Blood values in free-ranging nesting leatherback sea turtles (Dermochelys coriacea) on the coast of the Republic of Gabon.

Leatherback sea turtles (Dermochelys coriacea) are the most endangered of the seven species of sea turtles. The health status of leatherbacks is largely unknown, although the number of nesting females recorded throughout the world has decreased precipitously in the last few decades. Central African beaches may provide one of the last strongholds for nesting leatherback females. In the region, oil extraction and incidental capture pose significant threats to the health of the population. Physical examinations, hematology, plasma biochemistry, plasma corticosterone concentration, plasma protein electrophoresis, plasma vitamin concentrations, and toxicological parameters were evaluated in nesting female leatherbacks in the Republic of Gabon. The general clinical condition of the 35 turtles examined in this study was rated as good. The blood value results for a subset of these turtles are presented and compared to published results from other sea turtles. To the authors' knowledge, these are the first published baseline hematology, plasma biochemistry, and plasma protein electrophoresis values from clinically healthy nesting leatherback turtles.     

Ocular morphology of the Leatherback sea turtle (Dermochelys coriacea)

Objective The Leatherback sea turtle is the largest extant reptile and the sole member of the family Dermochelyidae. Here, the eye of this critically endangered marine turtle was investigated to determine the anatomy, optics, and optical sensitivity. Animals studied Three Leatherback sea turtles, Dermochelys coriacea. Results The eye is small in proportion to body size of the adult compared to other vertebrates, with prominence of the retractor bulbi and pyramidalis muscles. The nictitans shows extensive folding of the bulbar conjunctiva as an apparent mechanism to increase the surface area for mucus secretion. The intraocular anatomy is consistent with an eye adapted to aquatic vision with minimal curvature of the cornea, a near‐spherical lens, deep ciliary cleft and highly vascularized ciliary body. The optical sensitivity, a measure of the sensitivity to light of a given optical system, is higher than in other marine turtles studied but lower than those found in teleost fish that share a habitat with the Leatherback sea turtle. Conclusions The Leatherback sea turtle shows ocular features that are characteristic of Chelonians with similarities to aquatic mammals. The calculated optical sensitivity suggests that compared to pelagic fishes, for instance, the Leatherback sea turtle eye is not particularly well adapted for vision in dim light even though this species is known to venture into deep, dark waters, and might feed at night.     

Ultrasonographic imaging of loggerhead sea turtles (Caretta caretta)

Twenty live and five dead juvenile and subadult loggerhead sea turtles were examined ultrasonographically. Ten soft tissue areas of the integument were used as acoustic windows: cervical-dorsal and cervical-ventral, left and right cervicobrachial, left and right axillary, left and right prefemoral and left and right postfemoral windows. Anatomical cross-sections were performed on the dead turtles to provide reference data. The fourth and fifth cervical vertebrae, the spinal cord, and the venous sinuses of the external jugular vein were clearly visible through the cervical-dorsal acoustic window, and the oesophagus and the heart were imaged through the cervical-ventral acoustic window. The stomach was more frequently visible through the left axillary acoustic window. The liver could be imaged through both sides, but the right axillary acoustic window was better for visualising the gall bladder. The large and small intestines and the kidneys were visible through the right and left prefemoral acoustic windows; the kidneys were easily identified by their intense vasculature.     

Ultrastructural characteristics of blood cells of juvenile loggerhead sea turtles (Caretta caretta)

Ultrastructural characteristics of erythrocytes, heterophils, eosinophils, lymphocytes, monocytes and thrombocytes of the loggerhead sea turtle (Caretta caretta) were evaluated, using blood samples from 15 healthy juvenile animals. Except for the eosinophils, the rest of the white blood cells from loggerhead turtles had similar ultrastructural characteristics compared with blood cells from other sea turtle species. Eosinophils from loggerhead turtles were homogeneous in size, and no crystalline structures were observed within the granules. This paper provides an ultrastructural characterization of blood cells of loggerhead sea turtles, as a reference for future haematological studies of this species.     

Ingesta passage and gastric emptying times in loggerhead sea turtles (Caretta caretta)

Ingesta passage times of soft flat foam dishes and gastric emptying time of barium-impregnated polyethylene spheres (BIPS) were measured in 22 and 8 loggerhead sea turtles (Caretta caretta), respectively. Transit time (T(1)) was considered as the time between ingestion and first elimination, and retention time (T(50)) and total transit time (T(85)) the expulsion time of 50% and 85% of the markers, respectively. The experiments were carried out at different times of the year and water temperature was recorded. A set of dorso-ventral radiographs was taken to locate the BIPS, and the gastrointestinal anatomy of 5 dead turtles was studied to help with interpretation of the radiographs. No significant correlation was observed between T(1), T(50), T(85) and minimum straight carapace length (SCLmin) or body mass and no statistical difference was found in ingesta passage transit times between juvenile (n = 6) and sub-adult turtles (n = 16). Mean passage times of the dishes (in days) were: T(1) = 9.05, T(50) = 12.00 and T(85) = 13.19. Gastric emptying time using BIPS was 24-48 h. The transit time (T(1)) for the BIPS was longer (13.25 +/- 4.86 days) than the foam markers (8.5 +/- 2.73 days) in 8 turtles studied simultaneously. Although the total transit time tended to be faster in turtles submitted to water temperatures between 20 degrees C and 23.6 degrees C no significant correlation was observed between T(1), T(50) and T(85) and the temperature.     

Gram-negative bacterial infections and cardiovascular parasitism in green sea turtles (Chelonia mydas)

Objective To investigate causes of ill health and mortality in juvenile wild green sea turtles ( Chelonia mydas ) found along the mid-north west coast of Western Australia between June and October of 1997.
Procedure Department of Conservation and Land Management rangers submitted four dead or dying green sea turtles from separate incidents for veterinary examination, necropsy, and bacteriological, parasitological and histopatho-logical examination.
Results Numerous different species of trematodes belonging to the families Pronocephalidae, Microscaphidiidae and Paramphistomidae were detected in the intestines of two turtles examined, and in all turtles there was severe spirorchid fluke infection including Haemoxenicon sp, Amphiorchis sp and Hapalotrema sp. Histopathological examination demonstrated severe multifocal to diffuse granulomatous vasculitis, aggregations of spirorchid fluke eggs and microabscesses throughout various tissues including intestines, kidney, liver, lung and brain. Cultures and or histopathological examination demonstrated disseminated Gram-negative bacterial infections including salmonella, E coli , Citrobacter freundii and Moraxella sp.
Conclusion Infections caused by salmonellae, E coli and other Gram-negative bacteria should be considered as causes of systemic illness and death in wild green sea turtles infected with spirorchid cardiovascular flukes and other internal parasites.     

Two herpesviruses associated with disease in wild Atlantic loggerhead sea turtles (Caretta caretta)

Herpesviruses are associated with lung-eye-trachea disease and gray patch disease in maricultured green turtles (Chelonia mydas) and with fibropapillomatosis in wild sea turtles of several species. With the exception fibropapillomatosis, no other diseases of wild sea turtles of any species have been associated with herpesviral infection. In the present study, six necropsied Atlantic loggerhead sea turtles (Caretta caretta) had gross and histological evidence of viral infection, including oral, respiratory, cutaneous, and genital lesions characterized by necrosis, ulceration, syncytial cell formation, and intranuclear inclusion bodies. Nested polymerase chain reaction targeting a conserved region of the herpesvirus DNA-dependent-DNA polymerase gene yielded two unique herpesviral sequences referred to as loggerhead genital-respiratory herpesvirus and loggerhead orocutaneous herpesvirus. Phylogenetic analyses indicate that these viruses are related to and are monophyletic with other chelonian herpesviruses within the subfamily alpha-herpesvirinae. We propose the genus Chelonivirus for this monophyletic group of chelonian herpesviruses.     

Radiographic features of the limbs of juvenile and subadult loggerhead sea turtles (Caretta caretta)

This study aimed to provide the normal radiographic anatomic appearance of the limbs of the loggerhead sea turtle, Caretta caretta. Dorsopalmar and dorsoplantar radiographs were taken of the forelimbs and hindlimbs of 15 juvenile and 15 subadult loggerhead sea turtles, 17 alive and 13 dead. For comparison, computed tomographic, gross anatomic, osteologic, and histologic studies were performed on the limbs of 5 of the sea turtles. Bones from the distal part of the fore and hind flippers were seen in detail with a mammographic film-screen combination. The pectoral and pelvic girdles, superimposed by the carapace, were better seen on standard radiographs with the use of rare-earth intensifying screens. Mammographic radiographs of the manus of 5 small juvenile turtles showed active growth zones. Visualization of bone contours in the distal part of the limbs was clearer than in mammals owing to the very few superimpositions. The presence of a substantial amount of cartilage in the epiphyses produced better visibility of limb ends. We conclude that use of a mammography film-screen combination is the best way to evaluate the bony and joint structures of the limbs of sea turtles. Radiography provides reliable images for clinical purposes. Considering the low cost and logistics of this technique, it is a practical ancillary test for marine animal rehabilitation centers to use.     

Intraocular pressure of juvenile loggerhead sea turtles (Caretta caretta) held in different positions.

The intraocular pressure of 12 apparently healthy juvenile loggerhead sea turtles (Caretta caretta) was determined by applanation tonometry while the turtles were held in dorsoventral, ventrodorsal, and head-down suspended positions. The median intraocular pressures were 5 mmHg (range 4 to 9 mmHg) in the dorsoventral position, 7 mmHg (range 5 to 12 mmHg) in the ventrodorsal position, and 23 mmHg (range 17 to 33 mmHg) in the suspended position.     

Morphologic and cytochemical characteristics of blood cells of juvenile loggerhead sea turtles (Caretta caretta)

A morphologic classification based on the cytochemical characteristics of blood cells of 35 juvenile loggerhead sea turtles (Caretta caretta) is described. Cytochemical stains included benzidine peroxidase, chloroacetate esterase, alpha-naphthyl butyrate esterase (with and without sodium fluoride), acid phosphatase (with and without tartaric acid), Sudan black B, periodic acid-Schiff, and toluidine blue. The morphologic characteristics of erythrocytes were similar to those reported in green turtles. Six types of white blood cells were identified: heterophils, eosinophils, basophils, lymphocytes, monocytes and thrombocytes. Except for the basophils, the rest of the white blood cells from loggerhead turtles had different cytochemical characteristics compared to blood cells from other sea turtle species. The leukocyte differential count was different from that reported for other sea turtle species. Heterophils were the most numerous leukocytes from these loggerhead turtles, followed by lymphocytes, eosinophils, monocytes and basophils. This paper provides a morphologic classification of blood cells of loggerhead sea turtles that is useful for veterinary surgeons involved in sea turtle conservation.     

Isoflurane anaesthesia in four sea lions (Otaria byronia and Zalophus californianus)

OBJECTIVE: To (1) evaluate a purpose-built chamber for inducing isoflurane anaesthesia in sea lions and (2) assess isoflurane as an anaesthetic for dental surgery in these species. STUDY DESIGN: Prospective case study. ANIMALS: Four sea lions, aged between 5 and 12 years and weighing 74-110 kg, with dental disease. METHODS: Sea lions were restrained in a custom-built acrylic chamber into which 5% isoflurane (vapourizer setting) was delivered in O(2) (30 L minute(-1)) from three anaesthetic machines. When the animals were recumbent, the chamber was opened and induction completed using a face mask. Anaesthesia was maintained with 1.5-3.0% isoflurane (vapourizer setting) for 10-15 minutes and after tracheal intubation, was maintained with 1.0-3.0% isoflurane (end-tidal) for 41-255 minutes, using a partial rebreathing system with CO(2) absorption. RESULTS: During induction, the sea lions attempted to support their weight on their thoracic limbs before slipping into sternal or lateral recumbency. Sea lions underwent either root canal surgery, 'crowning' or canine tooth extraction. The animals were completely unresponsive during these operations and apnoea was never encountered at any point during anaesthesia. After surgery, the sea lions were placed into transport cages and their tracheae extubated once they began to move their heads. Thereafter, recovery from anaesthesia was smooth and no signs of distress were observed. Animals were able to raise their forequarters using their flippers within 1 hour of the operation and were returned to the aquarium about 2 hours after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: The purpose-built induction chamber is safe for inducing isoflurane anaesthesia in spontaneously breathing sea lions and isoflurane is an effective anaesthetic in this species.     

The use of echocardiography as a health assessment tool in green sea turtles (Chelonia mydas)

There are limited techniques available to assess the health of sea turtles as physical examination has little correlation to clinical findings, and blood reference intervals are broad and provide limited prognostic significance. Advances in the portability of ultrasound machines allow echocardiography to be increasingly used in the health assessments of wild animals. This study performed blood analysis and echocardiograms on 11 green sea turtles upon admission to a rehabilitation clinic and six animals before release. Significant differences were seen between groups, with admission animals having significantly smaller diameters of the cavum arteriosum at systole and diastole, smaller E‐waves and an increased fractional shortening. Pre‐release animals displayed significant increases in the maximum blood velocities of both the pulmonary artery and the left aorta. Significant negative correlations were seen between fractional shortening and uric acid and between the velocity time integral of the pulmonary artery and urea. The pulmonary artery velocity time integral was also significantly correlated to the E wave. Furthermore, there was asynchrony between the cavum arteriosum and the cavum pulmonale and the detection of a parasitic granuloma in the ventricular outflow tract of one animal. Overall, the results suggest that cardiac function in stranded green sea turtles is significantly impaired and that echocardiography has applications in the health assessments of green sea turtles.     

Pharmacokinetics of tolfenamic acid in green sea turtles (Chelonia mydas) after intravenous and intramuscular administration

The present study aimed to evaluate the pharmacokinetic features of tolfenamic acid (TA) in green sea turtles, Chelonia mydas. Green sea turtles were administered single either intravenous (i.v.) or intramuscular (i.m.) injection of TA, at a dose of 4 mg/kg body weight (b.w.). Blood samples were collected at preassigned times up to 168 hr. The plasma concentrations of TA were measured using a validated liquid chromatography tandem mass spectrometry method. Tolfenamic acid plasma concentrations were quantifiable for up to 168 hr after i.v. and i.m. administration. The concentration of TA in the experimental green sea turtles with respect to time was pharmacokinetically analyzed using a noncompartment model. The C_max values of TA were 55.01 ± 8.34 µg/ml following i.m. administration. The elimination half-life values were 32.76 ± 4.68 hr and 53.69 ± 3.38 hr after i.v. and i.m. administration, respectively. The absolute i.m. bioavailability was 72.02 ± 10.23%, and the average binding percentage of TA to plasma protein was 19.43 ± 6.75%. Based on the pharmacokinetic data, the i.m. administration of TA at a dosage of 4 mg/kg b.w. might be sufficient to produce a long-lasting anti-inflammatory effect (7 days) for green sea turtles. However, further studies are needed to determine the clinical efficacy of TA for treatment of inflammatory disease after single and multiple dosages.     

Pharmacokinetics of marbofloxacin after a single oral dose to loggerhead sea turtles (Caretta caretta)

The single-dose disposition kinetics of marbofloxacin (MBX) were determined in clinically healthy loggerhead sea turtles (n = 5) after oral (PO) administration of 2 mg kg⁻¹ bodyweight. Marbofloxacin plasma concentrations were determined by DAD–HPLC (LOD/LOQ 0.015/0.05 μg ml⁻¹). Data were subjected to non-compartmental analysis. Following PO administration, marbofloxacin achieved maximum plasma concentrations of 11.66 ± 2.53 mg L⁻¹ at 15.00 ± 3.00 h. The absence of general adverse reactions in the turtles of the study, and the favourable pharmacokinetic properties (long half-life and high maximum plasma concentration) of MBX administered PO at the single-dose of 2 mg kg⁻¹ suggest the possibility of its safe and effective clinical use in loggerhead sea turtles.     

Pharmacokinetics of florfenicol in loggerhead sea turtles (Caretta caretta) after single intravenous and intramuscular injections.

The pharmocodynamics of single injections of florfenicol in yearling loggerhead sea turtles (Caretta caretta) were determined. Eight juvenile loggerhead sea turtles weighing 1.25 (+/- 0.18) kg were divided into two groups. Four animals received 30 mg/kg of florfenicol i.v., and four received the same dose i.m. Plasma florfenicol concentrations were analyzed by reverse-phase high performance liquid chromatography. After the i.v. dose, there was a biphasic decline in plasma florfenicol concentration. The initial steep phase from 3 min to 1 hr had a half-life of 3 min, and there was a longer slow phase of elimination, with a half-life that ranged from 2 to 7.8 hr among turtles. The volume of distribution varied greatly and ranged from 10.46 to -60 L/kg. Clearance after the i.v. dose was 3.6-6.3 L/kg/hr. After the i.m. injection, there was a peak within 30 min of 1.4-5.6 microg/ml, and florfenicol was thereafter eliminated with a half-life of 3.2-4.3 hr. With either route, florfenicol plasma concentrations were below the minimum inhibitory concentrations for sensitive bacteria within 1 hr. Florfenicol does not appear to be a practical antibiotic in sea turtles when administered at these doses.     

Pharmacokinetics of oxytetracycline in loggerhead sea turtles (Caretta caretta) after single intravenous and intramuscular injections.

The pharmacokinetics of oxytetracycline in 2-yr-old loggerhead sea turtles (Caretta caretta) after single i.v. and i.m. injections were studied for biologic marking and therapeutic applications. Twenty juvenile turtles were divided into two treatment groups. Ten animals received 25 mg/kg of oxytetracycline i.v. and 10 received the same dosage i.m. Plasma oxytetracycline concentrations were analyzed by reverse-phase high-performance liquid chromatography. Data from the i.v. route best fit a three-compartment model, whereas noncompartmental analysis was used to compare data from both the i.v. and i.m routes. For the i.v. route, means for maximum plasma concentration, terminal phase half-life, systemic clearance, and apparent volume of distribution at steady state were 6.6 microg/ml, 66.1 hr, 290.7 ml/hr/kg, and 18.4 L, respectively. For the i.m. route, means for systemic availability, maximum plasma concentration, and elimination half-life were 91.8%, 1.6 microg/ml, and 61.9 hr, respectively. The remarkably high apparent volume of distribution may possibly be associated with a deep compartment of drug disposition such as bone deposition associated with the large skeletal mass of turtles and the fact that these were well-nourished, growing juveniles. Although maximum plasma concentration by i.m. administration was lower than for the i.v. route, the long elimination time indicates that an infrequent dosing interval may be effective for sensitive bacteria.