Phaeohyphomycosis due to Exophiala in Aquarium-Housed Lumpfish (Cyclopterus lumpus): Clinical Diagnosis and Description.

Phaeohyphomycosis caused by Exophiala species represents an important disease of concern for farmed and aquarium-housed fish. The objective of this study was to summarize the clinical findings and diagnosis of Exophiala infections in aquarium-housed Cyclopterus lumpus. Clinical records and postmortem pathology reports were reviewed for 15 individuals from 5 public aquaria in the United States and Canada from 2007 to 2015. Fish most commonly presented with cutaneous ulcers and progressive clinical decline despite topical or systemic antifungal therapy. Antemortem fungal culture of cutaneous lesions resulted in colonial growth for 7/12 samples from 8 individuals. Amplification of the internal transcribed spacer region (ITS) of nuclear rDNA identified Exophiala angulospora or Exophiala aquamarina in four samples from three individuals. Postmortem histopathologic findings were consistent with phaeohyphomycosis, with lesions most commonly found in the integument (11/15), gill (9/15), or kidney (9/15) and evidence of fungal angioinvasion and dissemination. DNA extraction and subsequent ITS sequencing from formalin-fixed paraffin-embedded tissues of seven individuals identified E. angulospora, E. aquamarina, or Cyphellophora sp. in four individuals. Lesion description, distribution, and Exophiala spp. identifications were similar to those reported in farmed C. lumpus. Antemortem clinical and diagnostic findings of phaeohyphomycosis attributable to several species of Exophiala provide insight on the progression of Exophiala infections in lumpfish that may contribute to management of the species in public aquaria and under culture conditions.

Renal Disease in Teleost Patients.

The number of fish as pets far exceeds the populations of any other companion animal. As our knowledge of aquatic animal species and aquatic animal medicine continues to expand, veterinary expertise is becoming more critical to the client, researcher, fisheries biologist, aquarist, farmer, and fish hobbyist. Similar to other vertebrates, fish are susceptible to infectious and noninfectious renal disease. This article compares vertebrate renal anatomy and physiology and highlights some renal disease examples.

COCCIDIAL INFECTION OF THE ADRENAL GLANDS OF LEATHERBACK SEA TURTLES (DERMOCHELYS CORIACEA).

Histologic lesions incidental to the cause of death were observed in the adrenal glands of 17 subadult and adult leatherback sea turtles ( Dermochelys coriacea ) found dead or moribund on or near shore in North America. Round bodies, 250-300 µm in diameter composed of an outer capsule and large multinucleated cells surrounding a central mass of acellular material were distributed throughout the affected glands. Protozoal etiology was suspected based on some resemblance to coccidia; however, features diagnostic for coccidial infection were lacking in all but one case, which had a focal area of adrenalitis containing zoites. A novel eucoccidian partial 18S rRNA genetic sequence was consistently detected in adrenal glands with lesions. With the use of quantitative PCR, a specific area of the V4 region of the coccidian 18S gene was quantified in affected adrenal glands and correlated significantly with density of the histologic lesions. A second distinct, but closely related, 18S sequence was also amplified from the adrenal gland of one turtle and from a fecal sample containing unsporulated coccidian oocysts. The two 18S sequences identified from leatherback sea turtles form a clade within the family Eimeriidae. Further investigation is required to understand better the morphology of the life stages, life cycle, and potential effects of this coccidian parasite on adrenal function.

New disease records for hatchery-reared sturgeon. I. Expansion of frog virus 3 host range into Scaphirhynchus albus.

In 2009, juvenile pallid sturgeon Scaphirhynchus albus, reared at the Blind Pony State Fish Hatchery (Missouri, USA) to replenish dwindling wild stocks, experienced mass mortality. Histological examination revealed extensive necrosis of the haematopoietic tissues, and a virus was isolated from affected organs in cell culture and then observed by electron microscopy. Experimental infection studies revealed that the virus is highly pathogenic to juvenile pallid sturgeon, one of several species of sturgeon currently listed as Endangered. The DNA sequence of the full length major capsid protein gene of the virus was identical to that of the species Frog virus 3 (FV3), the type species for the genus Ranavirus, originally isolated from northern leopard frog Lithobates pipiens. Although FV3 infections and epizootics in amphibians and reptiles are well documented, there is only 1 prior report of a natural infection of FV3 in fish. Our results illustrate the broad potential host range for FV3, with the known potential to cause significant mortality in poikilothermic vertebrates across 3 taxonomic classes including bony fishes, anuran and caudate amphibians, and squamate and testudine reptiles.

Diagnosis and management of Enterococcus spp infections during rehabilitation of cold-stunned Kemp's ridley turtles (Lepidochelys kempii): 50 cases (2006-2012).

OBJECTIVE: To evaluate clinical data for cold-stunned Kemp's ridley turtles (Lepidochelys kempii) with Enterococcus spp infections during rehabilitation. DESIGN: Retrospective case series. ANIMALS: 50 stranded cold-stunned Kemp's ridley turtles hospitalized between 2006 and 2012. PROCEDURES: Medical records for turtles from which Enterococcus spp were isolated were reviewed retrospectively, and clinical data, including morphometric data, body temperature at admission, physical examination findings, antimicrobial medication history, history of medications administered IV, environmental data, day of diagnosis, clinical signs at diagnosis, microbiological testing results, sources of positive culture results, hematologic and plasma biochemical data, cytologic and histopathologic results, radiographic findings, antimicrobial treatments, time to first negative culture result, treatment duration, results of subsequent cultures, and case outcome, were collated and analyzed. RESULTS: Enterococcus spp were isolated from bacteriologic cultures of blood, bone, joint, and respiratory tract samples and a skin lesion, with supporting evidence of infection provided by histopathologic, cytologic, and radiographic data. Positive culture results were associated with clinical problems such as lethargy, anorexia, and lameness. Most (34/43 [79%]) turtles for which an antemortem diagnosis was made survived with treatment and were released into the wild. CONCLUSIONS AND CLINICAL RELEVANCE: Cold-stunned Kemp's ridley turtles may be affected by serious Enterococcus spp infections during rehabilitation. Recognition and treatment of these infections are important for successful rehabilitation.

Intraerythrocytic iridovirus in central bearded dragons (Pogona vitticeps).

Three adult central bearded dragons (Pogona vitticeps) originating from a commercial breeding facility presented with clinical signs, including anorexia, dehydration, white multifocal lesions on the dorsal aspect of the tongue, blepharospasm, and weight loss. In 1 of 3 lizards, a marked regenerative anemia was noted, and all 3 bearded dragons had erythrocytic intracytoplasmic inclusion bodies. Nine bearded dragons housed in contact also had identical, but fewer intraerythrocytic inclusions. Inclusion bodies examined by electron microscopy had particles consistent with iridoviruses. Attempts to culture the virus were unsuccessful; however, amplification and sequencing of regions of the viral DNA polymerase by polymerase chain reaction confirmed the presence of an iridovirus. One of the bearded dragons died, while the 2 others showing clinical signs were euthanized. The remaining 9 infected bearded dragons of the teaching colony were also euthanized. Postmortem examination revealed a moderate, multifocal, lymphoplasmacytic or mononuclear adenitis of the tongue in the 3 bearded dragons, and a lymphohistiocytic hepatitis with bacterial granulomas in 2 lizards.

A veterinary guide to the fish gastrointestinal tract.

For veterinarians to better understand aquatic animal health, the most basic veterinary foundation begins with understanding piscine anatomy and physiology. General observations of fish behavior, anatomy, and food apprehension can provide more valuable diagnostic information than advanced laboratory testing alone. This article highlights anatomic differences of fish species occupying different environmental niches, using a case to show the use of modern veterinary diagnostics, and introduces additional topics in piscine gastroenterology related to toxins, nutrition, probiotics, and infectious diseases.

Fatal hepatic tetratrichomoniasis in a juvenile Waldrapp ibis (Geronticus eremita).

Waldrapp ibis (Geronticus eremita) are a critically endangered species, and there are currently more birds in captivity than in the wild. A juvenile, male Waldrapp ibis housed in a mixed-species exhibit was found dead with no premonitory signs. Necropsy revealed extensive necrotizing hepatitis associated with numerous pleomorphic protozoa that were immunohistochemically reactive with antibodies raised against Tritrichomonas foetus, a parasite of cattle. Electron microscopy confirmed the organisms as members of family Trichomonadidae, and sequence analysis of the first ribosomal internal transcribed spacer region (ITS1), 5.8S ribosomal RNA, and ITS2 regions indicated high genetic similarity (96-97%) to members of the Tetratrichomonas gallinarum complex. The animal was born in captivity, and no introductions in this exhibit had occurred since 2009. Other Waldrapp ibis that had contact with the infected male were negative for flagellate infections by fecal examination, thus cross-species transmission is proposed as the source of infection. The host range of the T. gallinarum complex is very large and although the pathogenicity of its members, especially for wild birds, is controversial, these parasites should be considered as a possible cause of acute mortality in Waldrapp ibis. In addition, immunohistochemistry with T. foetus antibodies and molecular diagnostics may be useful tools for preventative veterinary care of endangered bird populations. A greater understanding of the ecology and pathogenesis of this pathogen may also be vital for screening subclinical captive populations and existing wild populations prior to reintroduction efforts.

Prevalence, distribution, and progression of radiographic abnormalities in the lungs of cold-stunned Kemp's ridley sea turtles (Lepidochelys kempii): 89 cases (2002-2005).

OBJECTIVE: To evaluate the prevalence, distribution, and progression of radiographic abnormalities in the lungs of cold-stunned Kemp's ridley sea turtles (Lepidochelys kempii) and associations between these abnormalities and body weight, carapace length, and hematologic and plasma biochemical variables. DESIGN: Retrospective case series. ANIMALS: 89 cold-stunned juvenile Kemp's ridley sea turtles. PROCEDURES: Medical records were reviewed. Dorsoventral and horizontal beam craniocaudal radiographs were evaluated for the presence, distribution, and progression of lung abnormalities. Turtles were categorized as having radiographically normal or abnormal lungs; those with abnormalities detected were further categorized according to the distribution of abnormalities (left lung, right lung, or both affected). Body weight, carapace length, and hematologic and plasma biochemical data were compared among categories. RESULTS: 48 of 89 (54%) turtles had radiographic abnormalities of the lungs. Unilateral abnormalities of the right or left lung were detected in 14 (16%) and 2 (2%), respectively; both lungs were affected in 32 (36%). Prevalence of unilateral abnormalities was significantly greater for the right lung than for the left lung. Evaluation of follow-up radiographs indicated clinical improvement over time for most (18/31 [58%]) turtles. Prevalence of bilateral radiographic abnormalities was positively correlated with body weight and carapace length. There was no significant association between radiographic category and hematologic or plasma biochemical variables. CONCLUSIONS AND CLINICAL RELEVANCE: Radiographic abnormalities of the lungs were commonly detected in cold-stunned Kemp's ridley turtles. Results of this study may aid clinicians in developing effective diagnostic and treatment plans for these patients.

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

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 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.

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

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 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.

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 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.

Bacterial and parasitic diseases of pet fish.

Bacterial and parasitic diseases are very common problems in pet fish. Diagnostic testing for bacterial and parasitic diseases is simple to do; many tests can be done on ambulatory visits. When logical treatment strategies are initiated and supported by diagnostic testing, a successful outcome is possible. Identification of the correct pathogens also allows an educational opportunity for discussions on prevention and biosecurity practices with clients and although fish are poikilothermic, there are some bacterial and parasitic pathogens that are zoonotic.

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

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 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.

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 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).

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 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.

Fish cardiovascular physiology and disease.

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 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.

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

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 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.

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

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 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.