E Scott Weber

Publications of E Scott Weber

• Systemic iridovirus from threespine stickleback Gasterosteus aculeatus represents a new megalocytivirus species (family Iridoviridae).

  Authors: Thomas B Waltzek, Gary D Marty, Michael E Alfaro, William R Bennett, Kyle A Garver, Martin Haulena, E Scott Weber, Ronald P Hedrick

  Diseases of aquatic organisms. 02/2012; 98(1):41-56.

  Megalocytiviruses have been associated with epizootics resulting in significant economic losses in public aquaria and food-fish and ornamental fish industries, as well as threatening wild fishMegalocytiviruses have been associated with epizootics resulting in significant economic losses in public aquaria and food-fish and ornamental fish industries, as well as threatening wild fish stocks. The present report describes characteristics of the first megalocytivirus from a wild temperate North American fish, the threespine stickleback Gasterosteus aculeatus. Moribund and dead fish sampled after transfer to quarantine for an aquarium exhibit had amphophilic to basophilic intracytoplasmic inclusions (histopathology) and icosahedral virions (transmission electron microscopy) consistent with an iridovirus infection. Phylogenetic analyses of the major capsid, ATPase, and DNA polymerase genes confirmed the virus as the first known member of the genus Megalocytivirus (family Iridoviridae) from a gasterosteid fish. The unique biologic and genetic properties of this virus are sufficient to establish a new Megalocytivirus species to be formally known as the threespine stickleback iridovirus (TSIV). The threespine stickleback is widely distributed throughout the northern hemisphere in both freshwater and estuarine environments. The presence of megalocytiviruses with broad host specificity and detrimental economic and ecologic impacts among such a widely dispersed fish species indicates the need for sampling of other stickleback populations as well as other North American sympatric marine and freshwater ichthyofauna.

• Single-dose pharmacokinetics of ceftazidime and fluconazole during concurrent clinical use in cold-stunned Kemp's ridley turtles (Lepidochelys kempii).

  Authors: C J Innis, M L Ceresia, C Merigo, E Scott Weber, M G Papich

  Journal of veterinary pharmacology and therapeutics. 04/2011; 35(1):82-9.

  Single-dose pharmacokinetics of intramuscularly administered ceftazidime (22 mg/kg) and subcutaneously administered fluconazole (21 mg/kg) were investigated during concurrent clinical use inSingle-dose pharmacokinetics of intramuscularly administered ceftazidime (22 mg/kg) and subcutaneously administered fluconazole (21 mg/kg) were investigated during concurrent clinical use in naturally cold-stunned Kemp's ridley turtles (Lepidochelys kempii). Maximum mean concentration for ceftazidime was 61.31 μg/mL, and time of maximum concentration was 1.56 h postinjection. Maximum mean concentration for fluconazole was 26.16 μg/mL, and time of maximum concentration was 0.79 h postinjection. Results indicate that the ceftazidime dose and dosing interval used in this study are likely to be effective in treating susceptible strains of bacteria in Kemp's ridley turtles. However, the fluconazole dose and dosing interval are not likely to be effective against filamentous fungal pathogens that are often involved in marine turtle fungal infections.

• Fish analgesia: pain, stress, fear aversion, or nociception?

  Authors: E Scott Weber

  The veterinary clinics of North America. Exotic animal practice. 01/2011; 14(1):21-32.

  The increasing use of fish resources and a greater understanding of aquatic animal medicine demands providing evidence-based veterinary care for these animals. Because fish are aquatic as well asThe increasing use of fish resources and a greater understanding of aquatic animal medicine demands providing evidence-based veterinary care for these animals. Because fish are aquatic as well as being pokilothermic, there are several unique anatomic and physiologic considerations that must be understood when working with these animals. Veterinarians need to adapt methodologies for examining, performing diagnostics, and treating fish patients to decrease stress, decrease fear, and avoid and/or decrease nociception. This article briefly defines stress, reviews and compares fish neuroanatomic pathways associated with nociception, discusses behavioral observations, summarizes current use of analgesics for fish patients, and concludes with the ongoing controversy regarding pain on this topic.

• Geriatric veterinary care for fish patients.

  Authors: E Scott Weber

  The veterinary clinics of North America. Exotic animal practice. 01/2010; 13(1):1-14.

  There is little evidence-based research and scientific literature available for providing geriatric care for fish patients. Fish can have tremendous longevity. Although the average life span for mostThere is little evidence-based research and scientific literature available for providing geriatric care for fish patients. Fish can have tremendous longevity. Although the average life span for most fish species can be only a few days to weeks for the beginning hobbyist, it is becoming more common for clients to have animals for several decades with the advent and continued development of improved life-support systems, husbandry, water quality additives, and fish nutrition. This article discusses fish longevity for several popular species, addresses environmental quality issues for geriatric patients, and provides information on the most common challenges, from a veterinary perspective, to maintain fish over the years.

• Hematologic and plasma biochemical findings in cold-stunned Kemp's ridley turtles: 176 cases (2001-2005).

  Authors: Charles J Innis, Jared B Ravich, Michael F Tlusty, Melissa S Hoge, Denise S Wunn, Leslie B Boerner-Neville, Constance Merigo, E Scott Weber

  Journal of the American Veterinary Medical Association. 09/2009; 235(4):426-32.

  Objective-To document hematologic and plasma biochemical values for a large number of cold-stunned Kemp's ridley turtles at the beginning of rehabilitation, to investigate differences in hematologicObjective-To document hematologic and plasma biochemical values for a large number of cold-stunned Kemp's ridley turtles at the beginning of rehabilitation, to investigate differences in hematologic and plasma biochemical values of turtles that ultimately survived versus those that died, and to compare values of survivors during convalescence with initial values obtained at the time of admission. Design-Retrospective case series. Animals-176 stranded, cold-stunned Kemp's ridley turtles hospitalized between 2001 and 2005. Procedures-Hematologic and plasma biochemical values obtained at the time of admission were compared retrospectively for turtles that died versus turtles that survived. Initial results for survivors were compared with convalescent results obtained later in rehabilitation. Results-Turtles that died had significantly greater plasma concentrations of sodium, chloride, potassium, calcium, phosphorus, and uric acid than did turtles that survived. For survivors, values obtained during convalescence for BUN concentration and plasma calcium concentration were significantly greater than initial values obtained at the time of admission, whereas values obtained during convalescence for glucose, sodium, and uric acid concentrations were significantly lower than initial values. Conclusions and Clinical Relevance-Cold-stunned Kemp's ridley turtles may be affected by electrolyte derangements, dehydration, and decreased renal function. Hematologic and plasma biochemical evaluation of such turtles provided useful clinical and prognostic information during the rehabilitation process.

• Pathologic and parasitologic findings of cold-stunned kemp's ridley sea turtles (lepidochelys kempii) stranded on cape cod, massachusetts, 2001-2006.

  Authors: Charles Innis, Akinyi C Nyaoke, C Rogers Williams, Bridget Dunnigan, Constance Merigo, Denise L Woodward, E Scott Weber, Salvatore Frasca

  Journal of wildlife diseases. 08/2009; 45(3):594-610.

  Necropsy reports for 28 stranded, cold-stunned Kemp's ridley sea turtles (Lepidochelys kempii) that died between 2001 and 2006 were reviewed retrospectively. Gross and microscopic lesions wereNecropsy reports for 28 stranded, cold-stunned Kemp's ridley sea turtles (Lepidochelys kempii) that died between 2001 and 2006 were reviewed retrospectively. Gross and microscopic lesions were compiled to describe the pathologic and parasitologic findings in turtles that were found freshly dead on the beach or that died within 48 hr of stranding. Anatomic lesions of varying severity were identified in each of the examined turtles and were identified in tissues of the alimentary, respiratory, integumentary, nervous and sensory, and urogenital systems in order of decreasing frequency. Necrotizing enterocolitis and bacterial or fungal pneumonia were the most frequently encountered lesions that were considered clinically significant. Parasites and parasitic lesions were identified primarily in tissues of the alimentary system and included intestinal cestodiasis and parasitic granulomas containing larval cestodes or nematodes. Postlarval cestodes were also found in the coelom of two turtles. In many cases, the extent and severity of lesions were judged to be insufficient to have solely caused mortality, suggesting that additional factors such as metabolic, respiratory, and electrolyte derangements; hypothermia; and drowning may be important proximate causes of death in cold-stunned turtles. Results of this study provide insight into pathologic conditions that may be of clinical relevance to rehabilitation efforts for cold-stunned sea turtles.

• Systemic iridovirus infection in the Banggai cardinalfish (Pterapogon kauderni Koumans 1933).

  Authors: E Scott Weber, Thomas B Waltzek, Devon A Young, Erica L Twitchell, Amy E Gates, Alejandro Vagelli, Guillermo R Risatti, Ronald P Hedrick, Salvatore Frasca

  Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc. 06/2009; 21(3):306-20.

  Iridoviruses infect food and ornamental fish species from a wide range of freshwater to marine habitats across the globe. The objective of the current study was to characterize an iridovirus causingIridoviruses infect food and ornamental fish species from a wide range of freshwater to marine habitats across the globe. The objective of the current study was to characterize an iridovirus causing systemic infection of wild-caught Pterapogon kauderni Koumans 1933 (Banggai cardinalfish). Freshly frozen and fixed specimens were processed for histopathologic evaluation, transmission electron microscopic examination, virus culture, molecular virologic testing, microbiology, and in situ hybridization (ISH) using riboprobes. Basophilic granular cytoplasmic inclusions were identified in cytomegalic cells often found beneath endothelium, and hexagonal virus particles typical of iridovirus were identified in the cytoplasm of enlarged cells by transmission electron microscopy. Attempts at virus isolation in cell culture were unsuccessful; however, polymerase chain reaction (PCR)-based molecular testing resulted in amplification and sequencing of regions of the DNA polymerase and major capsid protein genes, along with the full-length ATPase gene of the putative iridovirus. Virus gene sequences were then used to infer phylogenetic relationships of the P. kauderni agent to other known systemic iridoviruses from fishes. Riboprobes, which were transcribed from a cloned PCR amplification product from the viral genome generated hybridization signals from inclusions within cytomegalic cells in histologic sections tested in ISH experiments. To the authors' knowledge, this is the first report of a systemic iridovirus from P. kauderni. The pathologic changes induced and the genomic sequence data confirm placement of the Banggai cardinalfish iridovirus in the genus Megalocytivirus family Iridoviridae. The ISH provides an additional molecular diagnostic technique for confirmation of presumptive infections detected in histologic sections from infected fish.

• Disseminated phaeohyphomycosis in weedy seadragons (Phyllopteryx taeniolatus) and leafy seadragons (Phycodurus eques) caused by species of Exophiala, including a novel species.

  Authors: Akinyi Nyaoke, E Scott Weber, Charles Innis, Donald Stremme, Cynthia Dowd, Lynn Hinckley, Timothy Gorton, Brian Wickes, Deanna Sutton, Sybren de Hoog, Salvatore Frasca

  Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc. 02/2009; 21(1):69-79.

  During the period from January 2002 to March 2007, infections by melanized fungi were identified with greater frequency in aquarium-maintained leafy seadragons (Phycodurus eques) and weedy seadragonsDuring the period from January 2002 to March 2007, infections by melanized fungi were identified with greater frequency in aquarium-maintained leafy seadragons (Phycodurus eques) and weedy seadragons (Phyllopteryx taeniolatus), pivotal species to the educational and environmental concerns of the aquarium industry and conservation groups. The objective of this study was to characterize the pathology and identify fungi associated with phaeohyphomycotic lesions in these species. Samples from 14 weedy and 6 leafy seadragons were received from 2 institutions and included fresh, frozen, and formalin-fixed tissues from necropsy and biopsy specimens. Fresh and frozen tissues were cultured for fungi on Sabouraud dextrose agar only or both Sabouraud dextrose agar and inhibitory mold agar with gentamicin and chloramphenicol at 30 degrees C. Isolates were processed for morphologic identification and molecular sequence analysis of the internal transcribed spacer region and D1/D2 domains of the large subunit ribosomal RNA gene. Lesions were extensive and consisted of parenchymal and vascular necrosis with fungal invasion of gill (11/20), kidney (14/20), and other coelomic viscera with or without cutaneous ulceration (13/20). Exophiala sp. isolates were obtained from 4 weedy and 3 leafy seadragons and were identified to species level in 6 of 7 instances, namely Exophiala angulospora (1) and a novel species of Exophiala (5), based on nucleotide sequence comparisons and phylogenetic analyses. Disseminated phaeohyphomycosis represents an important pathologic condition of both weedy and leafy seadragons for which 2 species of Exophiala, 1 a novel species, have been isolated.

• Fish cardiovascular physiology and disease.

  Authors: Johanna Sherrill, E Scott Weber, Gary D Marty, Stephen Hernandez-Divers

  The veterinary clinics of North America. Exotic animal practice. 02/2009; 12(1):11-38.

  Fish patients with cardiovascular disorders present a challenge in terms of diagnostic evaluation and therapeutic options. Veterinarians can approach these cases in fish using methods similar toFish patients with cardiovascular disorders present a challenge in terms of diagnostic evaluation and therapeutic options. Veterinarians can approach these cases in fish using methods similar to those employed for other companion animals. Clinicians who evaluate and treat fish in private, aquarium, zoologic, or aquaculture settings need to rely on sound clinical judgment after thorough historical and physical evaluation. Pharmacokinetic data and treatments specific to cardiovascular disease in fish are limited; thus, drug types and dosages used in fish are largely empiric. Fish cardiovascular anatomy, physiology, diagnostic evaluation, monitoring, common diseases, cardiac pathologic conditions, formulary options, and comprehensive references are presented with the goal of providing fish veterinarians with clinically relevant tools.

• Eastern equine encephalitis in a captive harbor seal (Phoca vitulina).

  Authors: Michael P McBride, Michele A Sims, Robert W Cooper, Akinyi C Nyaoke, Cheryl Cullion, Matti Kiupel, Salvatore Frasca, Naomi Forrester, Scott C Weaver, E Scott Weber

  Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians. 01/2009; 39(4):631-7.

  A 31-yr-old male, captive harbor seal (Phoca vitulina) was evaluated for a 48-hr period of anorexia followed by the onset of seizures. A prolonged seizure failed to respond to anticonvulsant therapyA 31-yr-old male, captive harbor seal (Phoca vitulina) was evaluated for a 48-hr period of anorexia followed by the onset of seizures. A prolonged seizure failed to respond to anticonvulsant therapy and the animal was euthanized. At necropsy, no significant gross lesions were identified. Reverse transcriptase-polymerase chain reaction testing of brain samples was positive for eastern equine encephalitis virus (EEEV) RNA, and serum was positive for anti-EEEV antibodies by plaque reduction neutralization. Histopathologic evaluation revealed severe and multifocal encephalitis with leptomeningitis, characterized by neutrophilic infiltrates in neuropil, neuronal necrosis, satellitosis, neuronophagia, and perivascular cuffs of lymphocytes, macrophages, and neutrophils. Additionally there was moderate, multifocal, adrenal cortical necrosis. Immunohistochemical staining for EEEV demonstrated viral antigen within necrotic neurons and glial cells. Virus was isolated from frozen brain tissue, sequenced for comparison to other strains, and determined to be a typical North American strain. EEEV should be included as a possible cause of neurologic disease in harbor seals with compatible signs located in geographic regions where vector transmission of EEEV is encountered.

• Metabolic and respiratory status of cold-stunned Kemp's ridley sea turtles (Lepidochelys kempii).

  Authors: Charles J Innis, Michael Tlusty, Constance Merigo, E Scott Weber

  Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology. 09/2007; 177(6):623-30.

  "Cold-stunning" of sea turtles has been reported as a naturally occurring stressor for many years; however, the physiologic status of cold-stunned turtles has only been partially described. This"Cold-stunning" of sea turtles has been reported as a naturally occurring stressor for many years; however, the physiologic status of cold-stunned turtles has only been partially described. This study investigated initial and convalescent venous blood gas, acid-base, and critical plasma biochemical data for 26 naturally cold-stunned Kemp's ridley sea turtles (Lepidochelys kempii) from Cape Cod, MA, USA. Samples were analyzed for pH, pCO(2), pO(2), bicarbonate, plasma osmolality, sodium, potassium, chloride, ionized calcium, ionized magnesium, glucose, lactate, and blood urea nitrogen using a clinical point-of-care analyzer. Data were corrected for the patient's body temperature using both species-specific and more general correction methods. In general, venous blood gas, acid-base, and plasma biochemical data obtained for surviving cold-stunned Kemp's ridley sea turtles were consistent with previously documented data for sea turtles exposed to a wide range of temperatures and physiologic stressors. Data indicated that turtles were initially affected by metabolic and respiratory acidosis. Initial pH-corrected ionized calcium concentrations were lower than convalescent concentrations, and initial pH-corrected ionized magnesium concentrations were higher than convalescent concentrations.

• Piscine patients: basic diagnostics.

  Authors: E Scott Weber, Charles Innis

  Compendium (Yardley, PA). 06/2007; 29(5):276-7, 280, 282-6; quiz 286, 288.

  This article can serve as an introduction for practitioners who are interested in adding fish to their practice. It reviews the current literature, includes contributions from institutionalThis article can serve as an introduction for practitioners who are interested in adding fish to their practice. It reviews the current literature, includes contributions from institutional collaborators, and draws on clinical expertise from diverse cases and applied research from the Animal Health Department at the New England Aquarium. Basic diagnostic approaches to piscine patients are featured. We hope to inspire other veterinary professionals to pursue diagnostics, perform surgery, and practice preventive medicine in aquatic animal patients.

• Isolation and characterization of Mycoplasma sphenisci sp. nov. from the choana of an aquarium-reared jackass penguin (Spheniscus demersus).

  Authors: Salvatore Frasca, E Scott Weber, Heather Urquhart, Xiaofen Liao, Martha Gladd, Katharine Cecchini, Paul Hudson, Meghan May, Rebecca J Gast, Timothy S Gorton, Steven J Geary

  Journal of clinical microbiology. 07/2005; 43(6):2976-9.

  Strain UCMJ was isolated from the choana of a jackass penguin (Spheniscus demersus) with recurrent mucocaseous choanal discharge. Isolation of this mycoplasma expands the known range of speciesStrain UCMJ was isolated from the choana of a jackass penguin (Spheniscus demersus) with recurrent mucocaseous choanal discharge. Isolation of this mycoplasma expands the known range of species hosting mycoplasmas. The name Mycoplasma sphenisci sp. nov. is proposed for this new species, for which strain UCMJ is the type strain.

• Gastroenterology for the piscine patient.

  Authors: E Scott Weber

  The veterinary clinics of North America. Exotic animal practice. 06/2005; 8(2):247-76.

• Erysipelothrix septicemia in a little blue penguin (Eudyptula minor).

  Authors: Leslie Boerner, Kathleen R Nevis, Lynn S Hinckley, E Scott Weber, Salvatore Frasca

  Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc. 04/2004; 16(2):145-9.

  On June 25, 2002, aquarium veterinarians treated a 5-year-old, male little blue penguin (Eudyptula minor) that was acutely recumbent and dull, with inappetence of 24-hour duration. The penguin diedOn June 25, 2002, aquarium veterinarians treated a 5-year-old, male little blue penguin (Eudyptula minor) that was acutely recumbent and dull, with inappetence of 24-hour duration. The penguin died within 10 minutes of presentation despite emergency resuscitation efforts. Gross pathologic findings consisted of pulmonary congestion and intestinal hemorrhage. Histopathologic findings included necrosis of tips of intestinal villi, increased numbers of mononuclear cells in pulmonary interstitium and hepatic sinusoids, and gram-positive bacteria in systemic microvasculature. Transmission electron microscopic examination revealed short gram-positive bacilli located in lumina of glomerular capillaries and in cytoplasm of mononuclear phagocytic cells in the lung and liver. Erysipelothrix rhusiopathiae was recovered from the lung, liver, and intestine by bacteriologic culture. Amplicons from polymerase chain reaction (PCR) tests using Erysipelothrix genus-specific primers and total genomic DNA extracted from formalin-fixed, paraffin-embedded tissue sections of lung and intestine demonstrated 99% nucleotide sequence identity with 16S small-subunit ribosomal DNA of E. rhusiopathiae and E. tonsillarum. The source of infection was speculated to be fish in the diet; however, repeated attempts to detect Erysipelothrix spp. from the mucous layer of food fish using bacteriologic culture and PCR were unsuccessful. This is the first report of erysipelas in a captive aquatic bird. Details of the isolation of E. rhusiopathiae and the application of molecular testing to identify Erysipelothrix DNA in formalin-fixed, paraffin-embedded tissue sections are given.