PHARMACOKINETICS OF TRAMADOL AND O-DESMETHYLTRAMADOL IN GIANT TORTOISES (CHELONOIDIS VANDENBURGHI, CHELONOIDIS VICINA).

The objective of this study was to determine the pharmacokinetics of two orally administered doses of tramadol (1 mg/kg and 5 mg/kg) and its metabolite, O-desmethyltramadol (M1) in giant tortoises (Chelonoidis vandenburghi, Chelonoidis vicina). Eleven giant tortoises (C. vandenburghi, C. vicina) received two randomly assigned, oral doses of tramadol (either 1 mg/kg or 5 mg/kg), with a washout period of 3 wk between each dose. The half-life (t½) of orally administered tramadol at 1 mg/kg and 5 mg/kg was 11.9 ± 4.6 h and 13.2 ± 6.1 h, respectively. After oral administration of tramadol at 1 mg/kg and 5 mg/kg, the maximum concentration (Cmax) was 125 ± 69 ng/ml and 518 ± 411 ng/ml, respectively. There were not enough data points to determine pharmacokinetic (PK) parameters for the M1 metabolite from either dose. Tramadol administered orally to giant tortoises at both doses provided measurable plasma concentrations of tramadol for approximately 48 h with occasional transient sedation. Oral tramadol at 5 mg/kg, on average, achieves concentrations of >100 ng/ml, the reported human therapeutic threshold, for 24 h. Based on the low levels of M1 seen in this study, M1 may not be a major metabolite in this taxon.

Lidocaine constant rate infusion improves the probability of survival in rabbits with gastrointestinal obstructions: 64 cases (2012-2021).

OBJECTIVE: To determine the survival to discharge rate of rabbits with gastrointestinal obstructions treated with lidocaine constant rate infusion (CRI) and other factors associated with survival. ANIMALS: Cases of gastrointestinal obstruction in rabbits (n = 56, including 64 events) that had presented to a veterinary teaching hospital from 2012 to 2021. METHODS: This was a retrospective study in which data on rabbits with evidence of gastrointestinal obstruction were extracted from veterinary teaching hospital medical records over a 9-year period. Systemic lidocaine treatment, breed, sex, age, temperature at presentation, blood glucose at presentation, and time to discharge or death were evaluated with univariate and multivariate logistic regression to identify factors significantly associated with survival to hospital discharge in rabbits with gastrointestinal obstruction. RESULTS: Comparatively, 89.7% of rabbits treated with lidocaine CRI (n = 39) survived to hospital discharge, while only 56% of rabbits that were not treated with lidocaine CRI (25) survived. In the final multivariate analysis, 2 factors were associated with survival to discharge: rabbits treated with systemic lidocaine and male rabbits had increased odds of survival compared to those not treated with systemic lidocaine and female rabbits, respectively. CLINICAL RELEVANCE: Results demonstrated that rabbits with gastrointestinal obstruction and treated with a lidocaine CRI were more likely to survive compared to rabbits not treated with lidocaine CRI.

Treatment of Pain in Fish.

This chapter provides an overview of our current understanding of clinical analgesic use in fish. Recently, the efficacy and pharmacokinetics of several analgesic drugs for use in fish have been investigated, and the most important data indicates that µ-opioid agonist drugs (e.g, morphine) are consistently effective as analgesics across fish species. In addition, bath application of some analgesic drugs may be useful, which affords multiple methods for delivering analgesics to fish. Although few published studies of non-steroidal anti-inflammatory drugs administered to fish show promise, we have much to learn about the analgesic efficacy of most drugs in this class.

Treatment of Pain in Reptiles.

This chapter provides an overview of our current understanding of clinical analgesic use in reptiles. Currently, µ-opioid agonist drugs are the standard of care for analgesia in reptiles. Reptile pain is no longer considered a necessary part of recovery to keep the reptile from becoming active too early. Rather, treating pain allows for the reptile to begin normalizing their behavior. This recognition of pain and analgesia certainly benefits our reptile patients and greatly improves reptile welfare, but it also benefits our students and house officers, who will carry the torch and continue to demand excellence in reptile medicine.

Analgesic Efficacy of Tramadol and Morphine in White's Tree Frogs (Litoria caerulea).

Published data are sparse regarding the recognition of clinically relevant pain and appropriate analgesia in amphibians. The amphibian analgesia literature has primarily focused on nociceptive pathways in a single species, the northern leopard frog (Rana pipiens). The objective of the current study was to assess the analgesic efficacy and safety of oral tramadol and subcutaneous morphine in a commonly maintained zoo and pet species, White's tree frog (Litoria caerulea). We hypothesized that tramadol and morphine would provide dose-dependent antinociception, as measured by significant increases in hindlimb withdrawal latency after exposure to a noxious thermal stimulus. Two randomized, placebo-controlled, complete crossover studies were performed, with tramadol (n = 12) administered at 15, 25, and 40 mg/kg PO and morphine (n = 12) administered at 5 and 10 mg/kg SC. Hindlimb withdrawal latency was measured for a maximum of 72 h. No adverse side effects or signs of sedation were observed with any dose or drug evaluated. No significant difference in withdrawal latency was detected between the control and either tramadol or morphine. These negative results were surprising, suggesting that the thermal nociceptive model may not be biologically relevant in amphibian species.

Comparison of Thermal and Mechanical Noxious Stimuli for Testing Analgesics in White's Tree Frogs (Litoria caerulea) and Northern Leopard Frogs (Lithobates pipiens).

Determining the clinical efficacy of analgesic drugs in amphibians can be particularly challenging. The current study investigated whether a thermal nociceptive stimulus is useful for the evaluation of analgesic drugs in 2 amphibian species. The objectives of this study were 2-fold: 1) compare 2 models of nociception (thermal and mechanical) using 2 frog species; White's Tree Frogs (Litoria caerulea; WTF) and Northern Leopard Frogs (Lithobates pipiens; NLF) after administration of saline or morphine sulfate; and 2) evaluate antinociceptive efficacy of morphine sulfate at 2 doses in a common amphibian research species, the NLF, using a mechanical stimulus. Neither WTF nor NLF displayed consistent drug-dependent changes in withdrawal responses to a noxious thermal stimulus applied using the Hargreaves apparatus, but NLF exposed to the noxious mechanical stimulus demonstrated a significant dose-dependent antinociceptive response to morphine sulfate. These results indicate that morphine is not antinociceptive in WTF, supporting previously reported results, and demonstrate the importance of using an appropriate experimental antinociceptive test in amphibians. Our data suggest that nociception in amphibian species may be best evaluated by using mechanical nociceptive models, although species differences must also be considered.

Pharmacokinetics of ceftazidime in Northern leopard frogs (Lithobates pipiens) at two different doses and administration routes.

OBJECTIVE: To determine an optimal ceftazidime dosing strategy in Northern leopard frogs (Lithobates pipiens) by evaluation of 2 different doses administered SC and 1 dose administered transcutaneously. ANIMALS: 44 Northern leopard frogs (including 10 that were replaced). PROCEDURES: Ceftazidime was administered to frogs SC in a forelimb at 20 mg/kg (n = 10; SC20 group) and 40 mg/kg (10; SC40 group) or transcutaneously on the cranial dorsum at 20 mg/kg (10; TC20 group). Two frogs in each ceftazidime group were euthanized 12, 24, 48, 72, and 96 hours after drug administration. Plasma, renal, and skin concentrations of ceftazidime were measured by means of reversed-phase high-performance liquid chromatography. Four control frogs were used for assay validation. RESULTS: Mean plasma half-life of ceftazidime in the SC20, SC40, and TC20 groups was 9.01 hours, 14.49 hours, and too low to determine, respectively. Mean maximum plasma ceftazidime concentration was 92.9, 96.0, and 1.3 µg/mL, respectively. For 24 hours after drug administration in the SC20 and SC40 groups, plasma ceftazidime concentration exceeded 8 µg/mL. Renal and skin concentrations were detectable at both doses and routes of administration; however, skin concentrations were significantly lower than renal and plasma concentrations. CONCLUSIONS AND CLINICAL RELEVANCE: Findings indicated that ceftazidime administration to Northern leopard frogs at 20 mg/kg, SC, every 24 hours would achieve a plasma concentration exceeding the value considered effective against common amphibian pathogens. Transcutaneous administration of the injectable ceftazidime formulation at 20 mg/kg warrants further investigation but is not currently recommended because of a potential lack of efficacy.

Respiratory and antinociceptive effects of dexmedetomidine and doxapram in ball pythons (Python regius).

OBJECTIVE: To determine the effects of dexmedetomidine, doxapram, and dexmedetomidine plus doxapram on ventilation ([Formula: see text]e), breath frequency, and tidal volume (Vt) in ball pythons (Python regius) and of doxapram on the thermal antinociceptive efficacy of dexmedetomidine. ANIMALS: 14 ball pythons. PROCEDURES: Respiratory effects of dexmedetomidine and doxapram were assessed with whole-body, closed-chamber plethysmography, which allowed for estimates of [Formula: see text]e and Vt. In the first experiment of this study with a complete crossover design, snakes were injected, SC, with saline (0.9% NaCl) solution, dexmedetomidine (0.1 mg/kg), doxapram (10 mg/kg), or dexmedetomidine and doxapram, and breath frequency, [Formula: see text]e, and Vt were measured before and every 30 minutes thereafter, through 240 minutes. In the second experiment, antinociceptive efficacy of saline solution, dexmedetomidine, and dexmedetomidine plus doxapram was assessed by measuring thermal withdrawal latencies before and 60 minutes after SC injection. RESULTS: Dexmedetomidine significantly decreased breath frequency and increased Vt but did not affect [Formula: see text]e at all time points, compared with baseline. Doxapram significantly increased [Formula: see text]e, breath frequency, and Vt at 60 minutes after injection, compared with saline solution. The combination of dexmedetomidine and doxapram, compared with dexmedetomidine alone, significantly increased [Formula: see text]e at 30 and 60 minutes after injection and did not affect breath frequency and Vt at all time points. Thermal withdrawal latencies significantly increased when snakes received dexmedetomidine or dexmedetomidine plus doxapram, versus saline solution. CONCLUSIONS AND CLINICAL RELEVANCE: Concurrent administration of doxapram may mitigate the dexmedetomidine-induced reduction of breathing frequency without disrupting thermal antinociceptive efficacy in ball pythons.

Evaluation of subcutaneous administration of alfaxalone-midazolam and dexmedetomidine-midazolam for sedation of ball pythons (Python regius).

OBJECTIVE: To evaluate SC administration of alfaxalone-midazolam and dexmedetomidine-midazolam for sedation of ball pythons (Python regius). ANIMALS: 12 healthy juvenile ball pythons. PROCEDURES: In a randomized crossover study, each snake was administered a combination of alfaxalone (5 mg/kg [2.3 mg/lb]) and midazolam (0.5 mg/kg [0.23 mg/lb]) and a combination of dexmedetomidine (0.05 mg/kg [0.023 mg/lb]) and midazolam (0.5 mg/kg), SC, with a washout period of at least 7 days between protocols. Respiratory and heart rates and various reflexes and behaviors were assessed and compared between protocols. Forty-five minutes after protocol administration, sedation was reversed by SC administration of flumazenil (0.05 mg/kg) alone or in combination with atipamezole (0.5 mg/kg; dexmedetomidine-midazolam protocol only). Because of difficulties with visual assessment of respiratory effort after sedative administration, the experiment was repeated for a subset of 3 ball pythons, with plethysmography used to assess respiration. RESULTS: Both protocols induced a similar level of moderate sedation with no adverse effects aside from transient apnea. Cardiopulmonary depression was more profound, but time to recovery after reversal was significantly shorter, for the dexmedetomidine-midazolam protocol than for the alfaxalone-midazolam protocol. Plethysmographic findings were consistent with visual observations and suggested that snakes compensated for a decrease in respiratory rate by increasing tidal volume amplitude. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that both protocols induced clinically relevant sedation in ball pythons and should be useful for minor procedures such as venipuncture and diagnostic imaging. However, caution should be used when sedating snakes with compromised cardiopulmonary function. (J Am Vet Med Assoc 2020;256:573-579.

COMPARISON OF SUBCUTANEOUS ADMINISTRATION OF ALFAXALONE-MIDAZOLAM-DEXMEDETOMIDINE WITH KETAMINE-MIDAZOLAM-DEXMEDETOMIDINE FOR CHEMICAL RESTRAINT IN JUVENILE BLUE POISON DART FROGS (DENDROBATES TINCTORIUS AZUREUS).

Blue poison dart frogs (Dendrobates tinctorius azureus) are commonly maintained in zoological institutions and are becoming popular in the pet trade industry. Sedation or light anesthesia is required for safe and effective handling of this species. In this study, the sedative effects of subcutaneously administered alfaxalone-midazolam-dexmedetomidine (AMD) (20, 40, 5 mg/kg, respectively) and ketamine-midazolam-dexmedetomidine (KMD) (100, 40, 5 mg/kg, respectively) were compared in a prospective, randomized, blinded, crossover study in juvenile blue poison dart frogs (n = 10). Both protocols were partially reversed 45 min after administration of either protocol with subcutaneously administered flumazenil (0.05 mg/kg) and atipamezole (50 mg/kg). Heart rate, pulmonic respiratory rate, various reflexes, and behavioral parameters were monitored after drug administration. Both protocols resulted in rapid loss of righting reflex [median (range): AMD, 5 min (5-5 min); KMD, 5 min (5-10 min)]. Time to complete recovery was similar with both protocols (mean ± SD: AMD, 97.5 ± 11.4 min; KMD, 96.5 ± 25.4 min). The AMD protocol resulted in pulmonic respiratory depression, whereas no significant difference in heart rate was found between the two protocols. All frogs were observed eating within 24 hr of chemical restraint. Gastric prolapses occurred in four frogs (AMD 3, KMD 1) that were easily reduced with a cotton-tip application. No other adverse reactions were observed. The results of this study provide two different subcutaneous chemical restraint protocols in juvenile blue poison dart frogs.

Effect of injection site on dexmedetomidine-ketamine induced sedation in leopard geckos (Eublepharis macularius).

OBJECTIVE To evaluate whether the sedative effects of a combination of dexmedetomidine and ketamine differed when it was administered IM in a hind limb versus a forelimb of leopard geckos (Eublepharis macularius). DESIGN Randomized crossover study. ANIMALS 9 healthy adult leopard geckos. PROCEDURES Each gecko received a combination of dexmedetomidine (0.1 mg/kg [0.045 mg/lb]) and ketamine (10 mg/kg [4.5 mg/lb]; DK), IM, in a forelimb and hind limb in a randomized order and with a 7-day interval between treatments. All geckos received atipamezole (1 mg/kg [0.45 mg/lb], SC) 45 minutes after DK administration. Palpebral and righting reflexes, jaw tone, and superficial pain and escape responses were each assessed on a 3-point scale, and the scores for those variables were summed to calculate a sedation score. Those variables and heart and respiratory rates were evaluated at predetermined times before and for 1 hour after DK administration. RESULTS For the forelimb treatment, mean sedation score was higher and mean heart rate was lower than the corresponding values for the hind limb treatment at most time points after DK administration. The righting reflex remained intact for all 9 geckos following the hind limb treatment but became absent in 7 geckos following the forelimb treatment. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the extent of DK-induced sedation was greater when the combination was injected IM in a forelimb versus a hind limb of leopard geckos, likely owing to a hepatic first-pass effect following hind limb injection. In reptiles, IM hind limb administration of drugs that undergo hepatic metabolism and excretion is not recommended.

Antinociceptive efficacy and respiratory effects of dexmedetomidine in ball pythons (Python regius).

OBJECTIVE To determine antinociceptive efficacy, behavioral patterns, and respiratory effects associated with dexmedetomidine administration in ball pythons (Python regius). ANIMALS 12 ball pythons. PROCEDURES Antinociception was assessed by applying an infrared heat stimulus to the cranioventral surface of snakes during 2 experiments. Thermal withdrawal latency was measured at 0, 2, and 24 hours after SC injections of dexmedetomidine (0.1 or 0.2 mg/kg) or saline (0.9% NaCl) solution and at 0 to 60 minutes after injection of dexmedetomidine (0.1 mg/kg) or saline solution. Behaviors were recorded at 0, 2, and 24 hours after administration of dexmedetomidine (0.1 mg/kg) or saline solution. Tongue flicking, head flinch to the approach of an observer's hand, movement, and righting reflex were scored. Respiratory frequency was measured by use of plethysmography to detect breathing-related movements after injection of dexmedetomidine (0.1 mg/kg) or saline solution. RESULTS Mean baseline withdrawal latency was 5 to 7 seconds; saline solution did not alter withdrawal latency. Dexmedetomidine increased withdrawal latency by 18 seconds (0.2 mg/kg) and 13 seconds (0.1 mg/kg) above baseline values at 2 hours. Increased withdrawal latency was detected within 15 minutes after dexmedetomidine administration. At 2 hours after injection, there were few differences in behavioral scores. Dexmedetomidine injection depressed respiratory frequency by 55% to 70%, compared with results for saline solution, but snakes continued to breathe without prolonged apnea. CONCLUSIONS AND CLINICAL RELEVANCE Dexmedetomidine increased noxious thermal withdrawal latency without causing excessive sedation. Therefore, dexmedetomidine may be a useful analgesic drug in ball pythons and other snake species.

Diagnosis and management of inflammatory bowel disease in a harpy eagle (Harpia harpyja) with suspected fenbendazole toxicosis.

CASE DESCRIPTION A 14-year-old 4.1-kg (9.02-lb) male harpy eagle (Harpia harpyja) was evaluated because of vomiting, anorexia, lethargy, and weight loss (decrease of 0.35 kg [0.77 lb]) of 4 weeks' duration. The bird had previously been treated orally with fenbendazole after the initial onset of clinical signs. CLINICAL FINDINGS An initial CBC revealed marked heteropenia and anemia, but whole-body contrast-enhanced CT images and other diagnostic test findings were unremarkable. Clinical signs persisted, and additional diagnostic testing failed to reveal the cause. During celiotomy, a biopsy specimen of the duodenum was obtained for histologic examination, which revealed lymphoplasmacytic inflammation, consistent with inflammatory bowel disease (IBD). TREATMENT AND OUTCOME Prior to histopathologic diagnosis of IBD, barium sulfate administered via gavage resulted in a temporary improvement of clinical signs. Following diagnosis of IBD, corticosteroid administration was initiated in conjunction with antifungal prophylaxis. Cessation of vomiting and a return to normal appetite occurred within 3 days. Fifteen months after cessation of corticosteroid treatment, the eagle continued to do well. CLINICAL RELEVANCE To our knowledge, this was the first report of diagnosis and management of IBD in an avian species. For the eagle of the present report, results of several diagnostic tests increased clinical suspicion of IBD, but histologic examination of an intestinal biopsy specimen was required for definitive diagnosis. Although successful in this case, steroid administration in avian species must be carefully considered. Conclusive evidence of fenbendazole toxicosis was not obtained, although it was highly suspected in this bird.

Urethral diverticulum and urolithiasis in a female guinea pig (Cavia porcellus).

CASE DESCRIPTION A 5-year-old sexually intact female guinea pig was evaluated because of mild dysuria and a subcutaneous mass located cranioventral to the urogenital openings. CLINICAL FINDINGS Non-contrast-enhanced CT and surgical exploration of the distal aspect of the urethra revealed a urethral diverticulum with an intraluminal urolith. Analysis revealed that the urolith was composed of calcium carbonate and struvite. TREATMENT AND OUTCOME The urolith was surgically removed and ablation of the urethral diverticulum was attempted. Approximately 3 months later, the guinea pig was reevaluated for masses in the perineal region, and positive-contrast urethrocystography revealed 2 uroliths present in the same diverticulum. Uroliths were manually expressed with the patient under general anesthesia. Approximately 2 weeks later, urethroplasty was performed to create an enlarged stoma with the diverticulum, thereby preventing urine from pooling in the diverticulum and potentially reducing the risk of future urolith formation. The urethroplasty site healed well with no reported complications or evidence of urolith recurrence 6 months after surgery. CLINICAL RELEVANCE Urolithiasis is common in guinea pigs, and urethral diverticulum and intraluminal urolith formation should be considered as a potential differential diagnosis for a subcutaneous mass along the distal aspect of the urethra. Creation of a urethral stoma from a urethral diverticulum via urethroplasty achieved a successful outcome in this patient.

Comparison of subcutaneous dexmedetomidine-midazolam versus alfaxalone-midazolam sedation in leopard geckos (Eublepharis macularius).

OBJECTIVE: To compare dexmedetomidine-midazolam with alfaxalone-midazolam for sedation in leopard geckos (Eublepharis macularius). STUDY DESIGN: Prospective, randomized, blinded, complete crossover study. ANIMALS: Nine healthy adult leopard geckos. METHODS: Geckos were administered a combination of dexmedetomidine (0.1 mg kg-1) and midazolam (1.0 mg kg-1; treatment D-M) or alfaxalone (15 mg kg-1) and midazolam (1.0 mg kg-1; treatment A-M) subcutaneously craniodorsal to a thoracic limb. Heart rate (HR), respiratory rate (fR), righting reflex, palpebral reflex, superficial and deep pain reflexes, jaw tone and escape response were assessed every 5 minutes until reversal. Conditions for intubation and response to needle prick were evaluated. Antagonist drugs [flumazenil (0.05 mg kg-1) ± atipamezole (1.0 mg kg-1)] were administered subcutaneously, craniodorsal to the contralateral thoracic limb, 45 minutes after initial injection, and animals were monitored until recovery. RESULTS: HR, but not fR, decreased significantly over time in both treatments. HR was significantly lower than baseline at all time points in D-M and for all but the 5 and 10 minute time points in A-M. HR was significantly higher in A-M at all time points after drug administration when compared with D-M. Sedation scores between protocols were similar for most time points. All animals in A-M lost righting reflex compared with seven out of nine (78%) geckos in D-M. Geckos in A-M lost righting reflex for significantly longer time. Mean ± standard deviation time to recovery after antagonist administration was 6.1 ± 2.2 minutes for D-M and 56 ± 29 minutes for A-M, and these times were significantly different. CONCLUSIONS AND CLINICAL RELEVANCE: Combination D-M or A-M provided sedation of a level expected to allow physical examinations and venipuncture in leopard geckos. A-M provided a faster onset of sedation compared with D-M. Recovery was significantly faster following antagonist reversal of D-M, compared with A-M.

Antinociceptive efficacy of intramuscular administration of morphine sulfate and butorphanol tartrate in tegus (Salvator merianae).

OBJECTIVE To evaluate the antinociceptive efficacy of IM morphine sulfate or butorphanol tartrate administration in tegus (Salvator merianae). ANIMALS 6 healthy juvenile (12- to 24-month-old) tegus (mean ± SD body weight, 1,484 ± 473 g). PROCEDURES In a crossover study design, tegus were randomly assigned to treatment order, with a minimum washout period of 15 days between treatments. Each of 5 treatments was administered IM in a forelimb: saline (0.9% NaCl) solution (0.5 mL), morphine sulfate (5 or 10 mg/kg), or butorphanol tartrate (5 or 10 mg/kg). A withdrawal latency test was used to evaluate antinociception, with a noxious thermal stimulus applied to the plantar surface of the hind limb before (0 hours; baseline) and 0.5, 1, 2, 3, 4, 6, 12, and 24 hours after each treatment. Observers were unaware of treatment received. RESULTS With saline solution, mean hind limb withdrawal latencies (interval to limb withdrawal from the thermal stimulus) remained constant, except at 12 hours. Tegus had higher than baseline mean withdrawal latencies between 0.5 and 1 hour and at 12 hours with morphine at 5 mg/kg and between 1 and 12 hours with morphine at 10 mg/kg. With butorphanol at 5 and 10 mg/kg, tegus maintained withdrawal responses similar to baseline at all assessment points. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that morphine, but not butorphanol, provided antinociception at 5 and 10 mg/kg in tegus as measured by thermal noxious stimulus testing. These data supported the hypothesis that µ-opioid (but not κ-opioid) receptor agonists provide antinociception in reptiles.

Antinociceptive and respiratory effects following application of transdermal fentanyl patches and assessment of brain µ-opioid receptor mRNA expression in ball pythons.

OBJECTIVE To quantify plasma fentanyl concentrations (PFCs) and evaluate antinociceptive and respiratory effects following application of transdermal fentanyl patches (TFPs) and assess cerebrospinal µ-opioid receptor mRNA expression in ball pythons (compared with findings in turtles). ANIMALS 44 ball pythons (Python regius) and 10 turtles (Trachemys scripta elegans). PROCEDURES To administer 3 or 12 µg of fentanyl/h, a quarter or whole TFP (TFP-3 and TFP-12, respectively) was used. At intervals after TFP-12 application in snakes, PFCs were measured by reverse-phase high-pressure liquid chromatography. Infrared heat stimuli were applied to the rostroventral surface of snakes to determine thermal withdrawal latencies after treatments with no TFP (control [n = 16]) and TFP-3 (8) or TFP-12 (9). Breathing frequency was measured in unrestrained controls and TFP-12-treated snakes. µ-Opioid receptor mRNA expression in brain and spinal cord tissue samples from snakes and turtles (which are responsive to µ-opioid receptor agonist drugs) were quantified with a reverse transcription PCR assay. RESULTS Mean PFCs were 79, 238, and 111 ng/mL at 6, 24, and 48 hours after TFP-12 application, respectively. At 3 to 48 hours after TFP-3 or TFP-12 application, thermal withdrawal latencies did not differ from pretreatment values or control treatment findings. For TFP-12-treated snakes, mean breathing frequency significantly decreased from the pretreatment value by 23% and 41% at the 24- and 48-hour time points, respectively. Brain and spinal cord tissue µ-opioid receptor mRNA expressions in snakes and turtles did not differ. CONCLUSIONS AND CLINICAL RELEVANCE In ball pythons, TFP-12 application resulted in high PFCs, but there was no change in thermal antinociception, indicating resistance to µ-opioid-dependent antinociception in this species.

SEROSURVEY OF SELECTED ARBOVIRAL PATHOGENS IN FREE-RANGING, TWO-TOED SLOTHS (CHOLOEPUS HOFFMANNI) AND THREE-TOED SLOTHS (BRADYPUS VARIEGATUS) IN COSTA RICA, 2005-07.

We screened for antibodies to 16 arboviruses in four populations of free-ranging sloths in Costa Rica. Blood samples were taken from 16 Hoffman's two-toed sloths (HTSs; Choloepus hoffmanni ) and 26 brown-throated sloths (BTSs; Bradypus variegatus ) over a 3-yr period. We used serologic assays to detect antibodies against 10 arboviruses previously described in sloths (St. Louis encephalitis [SLEV], Changuinola, Venezuelan equine encephalitis, Ilheus [ILHV], Oropouche, Mayaro, Utinga, Murutucu, Punta Toro, and vesicular stomatitis [VSV] viruses) and six arboviruses not described in sloths (Rio Grande, West Nile [WNV], eastern equine encephalitis, Piry, Munguba, and La Crosse viruses). Overall, 80% of sloths had detectable antibodies to SLEV, 67% had antibodies to ILHV, 32% to Punta Toro virus, 30% to Changuinola virus, 15% to WNV, 14% to VSV, 11% to Venezuelan equine encephalitis virus, and 10% to Rio Grande virus. No samples had detectable antibodies to the remaining eight viruses. We found a significant increase in prevalence of antibody to VSV in HTSs between 2005 and 2007, and for WNV antibody between 2005 and 2006. We found no significant differences in the prevalences of antibodies to the sampled viruses between the two locations. Antibody prevalences were significantly higher in HTSs than in BTSs for SLEV in 2005. Antibody-positive results for ILHV were likely due to cross-reaction with SLEV. The novel finding of antibodies to Rio Grande virus in sloths could be due to cross-reaction with another phlebovirus. These findings might have implications for land management and domestic animal health. Due to the nature of the study, we could not determine whether sloths could represent amplification hosts for these viruses, or whether they were only exposed and could be used as sentinel species. Further studies are needed to fully characterize arboviral exposure in sloths.

Bilateral Uveitis and Hyphema in a Catalina Macaw (Ara ararauna × Ara macao ) With Multicentric Lymphoma.

A 20-year-old, female Catalina macaw (Ara ararauna × Ara macao ) was presented with bilateral uveitis and hyphema. The hyphema initially improved with 0.12% prednisolone acetate ophthalmic drops (1 drop OU q4h for 7 days), but the hyphema recurred after the drops were tapered. The bird subsequently developed inappetance, weight loss, regurgitation, and lethargy and was euthanatized 24 days after initial presentation. Necropsy revealed marked splenomegaly and hepatomegaly, with significant mucosal ulcerations of the proventriculus and petechiation associated with both kidneys. Histopathologic examination revealed multicentric lymphoma, with neoplastic cells observed in ocular, splenic, hepatic, renal, proventricular, intestinal, pancreatic, and choanal tissue. Neoplastic lymphocytes effaced the iris, ciliary body, and the choroid of the eyes, and neoplastic lymphocytes were attached to the corneal endothelium and infiltrated the sclera, episclera, and conjunctivae. Immunohistochemical results indicated that the neoplastic lymphocytes were CD3(+) and CD79a(-), which is consistent with T-cell lymphoma.

Fish Surgery: Presurgical Preparation and Common Surgical Procedures.

Fish surgical procedures are commonplace in aquaria, zoos, laboratory facilities, and pet clinical practice. To incorporate fish surgery into a clinical setting, an understanding of anatomic differences between mammals and fish, bath anesthetics, and recirculating anesthesia techniques must be developed; a system or different size systems to accommodate anesthesia and surgery of particular species of concern at an institution or practice constructed; and familiar mammalian surgical principles applied with some adaptations. Common surgical procedures in fish include coeliotomy for intracoelomic mass removal, reproductive procedures, gastrointestinal foreign body removal, radiotransmitter placement, and integumentary mass excision.