Determination of water balance maintenance in Orcinus orca and Tursiops truncatus using oxygen isotopes.

The secondary adaptation of Cetacea to a fully marine lifestyle raises the question of their ability to maintain their water balance in a hyperosmotic environment. Cetacea have access to four potential sources of water: surrounding salt oceanic water, dietary free water, metabolic water and inhaled water vapour to a lesser degree. Here, we measured the 18O/16O oxygen isotope ratio of blood plasma from 13 specimens belonging to two species of Cetacea raised under human care (four killer whales Orcinus orca, nine common bottlenose dolphins Tursiops truncatus) to investigate and quantify the contribution of preformed water (dietary free water, surrounding salt oceanic water) and metabolic water to Cetacea body water using a box-modelling approach. The oxygen isotope composition of Cetacea blood plasma indicates that dietary free water and metabolic water contribute to more than 90% of the total water input in weight for cetaceans, with the remaining 10% consisting of inhaled water vapour and surrounding water accidentally ingested or absorbed through the skin. Moreover, the contribution of metabolic water appears to be more important in organisms with a more lipid-rich diet. Beyond these physiological and conservation biology implications, this study opens up questions that need to be addressed, such as the applicability of the oxygen isotope composition of cetacean body fluids and skeletal elements as an environmental proxy of the oxygen isotope composition of present and past marine waters.

Suspected Mefloquine Toxicity in a Colony of Humboldt Penguins (Spheniscus humboldti).

Avian malaria is an important cause of mortality in captive penguins housed in outdoor exhibits. Mefloquine was used as a prophylaxis to treat a colony of 19 Humboldt penguins (Spheniscus humboldti) for avian malaria. A target dose of 30 mg/kg was obtained from anecdotal literature for sphenisciforms that was not based on pharmacokinetic or toxicity studies. For this reason, preliminary plasma concentrations of mefloquine were acquired after the first dose in some penguins to ensure that plasma concentrations reached human malaria prophylactic concentrations. Afterward, each penguin in the entire colony received mefloquine (26-31 mg/kg [125 mg in toto] PO q7d). Regurgitation was frequently observed starting after the fourth weekly administration. Plasma concentrations of mefloquine after the seventh dose showed elevated concentrations, and the treatment was immediately terminated. Eight penguins died during and after the treatment period. The first fatality occurred after the fifth weekly administration, and 7 birds died within 7-52 days after the seventh weekly administration. Three penguins were found dead without previous symptoms. The other five presented with marked lethargy, dyspnea, poor appetite, and vomiting, and all died despite medical care. The remaining 11 penguins of the colony survived without any supportive care; 5 did not exhibit any clinical disease signs, while the other 6 showed a mild apathy and decreased appetite. Mefloquine toxicity was highly suspected on the basis of clinical signs, the elevated mefloquine plasma concentrations, and no other underlying pathologic disease conditions identified through postmortem examinations. Nonspecific lesions, including pulmonary congestion and edema and hepatic perivascular hematopoiesis, were noted in the birds that died. Additionally, 1 case presented with myocarditis, and mycobacteria were observed within granulomas in the respiratory tract of 2 penguins. Caution is advised, and further studies are encouraged before administering mefloquine to penguins.

ANTIBODY RESPONSE TO EPSILON TOXIN OF CLOSTRIDIUM PERFRINGENS IN CAPTIVE RED DEER (CERVUS ELAPHUS) OVER A 13-MONTH PERIOD.

Deer are sensitive to clostridial diseases, and vaccination with clostridial toxoids is the method of choice to prevent these infections in ruminants. The purpose of this study was to evaluate the serologic responses in red deer (Cervus elaphus) over a 13-mo period after vaccination with a multivalent clostridial vaccine, containing an aluminium hydroxide adjuvant. Antibody production to the Clostridium perfringens type D epsilon toxin component of the vaccine was measured using an indirect enzyme-linked immunosorbent assay. Animals from group 1 (9 mo old; n = 6) were naïve and received an initial vaccination with a booster vaccine 4 wk apart and one annual booster. Animals from group 2 (21 mo old; n = 10) had been previously vaccinated 12 mo prior and received a first annual booster at the beginning of this study and a second annual booster 12 mo later. The multivalent clostridial vaccine induced a high antibody response that peaked after each injection and then slowly decreased with time. In group 1, a booster vaccine was required to obtain an initial high humoral response. The annual booster injection induced a strong, rapid, and consistent anamnestic response in both groups. The serologic responses persisted significantly over the baseline value for 9-12 mo in group 1, but more than 12 mo in group 2. It is unknown whether the measured humoral immune responses would have been protective as no challenge studies were performed. Further investigation is needed to determine the protective antibody titers to challenge and how long this immunity might persist after vaccination.

Bilateral Granulomatous and Fibrinoheterophilic Otitis Interna due to Pseudomonas aeruginosa in a Captive Little Bustard ( Tetrax tetrax ).

A captive juvenile little bustard ( Tetrax tetrax ) was presented for acute onset of right head tilt and right circling. The bird failed to respond to supportive care and systemic antibiotic therapy. A bilateral granulomatous and fibrinoheterophilic otitis interna due to Pseudomonas aeruginosa was diagnosed postmortem by histopathologic examination and bacterial culture. In bustards, Pseudomonas species have been documented in the normal bacterial flora of the oropharynx and are frequently reported in upper respiratory tract infections. This is the first report of a peripheral vestibular syndrome due to P aeruginosa otitis interna in a bustard species. Pseudomonas aeruginosa should be included as a possible cause of otitis and peripheral vestibular syndrome in bustards.

Population pharmacokinetics of methadone hydrochloride after a single intramuscular administration in adult Japanese sika deer (Cervus nippon nippon).

OBJECTIVE: To assess the population pharmacokinetics of methadone in deer. STUDY DESIGN: Prospective non-randomized experimental trial. ANIMALS: Twelve healthy adult sika deer (nine males and three females). METHODS: Deer received intramuscular administration of racemic methadone hydrochloride at 0.5 mg kg(-1) or 1 mg kg(-1) . Plasma methadone and its metabolite 2-Ethylidene-1,5-Dimethyl-3,3-Diphenyl-Pyrolidine (EDDP) concentrations were determined by validated liquid chromatography coupled to tandem mass spectrometry methods, at times 0, 30 minutes, 1, 2, 3, 4, 5, 6, 8, 12 and 24 hours. Population pharmacokinetics analysis was undertaken using a non-linear mixed effects modelling (NONMEM). RESULTS: A two-compartment linear disposition model best described observed time-concentration profiles of methadone and EDDP. Population parameter estimates of methadone were elimination clearance (17.3 L hour(-1) ), metabolic clearance (34.6 L hour(-1) ), volume of distribution of compartment 1 (216.0 L) and volume of distribution of compartment 2 (384.0 L). Population parameter estimates of EDDP were elimination clearance (121.0 L hour(-1) ), volume of distribution of compartment 3 (1.08 L) and volume of distribution of compartment 4 (499.5 L). The total clearance and total volume of distribution of methadone and EDDP were 51.9 L hour(-1) , 121.0 L hour (-1) , 600.0 L and 500.6 L, respectively. The methadone terminal elimination half-life was 8.19 hours. No adverse effects were observed after methadone administration. CONCLUSIONS AND CLINICAL RELEVANCE: Following intramuscular injection, methadone was characterized by a large total volume of distribution, high systemic clearance and intermediate terminal half-life in sika deer.

Hematuria and urinary bladder lesions compatible with bracken fern (Pteridium aquilinum) intoxication in captive fallow deer (Dama dama).

Hemangiosarcoma, hemangioma, transitional cell carcinoma, and chronic cystitis were diagnosed in the urinary bladder of six captive fallow deer (Dama dama). Hematuria and thin body condition were observed in the advanced cases. These findings were compatible with chronic enzootic hematuria and were suspected to have been induced by chronic ingestion of bracken fern (Pteridium aquilinum) present on the premises. These lesions were similar to those described in bovine enzootic hematuria in cattle. Hemangiosarcoma metastases, hydronephrosis, and renal carcinoma were also associated in some cases. This is the first report of hemangioma, hemangiosarcoma, transitional cell carcinoma, and renal carcinoma of the urinary bladder in fallow deer and the first indication of bracken fern intoxication in deer.

Lymphocytic leukemia in a captive dhole (Cuon alpinus).

A captive 3-yr-old male dhole (Cuon alpinus) was presented for poor body condition. Pancytopenia concurrent with bone marrow aspiration that revealed severe medullary infiltration by a population of initially small lymphocytes was diagnostic of an aleukemic chronic lymphocytic leukemia. Chemotherapy was initiated, but euthanasia was elected after the animal's rapid deteriorating condition and sudden lymphoid organs hypertrophy several days after initial presentation. Histology revealed lymphoid organs and bone marrow infiltration by highly proliferating immature lymphocytes compatible with a blast crisis. On immunohistochemistry, neoplastic cells appeared CD3 positive, confirming a T lymphoid origin. This is the first report of a lymphocytic leukemia in a wild canid species.