 male, 10 female), 11 free-ranging king eiders (Somateria spectabilis; 6 male, 5 female), and 20 female common eiders (Somateria mollissima) were anesthetized with propofol, bupivacaine, and ketoprofen for the surgical implantation of satellite transmitters. Propofol was given to induce and maintain anesthesia (mean total dose, 26.2–45.6 mg/kg IV), bupivacaine (2–10 mg/kg SC) was infused into the incision site for local analgesia, and ketoprofen (2–5 mg/kg IM) was given at the time of surgery for postoperative analgesia. Four of 10 male spectacled eiders and 5 of 6 male king eiders died within 1–4 days after surgery. None of the female spectacled or common eiders and only 1 of the 5 female king eiders died during the same postoperative period. Histopathologic findings in 2 dead male king eiders were severe renal tubular necrosis, acute rhabdomyolysis, and mild visceral gout. Necropsy findings in 3 other dead male king eiders were consistent with visceral gout. We suspect that the perioperative use of ketoprofen caused lethal renal damage in the male eiders. Male eiders may be more susceptible to renal damage than females because of behavioral differences during their short stay on land in mating season. The combination of propofol, bupivacaine, and ketoprofen should not be used to anesthetize free-ranging male eiders, and nonsteroidal anti-inflammatory drugs should not be used perioperatively in any bird that may be predisposed to renal insufficiency.

Real-Time Polymerase Chain Reaction Testing for the Detection of Mycobacterium genavense and Mycobacterium avium Complex Species in Avian Samples

Abstract SUMMARY. Diagnosis of avian mycobacteriosis, caused by Mycobacterium genavense or species belonging to the Mycobacterium avium complex (MAC), is problematic. Polymerase chain reaction (PCR) offers rapid and sensitive detection of minute quantities of DNA, and conventional protocols have been used for evaluating avian specimens. The recent development of real-time PCR offers several advantages over conventional PCR. In attempts to improve diagnosing avian mycobacteriosis, a real-time TaqMan® PCR assay was developed targeting the 65-kD heat shock protein gene of M. genavense and MAC spp. Nineteen reference isolates, 16 clinical isolates, and 32 avian tissue samples were used to evaluate the assay. When sufficient amplicons were produced, the species of mycobacteria was determined by standard sequencing of TaqMan® PCR products and compared with results from commercial mycobacteriology laboratories and/or standard sequencing of conventional PCR products. The TaqMan® PCR detected DNA from reference isolates of M. genavense, MAC spp., and Mycobacterium tuberculosis complex spp. Of the clinical isolates, the TaqMan® PCR detected DNA from 10 of 12 Mycobacterium avium avium isolates and two of three Mycobacterium avium intracellulare isolates. For the tissue samples, the TaqMan® PCR amplified DNA in six of nine samples that were identified by sequencing of conventional PCR products and/or by commercial mycobacteriology laboratories as being MAC spp. positive and three of four samples that were positive for M. genavense. There was some disagreement between speciation results from the TaqMan® PCR and those from commercial mycobacteriology laboratories or conventional PCR or both. This disagreement was suspected to be because of relatively small numbers of base pairs in the TaqMan® PCR products. The TaqMan® PCR may provide a useful tool for evaluating clinical samples for DNA from mycobacteria species that most commonly infect birds; however, further refinement is needed in order to improve sensitivity and provide more accurate speciation.

Development of an avian brachial plexus nerve block technique for perioperative analgesia in mallard ducks (Anas platyrhynchos).

Abstract Surgical procedures of the wing are commonly performed in companion, captive, and wild avian species. To develop a clinically applicable brachial plexus nerve block technique for perioperative analgesia in birds, 8 adult female mallard ducks (Anas platyrhynchos) were anesthetized and used in several local anesthetic trials with bupivacaine (2 or 8 mg/kg) or a combination of lidocaine (15 mg/kg) and epinephrine (3.8 µg/kg) perineurally; equal volumes of saline were administered as control treatments. Both axillary and dorsal approaches to the brachial plexus were evaluated. With the axillary approach, radial and ulnar compound nerve action potentials (CNAP), sensory nerve conduction velocities (SNCVs), and cord dorsum potentials (CDPs) were recorded after distal sensory nerve stimulation. Values were recorded before and at 5, 30, and 60 minutes after injection of local anesthetic or saline. Birds were monitored for the presence of a wing droop and a change in motor function on recovery from anesthesia. Results were highly variable for all techniques. No technique significantly decreased CDPs or resulted in consistent wing droop. Radial and ulnar CNAPs, SNCVs, and CDPs were consistently recorded in all birds. Variable results might indicate that the treatment, concentration, or volume of local anesthetic used was ineffective in producing local anesthesia. Electrodiagnostic methods used in these ducks to assess loss of sensory nerve conduction might not be sensitive enough to assess the effects of local anesthesia. Further research is needed to identify methods for assessing the efficacy of brachial plexus nerve blockade in birds.

Minimum anesthetic concentration of isoflurane in captive thick-billed parrots (Rhynchopsitta pachyrhyncha)

OBJECTIVE To determine the minimum anesthetic concentration (MAC) of isoflurane in thick-billed parrots (Rhynchopsitta pachyrhyncha). ANIMALS 15 healthy thick-billed parrots. PROCEDURES Anesthesia was induced and maintained with isoflurane in oxygen. In the first bird that was anesthetized, end-tidal isoflurane concentration was maintained at 1.0% for 15 minutes. After this period of anesthetic equilibration, an end-tidal gas sample was obtained for verification of isoflurane concentration. A toe was pinched to determine the birds response to pain, and the bird was then allowed to recover from aesthesia. To determine MAC, a so-called up-and-down approach was subsequently used in all 15 birds. Compared with the isoflurane concentration used for MAC determination in the first bird, maintenance isoflurane concentration for the second bird was increased by approximately 10% if the first bird reacted and decreased by approximately 10% if the first bird did not react to a toe pinch. These steps were then followed until all 15 birds had been anesthetized. Crossover events occurred when birds in sequence had discordant results (ie, 1 reactor and 1 nonreactor). The MAC was defined as the mean of the isoflurane concentrations measured during these crossover events. RESULTS Mean MAC of isoflurane in thick-billed parrots was estimated to be 1.07% (95% confidence interval, 0.97% to 1.16%). CONCLUSIONS AND CLINICAL RELEVANCE Isoflurane MAC appears to be lower in thick-billed parrots than the MAC determined for other bird species. Determination of the species-specific requirements of thick-billed parrots should allow isoflurane anesthesia to be performed more safely in this endangered species.

Evaluation of DNA Extraction Techniques for Detecting Mycobacterium tuberculosis Complex Organisms in Asian Elephant Trunk Wash Samples

ABSTRACT Rapid and sensitive diagnostic assays for the detection of tuberculous mycobacteria in elephants are lacking. DNA extraction with PCR analysis is useful for tuberculosis screening in many species but has not been validated on elephant trunk wash samples. We estimated the analytical sensitivity and specificity of three DNA extraction methods to detect Mycobacterium tuberculosis complex organisms in trunk wash specimens. A ZR soil microbe DNA kit (ZR) and a traditional salt and ethanol precipitation (TSEP) approach were evaluated under three different treatment conditions: heat treatment, phenol treatment, and contamination with Mycobacterium avium. A third approach, using a column filtration method, was evaluated for samples contaminated with soil. Trunk wash samples from uninfected elephants were spiked with various concentrations of M. bovis cells and subjected to the described treatment conditions prior to DNA extraction. Extracted DNA was amplified using IS6110-targeted PCR analysis. The ZR and TSEP methods detected as low as 1 to 5 M. bovis cells and 10 M. bovis cells, respectively, per 1.5 ml of trunk wash under all three conditions. Depending on the amount of soil present, the column filtration method detected as low as 5 to 50 M. bovis cells per 1.5 ml of trunk wash. Analytical specificity was assessed by DNA extraction from species of nontuberculous mycobacteria and amplification using the same PCR technique. Only M. bovis DNA was amplified, indicating 100% analytical specificity of this PCR technique. Our results indicate that these DNA extraction techniques offer promise as useful tests for detection of M. tuberculosis complex organisms in elephant trunk wash specimens.

Post-release survival of surf scoters following an oil spill: An experimental approach to evaluating rehabilitation success

Birds are often the most numerous vertebrates damaged and rehabilitated in marine oil spills; however, the efficacy of avian rehabilitation is frequently debated and rarely examined experimentally. We compared survival of three radio-marked treatment groups, oiled, rehabilitated (ORHB), un-oiled, rehabilitated (RHB), and un-oiled, non-rehabilitated (CON), in an experimental approach to examine post-release survival of surf scoters (Melanitta perspicillata) following the 2007 M/V Cosco Busan spill in San Francisco Bay. Live encounter-dead recovery modeling indicated that survival differed among treatment groups and over time since release. The survival estimate (±SE) for ORHB was 0.143±0.107 compared to CON (0.498±0.168) and RHB groups (0.772±0.229), suggesting scoters tolerated the rehabilitation process itself well, but oiling resulted in markedly lower survival. Future efforts to understand the physiological effects of oil type and severity on scoters are needed to improve post-release survival of this species.

Validation of lactate measurement in American flamingo (Phoenicopterus ruber) plasma and correlation with duration and difficulty of capture.

Capture myopathy and associated death have been reported with capture and restraint of greater flamingos (Phoenicopterus ruber roseus) and lesser flamingos (Phoeniconaias minor). In chickens (Gallus gallus), blood lactate concentration levels have been used as indicators of muscle damage. Lactate has also been used to predict survival in humans and dogs. The goals of this study were to validate two common methods for measuring lactate (i-STAT and VetTest analyzers) in flamingo plasma by comparing measurements to a reference analyzer; and to correlate blood lactate concentration levels in captured flamingos with the duration and difficulty of capture as a possible indicator of capture myopathy. Twenty-seven banked flamingo plasma samples were run in triplicate on each of the three blood analyzers. Values from the i-STAT analyzer were consistently lower than those from the ABL analyzer, while values from the VetTest were consistently higher than those from the ABL analyzer. However, there was a good level of correlation between all three analyzers. Two of the three analyzers were determined to have acceptable total allowable error levels, calculated at 3.6% for the ABL and 10.7% for the VetTest. For clinical purposes, both the i-STAT and the VetTest analyzers provide adequate evaluation of lactate levels when serial samples are measured on the same analyzer. After validating the assay, 34 captive flamingos were captured for routine examinations. Blood lactate concentration levels were positively correlated with the length of time of the individual capture, but lactate did not increase significantly as capture difficulty increased. Only one animal was considered to have a difficult capture. No flamingos demonstrated clinical signs of capture myopathy during this study. Further research is required to determine if blood lactate concentration is a useful indicator of capture myopathy.

Failure to Transmit Avian Vacuolar Myelinopathy to Mallard Ducks

Avian vacuolar myelinopathy (AVM) is a neurologic disease that has been diagnosed in free-ranging birds in the southeastern United States. Bald eagles (Haliaeetus leuocephalus), American coots (Fulica americana), and mallards (Anas platyrhynchos) have been affected. Previous investigations have not determined the etiology of this disease. In November and December 2002, we attempted to induce AVM in game-farmed mallards through four, 7-day exposure trials. Mallards were housed in six groups of eight, with two of these groups serving as controls. One group was housed with AVM-affected coots; one group was tube fed daily with water from the lake where affected coots were captured; one group was tube fed daily with aquatic vegetation (Hydrilla verticillata) from the same lake; and another group was tube fed daily with sediment from the lake. No ducks exhibited clinical neurologic abnormalities consistent with AVM and no evidence of AVM was present at histopathologic examination of brain tissue. Although limitations in sample size, quantity of individual doses, frequency of dose administration, duration of exposure, and timing of these trials restrict the interpretation of the findings, AVM was not readily transmitted by direct contact, water, hydrilla, or sediment in this investigation.

Somatosensory evoked potentials and sensory nerve conduction velocities in the thoracic limb of mallard ducks (Anas platyrhynchos)

OBJECTIVE To develop a clinically applicable technique for recording cord dorsum potentials (CDPs) following stimulation of the radial and ulnar nerves and establish reference values for radial and ulnar sensory nerve conduction velocities (SNCVs) in the wings of ducks. ANIMALS 8 clinically normal adult female mallard ducks (Anas platyrhynchos). PROCEDURES Radial and ulnar compound nerve action potentials (CNAPs) and CDPs were recorded following distal sensory nerve stimulation. The CDPs were recorded from the interarcuate space between the last cervical vertebra and the first thoracic vertebra. Surgical dissection and transection of the brachial plexus in 1 anesthetized duck were performed to identify nerve root location and confirm functional loss of nerve conduction assessed by loss of the CDP. RESULTS Radial and ulnar CNAPs and CDPs were consistently recorded in all birds. Median radial SNCV was 38.3 m/s (range, 36.0 to 49.0 m/s), and ulnar SNCV was 35.3 m/s (range, 28.0 to 40.0 m/s). Surgical transection of the brachial plexus resulted in complete loss of the CDP. CONCLUSIONS AND CLINICAL RELEVANCE Measurement of radial and ulnar SNCV or CDP is feasible in isoflurane-anesthetized mallard ducks. The CDP accurately reflects sensory nerve conduction through the brachial plexus. Assessment of brachial plexus function in mallard ducks via evaluations of SNCVs and CDPs may have application for diagnosis of traumatic injuries to the brachial plexus, evaluation of neuropathies associated with exposure to toxic chemicals, and assessment of the efficacy of interventions such as brachial plexus nerve blockade.

Maxillary Lymphosarcoma in a White-tailed Deer (Odocoileus virginianus)

In 1996, lymphosarcoma was observed in a captive adult female white-tailed deer (Odocoileus virginianus) from northeastern Kansas (USA). A subcutaneous mass on the deers left cheek was surgically removed and lymphosarcoma was diagnosed. The mass recurred within 3 wk. A second surgical removal was attempted but the tumor had grown much larger, had become intimately involved with the buccal mucosa, and was beginning to interfere with mastication. For these reasons, the deer was euthanized. At postmortem examination the only abnormal findings were the primary tumor and enlarged ipsilateral parotid and mandibular lymph nodes. Histologically these tissues demonstrated changes characteristic of lymphosarcoma but no other organs had evidence of neoplastic disease. A diagnosis of focal lymphosarcoma with local metastasis was made. The organ distribution of lymphosarcoma in this deer differs from previously described cases of lymphosarcoma in cervids.