Wednesday Presentation Abstracts
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Discospondylitis in a Green Moray Eel (Gymnothorax funebris)
Dr. Shane Boylan, Jennifer Oliverio and Jason Cassell, South Carolina Aquarium Watch Video (Login required) Full Abstract
A green moray eel of 12+ years presented with a rapid onset of positive buoyancy and inappetence. The animal was floating horizontally with a 90° bend at the swim bladder with the tail pointing ventrally. Blood-work, GI endoscopy and ultrasound revealed no abnormalities while radiography, confirmed by CT, detected spinal compression cranial to a hyper-inflated swim bladder. Conservative therapies of time, vitamins, glycoaminoglycans and steroids did not improve the condition after several months. Alternative therapies were then chosen, and twice weekly near-infrared/cold laser therapy was conducted for two months. Habituation to handling allowed for laser therapy to occur without sedatives. Laser therapy continued once weekly for nine months with improvement in sinusoidal body movement, but buoyancy remained positive with intermittent control of orientation. Experiments with swim bladder deflation followed by anticholinergics +/- oxytetracycline failed to effectively prevent swim bladder inflation. However, four months of normal buoyancy on display were achieved with aspiration of gas and an intraluminal injection of hetastarch and 100mg/ml enrofloxacin. After positive buoyancy returned, we attempted a surgical approach to inject cyanoacrylate into the swim bladder to permanently prevent gas release, with gas volume controlled by aspiration/injection. For an additional month, buoyancy was controlled, but orientation remained inconsistent. After two years of therapy, the eel was humanely euthanized under MS-222 anesthesia to evaluate the swim bladder and spine. In conclusion, improvements in movement and appetite suggest some benefit to the therapies. In addition, the location of the swim bladder rete was unknown until necropsy, and current anatomical knowledge will greatly help future cases. |
Fish Anesthesia:
Alternatives to MS-222 Dr. Kate Bailey, NC State University College of Veterinary Medicine Watch Video (Login required) Full Abstract
The necessity for fish anesthesia on a daily basis is a reality for many of those working in the aquarium setting. This necessity should produce a driving force for the exploration of more predictable ways to produce anesthesia, both for animal welfare, and the peace of mind of people providing care. There is a paucity of literature investigating reliable and predictable anesthetic agents in fish. Currently, the only FDA-approved fish anesthetic agent is MS-222 (tricaine methanesulfonate), a sodium channel blocker in peripheral neural tissue, but has no known mechanism of action for production of general anesthesia. Due to our lack of knowledge surrounding MS-222, it is logical to investigate alternative anesthetic agents with known mechanisms of action. Potential alternative anesthetics include alfaxalone and propofol, both of which are GABA agonists that are used routinely as injectables for general anesthesia in companion animals. Fish have GABA receptors in their brain, and the findings from initial investigations using koi carp are promising. Alfaxalone has been investigated for both immersion anesthesia and intramuscular injectable anesthesia. While immersion provided rapid and reliable anesthesia, intramuscular injection produced variable results, and resulted in an unacceptable incidence of morbidity and mortality. Propofol was investigated as an immersion agent, and also provided rapid and reliable anesthesia. While this is useful information for small and easily confined fish species, it is much less useful for large and hard to confine species. Other drugs such as ketamine and dexmedetomine are used for injectable anesthesia with varying success. Further studies are needed to investigate alternative options for injectable anesthesia, especially in larger fish, as the options currently available are frequently unreliable and variable in efficacy and utility. |
Public Display Aquatic Invertebrates: Medical Advances
Dr. Gregory A. Lewbart, NC State University College of Veterinary Medicine Watch Video (Login required) Full Abstract
Invertebrate animals comprise over 95% of animal species, yet non-parasitic invertebrates are vastly underrepresented in the typical veterinary school curriculum. This presentation will provide a brief introduction to the more prominent aquatic invertebrate groups (coelenterates, mollusks, crustaceans, echinoderms, horseshoe crabs) and introduce some recent medical advances that apply to maintaining these species in captivity. Specific topics for review include: white patch disease of sponges, eversion syndrome of jellyfishes, aspergillosis of soft corals, white and brown jelly syndrome of hard corals, growth anomalies of Acropora spp. and Montipora spp., acroporid serratiosis, green algal disease and pharmacokinetics in horseshoe crabs, diet-induced shell disease of crustaceans, and pain recognition in shore crabs. The emerging and important topic of animal welfare for aquatic invertebrates also will be reviewed. |
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A Customized 3D-Printed Splint
for Stabilization of an Open Front Flipper Fracture in a Green Sea Turtle (Chelonia mydas) Dr. Emily F. Christiansen, NC State University College of Veterinary Medicine Watch Video (Login required) Full Abstract
Sea turtles frequently present to veterinarians and rehabilitation centers with traumatic injuries caused by boat strikes or similar impacts. These injuries commonly include fractures of the extremities, with or without open wounds. While sea turtles have an impressive capacity to heal without significant intervention, the preservation of maximal function in these flippers is a priority for successful return to the wild. Various forms of surgical and external coaptation have been attempted in sea turtles, with limited success. Their natural saltwater environment is not conducive to typical bandaging and splinting materials, and the forces applied against a flipper in the aquatic medium are substantial enough to cause most types of surgical fixators to fail, even in smaller individuals. In July 2013, a juvenile green sea turtle was found floating at the surface in near-shore waters of central North Carolina. The turtle had sustained an open fracture of the right radius and ulna with ventral exposure of bone fragments, along with other injuries. The flipper exhibited severe dorsoflexion at the fracture site, but the tissue distal to the injury retained adequate circulation and nervous function. A 3-D printer was used to create a customized form-fitting plastic polymer splint designed using modeling software around CT-derived tridimensional renderings of the fractured and intact flippers. The splint was generated in a two-piece clamshell design with multiple perforations, with a hinge along the cranial edge, and included a large window over the open wound to allow for cleaning and monitoring. The splint was initially applied under sedation, and secured onto the flipper with synthetic suture material. The turtle tolerated the splint very well, and showed increased swimming confidence within minutes of being placed in the water. The splint remained in place for 40 days, providing considerable external stabilization with no obvious side effects. |
Whole Blood Transfusion
in a Cownose Ray (Rhinoptera bonasus) Dr. Alexa McDermott, Dr. Cara Field, Dr. Tonya Clauss, Lynda Leppert, Nicole Hatcher, Jeffery Ingle and Mayela Alsina, Georgia Aquarium Watch Video (Login required) Full Abstract
A female cownose ray (Rhinoptera bonasus) presented for extreme lethargy and pale coloration. Examination revealed a heavy Branchellion torpedinis leech load in the oral cavity, and the leeches were manually removed. A blood sample taken from a ventral wing vein showed hematocrit (HCT) levels at 1% (normal individual at 20%). Due to severe anemia and weakness the prognosis was poor, so a whole blood transfusion was carried out in an attempt to save the ray. A 20 kg cownose ray with a HCT of 35% served as the blood donor. Sixty ml of whole blood was collected from the donor into heparinized syringes at a ratio of 1:10 heparin to blood. The solution was then delivered directly to the recipient via a ventral wing vein, administered over a 25-minute time frame. The recipient received a prednisolone injection to minimize possible transfusion reaction, as well as antibiotics and supportive iron dextran and Vitamin B complex injections. Post-transfusion, a major cross match was performed with no signs of agglutination. One day following the transfusion, the recipient’s HCT had increased to 4.5%. Four days post- transfusion, the ray’s coloration had drastically improved, and the HCT had increased to 9.5%. Over subsequent days the ray began swimming with more vigor, and the HCT continued to increase. At 55 days post transfusion, the ray had a HCT of 22% and was behaving normally. |
Common Causes for Mortality Events in Captive Sand Tiger Sharks (Carcharias taurus) Dr. Robert George, Ripley’s Aquariums Watch Video (Login required) Full Abstract
Sand tiger sharks, Carcharias taurus, are the most common large sharks displayed in public aquariums. In the wild, female sand tigers mature at 9-10 years of age, while males reach maturity in only 6-7 years. Exhibited sand tigers often live in captivity for 10-15 years, and in some cases survival times extend well over 20 years after capture have been reported. With exhibit sand tigers routinely reaching geriatric ages, it would be expected for such animals to eventually show systemic problems associated with age-related organ failure. In addition to organ failure as a cause of death, a variety of physical issues such as prolapse of the spiral valve, gastric prolapse, gastro-intestinal foreign bodies, and reproductive disorders can occur. This presentation will review some of the most common causes of mortality for these sharks. |
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Successful Treatment of Neobenedenia Monogeneans in Quarantined Teleosts
Dr. Catherine Hadfield, Dr. Leigh Clayton and Ashleigh Clews, National Aquarium Watch Video (Login required) Full Abstract
Neobenedenia are capsalid monogeneans that infect the skin of marine teleosts and are a common cause of recurrent morbidity and mortality in aquarium systems. The life cycle is direct and eggs can survive in the environment for extended periods. Twenty-two shipments of tropical marine teleosts from Queensland, Australia were received by the National Aquarium between March 2012 and May 2013; Neobenedenia was identified on fish from most of the shipments. Infection was often subclinical, but disease was observed in two outbreaks, with surgeonfish and tangs particularly susceptible. Early signs consisted of subtle changes in behavior, reduced appetite, and brown coalescing spots on the dorsum and pectoral fins. Later signs consisted of dark coloration, intermittent flashing, clamped fins, ulcerative keratitis, lethargy, and mortalities. Praziquantel immersion was the most effective treatment, at a dosage of 4 mg/L every four days for at least 15 doses. Outcomes were monitored using visual exams, skin scrapes, opportunistic necropsies, and fine-mesh egg traps. All systems remained on treatment until the fish were moved to exhibit (a minimum of 60 days after parasites were last seen), and all fish received freshwater dips prior to transfer. Ongoing monitoring shows no recurrence of Neobenedenia. Although the quarantine cost was high, the potential cost of managing Neobenedenia on exhibit would have been higher. Quarantine protocols for incoming Indo-Pacific fish now include praziquantel immersion on arrival (5 mg/L for 2 hr after acclimation), copper sulfate (0.18-0.20 mg/L for 21 d), with praziquantel (4 mg/L q 4 d for 8 tx) starting during copper therapy, and freshwater dips prior to transfer. |