Neoplasia in an assurance population of Puerto Rican crested toads (Peltophryne lemur)

Disease monitoring of amphibian assurance populations is an important buffer against ongoing global extinctions. This study documents a high incidence of neoplasia in a zoo-managed assurance population of Puerto Rican crested toads (Peltophryne lemur; PRCTs). Over 5 years, neoplasia was diagnosed in 17/49 (35%) submitted adult PRCTs and was the cause of death or euthanasia in 13/17 (72%). Most toads were male (16/17; 94%) and 6 to 11-years-old (average 8.1 years). Notably, seven toads (41%) had multiple neoplasms. Of the 29 neoplasms identified, 17 (59%) were cutaneous or subcutaneous. The most common neoplasms included mast cell tumors (MCTs; 8/29; 28%), histiocytic sarcomas (6/29; 21%), lymphoma/leukemia (4/29; 14%), and squamous cell carcinomas (3/29; 10%). Distant metastases were documented in 6/8 (75%) toads with MCTs. Causes for neoplasia in this population were not determined though may include genetic or environmental factors. Continued investigations of managed endangered amphibians will help elucidate mechanisms of carcinogenesis.

COMPARISON OF SUBCUTANEOUS ALFAXALONE AND SUBCUTANEOUS ALFAXALONE-DEXMEDETOMIDINE FOR SEDATION IN THE HOUSTON TOAD (ANAXYRUS HOUSTONENSIS)

The Houston toad (Anaxyrus houstonensis), a primarily terrestrial amphibian of south-central Texas, has been listed as federally endangered since 1970. Sedation is an important tool for obtaining diagnostics and providing treatment in this species. This prospective, randomized, and blinded study compared the sedative effects of SC alfaxalone (Protocol A) at approximately 12 mg/kg (median [range] = 12.70 [12.09-13.95] mg/kg] to SC alfaxalone-dexmedetomidine (Protocol AD) at approximately 12 mg/kg (median [range] = 12.68 [12.16-13.56] mg/kg) and 0.1 mg/kg (median [range] = 0.1 [0.07-0.13] mg/kg), respectively, in adult Houston toads (n = 26). Toads from Protocol AD received atipamezole SC at approximately 1 mg/kg (median [range] = 0.96 [0.75-1.25] mg/kg) 45 min postinduction, whereas toads from Protocol A received the equivalent volume of SC sterile saline at the same time point. Heart rate, gular rate, and times to first effect, loss of righting reflex, ability to position for radiographs, loss of nociception, return of righting reflex, and full recovery were recorded. A significantly greater number of toads lost righting reflex, positioned for radiographs, and lost nociception with Protocol AD compared with Protocol A. Additionally, time to return of righting reflex and time to full recovery were significantly longer with Protocol AD than with Protocol A. The protocols did not differ significantly in time to first effect, time to radiographic positioning, or time to loss of nociception. Histologic examination of four toads euthanized during the study revealed acute injection site reactions from all administered drugs, including saline. No clinical adverse reactions were observed. This study demonstrates that the combination of SC alfaxalone and dexmedetomidine results in deeper sedation than SC alfaxalone alone, but also correlates with longer recovery times despite antagonist administration.

METASTATIC MINERALIZATION IN A ZOOLOGIC COLLECTION OF SPOT-TAILED EARLESS LIZARDS (HOLBROOKIASPP.)

Vitamin and mineral supplements are commonly used in diets for zoologic and companion animals. Because specific nutrient requirements are often unknown, informed decisions are based on literature for related species. Over 18 mon beginning in November 2017, an entire population of spot-tailed earless lizards (Holbrookia lacerata and Holbrookia subcaudalis) died (N = 33). All but two lizards were submitted for histopathology (94%). All examined cases had mineralization in at least one tissue; 71% (22 of 31) had multisystemic mineral deposits consistent with metastatic mineralization. No underlying causes were detected histologically. The supplement used for dusting the food items fed five to six times per week was inadvertently switched for 2 to 4 mon, and the incorrect supplement was found to contain fourfold the intended vitamin D3 concentration. Thus, hypervitaminosis D was considered the most likely cause. Interestingly, eastern collared lizards (Crotaphytus collaris), also fed prey supplemented five to six times a week, and over 50 other insectivorous reptile and amphibian species possibly receiving the supplement one to seven times a week did not appear affected. During this time, only two other cases of metastatic mineralization were diagnosed in other herpetofauna at this institution. Prior to receiving the incorrect supplement, there were no cases of metastatic mineralization detected in the earless lizard population. These cases highlight species-specific sensitivities, and the deleterious effects of excessive or inappropriate supplementation. It is important to confirm product identification on arrival, regularly conduct chemical analysis of supplements, and educate keepers and owners about adverse effects of inappropriate supplementation.

Novel Paranannizziopsis species in a Wagler's viper (Tropidolaemus wagleri), tentacled snakes (Erpeton tentaculatum), and a rhinoceros snake (Rhynchophis boulengeri) in a zoological collection

We report several cases of fungal infections in snakes associated with a new species within the genus Paranannizziopsis. Three juvenile Wagler's vipers (Tropidolaemus wagleri) presented with skin abnormalities or ulcerative dermatitis, and two snakes died. Histologic examination of skin from the living viper revealed hyperplastic, hyperkeratotic, and crusting epidermitis with intralesional fungal elements. The terrestrial Wagler's vipers were housed in a room with fully aquatic tentacled snakes (Erpeton tentaculatum), among which there had been a history of intermittent skin lesions. Approximately 2 months after the biopsy of the viper, a skin sample was collected from one tentacled snake (TS1) with skin abnormalities and revealed a fungal infection with a similar histologic appearance. Fungal isolates were obtained via culture from the Wagler's viper and TS1 and revealed a novel species, Paranannizziopsis tardicrescens, based on phenotypic characterization and molecular analysis. P. tardicrescens was cultured and identified by DNA sequence analysis 8 months later from a dead tentacled snake in an exhibit in an adjacent hallway and 13 months later from a living rhinoceros snake (Rhynchophis boulengeri) with two focal skin lesions. Antifungal susceptibility testing on three of four cultured isolates demonstrated potent in vitro activity for terbinafine and voriconazole.

Early life stress and novelty seeking behavior in adolescent monkeys

Recent evidence suggests that early exposure to mild stress promotes the development of novelty seeking behavior. Here we test this hypothesis in squirrel monkeys and investigate whether novelty seeking behavior is associated with differences in cerebrospinal fluid (CSF) levels of the serotonin metabolite 5-hydroxyindoleacetic acid (5HIAA), the dopamine metabolite homovanillic acid (HVA), the norepinephrine metabolite 3-methoxy-4-hydroxyphenylethylene glycol (MHPG), and the neuropeptide corticotrophin-releasing factor (CRF). Monkeys were randomized early in life to either mild intermittent stress (IS) or no stress (NS) conditions, and subsequently presented with opportunities to interact with a familiar or novel object in a test box that was connected to each monkey's home cage. To further minimize the potentially stressful nature of the test situation, monkeys were acclimated to the test procedures prior to study initiation. Post-test plasma levels of cortisol in IS and NS monkeys did not differ significantly from baseline levels measured in undisturbed conditions. During testing, more IS than NS monkeys voluntarily left the home cage, and IS monkeys spent more time in the test box compared to NS monkeys. More IS than NS monkeys engaged in object exploration in the test box, and IS monkeys preferred to interact with the novel vs. familiar object. Novelty seeking was not associated with differences in 5HIAA, HVA, MHPG, or CRF, but correlated with differences in object exploration observed in a different test situation at an earlier age. These trait-like differences in novelty seeking appear to reflect mild early stress-induced adaptations that enhance curiosity and resilience.