Brad A. Lock

The Reptilian Thyroid and Parathyroid Glands

The field of reptilian clinical endocrinology is still in its infancy. The thyroid and parathyroid glands are intimately involved with many basic metabolic functions. These glands have been the subject of extensive research studies in reptilian species; however, the effects of abnormal gland function have been poorly documented in clinical cases. These glands play a major role in maintaining physiologic homeostasis in all vertebrates. With the advent of more sensitive assays, it should be possible to measure the small amounts of hormones found in reptilian species. The purpose of this article is to review the literature regarding clinical endocrinology of the thyroid and parathyroid glands in reptiles.

Preliminary Evaluation of Medetomidine/Ketamine Combinations for Immobilization and Reversal with Atipamezole in Three Tortoise Species

ABSTRACT Twenty immobilizations, for various minor clinical procedures, were performed on 12 adult and sub-adult leopard, Geochelone pardalis, yellow foot, Geochelone denticulata, and Aldabra, Aldabrachelys gigantea, tortoises with a combination of medetomidine and ketamine. An intravenous dose rate of 100 μg/kg medetomidine for leopard and yellow foot tortoises and 25 - 80 μg/kg for Aldabra tortoises resulted in induction times (time from drug injection until the head could be pulled out and the mouth opened) that ranged between 4 and 16 minutes (median 10) and 15 - 45 minutes (45) respectively. Recovery times (time from drug injection until the tortoise was able to withdraw its head with strength) using intravenous atipamezole at a dose rate of 400 μg/kg for leopard and yellow foot and 100 - 380 μg/kg for Aldabra tortoises ranged between 2 and 30 minutes (5) and 5 - 15 minutes (5) respectively. Most (90%) of leopard and yellow foot tortoises experienced a drop in heart rate from baseline following medet...

IVERMECTIN TOXICOSIS AFTER TOPICAL ADMINISTRATION IN DOG-FACED FRUIT BATS (CYNOPTERUS BRACHYOTIS)

Abstract Forty dog-faced fruit bats (Cynopterus brachyotis) were administered 1 drop of 1% ivermectin topically as part of a routine physical exam and deworming program, and 11 developed sudden generalized paresis. Six of the bats recovered within 24–48 hr, and the remaining 5 were presented recumbent and weak to the University of Florida Veterinary Medical Teaching Hospital. Ivermectin toxicosis was suspected, and the admitted bats died or were euthanatized within 3–5 days of the development of clinical signs despite supportive care. Three of the dead bats had renal tubular necrosis.

AN EPIZOOTIC OF CHRONIC REGURGITATION ASSOCIATED WITH CHLAMYDOPHILOSIS IN RECENTLY IMPORTED EMERALD TREE BOAS (CORALLUS CANINUS)

Abstract One hundred and five wild-caught emerald tree boas (Corallus caninus) were added to a collection of 15 others, in Central Florida, during a 4-mo period. Eighty-one boas (67%) developed repetitive regurgitation during the 23-mo period after the initial introduction, and 61 (75%) of these died. Regurgitation occurred 3–4 days after feeding. Prevalence of regurgitation in this population of snakes was 25%/mo (range 0–42%), and incidence was 3.52/mo (range 0–13/mo). The cumulative mortality for those boas developing repetitive regurgitation (61 of 120) during the 23-mo epizootic was 51%. Hematologic findings included anemia and leukocytosis, with lymphocytosis, monocytosis, and azurophilia. Histologic evaluation of the gastrointestinal tract showed multifocal to diffuse lymphoplasmacytic inflammation with granuloma formation and positive immunohistochemical staining for chlamydial antigen. Electron microscopic evaluation of granulomas showed organisms consistent with Chlamydophila sp.

NASOPHARYNGEAL MYXOSARCOMA IN A BENGAL TIGER (PANTHERA TIGRIS)

Abstract An 18- to 25-yr-old intact female Bengal tiger (Panthera tigris) was diagnosed antemortem and postmortem with nasopharyngeal myxosarcoma metastatic to the lung, chronic lymphoplasmacytic otitis media, and lymphoplasmacytic and eosinophilic stomatitis. Myxosarcomas are rare in domestic animals and seldom metastasize; this tumor has not been previously reported in an exotic felid. Computed tomography of the skull was used during the diagnoses.

Lymphosarcoma with Lymphoid Leukemia in an Aruba Island Rattlesnake, Crotalus unicolor

ABSTRACT A six year old male, Aruba Island rattlesnake, Crotalus unicolor, with diffuse cranial swelling and anorexia was diagnosed with multicentric lymphosarcoma with lymphoid leukemia. Significant hematologic findings included a marked leucocytosis (137,000), monocytosis and basophilia with marked heteropenia and mature lymphopenia. The predominant (95.5%) white cells were large blast-like cells. Cytological examination of a tissue aspirate from the head revealed a highly cellular monomorphic population of round mononuclear cells. Histologic examination revealed that most parenchymal organs and tissues contained monotonous sheets of neoplastic lymphoid cells.

Determining the Value of Bovine Albumin as a Blood Cell Stabilizer for Pancake Tortoise, Malacochersus tornieri, Blood Smears

ABSTRACT Complete blood counts are an important diagnostic test used to manage chelonian cases. For this diagnostic test to have value, however, it is important to minimize any potential bias in th...

Use of an ELISA to Survey Exposure of Wild Caught Boa Constrictors, Boa Constrictor, to Retroviruses Isolated from Boids with Inclusion Body Disease

ABSTRACT Fifty eight plasma samples, collected in the wild, from Brazilian boa constrictors, Boa constrictor, were evaluated by enzyme-linked immunosorbent assay (ELISA) for exposure to a retrovirus isolate obtained from captive boa constrictors with inclusion body disease (IBD). Monoclonal antibodies (HL 1785 and HL 1787) specific for boa immunoglobulin (IgG) were used to detect binding of boa IgG to the retroviral isolate. Mean optical density (OD405) at a 1:1250 dilution of boa plasma was 0.161 (range 0.110 – 0.258 [standard deviation 0.034]) for HL 1785 and 0.170 (0.134 – 0.266 [0.023]) for HL 1787. The values from this study can be used as baseline reference range for future comparison to known IBD positive snakes and the eventual establishment of a group of naive boas to be used in transmission studies, needed to establish a causal relationship between previously isolated retroviruses and IBD.

Intrahepatic portosystemic venous shunt in a neonatal roan antelope (Hippotragus equinus cottoni).

Abstract A 6-day-old, female roan antelope (Hippotragus equinus cottoni) was diagnosed with a single intrahepatic portosystemic venous shunt at necropsy. Clinical signs had included weakness, lethargy, hypothermia, diarrhea, and a weak suckle response. Multiple seizure episodes were associated with hypoglycemia and characterized by vocalization, muscle fasciculations, and disorientation. Hematologic abnormalities included anemia with hypochromasia, anisocytosis, poikilocytosis, and leukopenia with neutropenia and lymphopenia. Serum biochemical abnormalities included elevations in blood urea nitrogen and total serum bile acid concentration. A portosystemic vascular anomaly should be a differential diagnosis for nonthriving, exotic ruminant calves with overt or subtle neurologic signs, persistent hypoglycemia, and/or elevated bile acids. In very young calves, total bile acid concentration may be more useful in establishing a diagnosis than blood ammonia concentration.

EFFECTS OF A LIGHT-EMITTING DIODE ON THE PRODUCTION OF CHOLECALCIFEROL AND ASSOCIATED BLOOD PARAMETERS IN THE BEARDED DRAGON (POGONA VITTICEPS)

Abstract The importance of vitamin D3 has been documented in multiple reptile species, with deficiencies resulting in alterations in calcium homeostasis, including nutritional secondary hyperparathyroidism. Though vitamin D3 can be obtained directly from dietary sources or from photobiosynthetic production, species variability in diet and behavior makes exposure to ultraviolet B (UVB) radiation an essential requirement for some diurnal species. The effect of different bulbs to promote synthesis of cholecalciferol (vitamin D3) in the bearded dragon (Pogona vitticeps) was evaluated. Individual animals (n = 5 for each group) were exposed to industry standard fluorescent bulbs (UVB), non–UVB producing bulbs (UVBN), and light-emitting diode (LED) UVB (LED) bulbs for a period of 11 mo. Weekly measurements of UV index (UVI) were recorded for each bulb. Plasma vitamin D3, 25-hydroxycholecalciferol (25OHD3), ionized calcium (iCa), total calcium (TCa), and phosphorus (P) were measured at time zero and at 4 mo, 8 mo, and 11 mo. Parameters were measured between groups and time points. There were decreases (P < 0.05) with time for iCa for the LED and UVB groups, for TCa in the UVB group, and for vitamin D3 in the LED and UVBN groups. There were no significant differences between study groups for vitamin D3, iCa, TCa, or P. Overall plasma concentration for 25OHD3 in the LED group was greater than for the UVB (P = 0.0347) and the UVBN (P = 0.0490) groups.