Haematology and plasma biochemistry reference intervals in wild bearded dragons (Pogona vitticeps)

Lactococcus garvieae-associated septicemia in a central bearded dragon

Lactococcus garvieae is the causative agent of lactococcosis in fish and an emerging zoonotic pathogen with high levels of antimicrobial resistance. We report a case of L. garvieae-associated septicemia in a central bearded dragon (Pogona vitticeps) confirmed via whole-blood PCR and direct sequencing. Following a 30-d course of ceftazidime (20 mg/kg IM q72h), the animal's clinical condition had not resolved; leukopenia persisted, with heterophil toxic change. Coelomic ultrasound findings were consistent with preovulatory follicular stasis, folliculitis, and coelomitis. Following surgical ovariectomy and an additional 30-d course of ceftazidime, the animal's behavior and appetite returned to normal, the animal tested negative via whole-blood PCR assay, and the CBC was unremarkable. To our knowledge, L. garvieae with L. garvieae-associated clinical disease has not been reported previously in a bearded dragon. We conclude that L. garvieae should be considered as a possible etiologic agent in cases of septicemia in bearded dragons, with the potential for zoonotic transmission warranting further investigation.

Diagnostic Clinical Pathology of the Bearded Dragon (Pogona vitticeps)

The bearded dragon (Pogona vitticeps), an omnivorous Agamid lizard native to inland Australia, is one of the most popular reptile pets due to their sociable behavior, tame demeanor, low-maintenance care, and relative ease of breeding. Because they are generally stoic animals, thorough physical examination in conjunction with routine clinicopathologic data can prove invaluable in identifying disease and implementing appropriate therapy in a timely manner. The goal of this article is to assist the practicing clinician, based on literature review, on how to approach the diagnostic challenge encountered in everyday practice when working up various conditions in bearded dragons.

SHORT-TERM BIOLOGICAL VARIABILITY OF HEMATOLOGY PARAMETERS IN THE BEARDED DRAGON (POGONA VITTICEPS)

Determination of the biological variation of laboratory tests is essential for accurate interpretation during health assessments. Few studies investigate the biological variation of CBC variables in reptiles, and none of these involve squamates. Thus, we investigated the biological variation of hematology parameters in bearded dragons (Pogona vitticeps) to determine if conventional population-based reference intervals are appropriate in evaluating single laboratory samples. Blood was collected from 10 bearded dragons five separate times over 10 wk and placed in lithium heparin (LH) microtainers, and CBC were performed. WBC were evaluated via both a fresh, non-anticoagulated blood smear and a LH anticoagulated blood smear as well as two manual hemocytometer counts with blood stained with either Natt and Herrick's (NH) solution or Leukopet^™ (LO) solution. The between-animal coefficient of variation (CV_G), within-animal coefficient of variation (CV_I), reference change value (RCV), and index of individuality were determined for PCV, total solids (TS), and WBC using all leukocyte quantification methods. The RVC for PCV, TS, and WBC in bearded dragons were 37%, 84%, and >100%, respectively. The calculated index of individuality values all fell between 0.6 and 1.4, suggesting that the use of judiciously applied population-based reference intervals in interpreting the WBC, PCV, and TS in bearded dragons is appropriate.

Establishment of reference intervals for plasma protein electrophoresis and comparison of biochemical and protein electrophoresis evaluation of albumin in central bearded dragons (Pogona vitticeps)

The aim of this study is to develop a reference interval for plasma protein electrophoresis for wild free-roaming central bearded dragons (Pogona vitticeps). This will assist the veterinarian in diagnosing and monitoring diseases in wild and captive animals. The study group consisted of 29 wild central bearded dragons of which 22 were males and 7 were females. The plasma samples were obtained from animals in a previous study and were stored frozen at -20°C for 2-3 years before analysis. Plasma protein electrophoresis was performed on 100 uL of plasma. The data were evaluated for the difference between reproductively active females and pooled males with non-reproductively active females as well as the difference between biochemical and protein electrophoresis albumin. Biochemical albumin was found to be significantly higher than electrophoresis albumin in all animals, with a mild proportional bias present. Plasma protein electrophoresis identified albumin, α - 1 and 2, β - 1 and 2 and γ fractions. The reproductively active females in this study exhibited results that were distinct from pooled males and non-reproductively active females. This study provides a reference interval for plasma protein electrophoresis in central bearded dragons that can be used as a tool for health and disease monitoring and diagnosis. The importance of the use of method and sex/season appropriate reference intervals in reptile medicine is confirmed in this study.

Single-dose pharmacokinetics of orally administered terbinafine in bearded dragons (Pogona vitticeps) and the antifungal susceptibility patterns of Nannizziopsis guarroi

OBJECTIVE

To identify the antifungal susceptibility of Nanniziopsis guarroi isolates and to evaluate the single-dose pharmacokinetics of orally administered terbinafine in bearded dragons.

ANIMALS

8 healthy adult bearded dragons.

PROCEDURES

4 isolates of N guarroi were tested for antifungal susceptibility. A compounded oral solution of terbinafine (25 mg/mL [20 mg/kg]) was given before blood (0.2 mL) was drawn from the ventral tail vein at 0, 4, 8, 12, 24, 48, 72, and 96 hours after administration. Plasma terbinafine concentrations were measured with high-performance liquid chromatography.

RESULTS

The antifungal minimum inhibitory concentrations against N guarroi isolates ranged from 4,000 to > 64,000 ng/mL for fluconazole, 125 to 2,000 ng/mL for itraconazole, 125 to 2,000 ng/mL for ketoconazole, 125 to 1,000 ng/mL for posaconazole, 60 to 250 ng/mL for voriconazole, and 15 to 30 ng/mL for terbinafine. The mean ± SD peak plasma terbinafine concentration in bearded dragons was 435 ± 338 ng/mL at 13 ± 4.66 hours after administration. Plasma concentrations remained > 30 ng/mL for > 24 hours in all bearded dragons and for > 48 hours in 6 of 8 bearded dragons. Mean ± SD terminal half-life following oral administration was 21.2 ± 12.40 hours.

CLINICAL RELEVANCE

Antifungal susceptibility data are available for use in clinical decision making. Results indicated that administration of terbinafine (20 mg/kg, PO, q 24 to 48 h) in bearded dragons may be appropriate for the treatment of dermatomycoses caused by N guarroi. Clinical studies are needed to determine the efficacy of such treatment.