Publications by authors named "Frances M D Gulland"

108 Publications

Clinical signs, treatment, and outcome for California sea lions (Zalophus californianus) with Sarcocystis-associated polyphasic rhabdomyositis.

J Am Vet Med Assoc 2021 11;259(10):1196-1205

Objective: To describe clinical signs, treatment, and outcome for California sea lions (Zalophus californianus) with Sarcocystis-associated polyphasic rhabdomyositis.

Animals: 38 free-ranging juvenile to adult California sea lions examined at a rehabilitation center in California between September 2015 and December 2017.

Procedures: Medical records at The Marine Mammal Center were reviewed to identify sea lions in which sarcocystosis had been diagnosed.

Results: Clinical signs were highly variable and associated with polyphasic rhabdomyositis attributed to Sarcocystis neurona infection. Generalized severe muscle wasting, respiratory compromise, and regurgitation secondary to megaesophagus were the most profound clinical findings. Respiratory compromise and megaesophagus were associated with a poor prognosis. Eight of the 38 sea lions were treated and released to the wild, and 2 subsequently restranded and were euthanized. Two additional animals received no targeted treatment and were released. The remaining 28 animals were either euthanized or died during treatment.

Conclusions And Clinical Relevance: Results suggested that unlike other marine mammals, which typically develop encephalitis, California sea lions with sarcocystosis often have polyphasic rhabdomyositis with highly variable clinical signs and that extensive diagnostic testing may be required to confirm the diagnosis. Treatment with an antiprotozoal drug in combination with corticosteroids may resolve clinical disease, but the prognosis is guarded.
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http://dx.doi.org/10.2460/javma.20.06.0348DOI Listing
November 2021

Hi-C scaffolded short- and long-read genome assemblies of the California sea lion are broadly consistent for syntenic inference across 45 million years of evolution.

Mol Ecol Resour 2021 Oct 27;21(7):2455-2470. Epub 2021 Jun 27.

Division of Evolutionary Biology, Faculty of Biology, LMU Munich, München, Germany.

With the advent of chromatin-interaction maps, chromosome-level genome assemblies have become a reality for a wide range of organisms. Scaffolding quality is, however, difficult to judge. To explore this gap, we generated multiple chromosome-scale genome assemblies of an emerging wild animal model for carcinogenesis, the California sea lion (Zalophus californianus). Short-read assemblies were scaffolded with two independent chromatin interaction mapping data sets (Hi-C and Chicago), and long-read assemblies with three data types (Hi-C, optical maps and 10X linked reads) following the "Vertebrate Genomes Project (VGP)" pipeline. In both approaches, 18 major scaffolds recovered the karyotype (2n = 36), with scaffold N50s of 138 and 147 Mb, respectively. Synteny relationships at the chromosome level with other pinniped genomes (2n = 32-36), ferret (2n = 34), red panda (2n = 36) and domestic dog (2n = 78) were consistent across approaches and recovered known fissions and fusions. Comparative chromosome painting and multicolour chromosome tiling with a panel of 264 genome-integrated single-locus canine bacterial artificial chromosome probes provided independent evaluation of genome organization. Broad-scale discrepancies between the approaches were observed within chromosomes, most commonly in translocations centred around centromeres and telomeres, which were better resolved in the VGP assembly. Genomic and cytological approaches agreed on near-perfect synteny of the X chromosome, and in combination allowed detailed investigation of autosomal rearrangements between dog and sea lion. This study presents high-quality genomes of an emerging cancer model and highlights that even highly fragmented short-read assemblies scaffolded with Hi-C can yield reliable chromosome-level scaffolds suitable for comparative genomic analyses.
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http://dx.doi.org/10.1111/1755-0998.13443DOI Listing
October 2021

Unlocking the Role of a Genital Herpesvirus, Otarine Herpesvirus 1, in California Sea Lion Cervical Cancer.

Animals (Basel) 2021 Feb 13;11(2). Epub 2021 Feb 13.

Veterinary Sciences, The Marine Mammal Center, Sausalito, CA 94965, USA.

Urogenital carcinoma in California sea lions () is the most common cancer of marine mammals. Primary tumors occur in the cervix, vagina, penis, or prepuce and aggressively metastasize resulting in death. This cancer has been strongly associated with a sexually transmitted herpesvirus, otarine herpesvirus 1 (OtHV1), but the virus has been detected in genital tracts of sea lions without cancer and a causative link has not been established. To determine if OtHV1 has a role in causing urogenital carcinoma we sequenced the viral genome, quantified viral load from cervical tissue from sea lions with ( = 95) and without ( = 163) urogenital carcinoma, and measured viral mRNA expression using in situ mRNA hybridization (Basescope) to quantify and identify the location of OtHV1 mRNA expression. Of the 95 sea lions diagnosed with urogenital carcinoma, 100% were qPCR positive for OtHV1, and 36% of the sea lions with a normal cervix were positive for the virus. The non-cancer OtHV1 positive cases had significantly lower viral loads in their cervix compared to the cervices from sea lions with urogenital carcinoma. The OtHV1 genome had several genes similar to the known oncogenes, and RNA in situ hybridization demonstrated high OtHV1 mRNA expression within the carcinoma lesions but not in normal cervical epithelium. The high viral loads, high mRNA expression of OtHV1 in the cervical tumors, and the presence of suspected OtHV1 oncogenes support the hypothesis that OtHV1 plays a significant role in the development of sea lion urogenital carcinoma.
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http://dx.doi.org/10.3390/ani11020491DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7918579PMC
February 2021

An MRI protocol for anatomical and functional evaluation of the California sea lion brain.

J Neurosci Methods 2021 04 10;353:109097. Epub 2021 Feb 10.

Henry H. Wheeler, Jr. Brain Imaging Center, 188 Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, CA, 94720, USA. Electronic address:

Background: Domoic acid (DOM) is a neurotoxin produced by some harmful algae blooms in coastal waters. California sea lions (Zalophus californianus) exposed to DOM often strand on beaches where they exhibit a variety of symptoms, including seizures. These animals typically show hippocampal atrophy on MRI scans.

New Method: We describe an MRI protocol for comprehensive evaluation of DOM toxicosis in the sea lion brain. We intend to study brain development in pups exposed in utero. The protocol depicts the hippocampal formation as the primary region of interest. We include scans for quantitative morphometry, functional and structural connectivity, and a cerebral blood flow map.

Results: High-resolution 3D anatomical scans facilitate post hoc slicing in arbitrary planes and accurate morphometry. We demonstrate the first cerebral blood flow map using MRI, and the first structural tractography from a live sea lion brain.

Comparison With Existing Methods: Scans were compared to prior anatomical and functional studies in live sea lions, and structural connectivity in post mortem specimens. Hippocampal volumes were broadly in line with prior studies, with differences likely attributable to the 3D approach used here. Functional connectivity of the dorsal left hippocampus matched that found in a prior study conducted at a lower magnetic field, while structural connectivity in the live brain agreed with findings observed in post mortem studies.

Conclusions: Our protocol provides a comprehensive, longitudinal view of the functional and anatomical changes expected to result from DOM toxicosis. It can also screen for other common neurological pathologies and is suitable for any pinniped that can fit inside an MRI scanner.
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http://dx.doi.org/10.1016/j.jneumeth.2021.109097DOI Listing
April 2021

Using PacBio SMRT data for identification of class I MHC alleles in a wildlife species, Zalophus californianus (California sea lion).

Infect Genet Evol 2021 03 31;88:104700. Epub 2020 Dec 31.

Comparative Immunogenetics Laboratory, Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA; Department of Molecular Pathogenesis and Immunology, College of Medicine, Texas A&M Health Science Center, Bryan, TX 77807, USA. Electronic address:

High allelic polymorphism and association with disease susceptibility has made the genes encoding major histocompatibility complex (MHC) antigen presentation molecules in humans, domesticated animals, and wildlife species of wide interest to ecologists, evolutionary biologists, and health specialists. The often multifaceted polygenism and extreme polymorphism of this immunogenetic system have made it especially difficult to characterize in non-model species. Here we compare and contrast the workflows of traditional Sanger sequencing of plasmid-cloned amplicons to Pacific Biosciences SMRT circular consensus sequencing (CCS) in their ability to capture alleles of MHC class I in a wildlife species where characterization of these genes was absent. We assessed two California sea lions (Zalophus californianus), a species suffering from a high prevalence of an aggressive cancer associated with a sexually transmitted gamma herpesvirus. In this pilot study, SMRT CCS proved superior in identifying more alleles from each animal than the more laborious plasmid cloning/Sanger workflow (12:7, 10:7), and no alleles were identified with the cloning/Sanger approach that were not identified by SMRT CCS. We discuss the advantages and disadvantages of each approach including cost, allele rarefaction, and sequence fidelity.
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http://dx.doi.org/10.1016/j.meegid.2020.104700DOI Listing
March 2021

Assessment of clinical outcomes associated with mercury concentrations in harbor seal pups (Phoca vitulina richardii) in central California.

Sci Total Environ 2021 Mar 24;758:143686. Epub 2020 Nov 24.

Department of Veterinary Medicine, University of Alaska Fairbanks, 2141 Koyokuk Dr, Fairbanks, AK 99775-7750, USA; Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA.

Monomethyl mercury (MeHg) from the diet can cause mild to severe neurotoxicosis in fish-eating mammals. Chronic and low-level in utero exposure also can be neurotoxic, as documented in laboratory animal studies and epidemiologic investigations. In free-ranging animals, it is challenging to study low-level exposure related neurotoxicosis, and few studies have investigated the relationship between mercury (Hg) and adverse outcomes in wild populations. Relative to Hg concentrations on admission we evaluated different types of behaviors for 267 Pacific harbor seal (HS; Phoca vitulina richardii) pups at The Marine Mammal Center from 2015 to 2019 during rehabilitation after stranding and maternal separation. Admitted HS pups underwent a clinical exam; including sex and weight determination, and hair (partly lanugo grown in utero) and blood samples were collected for total Hg concentration ([THg]) determination. All pups were monitored weekly (behavior assessments included response to tactile stimulation, movement, swimming, interactions with other seals, hand feeding, and feeding independently), and days in rehabilitation and survival were recorded. There was a significant negative correlation between [THg] and responses to tactile stimulation and movements, measured in both hair and whole blood (p < 0.05). This relationship was found both during the intensive care unit (ICU) stage, and during the pool stage of rehabilitation. Additionally, there was a significant association between greater [THg] and number of days spent in rehabilitation, although there was no relationship between [THg] and survival. There was a significant sex difference, with greater [THg] in female pups, which contrasts with previously published findings in juvenile and adult harbor seals. Our findings support small, but significant associations between gestational THg exposure and clinical effects for tactile sensory response and movement, and longer rehabilitation durations for HS pups, although there was considerable variability among animals.
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http://dx.doi.org/10.1016/j.scitotenv.2020.143686DOI Listing
March 2021

Pathology findings and correlation with body condition index in stranded killer whales (Orcinus orca) in the northeastern Pacific and Hawaii from 2004 to 2013.

PLoS One 2020 2;15(12):e0242505. Epub 2020 Dec 2.

The SeaDoc Society, Karen C. Drayer Wildlife Health Center - Orcas Island Office, UC Davis School of Veterinary Medicine, Eastsound, Washington, United States of America.

Understanding health and mortality in killer whales (Orcinus orca) is crucial for management and conservation actions. We reviewed pathology reports from 53 animals that stranded in the eastern Pacific Ocean and Hawaii between 2004 and 2013 and used data from 35 animals that stranded from 2001 to 2017 to assess association with morphometrics, blubber thickness, body condition and cause of death. Of the 53 cases, cause of death was determined for 22 (42%) and nine additional animals demonstrated findings of significant importance for population health. Causes of calf mortalities included infectious disease, nutritional, and congenital malformations. Mortalities in sub-adults were due to trauma, malnutrition, and infectious disease and in adults due to bacterial infections, emaciation and blunt force trauma. Death related to human interaction was found in every age class. Important incidental findings included concurrent sarcocystosis and toxoplasmosis, uterine leiomyoma, vertebral periosteal proliferations, cookiecutter shark (Isistius sp.) bite wounds, excessive tooth wear and an ingested fish hook. Blubber thickness increased significantly with body length (all p < 0.001). In contrast, there was no relationship between body length and an index of body condition (BCI). BCI was higher in animals that died from trauma. This study establishes a baseline for understanding health, nutritional status and causes of mortality in stranded killer whales. Given the evidence of direct human interactions on all age classes, in order to be most successful recovery efforts should address the threat of human interactions, especially for small endangered groups of killer whales that occur in close proximity to large human populations, interact with recreational and commercial fishers and transit established shipping lanes.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0242505PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7710042PMC
January 2021

Reference genome and demographic history of the most endangered marine mammal, the vaquita.

Mol Ecol Resour 2021 May 20;21(4):1008-1020. Epub 2020 Nov 20.

Marine Mammal Research, Department of Bioscience, Aarhus University, Roskilde, Denmark.

The vaquita is the most critically endangered marine mammal, with fewer than 19 remaining in the wild. First described in 1958, the vaquita has been in rapid decline for more than 20 years resulting from inadvertent deaths due to the increasing use of large-mesh gillnets. To understand the evolutionary and demographic history of the vaquita, we used combined long-read sequencing and long-range scaffolding methods with long- and short-read RNA sequencing to generate a near error-free annotated reference genome assembly from cell lines derived from a female individual. The genome assembly consists of 99.92% of the assembled sequence contained in 21 nearly gapless chromosome-length autosome scaffolds and the X-chromosome scaffold, with a scaffold N50 of 115 Mb. Genome-wide heterozygosity is the lowest (0.01%) of any mammalian species analysed to date, but heterozygosity is evenly distributed across the chromosomes, consistent with long-term small population size at genetic equilibrium, rather than low diversity resulting from a recent population bottleneck or inbreeding. Historical demography of the vaquita indicates long-term population stability at less than 5,000 (Ne) for over 200,000 years. Together, these analyses indicate that the vaquita genome has had ample opportunity to purge highly deleterious alleles and potentially maintain diversity necessary for population health.
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http://dx.doi.org/10.1111/1755-0998.13284DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8247363PMC
May 2021

Complex Virome in a Mesenteric Lymph Node from a Californian Sea Lion ( with Polyserositis and Steatitis.

Viruses 2020 07 23;12(8). Epub 2020 Jul 23.

Vitalant Research Institute, 270 Masonic Ave, San Francisco, CA 94118, USA.

An emaciated subadult free-ranging California sea lion (Csl or died following stranding with lesions similar to 11 other stranded animals characterized by chronic disseminated granulomatous inflammation with necrotizing steatitis and vasculitis, involving visceral adipose tissues in the thoracic and peritoneal cavities. Histologically, affected tissues had extensive accumulations of macrophages with perivascular lymphocytes, plasma cells, and fewer neutrophils. Using viral metagenomics on a mesenteric lymph node six mammalian viruses were identified consisting of novel parvovirus, polyomavirus, rotavirus, anellovirus, and previously described Csl adenovirus 1 and Csl bocavirus 4. The causal or contributory role of these viruses to the gross and histologic lesions of this sea lion remains to be determined.
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http://dx.doi.org/10.3390/v12080793DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7472147PMC
July 2020

Linking longitudinal and cross-sectional biomarker data to understand host-pathogen dynamics: Leptospira in California sea lions (Zalophus californianus) as a case study.

PLoS Negl Trop Dis 2020 06 29;14(6):e0008407. Epub 2020 Jun 29.

Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, United States of America.

Confronted with the challenge of understanding population-level processes, disease ecologists and epidemiologists often simplify quantitative data into distinct physiological states (e.g. susceptible, exposed, infected, recovered). However, data defining these states often fall along a spectrum rather than into clear categories. Hence, the host-pathogen relationship is more accurately defined using quantitative data, often integrating multiple diagnostic measures, just as clinicians do to assess their patients. We use quantitative data on a major neglected tropical disease (Leptospira interrogans) in California sea lions (Zalophus californianus) to improve individual-level and population-level understanding of this Leptospira reservoir system. We create a "host-pathogen space" by mapping multiple biomarkers of infection (e.g. serum antibodies, pathogen DNA) and disease state (e.g. serum chemistry values) from 13 longitudinally sampled, severely ill individuals to characterize changes in these values through time. Data from these individuals describe a clear, unidirectional trajectory of disease and recovery within this host-pathogen space. Remarkably, this trajectory also captures the broad patterns in larger cross-sectional datasets of 1456 wild sea lions in all states of health but sampled only once. Our framework enables us to determine an individual's location in their time-course since initial infection, and to visualize the full range of clinical states and antibody responses induced by pathogen exposure. We identify predictive relationships between biomarkers and outcomes such as survival and pathogen shedding, and use these to impute values for missing data, thus increasing the size of the useable dataset. Mapping the host-pathogen space using quantitative biomarker data enables more nuanced understanding of an individual's time course of infection, duration of immunity, and probability of being infectious. Such maps also make efficient use of limited data for rare or poorly understood diseases, by providing a means to rapidly assess the range and extent of potential clinical and immunological profiles. These approaches yield benefits for clinicians needing to triage patients, prevent transmission, and assess immunity, and for disease ecologists or epidemiologists working to develop appropriate risk management strategies to reduce transmission risk on a population scale (e.g. model parameterization using more accurate estimates of duration of immunity and infectiousness) and to assess health impacts on a population scale.
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http://dx.doi.org/10.1371/journal.pntd.0008407DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7351238PMC
June 2020

HAIR, WHOLE BLOOD, AND BLOOD-SOAKED CELLULOSE PAPER-BASED RISK ASSESSMENT OF MERCURY CONCENTRATIONS IN STRANDED CALIFORNIA PINNIPEDS.

J Wildl Dis 2019 10 13;55(4):823-833. Epub 2019 May 13.

Department of Veterinary Medicine, College of Natural Science and Mathematics, University of Alaska Fairbanks, PO Box 757750, Fairbanks, Alaska 99775, USA.

Mercury (Hg) poses a health risk to wildlife populations and has been documented at relatively high concentrations in many marine mammals, including wild-caught pinnipeds along the central California, US coast. We measured total Hg concentrations ([THg]) in hair and blood of live-stranded harbor seals (HS; ), California sea lions (CSL; ), and northern elephant seals (NES; ) in California to quantify species, temporal, and spatial variability in [THg] and assess the relationships between [THg] measured by different methods (blood vs. filter paper) and in different matrices (blood vs. hair). We compared [THg] with toxicologic thresholds of concern to aid in identification of at-risk individuals or groups and better understand how the use of different methods and matrices affects assumed toxicologic risk. There was a wide range of [THg] in blood (<0.01-1.13 μg/g) and hair (0.45-81.98 μg/g), and NES had higher [THg] compared with HS and CSL. All three species had individuals with [THg] that exceeded the lower threshold for one or both matrices, but only HS pups had [THg] exceeding upper thresholds. Spatial differences in [THg] were detected, with higher concentrations in HS pups from areas surrounding San Francisco Bay, but differences were dependent on sampling year and matrix. The relationship between [THg] in blood and filter paper (=0.98) was strong, and differences had little influence on comparisons with toxicologic thresholds. Blood and hair [THg] were generally in agreement (=0.72), but large mismatches for a few seals underscore the importance of combined sampling in adverse effects studies where accurate assessment of Hg exposure is crucial. The wide range of [THg] in stranded HS pups that exceeded published thresholds of concern makes them a promising candidate for adverse effects studies, particularly because different matrices represent Hg exposure across key developmental stages.
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October 2019

Proportional loss of parvalbumin-immunoreactive synaptic boutons and granule cells from the hippocampus of sea lions with temporal lobe epilepsy.

J Comp Neurol 2019 10 22;527(14):2341-2355. Epub 2019 Mar 22.

Department of Comparative Medicine, Stanford University, Stanford, California.

One in 26 people develop epilepsy and in these temporal lobe epilepsy (TLE) is common. Many patients display a pattern of neuron loss called hippocampal sclerosis. Seizures usually start in the hippocampus but underlying mechanisms remain unclear. One possibility is insufficient inhibition of dentate granule cells. Normally parvalbumin-immunoreactive (PV) interneurons strongly inhibit granule cells. Humans with TLE display loss of PV interneurons in the dentate gyrus but questions persist. To address this, we evaluated PV interneuron and bouton numbers in California sea lions (Zalophus californianus) that naturally develop TLE after exposure to domoic acid, a neurotoxin that enters the marine food chain during harmful algal blooms. Sclerotic hippocampi were identified by the loss of Nissl-stained hilar neurons. Stereological methods were used to estimate the number of granule cells and PV interneurons per dentate gyrus. Sclerotic hippocampi contained fewer granule cells, fewer PV interneurons, and fewer PV synaptic boutons, and the ratio of granule cells to PV interneurons was higher than in controls. To test whether fewer boutons was attributable to loss versus reduced immunoreactivity, expression of synaptotagmin-2 (syt2) was evaluated. Syt2 is also expressed in boutons of PV interneurons. Sclerotic hippocampi displayed proportional losses of syt2-immunoreactive boutons, PV boutons, and granule cells. There was no significant difference in the average numbers of PV- or syt2-positive boutons per granule cell between control and sclerotic hippocampi. These findings do not address functionality of surviving synapses but suggest reduced granule cell inhibition in TLE is not attributable to anatomical loss of PV boutons.
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http://dx.doi.org/10.1002/cne.24680DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6656599PMC
October 2019

Domoic acid in California sea lion fetal fluids indicates continuous exposure to a neuroteratogen poses risks to mammals.

Harmful Algae 2018 11 7;79:53-57. Epub 2018 Jul 7.

The Marine Mammal Center, 2000 Bunker Road, Sausalito, CA 94965, United States.

Domoic acid (DA) is a neuroexcitotoxic amino acid that is naturally produced by some species of marine diatoms during harmful algal blooms (HABs). The toxin is transferred through the food web from plantivorous fish and shellfish to marine mammals resulting in significant morbidity and mortality. Due to the timing and location of DA producing HABs, it is well documented that pregnant female California sea lions (CSL) are regularly exposed to DA through their diet thereby posing exposure risks to a neuroteratogen in developing fetuses. In the present study, fluids from 36 fetuses sampled from naturally exposed pregnant CSLs were examined for DA. Domoic acid was detected in 79% of amniotic fluid (n = 24), 67% of allantoic fluid (n = 9), 75% of urine (n = 4), 41% of meconium (n = 17) and 29% of stomach content (n = 21) samples opportunistically collected from CSL fetuses. The distribution of DA in fetal samples indicates an increased prenatal exposure risk due to recirculation of DA in fetal fluids and continuous exposure to the developing brain.
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http://dx.doi.org/10.1016/j.hal.2018.06.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7297052PMC
November 2018

Ecotoxicoparasitology of the gastrointestinal tracts of pinnipeds: the effect of parasites on the potential bioavailability of total mercury (THg).

Sci Total Environ 2018 Aug 16;631-632:233-238. Epub 2018 Mar 16.

Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA.

Acanthocephalans, cestodes, and some species of nematodes acquire nutrients from the lumen contents in the gastrointestinal (GI) tract of their definitive host. These parasites are exposed to toxicants, such as mercury (Hg), through passive or active feeding mechanisms; therefore, the focus of this study was to determine if there is an effect of parasites on the dietary availability of total mercury (THg) within piscivorous pinniped hosts. THg concentrations ([THg]) in selected host tissues, parasites, and GI lumen contents from 22 California sea lions (Zalophus californianus), 15 ringed seals (Phoca hispida), and 4 spotted seals (Phoca largha) were determined. Among all pinnipeds, [THg] in acanthocephalans of the large intestine were significantly higher than concentrations in other samples (host lumen contents, other parasites and host intestinal wall), irrespective of location within the host GI tract. δN values of parasites depended both on parasite group and location within the GI tract. δN values were consistently higher in parasites inhabiting the large intestine, compared to elsewhere in the GI tract, for both sea lions and seals. δC values in parasites did not differ significantly from host GI tissues. Based on both [THg] and stable isotope values, parasites are likely affecting the Hg bioavailability within the GI lumen contents and host tissues, and toxicant-parasite interactions appear to depend on both parasitic taxon as well as their location within the host intestine.
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http://dx.doi.org/10.1016/j.scitotenv.2018.02.173DOI Listing
August 2018

Prevalence of Urogenital Carcinoma in Stranded California Sea Lions ( Zalophus californianus) from 2005-15.

J Wildl Dis 2018 07 2;54(3):581-586. Epub 2018 Mar 2.

2 The Marine Mammal Center, 2000 Bunker Road, Sausalito, California 94965, USA.

Urogenital carcinoma is common in wild California sea lions ( Zalophus californianus) along the west coast of the US. From 1979 to 1994, this cancer was observed in 18% (66/370) of necropsied subadult and adult sea lions at The Marine Mammal Center in Sausalito, California. A retrospective review of records from 1 January 2005 to 31 December 2015 was performed to characterize prevalence and characteristics of cancer over this decade. Fourteen percent (263/1917) of necropsied sea lions had cancer, of which 90% (237/263) were urogenital carcinoma. The prevalence of urogenital carcinoma was significantly higher in adults compared to juveniles and subadults. Advanced-stage disease with metastases was identified histologically in 78% (182/232) of cases and was the cause of death in 95% (172/182) of these cases. Metastases were most common in lung and lymph nodes, and hydronephrosis, secondary to ureter obstruction by metastases, was identified in 62% (114/185) of animals with advanced disease. No significant temporal change in prevalence was detected over the decade, and this highly aggressive, fatal cancer remains common in stranded California sea lions.
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http://dx.doi.org/10.7589/2017-08-208DOI Listing
July 2018

MHC class II DRB diversity predicts antigen recognition and is associated with disease severity in California sea lions naturally infected with Leptospira interrogans.

Infect Genet Evol 2018 01 26;57:158-165. Epub 2017 Nov 26.

USGS Western Ecological Research Center, 1 Shields Ave., University of California, Davis, CA 95616-5224, USA.

We examined the associations between California sea lion MHC class II DRB (Zaca-DRB) configuration and diversity, and leptospirosis. As Zaca-DRB gene sequences are involved with antigen presentation of bacteria and other extracellular pathogens, we predicted that they would play a role in determining responses to these pathogenic spirochaetes. Specifically, we investigated whether Zaca-DRB diversity (number of genes) and configuration (presence of specific genes) explained differences in disease severity, and whether higher levels of Zaca-DRB diversity predicted the number of specific Leptospira interrogans serovars that a sea lion's serum would react against. We found that serum from diseased sea lions with more Zaca-DRB loci reacted against a wider array of serovars. Specific Zaca-DRB loci were linked to reactions with particular serovars. Interestingly, sea lions with clinical manifestation of leptospirosis that had higher numbers of Zaca-DRB loci were less likely to recover from disease than those with lower diversity, and those that harboured Zaca-DRB.C or -G were 4.5 to 5.3 times more likely to die from leptospirosis, regardless of the infective serovars. We propose that for leptospirosis, a disadvantage of having a wider range of antigen presentation might be increased disease severity due to immunopathology. Ours is the first study to examine the importance of Zaca-DRB diversity for antigen detection and disease severity following natural exposure to infective leptospires.
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http://dx.doi.org/10.1016/j.meegid.2017.11.023DOI Listing
January 2018

No evidence for clonal transmission of urogenital carcinoma in California sea lions ( ).

Wellcome Open Res 2017 22;2:46. Epub 2017 Jun 22.

Transmissible Cancer Group, Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES, UK.

Urogenital carcinoma is a highly metastatic cancer affecting California sea lions ( ). The disease has high prevalence amongst stranded animals, and is one of the most commonly observed cancers in wildlife. The genital localisation of primary tumours suggests the possibility that coital transmission of an infectious agent could underlie this disease. Otarine herpesvirus type 1 has been associated with lesions, however a causative role for this virus has not been confirmed. We investigated the possibility that urogenital carcinoma might be clonally transmissible, spread by the direct transfer of cancer cells. Analysis of sequences at the mitochondrial DNA control region in seven matched tumour and host pairs confirmed that tumour genotypes were identical to those of their matched hosts and did not show similarity with tumours from other individuals. Thus our findings suggest that urogenital carcinoma in California sea lions is not clonally transmitted, but rather arises from transformed host cells.
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http://dx.doi.org/10.12688/wellcomeopenres.11483.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5527528PMC
June 2017

MODELING A MORBILLIVIRUS OUTBREAK IN HAWAIIAN MONK SEALS (NEOMONACHUS SCHAUINSLANDI) TO AID IN THE DESIGN OF MITIGATION PROGRAMS.

J Wildl Dis 2017 10 2;53(4):736-748. Epub 2017 May 2.

1   Pacific Islands Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 1845 Wasp Boulevard, No. 176, Honolulu, Hawaii 96818, USA.

We developed a stochastic susceptible-exposed-infectious-removed (SEIR) model to simulate a range of plausible morbillivirus outbreak scenarios in a randomly mixing population of 170 endangered Hawaiian monk seals (Neomonachus schauinslandi). We then modeled realistic vaccination and quarantine measures to determine the potential efficacy of such mitigation efforts. Morbillivirus outbreaks represent substantial risk to monk seals-91% of simulated baseline outbreaks grew (R>1), and in one-third of the scenarios all, or nearly all, individuals were infected. Simulated vaccination efforts in response to an outbreak were not effective in substantially reducing infections, largely because of the prolonged interval between vaccination and immunity. Prophylactic vaccination, in contrast, could be an effective tool for preventing outbreaks. Herd immunity is practically achievable because of the small sizes of monk seal populations and the animals' accessibility on shore. Adding realistic spatial structure to the model, as informed by movement of seals tracked in the main Hawaiian Islands with the use of telemetry, greatly reduced the simulated impact of outbreaks (≤10 seals were infected in 62% of spatially structured simulations). Although response vaccination remained relatively ineffective, spatial segregation allowed herd immunity to be achieved through prophylactic vaccination with less effort. In a randomly mixing population of 170 seals, 86% would need to be vaccinated to achieve herd immunity in 95% of simulated outbreaks, compared to only approximately 60% in three spatially segregated subgroups with the same combined abundance. Simulations indicate that quarantining a modest number (up to 20) of ill seals has the potential to extinguish even fast-growing outbreaks rapidly. The efficacy of quarantine, however, is highly dependent upon rapid detection and response. We conclude that prophylactic vaccination combined with a quarantine program supported by vigilant surveillance and rapid, reliable diagnosis could greatly mitigate the threat of a morbillivirus outbreak in Hawaiian monk seals.
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http://dx.doi.org/10.7589/2016-10-238DOI Listing
October 2017

Detecting signals of chronic shedding to explain pathogen persistence: Leptospira interrogans in California sea lions.

J Anim Ecol 2017 May 3;86(3):460-472. Epub 2017 Apr 3.

Department of Ecology and Evolutionary Biology, University of California - Los Angeles, Los Angeles, CA, USA.

Identifying mechanisms driving pathogen persistence is a vital component of wildlife disease ecology and control. Asymptomatic, chronically infected individuals are an oft-cited potential reservoir of infection, but demonstrations of the importance of chronic shedding to pathogen persistence at the population-level remain scarce. Studying chronic shedding using commonly collected disease data is hampered by numerous challenges, including short-term surveillance that focuses on single epidemics and acutely ill individuals, the subtle dynamical influence of chronic shedding relative to more obvious epidemic drivers, and poor ability to differentiate between the effects of population prevalence of chronic shedding vs. intensity and duration of chronic shedding in individuals. We use chronic shedding of Leptospira interrogans serovar Pomona in California sea lions (Zalophus californianus) as a case study to illustrate how these challenges can be addressed. Using leptospirosis-induced strands as a measure of disease incidence, we fit models with and without chronic shedding, and with different seasonal drivers, to determine the time-scale over which chronic shedding is detectable and the interactions between chronic shedding and seasonal drivers needed to explain persistence and outbreak patterns. Chronic shedding can enable persistence of L. interrogans within the sea lion population. However, the importance of chronic shedding was only apparent when surveillance data included at least two outbreaks and the intervening inter-epidemic trough during which fadeout of transmission was most likely. Seasonal transmission, as opposed to seasonal recruitment of susceptibles, was the dominant driver of seasonality in this system, and both seasonal factors had limited impact on long-term pathogen persistence. We show that the temporal extent of surveillance data can have a dramatic impact on inferences about population processes, where the failure to identify both short- and long-term ecological drivers can have cascading impacts on understanding higher order ecological phenomena, such as pathogen persistence.
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http://dx.doi.org/10.1111/1365-2656.12656DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7166352PMC
May 2017

Development and validation of a quantitative PCR for rapid and specific detection of California sea lion adenovirus 1 and prevalence in wild and managed populations.

J Vet Diagn Invest 2017 Mar 6;29(2):193-197. Epub 2017 Feb 6.

Departments of Small Animal Clinical Sciences (Cortes-Hinojosa, Archer, Wellehan) and Infectious Diseases and Pathology (Waltzek), College of Veterinary Medicine, University of Florida, Gainesville, FL.

California sea lion adenovirus 1 (CSLAdV-1) has been associated with hepatitis and enteritis in several wild and captive populations of diverse pinniped species. Currently available tests have been limited to pan-adenoviral polymerase chain reaction (PCR) followed by sequencing. We present the development of a quantitative probe-hybridization PCR (qPCR) assay for rapid, sensitive, and specific detection of this virus in California sea lions ( Zalophus californianus) and other pinnipeds. This assay did not amplify other mammalian adenoviruses and is able to detect consistently down to 10 viral copies per well. Compared with the gold standard conventional pan-adenovirus PCR/sequencing assay, diagnostic sensitivity and specificity of 100% and 88.2% were found, respectively. The lower diagnostic specificity of this qPCR assay may be the result of the lower limit of detection of this assay compared with the gold standard rather than the result of detection of true false-positives.
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http://dx.doi.org/10.1177/1040638716689113DOI Listing
March 2017

ISOLATION AND CHARACTERIZATION OF A NOVEL MARINE BRUCELLA FROM A SOUTHERN SEA OTTER (ENHYDRA LUTRIS NEREIS), CALIFORNIA, USA.

J Wildl Dis 2017 04 2;53(2):215-227. Epub 2017 Feb 2.

2   Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, One Shields Avenue, Davis, California 95616, USA.

We characterize Brucella infection in a wild southern sea otter ( Enhydra lutris nereis) with osteolytic lesions similar to those reported in other marine mammals and humans. This otter stranded twice along the central California coast, US over a 1-yr period and was handled extensively at two wildlife rehabilitation facilities, undergoing multiple surgeries and months of postsurgical care. Ultimately the otter was euthanized due to severe, progressive neurologic disease. Necropsy and postmortem radiographs revealed chronic, severe osteoarthritis spanning the proximal interphalangeal joint of the left hind fifth digit. Numerous coccobacilli within the joint were strongly positive on Brucella immunohistochemical labelling, and Brucella sp. was isolated in pure culture from this lesion. Sparse Brucella-immunopositive bacteria were also observed in the cytoplasm of a pulmonary vascular monocyte, and multifocal granulomas were observed in the spinal cord and liver on histopathology. Findings from biochemical characterization, 16S ribosomal DNA, and bp26 gene sequencing of the bacterial isolate were identical to those from marine-origin brucellae isolated from cetaceans and phocids. Although omp2a gene sequencing revealed 100% homology with marine Brucella spp. infecting pinnipeds, whales, and humans, omp2b gene sequences were identical only to pinniped-origin isolates. Multilocus sequence typing classified the sea otter isolate as ST26, a sequence type previously associated only with cetaceans. Our data suggest that the sea otter Brucella strain represents a novel marine lineage that is distinct from both Brucella pinnipedialis and Brucella ceti. Prior reports document the zoonotic potential of the marine brucellae. Isolation of Brucella sp. from a stranded sea otter highlights the importance of wearing personal protective equipment when handling sea otters and other marine mammals as part of wildlife conservation and rehabilitation efforts.
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http://dx.doi.org/10.7589/2015-12-326DOI Listing
April 2017

Cetacean Morbillivirus in Odontocetes Stranded along the Central California Coast, USA, 2000-15.

J Wildl Dis 2017 04 25;53(2):386-392. Epub 2017 Jan 25.

1 Marine Mammal Center, 2000 Bunker Road, Sausalito, California 94965, USA.

Effects of cetacean morbillivirus (CeMV) on dolphins vary from causing epidemics to subclinical infections. The former have been documented in the North Atlantic Ocean and Mediterranean Sea but not in the North Pacific Ocean, and the reasons for this are unknown. To explore the distribution of this virus in areas that have not experienced epidemics, we reviewed evidence for morbilliviral infection in odontocetes stranded along the California coast, US from 2000-15. Nine of 212 animals examined histologically had lesions compatible with morbilliviral infection, and 11 were tested for CeMV via reverse transcriptase-PCR. One striped dolphin ( Stenella coeruleoalba ) was PCR positive, and the sequenced product was most closely related to sequences in two strains found in cetaceans in Hawaii. This study suggests that CeMV may be a cause of morbidity and a rare contributor to mortality in cetaceans stranding along the California coast. Additional work is needed to understand CeMV distribution and host species susceptibility in this region.
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http://dx.doi.org/10.7589/2016-09-219DOI Listing
April 2017

An unprecedented coastwide toxic algal bloom linked to anomalous ocean conditions.

Geophys Res Lett 2016 Oct 9;43(19):10366-10376. Epub 2016 Oct 9.

Northwest Fisheries Science Center, National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington USA.

A coastwide bloom of the toxigenic diatom in spring 2015 resulted in the largest recorded outbreak of the neurotoxin, domoic acid, along the North American west coast. Elevated toxins were measured in numerous stranded marine mammals and resulted in geographically extensive and prolonged closures of razor clam, rock crab, and Dungeness crab fisheries. We demonstrate that this outbreak was initiated by anomalously warm ocean conditions. thrived north of its typical range in the warm, nutrient-poor water that spanned the northeast Pacific in early 2015. The seasonal transition to upwelling provided the nutrients necessary for a large-scale bloom; a series of spring storms delivered the bloom to the coast. Laboratory and field experiments confirming maximum growth rates with elevated temperatures and enhanced toxin production with nutrient enrichment, together with a retrospective analysis of toxic events, demonstrate the potential for similarly devastating ecological and economic disruptions in the future.
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http://dx.doi.org/10.1002/2016GL070023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5129552PMC
October 2016

Managing marine disease emergencies in an era of rapid change.

Philos Trans R Soc Lond B Biol Sci 2016 Mar;371(1689)

Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA.

Infectious marine diseases can decimate populations and are increasing among some taxa due to global change and our increasing reliance on marine environments. Marine diseases become emergencies when significant ecological, economic or social impacts occur. We can prepare for and manage these emergencies through improved surveillance, and the development and iterative refinement of approaches to mitigate disease and its impacts. Improving surveillance requires fast, accurate diagnoses, forecasting disease risk and real-time monitoring of disease-promoting environmental conditions. Diversifying impact mitigation involves increasing host resilience to disease, reducing pathogen abundance and managing environmental factors that facilitate disease. Disease surveillance and mitigation can be adaptive if informed by research advances and catalysed by communication among observers, researchers and decision-makers using information-sharing platforms. Recent increases in the awareness of the threats posed by marine diseases may lead to policy frameworks that facilitate the responses and management that marine disease emergencies require.
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http://dx.doi.org/10.1098/rstb.2015.0364DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4760146PMC
March 2016

Algal toxin impairs sea lion memory and hippocampal connectivity, with implications for strandings.

Science 2015 Dec 14;350(6267):1545-7. Epub 2015 Dec 14.

Dynamic Memory Lab, Center for Neuroscience, University of California-Davis, Davis, CA 95618, USA.

Domoic acid (DA) is a naturally occurring neurotoxin known to harm marine animals. DA-producing algal blooms are increasing in size and frequency. Although chronic exposure is known to produce brain lesions, the influence of DA toxicosis on behavior in wild animals is unknown. We showed, in a large sample of wild sea lions, that spatial memory deficits are predicted by the extent of right dorsal hippocampal lesions related to natural exposure to DA and that exposure also disrupts hippocampal-thalamic brain networks. Because sea lions are dynamic foragers that rely on flexible navigation, impaired spatial memory may affect survival in the wild.
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http://dx.doi.org/10.1126/science.aac5675DOI Listing
December 2015

A Systematic Review of Changes in Marine Mammal Health in North America, 1972-2012: The Need for a Novel Integrated Approach.

PLoS One 2015 18;10(11):e0142105. Epub 2015 Nov 18.

Office of Protected Resources, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Silver Spring, Maryland, United States of America.

Marine mammals are often cited as "sentinels of ocean health" yet accessible, synthesized data on their health changes that could effectively warn of ocean health changes are rare. The objectives of this study were to 1) perform a systematic review of published cases of marine mammal disease to determine spatial and temporal trends in disease from 1972-2012, including changes in regions and taxa affected and specific causes; and 2) compare numbers of published cases of neoplasia with known, hospital-based neoplasia records to explore the causes of discrepancy between numbers of published cases and true disease trends. Peer-reviewed literature was compiled, and data were collected from The Marine Mammal Center database in Sausalito, California for comparison of numbers of neoplasia cases. Toxicoses from harmful algal blooms appear to be increasing. Viral epidemics are most common along the Atlantic U.S. coastline, while bacterial epidemics, especially leptospirosis, are most common along the Pacific coast. Certain protozoal and fungal zoonoses appear to be emerging, such as Toxoplasma gondii in southern sea otters in California, and Cryptococcus gattii in cetaceans in the Pacific Northwest. Disease reports were most common from California where pinniped populations are large, but increased effort also occurs. Anthropogenic trauma remains a large threat to marine mammal health, through direct mortality and indirect chronic disease. Neoplasia cases were under-reported from 2003-2012 when compared to true number of cases, and over-reported in several years due to case duplication. Peer-reviewed literature greatly underestimates the true magnitude of disease in marine mammals as it focuses on novel findings, fails to reflect etiology of multifactorial diseases, rarely reports prevalence rather than simple numbers of cases, and is typically presented years after a disease first occurs. Thus literature cannot guide management actions adequately, nor inform indices of ocean health. A real-time, nationally centralized system for reporting marine mammal disease data is needed to be able to understand how marine mammal diseases are changing with ecosystem changes, and before these animals can truly be considered 'sentinels of ocean health'.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0142105PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4651562PMC
June 2016

A NOVEL GAMMAHERPESVIRUS IN NORTHERN FUR SEALS (CALLORHINUS URSINUS) IS CLOSELY RELATED TO THE CALIFORNIA SEA LION (ZALOPHUS CALIFORNIANUS) CARCINOMA-ASSOCIATED OTARINE HERPESVIRUS-1.

J Wildl Dis 2016 Jan 10;52(1):88-95. Epub 2015 Nov 10.

1  Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, 2015 SW 16th Ave., PO Box 100126, Gainesville, Florida 32610, USA.

Otarine herpesvirus 1 (OtHV1) is strongly associated with California sea lion (CSL, Zalophus californianus) urogenital carcinoma, the most common cancer documented in marine mammals. In addition to CSL, OtHV1 has also been found in association with carcinoma in South American fur seals (Arctocephalus australis), demonstrating it can infect related species. Northern fur seals (NFS, Callorhinus ursinus) are sympatric with CSL, and copulation between these species has been observed; yet, there are no reports of urogenital carcinoma in NFS. We describe a new Otarine herpesvirus found in vaginal swabs from NFS, herein called OtHV4. Partial sequencing of the polymerase gene and the glycoprotein B gene revealed OtHV4 is closely related to OtHV1, with 95% homology in the region of polymerase sequenced, and phylogenetic analyses demonstrate that they are sister taxa. An OtHV4-specific hydrolysis probe quantitative PCR was developed and validated, and its use on vaginal swabs revealed 16 of 50 (32%) wild adult female NFS were positive for OtHV4. The identification of a virus highly similar to the carcinoma-associated OtHV1 in a sympatric species without carcinoma suggests that comparative genomics of OtHV1 and OtHV4 may identify candidate viral oncogenes.
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http://dx.doi.org/10.7589/2015-03-060DOI Listing
January 2016

Proteomic analysis of cerebrospinal fluid in California sea lions (Zalophus californianus) with domoic acid toxicosis identifies proteins associated with neurodegeneration.

Proteomics 2015 Dec 13;15(23-24):4051-63. Epub 2015 Oct 13.

Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, USA.

Proteomic studies including marine mammals are rare, largely due to the lack of fully sequenced genomes. This has hampered the application of these techniques toward biomarker discovery efforts for monitoring of health and disease in these animals. We conducted a pilot label-free LC-MS/MS study to profile and compare the cerebrospinal fluid from California sea lions with domoic acid toxicosis (DAT) and without DAT. Across 11 samples, a total of 206 proteins were identified (FDR<0.1) using a composite mammalian database. Several peptide identifications were validated using stable isotope labeled peptides. Comparison of spectral counts revealed seven proteins that were elevated in the cerebrospinal fluid from sea lions with DAT: complement C3, complement factor B, dickkopf-3, malate dehydrogenase 1, neuron cell adhesion molecule 1, gelsolin, and neuronal cell adhesion molecule. Immunoblot analysis found reelin to be depressed in the cerebrospinal fluid from California sea lions with DAT. Mice administered domoic acid also had lower hippocampal reelin protein levels suggesting that domoic acid depresses reelin similar to kainic acid. In summary, proteomic analysis of cerebrospinal fluid in marine mammals is a useful tool to characterize the underlying molecular pathology of neurodegenerative disease. All MS data have been deposited in the ProteomeXchange with identifier PXD002105 (http://proteomecentral.proteomexchange.org/dataset/PXD002105).
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http://dx.doi.org/10.1002/pmic.201500167DOI Listing
December 2015

PHARMACOKINETICS OF TRAMADOL HYDROCHLORIDE AND ITS METABOLITE O-DESMETHYLTRAMADOL FOLLOWING A SINGLE, ORALLY ADMINISTERED DOSE IN CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS).

J Zoo Wildl Med 2015 Sep;46(3):476-81

Tramadol is a synthetic, centrally acting, opiate-like analgesic that is structurally related to codeine and morphine. The objective of this study was to determine the pharmacokinetics of tramadol hydrochloride and its major active metabolite O-desmethyltramadol (M1) in the California sea lion (Zalophus californianus). A single dose of tramadol was administered orally in fish at 2 mg/kg to a total of 15 wild California sea lions admitted for rehabilitation. Twenty-four total blood samples were collected post drug administration at 10, 20, 30, and 45 min and at 1, 3, 5, 6, 8, 12, and 24 hr. Blood plasma was separated and stored at -80°C until analysis with high-performance liquid chromatography was performed to determine levels of tramadol and M1, the major active metabolite. The results indicate that the plasma levels of parent tramadol are low or negligible during the first 30-45 min and then reach the predicted mean maximum plasma concentration of 358 ng/ml at 1.52 hr. The M1 metabolite was not detectable in 21 of 24 plasma samples, below the level of quantification of 5 ng/ml in one sample, and detectable at 11 and 17 ng/ml in two of the samples. This study suggests that a 2 mg/kg dose would need to be administered every 6-8 hr to maintain concentrations of tramadol above the minimum human analgesic level for mild to moderate pain. Based on dosing simulations, a dose of 4 mg/kg q8 hr or q12 hr, on average, may represent an adequate compromise, but further studies are needed using a larger sample size. Pharmacodynamic studies are warranted to determine if tramadol provides analgesic effects in this species. The potential for tramadol toxicosis at any dose also has not been determined in this species.
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http://dx.doi.org/10.1638/2014-0183.1DOI Listing
September 2015

LAPAROSCOPIC GASTROPEXY FOR CORRECTION OF A HIATAL HERNIA IN A NORTHERN ELEPHANT SEAL (MIROUNGA ANGUSTIROSTRIS).

J Zoo Wildl Med 2015 Jun;46(2):414-6

A female northern elephant seal (Mirounga angustirostris) weaned pup presented with malnutrition. During rehabilitation, the seal developed regurgitation and reduced lung sounds on auscultation. Radiographs and endoscopy performed under sedation suggested a diaphragmatic hernia. A Type I (or sliding) hiatal hernia was confirmed with a positive contrast upper gastrointestinal study, revealing varying degrees of herniation of the gastric fundus through the diaphragm into the caudal thorax as well as esophageal reflux. The animal was treated preoperatively with an H2 antagonist and antinausea medication. A laparoscopic gastropexy was performed under general anesthesia. The animal recovered well postoperatively and resolution of clinical signs was achieved. The animal was released back into the wild 21 kg above admit weight. To our knowledge, we report here the first surgical correction of a hiatal hernia in a marine mammal.
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http://dx.doi.org/10.1638/2014-0226R.1DOI Listing
June 2015
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