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311 result(s) for "Garner, Michael M."
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Elephant Genomes Reveal Accelerated Evolution in Mechanisms Underlying Disease Defenses
Disease susceptibility and resistance are important factors for the conservation of endangered species, including elephants. We analyzed pathology data from 26 zoos and report that Asian elephants have increased neoplasia and malignancy prevalence compared with African bush elephants. This is consistent with observed higher susceptibility to tuberculosis and elephant endotheliotropic herpesvirus (EEHV) in Asian elephants. To investigate genetic mechanisms underlying disease resistance, including differential responses between species, among other elephant traits, we sequenced multiple elephant genomes. We report a draft assembly for an Asian elephant, and defined 862 and 1,017 conserved potential regulatory elements in Asian and African bush elephants, respectively. In the genomes of both elephant species, conserved elements were significantly enriched with genes differentially expressed between the species. In Asian elephants, these putative regulatory regions were involved in immunity pathways including tumor-necrosis factor, which plays an important role in EEHV response. Genomic sequences of African bush, forest, and Asian elephant genomes revealed extensive sequence conservation at TP53 retrogene loci across three species, which may be related to TP53 functionality in elephant cancer resistance. Positive selection scans revealed outlier genes related to additional elephant traits. Our study suggests that gene regulation plays an important role in the differential inflammatory response of Asian and African elephants, leading to increased infectious disease and cancer susceptibility in Asian elephants. These genomic discoveries can inform future functional and translational studies aimed at identifying effective treatment approaches for ill elephants, which may improve conservation.
Chromatophoromas in Reptiles
Chromatophoromas are neoplasms that arise from pigment cells of reptiles, amphibians, and fish. They include melanophoromas (melanomas), iridophoromas, and xanthophoromas. Most chromatophoromas develop spontaneously, but genetic and environmental factors may also play a role in their oncogenesis. The diagnosis is typically through histologic examination. Immunohistochemistry and electron microscopy can be helpful for diagnosing poorly differentiated and/or poorly pigmented neoplasms. Aggressive surgical excision is the current treatment of choice. This review describes the clinical presentation, gross appearance, diagnostic applications, clinical behavior, and treatment of chromatophoromas in reptiles.
A Multi-Institutional Collaboration to Understand Neoplasia, Treatment and Survival of Snakes
This multi-institutional collaborative study of neoplasia in snakes reviewed medical records of snakes at each facility to determine species prevalence, survival, and methods of treatment. Complete species numbers of snakes were also collected at each facility. In total, 65 species, 133 snakes, and 149 unique neoplasias were included in this study. Affected species, age, sex, and their tumor prevalence, tumor type and location, metastasis, treatment, and survival data are reported. The highest species-specific tumor prevalence was in Common or Northern Watersnakes (Nerodia sipedon) (30.8%, n = 4 of 13), Eastern Diamond-Backed Rattlesnakes (Crotalus adamanteus) (26.3%, n = 5 of 19), and Timber rattlesnakes (Crotalus horridus) (22.7%, n = 5 of 22). Malignant tumors predominated (86.6%, n = 129 of 149) with soft tissue sarcomas being the most common (30.2%, n = 45 of 149). Snakes with malignant neoplasia, metastases, or indeterminate presence of metastases were statistically more likely to die from their neoplasms than snakes having either benign neoplasia or no diagnosed metastases (p < 0.05). Gender, taxonomic family, and species of those evaluated did not significantly affect the outcome of snakes with neoplasia. Only 27.1% (n = 36 of 133) of snakes received a reported form of treatment and, for those treated, surgical excision was the most common treatment modality. There was not a significant difference in outcome based on treatment; however, surgery and chemotherapy were associated with death from a cause other than their tumor.
The Emergence of Mucormycosis in Free-Ranging Marine Mammals of the Pacific Northwest
Primary fungal diseases in marine mammals are rare. Mucormycosis, a disease caused by fungi of the order Mucorales, has been documented in few cetaceans and pinnipeds. In 2012, the first case of mucormycosis in the Pacific Northwest was documented in a dead stranded harbor porpoise (Phocoena phocoena) in Washington state. Since then, mucormycosis has been detected in a total of 21 marine mammals; fifteen harbor porpoises, five harbor seals (Phoca vitulina), and one southern resident killer whale (Orcinus orca). Infected animals were predominately found in the inland waters of Washington and British Columbia, and one harbor seal was recovered in northern Oregon. Fungal hyphae were detected histologically in a variety of tissues, including brain, lung, spleen, pancreas, kidneys, muscle, lymph nodes, and skin. Three fungal species were identified from seven cases by PCR screening or fungal culture; Rhizomucor pusillus (four cases), Lichtheimia corymbifera (two cases), and Cunninghamella bertholletiae. Underlying conditions such as emaciation, current or recent pregnancy, multisystemic parasitism, protozoal infection, and herpesvirus were found in several affected animals. Reasons for the appearance and subsequent increase of these fungal infections in marine mammals are unknown. The emergence of this disease as a source of marine mammal mortality in the Pacific Northwest is of particular concern for endangered southern resident killer whales that spend time in this region. Current population-level stressors such as insufficient prey, high levels of contaminants, and noise pollution, could predispose them to these fatal infections.
Steatitis in Cold-Stunned Kemp’s Ridley Sea Turtles (Lepidochelys kempii)
The pathogenesis of steatitis that infrequently occurs in cold-stunned Kemp’s ridley sea turtles (KRT; Lepidochelys kempii) has been undetermined. The objectives of this study were to investigate the clinical (n = 23) and histologic findings (n = 11) in cold-stunned KRT, and to compare plasma concentrations of α-tocopherol (vitamin E), thiobarbituric acid reactive substances (TBARS), and the TBARS to vitamin E (T/E) ratio (an assessment of oxidative stress) between cold-stunned KRT with clinically and/or histologically confirmed steatitis (n = 10) and free-ranging KRT (n = 9). None of the cold-stunned turtles had clinically detectable steatitis at admission, and the median number of days to diagnosis of steatitis was 71 (range 33–469). Histologic findings of affected adipose tissue included heterophilic (n = 9) and/or histiocytic (n = 5) steatitis, fat necrosis (n = 7), myonecrosis (n = 2), and intralesional bacteria (n = 6). Cold-stunned KRT had significantly lower plasma vitamin E concentrations (median = 3.5 nmol/g), lower plasma TBARS concentrations (median = 1.6 nmol/g), and higher T/E ratios (median = 0.50), than controls (62.3 nmol/g; 2.1 nmol/g; 0.03, respectively). These results suggest a multifactorial etiology for the development of steatitis in KRT during rehabilitation, including tissue injury, septicemia, and various factors resulting in imbalances of anti-/oxidative status. By highlighting the need to provide more effective vitamin E supplementation, and the need to re-assess specific components of the diet, this study may lead to reduced incidence and improved medical management of steatitis in cold-stunned sea turtles.
A Novel Exophiala Species Associated With Disseminated Granulomatous Inflammation in a Captive Eastern Hellbender (Cryptobranchus alleganiensis alleganiensis)
The genus is composed of ubiquitous, pigmented, saprotrophic fungi and includes both terrestrial and waterborne species. Though species are generally considered opportunistic pathogens, exophialosis can be an important cause of morbidity and mortality in aquatic and semi-aquatic species. Over a 6-year period, a captive 32-year-old male eastern hellbender ( ), was treated for recurring, slow growing, ventral midline cutaneous masses. Excisional biopsies were characterized histologically by granulomatous dermatitis with low numbers of intralesional, pigmented fungal conidia and hyphae. Bacterial and fungal cultures of the masses and skin were negative on two separate submissions. Polymerase chain reaction amplification of a short fragment of the fungal 28S large subunit (LSU) ribosomal RNA was positive with 100% nucleotide sequence identity to several species of . Following recurrence after successive rounds of antifungal therapy, euthanasia was elected. At necropsy, similar dermal granulomatous inflammation and intralesional pigmented fungal elements as observed in excisional biopsies formed a thick band in the dermis and extended through the coelomic body wall. Visceral dissemination was noted in the lung and kidney. Postmortem DNA sequence analysis of a large portion of the fungal LSU as well as the internal transcribed spacer (ITS) from a portion of frozen affected dermis identified the fungus as a novel species, sp. 1 (UTHSCSA R-5437).
ANAPLASTIC MANDIBULAR CARCINOMA IN A MEERKAT (SURICATA SURICATTA)
An 8-yr-old female slender-tailed meerkat (Suricata suricatta) presented with a necrotic sublingual mass and osteolysis of the mandible. After 1 mo of palliative care, the meerkat was euthanized. The mass was diagnosed histologically as an anaplastic carcinoma with extensive rostral mandibular destruction. Immunohistochemistry for vimentin and cytokeratin was validated in this nontypical species and showed that neoplastic cells expressed both mesenchymal and epithelial characteristics, suggestive of a primitive and poorly differentiated tumor. A review of 150 adult slender-tailed meerkat histopathology reports showed a 2% prevalence of orofacial neoplasia, suggesting that oral neoplasms are uncommon in meerkats.
Fatal Meningoencephalitis From a Rhizomucor pusillus Infection in a Juvenile Magellanic Penguin (Spheniscus magellanicus)
A 7-month-old, male Magellanic penguin (Spheniscus magellanicus), housed in an outdoor exhibit, developed acute neurologic signs that progressed to death over 2 days. On gross examination, the bird had congested, edematous lungs, and cerebellar hemorrhage. Histologic examination identified granulomatous pneumonia and encephalitis, with thrombosis and eosinophilic, branching fungal hyphae that had invaded the meningeal vessel walls. Polymerase chain reaction identified the fungus in the brain as Rhizomucor pusillus, an uncommon cause of mucormycosis. This organism has previously been reported in respiratory, skeletal, and sino-orbital lesions of avian species. This clinical report describes meningoencephalitis associated with Rhizomucor pusillus in a penguin.