Animal Health Abstracts
|
Lazy Nettle Syndrome:
A Brief Update from the Tennessee Aquarium Sharyl Crossley, Tennessee Aquarium Watch Video (Login required) Full Abstract
In 2009, the Chrysaora fuscescens at the Tennessee Aquarium began to suffer from a total loss of pulsing ability, but they continued to collect some food and did not appear to die. The condition persisted through several groups of sea nettles at our facility and was also observed at other institutions. At RAW 2010, this distinct group of symptoms was affectionately dubbed “Lazy Nettle Syndrome” (LNS). The chronic and repeated nature of the syndrome made it clear that it was not an anomaly and required investigation. Subsequently several theories about cause(s) were put forward including source water quality, group origins (i.e. wild vs. captive raised), and nutritional deficiency. Following a colleague's suggestion, our jellyfish diets were fortified with the omega-3 fatty acid, DHA. Within a short period following this diet change, several specimens did display improvement but recovery was not complete or consistent throughout our collection. Most recently, a group of sea nettles reared at the Tennessee Aquarium on the enriched diet have been on exhibit since June 2012. This entire group remains healthy with no signs of LNS. Although unsuccessful at completely reversing the symptoms, the addition of supplemental DHA seems to be the key factor in the prevention of LNS. |
Techniques for Diagnosis and Treatment of Spironucleus vortens in Discus (Symphysodon aequifasciatus)
Nathan A. Farnau, Georgia Aquarium Watch Video (Login required) Full Abstract
Spironucleus vortens infection in Discus (Symphysodon aequifasciatus) is a persistent problem both in the public aquarium industry and in the ornamental fish trade. Further, many have linked this pathogen to cases of the poorly understood and insidious condition called Head and Lateral Line Erosion (HLLE). Consequently, hobbyists and aquarium professionals alike have tried, with varying results, to formulate techniques for diagnosis and treatment of Spironucleus. Diagnostics have often been limited to skin scrapes and/or fin clips. Treatments traditionally involve metronidazole - either added to food or administered via prolonged immersion. These approaches can work to a degree, but well-informed assessment of parasite load, before and after treatment, and accurate formulation of drug doses have always been problematic. Attempts to address these issues have led to techniques some may have avoided in the past due to Discus' relative fragility. Findings suggest that the preferred diagnostic tool, instead of a skin scrape, is a distal gut-contents analysis. Gut samples are collected by flushing the cloaca with sterile saline. Checking parasite load in the gut is critical since the infection is often not detectable in epidermal tissue. To solve the dosing issue, medicated gruel is administered, via catheter tube, directly into the stomach of the infected fish. Despite the relatively invasive nature of these procedures - which involve anesthesia, handling, and esophageal and cloacal tube insertion, vastly improved results were achieved with no negative effects on treated specimens. |
Wet Preps 101 – an essential part of diagnosis making Robert Jones, The Aquarium Vet Watch Video (Login required) Full Abstract
Wet Preps 101 – Good wet preparations from either live or dead fish form the basis of making many diagnoses that involve external and internal parasites, bacterial infections and in some cases even viral infections. What is a wet preparation and how to make them. We will look at gill preps, skin preps and fin clips, as well as the internal wet preparations (liver, spleen, kidney and gut) that should be conducted at every post-mortem. I will show a variety of examples of how useful they are as well as demonstrating what is normal and what is abnormal. |
|
Treatment of a black spot shell disease in California Spiny Lobster (Panulirus interruptus) Julie Crawford, Birch Aquarium Watch Video (Login required) Full Abstract
A common problem in crustacean health is black spot shell disease and it seems there have been few successful cases of treating it in the commercial and aquarium industry. Last year while responsible for a large California Spiny Lobster, I observed a black spot in the center of its carapace. It was removed from exhibit and placed into an isolation tank for further observation. The diagnosis was an extensive erosion of the end of its tail progressing forward as an open infection sight. It also had black areas on its legs and carapace. Microbiology results were inconclusive. Research found that malachite green is the best treatment previously used in the industry in similar situations, it is unobtainable in California, which led us to try something new. The lesions were treated with Doxycycline Hydrochloride bath. The lobster was removed from the tank every morning in conjunction with the antibiotic treatment and I topically applied a chemical called MinnFinn to the affected areas. The active ingredient in MinnFinn is Hydrogen Peroxide and has been traditionally used to treat Koi for bacterial and parasitic problems. The erosion on the tail resolved and it was then my goal to get the lobster to molt and get rid of any remnants of the disease. It was fed a special high Calcium diet and within 2 months, it molted successfully into a spot free shell. The tail area was still slightly deformed, but it was completely healed of diseased tissue. It has continued to get a high Calcium diet and has since molted another time with an even better tail region. It is going to be put back on exhibit in the next month and as far as we can tell, the situation has completely resolved. |
Ovariectomy of Sub-Adult Southern Rays (Dasyatis americana) to Prevent Reproduction and Future Reproductive Problems
Becca Gangler, Ripley’s Aquarium Myrtle Beach Watch Video (Login required) Full Abstract
The Southern Stingray (Dasyatis americana) is reproductively prolific in captivity. In an effort to curb the over production of rays many aquariums maintain single sex populations in their exhibits. Mature female Southern rays that are unable to reproduce in a natural manner while on exhibit often develop a suite of pathological problems. To avoid reproductive pathologies as well as limit the production of young rays the husbandry and veterinary staff at Ripley’s Aquarium teamed up to perform laparotomies on five female rays of varying ages and sizes. The rays varied in size from 55cm disc width to 83.5cmdisc width. The female southern rays were anesthetized using 70 ppm Tricaine Methanesulfonate. Before surgery, the ovary of each ray was located using digital ultrasonography. Each surgery lasted approximately 35 minutes, the rays recovered quickly from anesthesia and were returned to their respective exhibit or holding tank. Only two individuals were of the correct size and follicular development to allow for successful removal of the ovary. As a result, it was determined that the prime candidate for this surgical procedure must be in the 60-85cm disc width range. We believe that ultrasound can be used to stage animals in this size range to determine if the candidate has an ovary of appropriate size prior for surgical removal and that ovariectomy is a practical procedure for limiting the reproductive potential of Southern rays. |
Coelomic Distention and Anemia in a Manta Ray (Manta alfredi) Tonya Clauss, Georgia Aquarium Watch Video (Login required) Full Abstract
A reef manta ray, (Manta alfredi) at the Georgia Aquarium sustained impact to her dorsum during breaching in the exhibit, a normal activity for manta rays. An abnormal swim pattern and different posture was occasionally noted soon after, but food intake and behavior remained normal. Examination at the time was relatively unremarkable other than a possible abnormality along the vertebral column visualized via ultrasound. Over the next few months, her body condition declined despite normal food intake and coelomic distention became evident. Ultrasound revealed free fluid in the coelomic cavity and sand in the spiral colon, but no vertebral abnormalities were noted. Gastroscopy revealed large amounts of sand in the stomach, the result of frequent substrate sifting, a normal behavior in some mantas and one noted consistently in this animal since the time of acquisition. Stomach ulcers of varying degrees of severity were also visualized via endoscopy. Suction removal of the sand was only marginally successful. Blood work revealed a hypoproteinemia and anemia. Initial treatment consisted of a gel diet containing psyllium and mineral oil to help bind and remove the sand, sucralfate to coat the stomach ulcers and oral amikacin to treat possible infection in the gastrointestinal tract. The manta started refusing feeds within 5 days of the gel/psyllium/mineral oil addition to her diet. Normal feeding behavior returned when the gel was removed from the diet. Follow up exams revealed persistent sand and ulcerations in the gastrointestinal tract as well as persistently declining hematocrit and total protein. Sulfadimethoxine/ormetoprim was added to her treatment protocol to combat infection and as prophylaxis against Eimeria southwelli, previously diagnosed in other batoids in the same exhibit. Yunnan paiyo, iron dextran, and vitamin B complex were added to the treatment protocol because of the persistent anemia. After careful planning, permanent physical barriers were strategically placed on the bottom of the exhibit to prevent further sifting of substrate. With medication, physical removal of sand from her gastrointestinal tract and prevention of sand sifting, the manta gradually improved. The etiology of the manta's decline is unclear and the progression of her clinical signs not well understood, but the collaborative efforts of animal care and veterinary staff resulted in clinical resolution. |