Publications by authors named "Samantha Sander"

13 Publications

  • Page 1 of 1

A RETROSPECTIVE SURVEY OF NEOPLASIA IN MANAGED GIRAFFES ().

J Zoo Wildl Med 2021 Apr;52(1):332-336

College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA,

Giraffes () are commonly managed in zoos and conservation programs worldwide, but the current understanding of the occurrence and progression of neoplastic disease in this species is limited by the scarcity of published reports. This study collated documented cases of neoplasia on the basis of gross and histologic evaluation of ante- and postmortem samples. In total, 30 giraffes from 22 institutions across the United States were included. Subspecies was not reported in all cases, but those identified included Masai (), Rothschild (), and reticulated subspecies (). Thirteen animals died natural deaths, 15 were euthanized, and 2 were alive at the time of this article. A total of 38 tumors were reported and classified as 18 different diagnoses, including leiomyoma (7), adenoma (4), luteoma (4), lymphoma (4), pheochromocytoma (3), squamous cell carcinoma (3), adenocarcinoma (2), ameloblastic fibroma (1), carcinomatosis of undetermined cell lineage (1), cavernous hemangioma (1), cystic granulosa cell tumor (1), dysgerminoma (1), fibrosarcoma (1), leukemia (1), lipoma (1), pituitary nerve sheath tumor (1), rhabdomyosarcoma (1), and teratoma (1). Multiple concurrent neoplastic lesions were documented in six cases. Mesenchymal tumors (18) were the majority of neoplasms. The most prevalent location, regardless of tumor type, was the female reproductive tract (14). Twenty-four neoplastic lesions were incidental findings at necropsy, whereas eight neoplasms were considered to be the primary cause of death. The findings reported here identify multiple neoplastic lesions in giraffes and could provide insight to the future management of this species.
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http://dx.doi.org/10.1638/2020-0100DOI Listing
April 2021

PHARMACOKINETICS OF PRIMAQUINE PHOSPHATE AFTER A SINGLE ORAL ADMINISTRATION TO AFRICAN PENGUINS ().

J Zoo Wildl Med 2021 Apr;52(1):75-80

Maryland Zoo in Baltimore, Baltimore, MD 21217, USA.

Primaquine is an 8-aminoquinolone drug commonly used for the chemoprophylaxis and treatment of avian malarial infections in managed penguin populations worldwide. Little is known about its pharmacokinetic properties in avian species. The objective of this study was to describe the disposition of primaquine phosphate after a single oral dose in 15 healthy African penguins (). A single tablet containing 26.3 mg of primaquine phosphate (equivalent to 15 mg primaquine base) was administered orally to each bird in a herring fish. Blood samples were collected prior to drug administration and at predetermined timepoints through 144 hr postadministration. Plasma was analyzed for drug concentration by high-performance liquid chromatography with ultraviolet detection. Mean maximum plasma concentration of primaquine phosphate was 277 ± 96 ng/ml at approximately 3.1 hr following oral administration. The mean disappearance half-life was 3.6 ± 1.6 hr. Plasma concentrations were below detectable limits in all but one penguin by 36 hr. A single oral administration of 26.3 mg of primaquine phosphate in African penguins resulted in a pharmacokinetic profile comparable to those attained in human studies. These results suggest that a dosing interval similar to human regimens may be of potential use in the prevention and treatment of avian malaria in penguins. Additional clinical studies are needed to determine the efficacy and safety of this regimen.
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http://dx.doi.org/10.1638/2020-0172DOI Listing
April 2021

PARAMETERS FOR IDENTIFYING FAILURE OF PASSIVE TRANSFER IN SITATUNGA ().

J Zoo Wildl Med 2020 Jun;51(2):259-264

Maryland Zoo in Baltimore, Baltimore, MD 21217, USA.

Failure of passive transfer of immunity (FPT) leads to increased calf morbidity and mortality and requires intensive, time-sensitive, and often expensive management for nondomestic ruminants. Without species-specific information with which to make informed decisions, neonatal data from domestic ruminants are often extrapolated to nondomestic zoo-housed species. To date, there have been no studies evaluating FPT in sitatunga (). The goal of the present study was to establish parameters to characterize adequate passive transfer in sitatunga calves and compare them to published reference intervals in other species. Medical records of 22 sitatunga calves (12 female, 10 male) were reviewed. Seventeen of these calves were defined as "healthy," having survived at least 60 days without colostrum administration or a plasma transfusion. Calf weight, serum glucose, serum gamma-glutamyl transferase (GGT), total protein (TP), globulin concentrations, and results of a zinc sulfate turbidity test (ZSTT) were noted where possible. Mean birth weight of healthy calves at 24 hr was 4.5 kg (range: 3.76.5 kg, = 12). The mean blood glucose in healthy calves was 152 mg/dl (range: 80-182, = 16), mean serum TP concentration was 5.9 g/dl (range: 4.9-7.5, = 16), mean serum globulin concentration was 3.3 g/dl (range: 1.7-4.7, = 17), and mean serum GGT concentration was 466 U/L (range: 91-1901, = 16). A ZSTT was performed for 10 healthy calves, resulting in four negative ZSTT results despite having no clinical signs of FPT and the calves having been observed nursing before testing. Sitatunga appear to have lower values for normal FPT parameters than those developed for domestic cattle. This study illustrates the difficulty of cross-species comparisons, as even closely related species can vary greatly in biologic parameters.
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http://dx.doi.org/10.1638/2019-0199DOI Listing
June 2020

FACTORS AFFECTING ABNORMAL MOLTING IN THE MANAGED AFRICAN PENGUIN () POPULATION IN NORTH AMERICA.

J Zoo Wildl Med 2020 Jan;50(4):917-926

Maryland Zoo in Baltimore, Baltimore, Maryland 21217, USA.

Abnormal molting, including partial or incomplete molt, arrested molt cycle, or inappropriate frequency of molt, is a primary concern for the managed African penguin () population and is documented across institutions. To identify factors associated with increased odds of abnormal molts and characterize intervention opportunities, a comprehensive survey evaluating numerous husbandry and medical parameters was created. Survey results represent 45 North American African penguin holding facilities and 736 unique animals. Of these individuals, 135 (18.3%) demonstrated an abnormal molt over the 5-yr study period (2012-2017). Increased odds ratios for abnormal molt included biologic (age, sex, etc.), geographic (elevation, latitude), and husbandry (exhibit design, diet, etc.) variables. The mean age of affected animals was 15.2 yr (1-45 yr, = 135) compared with 9.92 yr (4 mo-38 yr, = 601) for unaffected animals. In addition, although statistically insignificant, males were overrepresented in the affected cohort compared with a near even distribution among unaffected animals. Identified factors with increased odds for abnormal molting included advanced age and facilities using freshwater pools. Normally molting penguins were more commonly found with saltwater pool access and natural lighting exposure. Anecdotal medical intervention attempts are discussed, although further research is needed to define their use. Of attempted interventions, subcutaneous 5.4-mg melatonin implants placed in anticipation of environmental molting cues showed the most promise at inducing catastrophic molt, with 14 of 17 (82.3%) of affected individuals molting normally following this treatment. Survey analysis indicated that abnormal molt is a complex, multifactorial process, and modifiable factors that may predispose animals to abnormally molt exist. Addressing these factors in future exhibit design may mitigate the prevalence of this condition. Despite these efforts, it is likely that medical interventions will be required to aid in the treatment of abnormal molting in this species.
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http://dx.doi.org/10.1638/2019-0080DOI Listing
January 2020

FATAL RANAVIRUS INFECTION IN A GROUP OF ZOO-HOUSED MELLER'S CHAMELEONS ().

J Zoo Wildl Med 2019 Sep;50(3):696-705

Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA,

A group of five juvenile Meller's chameleons () experienced 100% mortality over a period of 1 mo due to ranavirus infection. The index case was found dead without premonitory signs. The three subsequent cases presented with nonspecific clinical signs (lethargy, decreased appetite, ocular discharge) and were ultimately euthanatized. The final case died after initially presenting with skin lesions. Postmortem examination revealed thin body condition in all five animals and mild coelomic effusion and petechiae affecting the tongue and kidneys of one animal. Microscopically, all animals had multifocal necrosis of the spleen, liver, and kidney; four of five animals had necrosis of the nasal cavity; and two of five had necrosis of adrenal tissue, bone marrow, and skin. Numerous basophilic intracytoplasmic inclusions were present in the liver of all animals and nasal mucosa of three of the five animals. Consensus polymerase chain reaction for herpesvirus and adenovirus were negative, whereas ranavirus quantitative polymerase chain reaction was positive. Virus isolation followed by whole genome sequencing and Bayesian phylogenetic analysis classified the isolates as a strain of frog virus 3 (FV3) most closely related to an FV3 isolate responsible for a previous outbreak in the zoo's eastern box turtle () group. This case series documents the first known occurrence of ranavirus-associated disease in chameleons and demonstrates the potential for interspecies transmission between chelonian and squamate reptiles.
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http://dx.doi.org/10.1638/2018-0044DOI Listing
September 2019

COMPARISON OF CIRCULATING IRON, TOTAL IRON BINDING CAPACITY, AND PERCENT TRANSFERRIN SATURATION IN WILD AND CAPTIVE KORI BUSTARDS ( ARDEOTIS KORI).

J Zoo Wildl Med 2018 Jun;49(2):450-453

  The kori bustard ( Ardeotis kori) is one of the largest extant flighted birds and is displayed in zoos primarily in North America and Europe. In captivity, kori bustard diets are primarily based on animal proteins, whereas in the wild these birds eat a wide variety of plants, insects, and small vertebrate prey. The purpose of this study was to compare circulating iron, total iron binding capacity, and percent transferrin saturation levels in apparently healthy wild and captive kori bustards. Adult captive kori bustards had slightly higher percent transferrin saturation levels than juvenile captive birds, although this finding was not statistically significant. This information can be referenced as a guide for the assessment of nutrition and health in captive birds.
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http://dx.doi.org/10.1638/2017-0168.1DOI Listing
June 2018

CLINICAL EFFECT OF HEMOPARASITE INFECTIONS IN SNOWY OWLS ( BUBO SCANDIACUS).

J Zoo Wildl Med 2018 Mar;49(1):143-152

Vector-borne hemoparasites are commonly found in avian species. Plasmodium spp., the causative agent of avian malaria, are intraerythrocytic parasites that can cause signs ranging from subclinical infection to severe acute disease. In raptor species, most hemoparasites are associated with subclinical infection and are generally not treated when seen on blood evaluation. This case series reviews five cases of hemoparasite infection in snowy owls ( Bubo scandiacus). These animals were infected with a variety of hemoparasites, including Plasmodium, Haemoproteus, and Leukocytozoon spp. Death of one of these birds due to hemoparasite burden led to a change in the monitoring for and treatment of subclinical hemoparasitic infections in this species. Three subsequently infected snowy owls have been treated with primaquine and chloroquine. The birds that were treated survived infection, and parasite burdens in peripheral blood diminished. Postulated reasons for increased morbidity and mortality associated with hemoparasitic infections in captive snowy owls, as opposed to other raptor species, include stress, concurrent disease, novel pathogen exposure, and elevated environmental temperatures.
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http://dx.doi.org/10.1638/2017-0042R.1DOI Listing
March 2018

CALCINOSIS CIRCUMSCRIPTA IN A COHORT OF RELATED JUVENILE AFRICAN LIONS (PANTHERA LEO).

J Zoo Wildl Med 2017 09;48(3):813-817

Three juvenile, genetically related African lions (Panthera leo) were evaluated for discrete dome-shaped subcutaneous masses present over the proximal lateral metatarsal-tarsal area. The lesions measured 3-8 cm in diameter, were fluctuant to firm, nonulcerated, and attached to underlying structures. On radiographic evaluation, the lesions were characterized by well-circumscribed punctate mineralizations in the soft tissue surrounded by soft tissue swelling without evidence of adjacent bony involvement. On cut surface, the lesions were made of numerous loculi containing 2-5-mm round-to-ovoid, white-to-gray, firm structures interspersed with fibrous tissue and pockets of serosanguinous fluid. Hematology, serum biochemistry, serum thyroid screening (including total thyroxine, total triiodothyronine, free thyroxine, and free triiodothyronine), and serum vitamin D panels (including parathyroid hormone, ionized calcium, and 25-hydroxyvitamin D) were unremarkable. Histopathologic evaluation of the lesions was consistent with calcinosis circumscripta with fibroplasia, chronic inflammation, and seroma formation. An additional two genetically related lions were considered suspect for calcinosis circumscripta based on presentation, exam findings, and similarity to the confirmed cases. All masses self-regressed and were not associated with additional clinical signs other than initial lameness in two cases.
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http://dx.doi.org/10.1638/2016-0292.1DOI Listing
September 2017

CEREBELLAR AND MESENCEPHALON NEOPLASIA IN A NILE HIPOPPOTAMUS (HIPPOPOTAMUS AMPHIBIOUS).

J Zoo Wildl Med 2016 Dec;47(4):1093-1096

A 52-yr-old female Nile hippopotamus ( Hippopotamus amphibious ) was presented for acute onset anorexia, depression, lethargy, instability, and weakness in the pelvic limbs. Clinical signs were rapidly progressive, despite empiric therapy with anti-inflammatory medications, resulting in the death of the animal. Gross necropsy evaluation revealed two tan, firm masses in the cerebellum and mesencephalon and a single mass in the right cranial adrenal gland. All three masses had a similar histologic morphology, and immunohistochemical investigation confirmed the general diagnosis of an adenocarcinoma, but the exact cell of origin remains unclear. In addition, there was evidence of neuroendocrine differentiation in the adrenal gland and not in the brain. These findings suggest either two distinct neoplastic populations or a metastasizing adenocarcinoma with focal endocrine differentiation. In dogs, anal sac and clitoral adenocarcinomas have been reported to undergo focal endocrine differentiation, and both can cause widespread metastasis while the primary lesion can be small. A small neoplasm of these glands may have been missed on gross examination.
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http://dx.doi.org/10.1638/2015-0256.1DOI Listing
December 2016

ACUTE PHASE PROTEINS AS A MARKER OF RESPIRATORY INFLAMMATION IN PRZEWALSKI'S HORSE (EQUUS FERUS PRZEWALSKII).

J Zoo Wildl Med 2016 Jun;47(2):654-8

Acute phase proteins are sensitive markers of inflammation, which are highly conserved across taxa. Although the utility of these proteins are becoming well defined in human and domestic animal medical fields, their role in nondomestic species remains unclear. In this communication, a 20-yr-old Przewalski's horse was presented for unresolving aspiration pneumonia, which cultured a unique Actinomyces-like bacteria. Despite waxing and waning clinical signs and minimal changes on baseline hematologic analysis, protein electrophoresis, serum amyloid A, and surfactant protein D serum concentrations showed changes that more accurately reflected the clinical severity of this case.
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http://dx.doi.org/10.1638/2015-0059.1DOI Listing
June 2016

PHARMACOKINETICS OF A SINGLE DOSE OF METRONIDAZOLE AFTER RECTAL ADMINISTRATION IN CAPTIVE ASIAN ELEPHANTS (ELEPHAS MAXIMUS).

J Zoo Wildl Med 2016 Mar;47(1):1-5

Metronidazole is a nitroimidazole antibacterial and antiprotozoal drug with bacteriocidal activity against a broad range of anaerobic bacteria. It is a recognized treatment for elephants diagnosed with anaerobic bacterial infection or protozoal disease or exhibiting signs of colonic impaction, diarrhea, and colic. This study evaluated the pharmacokinetics of rectally administered metronidazole (15 mg/kg) in five adult female Asian elephants (Elephas maximus). Serum samples were collected from each animal for 96 hr after rectal administration of metronidazole. Serum concentrations of metronidazole and its primary metabolite, hydroxymetronidazole, were measured via ultraperformance liquid chromatography. Data were analyzed via a noncompartmental pharmacokinetic approach. Results indicated that serum levels of metronidazole were quantifiable at the 0.25 hr time point and absent in all elephants by the 96 hr time point. The serum peak concentration (mean ± SD, 13.15 ± 2.59 μg/ml) and area under the curve from time 0 to infinity (mean ± SD, 108.79 ± 24.77 hr × μg/ml) were higher than that reported in domestic horses after similar usage. Concurrently, the time of maximum serum concentration (mean ± SD, 1.2 ± 0.45 hr) and terminal elimination half-life (harmonic mean ± pseudo-SD, 7.85 ± 0.93 hr) were longer when compared to equine reports. Rectal administration of metronidazole was well tolerated and rapidly absorbed in all study elephants. Based on the findings in this study, metronidazole administered at a single dose of 15 mg/kg per rectum in the Asian elephant is likely to result in serum concentrations above 4 μg/ml for 8 hr and above 2 μg/ml for 24 hr after treatment is administered. Dosing recommendations should reflect the mean inhibitory concentration of metronidazole for each pathogen.
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http://dx.doi.org/10.1638/2015-0160.1DOI Listing
March 2016

Metronomic Chemotherapy for Myxosarcoma Treatment in a Kori Bustard (Ardeotis kori).

J Avian Med Surg 2015 Sep;29(3):210-5

A 22-year-old, wild-caught male kori bustard (Ardeotis kori) developed a large, slow-growing subcutaneous mass over the keel. The mass was surgically debulked and histopathologically described as a myxosarcoma. Surgical dehiscence and concurrent local tumor regrowth, with no evidence of metastasis, occurred over the subsequent 3 months, necessitating 2 additional surgical procedures to close the wound. At 19 weeks after the initial procedure, a second debulking surgical procedure was performed, at which time carboplatin-impregnated matrix beads were placed in the lesion. Moderate local tumor regrowth was clinically appreciable 4 weeks after surgery, at which time an oral metronomic chemotherapeutic protocol consisting of daily cyclophosphamide (10 mg/m(2)) and meloxicam (0.1 mg/kg) was initiated. Four months later, the tumor was no longer palpable. While oral therapy was discontinued during the breeding season, mass regrowth was observed, and the mass was surgically debulked before reinitiating oral chemotherapy. Treatment was extended for over 1 year with no hematologic evaluation or serum biochemical abnormalities, and the bird otherwise remained clinically healthy. To our knowledge, this is the first report of a myxosarcoma in a bustard species and the first report of successful clinical application of metronomic chemotherapy in an avian species.
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http://dx.doi.org/10.1647/2014-032DOI Listing
September 2015

Advancement flap as a novel treatment for a pododermatitis lesion in a red-tailed hawk (Buteo jamaicensis).

J Avian Med Surg 2013 Dec;27(4):294-300

Pododermatitis is a pathologic condition commonly reported in captive raptors and characterized by swelling, excoriation, ulceration, cellulitis, or abscessation of the plantar aspect of the foot. Its cause can be multifactorial, often involving abnormal weight bearing or poor sanitation, and medical and surgical techniques, in addition to environmental alterations, are hallmarks of treatment. In this case, a single pedicle advancement flap was used to treat chronic, nonresponsive grade V/VII pododermatitis of the right metatarsal pad in a red-tailed hawk (Buteo jamaicensis). The advancement flap was formed by using the interdigital skin between digits 3 and 4. The double layer of skin was incised and separated, and the leading edge of the flap was then advanced over the defect and secured with simple interrupted subcutaneous and skin sutures. The foot was bandaged after surgery to take pressure off the surgical site. At 58 days after the surgery, the hawk was deemed medically sound with no signs of pododermatitis and was released to a wildlife rehabilitator. The use of a single pedicle advancement flap has not previously been reported for the treatment of pododermatitis.
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http://dx.doi.org/10.1647/2012-055DOI Listing
December 2013