Publications by authors named "Denise J Greig"

27 Publications

  • Page 1 of 1

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

Spillover of ebolaviruses into people in eastern Democratic Republic of Congo prior to the 2018 Ebola virus disease outbreak.

One Health Outlook 2020 4;2(1):21. Epub 2020 Nov 4.

One Health Institute & Karen C Drayer Wildlife Health Center, School of Veterinary Medicine, University of California Davis, California, USA.

Background: The second largest Ebola virus disease (EVD) outbreak began in the Democratic Republic of Congo in July 2018 in North Kivu Province. Data suggest the outbreak is not epidemiologically linked to the 2018 outbreak in Equateur Province, and that independent introduction of Ebola virus (EBOV) into humans occurred. We tested for antibodies to ebolaviruses in febrile patients seeking care in North Kivu Province prior to the EVD outbreak.

Methods: Patients were enrolled between May 2017 and April 2018, before the declared start of the outbreak in eastern DRC. Questionnaires were administered to collect demographic and behavioural information to identify risk factors for exposure. Biological samples were evaluated for ebolavirus nucleic acid, and for antibodies to ebolaviruses. Prevalence of exposure was calculated, and demographic factors evaluated for associations with ebolavirus serostatus.

Results: Samples were collected and tested from 272 people seeking care in the Rutshuru Health Zone in North Kivu Province. All patients were negative for filoviruses by PCR. Intial screening by indirect ELISA found that 30 people were reactive to EBOV-rGP. Results were supported by detection of ebolavirus reactive linear peptides using the Serochip platform. Differential screening of all reactive serum samples against the rGP of all six ebolaviruses and Marburg virus (MARV) showed that 29 people exhibited the strongest reactivity to EBOV and one to Bombali virus (BOMV), and western blotting confirmed results. Titers ranged from 1:100 to 1:12,800. Although both sexes and all ages tested positive for antibodies, women were significantly more likely to be positive and the majority of positives were in February 2018.

Conclusions: We provide the first documented evidence of exposure to Ebola virus in people in eastern DRC. We detected antibodies to EBOV in 10% of febrile patients seeking healthcare prior to the declaration of the 2018-2020 outbreak, suggesting early cases may have been missed or exposure ocurred without associated illness. We also report the first known detection of antibodies to BOMV, previously detected in bats in West and East Africa, and show that human exposure to BOMV has occurred. Our data suggest human exposure to ebolaviruses may be more frequent and geographically widespread.
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http://dx.doi.org/10.1186/s42522-020-00028-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7609368PMC
November 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

Climate variability and life history impact stress, thyroid, and immune markers in California sea lions () during El Niño conditions.

Conserv Physiol 2019 15;7(1):coz010. Epub 2019 May 15.

Department of Biology, Sonoma State University, Rohnert Park, CA, USA.

Wildlife is exposed to a diverse set of extrinsic and intrinsic stressors, such as climatic variation or life history constraints, which may impact individual health and fitness. El Niño and climatic anomalies between 2013 and 2016 had major ecological impacts on the California Current ecosystem. As top marine predators, California sea lions (CSL) experienced decreased prey availability and foraging success, impacting their nutritional state. We hypothesize that chronic stress to juvenile CSL increased during the 2015-2016 El Niño and that breeding represents a period of chronic stress for adults, which impact a variety of physiological processes. We opportunistically captured and sampled juvenile CSL (female,  29; male,  38) in central California and adult male CSL ( 76) in Astoria, Oregon and quantified a suite of analytes in serum as indicators of acute stress markers, metabolism and thyroid function, and adaptive immune response. We found that stress hormones and glucose were decreased in juvenile CSL during 2016 relative to 2015 and in adult male CSL after the breeding season, which may indicate chronic stress downregulating HPA (hypothalamic-pituitary-adrenal) axis sensitivity with associated metabolic impacts. Conversely, thyroid hormones for both juvenile and adult male CSL were increased, suggesting greater energetic requirements resulting from increased foraging activity during suboptimal conditions in juveniles and breeding tenure in adult males. Immunoglobulin IgG was elevated in juveniles in 2016 but reduced in adult males post-breeding. This suggests that juveniles may face immunostimulatory pressure during anomalously warm ocean environments; however, for adult males, breeding is a significant energetic cost resulting in reductions to immune function. Our results indicate that environmental conditions and life history stage may influence physiological responses in an important marine predator and a sentinel species of changing ocean ecosystems.
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http://dx.doi.org/10.1093/conphys/coz010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6518924PMC
May 2019

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

Characterization of brominated, chlorinated, and phosphate flame retardants in San Francisco Bay, an urban estuary.

Sci Total Environ 2019 Feb 11;652:212-223. Epub 2018 Oct 11.

Cooperative Wildlife Research Laboratory and Department of Zoology, Southern Illinois University, Carbondale, IL 62901, USA.

Flame retardant chemical additives are incorporated into consumer goods to meet flammability standards, and many have been detected in environmental matrices. A uniquely wide-ranging characterization of flame retardants was conducted, including polybrominated diphenyl ethers (PBDEs) and 52 additional brominated, chlorinated, or phosphate analytes, in water, sediment, bivalves, and harbor seal blubber of San Francisco Bay, a highly urbanized estuary once considered a hot spot for PBDE contamination. Among brominated flame retardants, PBDEs remained the dominant contaminants in all matrices, though declines have been observed over the last decade following their phase-out. Hexabromocyclododecane (HBCD) and other hydrophobic, brominated flame retardants were commonly detected at lower levels than PBDEs in sediment and tissue matrices. Dechlorane Plus (DP) and related chlorinated compounds were also detected at lower levels or not at all across all matrices. In contrast, phosphate flame retardants were widely detected in Bay water samples, with highest median concentrations in the order TCPP > TPhP > TBEP > TDCPP > TCEP. Concentrations in Bay water were often higher than in other estuarine and marine environments. Phosphate flame retardants were also widely detected in sediment, in the order TEHP > TCrP > TPhP > TDCPP > TBEP. Several were present in bivalves, with levels of TDCPP comparable to PBDEs. Only four phosphate flame retardants were detected in harbor seal blubber: TCPP, TDCPP, TCEP, and TPhP. Periodic, multi-matrix screening is recommended to track contaminant trends impacted by changes to flammability standards and manufacturing practices, with a particular focus on contaminants like TDCPP and TPhP that were found at levels comparable to thresholds for aquatic toxicity.
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http://dx.doi.org/10.1016/j.scitotenv.2018.10.096DOI Listing
February 2019

Global patterns in coronavirus diversity.

Virus Evol 2017 Jan 12;3(1):vex012. Epub 2017 Jun 12.

One Health Institute & Karen C Drayer Wildlife Health Center, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, USA.

Since the emergence of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) and Middle East Respiratory Syndrom Coronavirus (MERS-CoV) it has become increasingly clear that bats are important reservoirs of CoVs. Despite this, only 6% of all CoV sequences in GenBank are from bats. The remaining 94% largely consist of known pathogens of public health or agricultural significance, indicating that current research effort is heavily biased towards describing known diseases rather than the 'pre-emergent' diversity in bats. Our study addresses this critical gap, and focuses on resource poor countries where the risk of zoonotic emergence is believed to be highest. We surveyed the diversity of CoVs in multiple host taxa from twenty countries to explore the factors driving viral diversity at a global scale. We identified sequences representing 100 discrete phylogenetic clusters, ninety-one of which were found in bats, and used ecological and epidemiologic analyses to show that patterns of CoV diversity correlate with those of bat diversity. This cements bats as the major evolutionary reservoirs and ecological drivers of CoV diversity. Co-phylogenetic reconciliation analysis was also used to show that host switching has contributed to CoV evolution, and a preliminary analysis suggests that regional variation exists in the dynamics of this process. Overall our study represents a model for exploring global viral diversity and advances our fundamental understanding of CoV biodiversity and the potential risk factors associated with zoonotic emergence.
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http://dx.doi.org/10.1093/ve/vex012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5467638PMC
January 2017

Per- and polyfluoroalkyl substances (PFASs) in San Francisco Bay wildlife: Temporal trends, exposure pathways, and notable presence of precursor compounds.

Chemosphere 2017 Oct 21;185:1217-1226. Epub 2017 Apr 21.

California Academy of Sciences, 55 Music Concourse Drive, San Francisco, CA 94118, USA. Electronic address:

Concentrations of perfluorooctane sulfonate (PFOS) in San Francisco Bay (SF Bay) wildlife have historically been among the highest reported globally. To track continuing exposures to PFASs and assess the impact of the 2002 phase-out of production of PFOS and related chemicals in the US, nine perfluoroalkyl carboxylic acids (PFCAs; C4-C12), three perfluoroalkyl sulfonic acids (PFSAs; C4, C6, C8) and perfluorooctane sulfonamide (PFOSA, a PFOS precursor) were measured in SF Bay cormorant eggs in 2012 and harbor seal serum sampled between 2009 and 2014. PFOS remained the dominant perfluoroalkyl acid (PFAA) in both cormorant eggs (36.1-466 ng/g) and seals (12.6-796 ng/g) from 2012 and 2014, respectively. Concentrations in seal and bird eggs from the South Bay have declined approximately 70% in both matrices. To elucidate potential pathways of exposure, prey fish, sediments and wastewater effluent were analyzed for PFASs, and in the case of sediment and effluent, a suite of PFAA precursors. PFOS was the dominant PFAA in prey fish and sediment. In effluent, different mixtures of PFAAs were measured, with PFOS, PFHxA, and PFOA detected in the highest concentrations. Polyfluoroalkyl phosphate diesters (PFCA-precursors) were observed at concentrations over an order of magnitude higher than PFCAs in sediment, highlighting their importance as a potential, on-going source of PFCAs to SF Bay wildlife. These findings suggest that the PFOS phase-out has resulted in reduced burdens to wildlife in SF Bay, but that exposure to diverse and incompletely characterized PFASs continues.
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http://dx.doi.org/10.1016/j.chemosphere.2017.04.096DOI 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

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

Blood and Hair Mercury Concentrations in the Pacific Harbor Seal (Phoca vitulina richardii) Pup: Associations with Neurodevelopmental Outcomes.

Ecohealth 2015 Sep 27;12(3):490-500. Epub 2015 Mar 27.

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

Monomethylmercury (MeHg(+)) is an environmental pollutant, which at sufficiently high exposures, has induced neurotoxicosis in several animal species, including humans. Adverse neurological effects due to gestational exposure are of particular concern as MeHg(+) readily crosses the blood-brain and placental barriers. The degree to which environmental concentrations in marine prey affect free-living piscivorous wildlife, however, remains largely undetermined. We examined associations of gestational exposures to mercury on neurodevelopment and survival using hair and blood concentrations of total mercury ([THg]) in a stranded population of Pacific harbor seal pups from central California. A positive association was determined for the presence of abnormal neurological symptoms and increasing [THg] in blood (P = 0.04), but not hair. Neither hair nor blood [THg] was significantly associated with survival, or the neurodevelopmental milestone 'free-feeding', which was measured from the onset of hand-assisted feeding to the time at which pups were able to consume fish independently. Both hair and blood [THg] exceeded threshold values considered potentially toxic to humans and other mammalian wildlife species. The higher [THg] in blood associated with abnormal neurological symptoms may indicate an adverse effect of this pollutant on neurodevelopment in harbor seal pups. These data have broader implications with respect to human health and public policy as harbor seals and humans consume similar fish species, and it is possible that safeguard levels established for marine mammals could also extend to human populations that regularly consume fish.
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http://dx.doi.org/10.1007/s10393-015-1021-8DOI Listing
September 2015

Antibiotic Efficacy in Eliminating Leptospiruria in California Sea Lions () Stranding with Leptospirosis.

Aquat Mamm 2015 26;41(2):203-212. Epub 2015 May 26.

Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA,

Stranded California sea lions () along the California coast have been diagnosed with leptospirosis every year since at least the 1980s. Between September 2010 and November 2011, we followed 14 stranded California sea lions that survived to release and evaluated antibiotic efficacy in eliminating leptospiruria (urinary shedding of leptospires). Leptospiruria was assessed by real-time PCR of urine and urine culture, with persistence assessed using longitudinally collected samples. Serum chemistry was used to assess recovery of normal renal function. Microscopic agglutination testing (MAT) was performed to assess serum anti- antibody titers, and the MAT reactivity patterns were consistent with serovar Pomona infection frequently observed in this population. Animals were initially treated for 6 to 16 d (median = 10.5; mean = 10.8) with antibiotics from the penicillin family, with some receiving additional antibiotics to treat other medical conditions. All urine cultures were negative; therefore, the presence of leptospiruria was assessed using PCR. Leptospiruria continued beyond the initial course of penicillin family antibiotics in 13 of the 14 sea lions, beyond the last antibiotic dose in 11 of the 14 sea lions, beyond recovery of renal function in 13 of the 14 sea lions, and persisted for at least 8 to 86 d (median = 45; mean = 46.8). Five animals were released with no negative urine PCR results detected; thus, their total shedding duration may have been longer. Cessation of leptospiruria was more likely in animals that received antibiotics for a greater duration, especially if coverage was uninterrupted. Real-time PCR results indicate that an antibiotic protocol commonly used to treat leptospirosis in rehabilitating California sea lions does not eliminate leptospiruria. It is possible that antibiotic protocols given for a longer duration and/or including other antibiotics may be effective in eliminating leptospiruria. These results may have important human and animal health implications, especially in rehabilitation facilities, as transmission may occur through contact with animals with persistent leptospiruria.
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http://dx.doi.org/10.1578/AM.41.2.2015.203DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6379896PMC
May 2015

Surveillance for zoonotic and selected pathogens in harbor seals Phoca vitulina from central California.

Dis Aquat Organ 2014 Sep;111(2):93-106

Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews KY16 8LB, UK.

The infection status of harbor seals Phoca vitulina in central California, USA, was evaluated through broad surveillance for pathogens in stranded and wild-caught animals from 2001 to 2008, with most samples collected in 2007 and 2008. Stranded animals from Mendocino County to San Luis Obispo County were sampled at a rehabilitation facility: The Marine Mammal Center (TMMC, n = 175); wild-caught animals were sampled at 2 locations: San Francisco Bay (SF, n = 78) and Tomales Bay (TB, n = 97), that differed in degree of urbanization. Low prevalences of Salmonella, Campylobacter, Giardia, and Cryptosporidium were detected in the feces of stranded and wild-caught seals. Clostridium perfringens and Escherichia coli were more prevalent in the feces of stranded (58% [78 out of 135] and 76% [102 out of 135]) than wild-caught (42% [45 out of 106] and 66% [68 out of 106]) seals, whereas Vibrio spp. were 16 times more likely to be cultured from the feces of seals from SF than TB or TMMC (p < 0.005). Brucella DNA was detected in 3.4% of dead stranded harbor seals (2 out of 58). Type A influenza was isolated from feces of 1 out of 96 wild-caught seals. Exposure to Toxoplasma gondii, Sarcocystis neurona, and type A influenza was only detected in the wild-caught harbor seals (post-weaning age classes), whereas antibody titers to Leptospira spp. were detected in stranded and wild-caught seals. No stranded (n = 109) or wild-caught (n = 217) harbor seals had antibodies to phocine distemper virus, although a single low titer to canine distemper virus was detected. These results highlight the role of harbor seals as sentinel species for zoonotic and terrestrial pathogens in the marine environment.
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http://dx.doi.org/10.3354/dao02762DOI Listing
September 2014

Pandemic H1N1 influenza isolated from free-ranging Northern Elephant Seals in 2010 off the central California coast.

PLoS One 2013 15;8(5):e62259. Epub 2013 May 15.

One Health Institute, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America.

Interspecies transmission of influenza A is an important factor in the evolution and ecology of influenza viruses. Marine mammals are in contact with a number of influenza reservoirs, including aquatic birds and humans, and this may facilitate transmission among avian and mammalian hosts. Virus isolation, whole genome sequencing, and hemagluttination inhibition assay confirmed that exposure to pandemic H1N1 influenza virus occurred among free-ranging Northern Elephant Seals (Mirounga angustirostris) in 2010. Nasal swabs were collected from 42 adult female seals in April 2010, just after the animals had returned to the central California coast from their short post-breeding migration in the northeast Pacific. Swabs from two seals tested positive by RT-PCR for the matrix gene, and virus was isolated from each by inoculation into embryonic chicken eggs. Whole genome sequencing revealed greater than 99% homology with A/California/04/2009 (H1N1) that emerged in humans from swine in 2009. Analysis of more than 300 serum samples showed that samples collected early in 2010 (n = 100) were negative and by April animals began to test positive for antibodies against the pH1N1 virus (HI titer of ≥1∶40), supporting the molecular findings. In vitro characterizations studies revealed that viral replication was indistinguishable from that of reference strains of pH1N1 in canine kidney cells, but replication was inefficient in human epithelial respiratory cells, indicating these isolates may be elephant seal adapted viruses. Thus findings confirmed that exposure to pandemic H1N1 that was circulating in people in 2009 occurred among free-ranging Northern Elephant Seals in 2010 off the central California coast. This is the first report of pH1N1 (A/Elephant seal/California/1/2010) in any marine mammal and provides evidence for cross species transmission of influenza viruses in free-ranging wildlife and movement of influenza viruses between humans and wildlife.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0062259PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3655164PMC
January 2014

Asymptomatic and chronic carriage of Leptospira interrogans serovar Pomona in California sea lions (Zalophus californianus).

Vet Microbiol 2013 May 4;164(1-2):177-83. Epub 2013 Feb 4.

Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA.

Since 1970, periodic outbreaks of leptospirosis, caused by pathogenic spirochetes in the genus Leptospira, have caused morbidity and mortality of California sea lions (Zalophus californianus) along the Pacific coast of North America. Yearly seasonal epizootics of varying magnitude occur between the months of July and December, with major epizootics occurring every 3-5 years. Genetic and serological data suggest that Leptospira interrogans serovar Pomona is the infecting serovar and is enzootic in the California sea lion population, although the mechanism of persistence is unknown. We report asymptomatic carriage of Leptospira in 39% (33/85) of wild, free-ranging sea lions sampled during the epizootic season, and asymptomatic seroconversion with chronic asymptomatic carriage in a rehabilitated sea lion. This is the first report of asymptomatic carriage in wild, free-ranging California sea lions and the first example of seroconversion and asymptomatic chronic carriage in a sea lion. Detection of asymptomatic chronic carriage of Leptospira in California sea lions, a species known to suffer significant disease and mortality from the same Leptospira strain, goes against widely-held notions regarding leptospirosis in accidental versus maintenance host species. Further, chronic carriage could provide a mechanism for persistent circulation of Leptospira in the California sea lion population, particularly if these animals shed infectious leptospires for months to years.
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http://dx.doi.org/10.1016/j.vetmic.2013.01.032DOI Listing
May 2013

Dynamics of Vibrio with virulence genes detected in Pacific harbor seals (Phoca vitulina richardii) off California: implications for marine mammal health.

Microb Ecol 2013 May 8;65(4):982-94. Epub 2013 Feb 8.

Moss Landing Marine Laboratories, 8272 Moss Landing Road, Moss Landing, CA 93059, USA.

Given their coastal site fidelity and opportunistic foraging behavior, harbor seals (Phoca vitulina) may serve as sentinels for coastal ecosystem health. Seals using urbanized coastal habitat can acquire enteric bacteria, including Vibrio that may affect their health. To understand Vibrio dynamics in seals, demographic and environmental factors were tested for predicting potentially virulent Vibrio in free-ranging and stranded Pacific harbor seals (Phoca vitulina richardii) off California. Vibrio prevalence did not vary with season and was greater in free-ranging seals (29 %, n = 319) compared with stranded seals (17 %, n = 189). Of the factors tested, location, turbidity, and/or salinity best predicted Vibrio prevalence in free-ranging seals. The relationship of environmental factors with Vibrio prevalence differed by location and may be related to oceanographic or terrestrial contributions to water quality. Vibrio parahaemolyticus, Vibrio alginolyticus, and Vibrio cholerae were observed in seals, with V. cholerae found almost exclusively in stranded pups and yearlings. Additionally, virulence genes (trh and tdh) were detected in V. parahaemolyticus isolates. Vibrio cholerae isolates lacked targeted virulence genes, but were hemolytic. Three out of four stranded pups with V. parahaemolyticus (trh+ and/or tdh+) died in rehabilitation, but the role of Vibrio in causing mortality is unclear, and Vibrio expression of virulence genes should be investigated. Considering that humans share the environment and food resources with seals, potentially virulent Vibrio observed in seals also may be of concern to human health.
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http://dx.doi.org/10.1007/s00248-013-0188-1DOI Listing
May 2013

Evaluation of circulating eosinophil count and adrenal gland function in California sea lions naturally exposed to domoic acid.

J Am Vet Med Assoc 2012 Oct;241(7):943-9

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

Objective: To determine the effect of natural exposure to domoic acid (DA) on eosinophil counts and adrenal gland function in California sea lions (Zalophus californianus).

Design: Cross-sectional prospective study.

Animals: 39 California sea lions.

Procedures: Adult female sea lions admitted to a rehabilitation hospital during 2009 were classified into 1 of 3 groups (acute DA toxicosis, chronic DA toxicosis, or no DA exposure) on the basis of clinical signs, DA concentration in urine or feces, and hippocampal morphology. Endoparasite burden, eosinophil count, and serum cortisol and plasma ACTH concentrations were determined for each sea lion. For a subset of 8 sea lions, fecal glucocorticoid concentration after IM administration of cosyntropin was determined.

Results: Sea lions exposed to DA (acute DA toxicosis, n = 11; chronic DA toxicosis, 19) had higher eosinophil counts and lower serum cortisol concentrations, compared with values for sea lions with no DA exposure (9). Eosinophil count was not associated with endoparasite burden. Serum cortisol concentration was associated with plasma ACTH concentrations in sea lions from the no DA exposure group but not in sea lions in the acute or chronic DA toxicosis groups. Following cosyntropin injection, fecal glucocorticoid concentrations increased in all sea lions evaluated except 1.

Conclusions And Clinical Relevance: In adult sea lions, eosinophilia may be a cost-effective biomarker for DA exposure and may reflect alterations in hypothalamic, pituitary gland, or adrenal gland function. Domoic acid exposure may have subtle health effects on marine animals in addition to induction of neurologic signs.
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http://dx.doi.org/10.2460/javma.241.7.943DOI Listing
October 2012

Brominated and chlorinated flame retardants in San Francisco Bay sediments and wildlife.

Environ Int 2012 Oct 4;47:56-65. Epub 2012 Jul 4.

San Francisco Estuary Institute, 4911 Central Avenue, Richmond, CA 94804, USA.

Restrictions on the use of polybrominated diphenyl ethers (PBDEs) have resulted in the use of alternative flame retardants in consumer products to comply with flammability standards. In contrast to PBDEs, information on the occurrence and fate of these alternative compounds in the environment is limited, particularly in the United States. In this study, a survey of flame retardants in San Francisco Bay was conducted to evaluate whether PBDE replacement chemicals and other current use flame retardants were accumulating in the Bay food web. In addition to PBDEs, brominated and chlorinated flame retardants (hexabromocyclododecane (HBCD) and Dechlorane Plus (DP)) were detected in Bay sediments and wildlife. Median concentrations of PBDEs, HBCD, and DP, respectively, were 4.3, 0.3, and 0.2 ng g⁻¹ dry weight (dw) in sediments; 1670, <6.0, and 0.5 ng g⁻¹ lipid weight (lw) in white croaker (Genyonemus lineatus); 1860, 6.5, and 1.3 ng g⁻¹ lw in shiner surfperch (Cymatogaster aggregata); 5500, 37.4, and 0.9 ng g⁻¹ lw in eggs of double-crested cormorant (Phalacrocorax auritus); 770, 7.1, and 0.9 ng g⁻¹ lw in harbor seal (Phoca vitulina) adults; and 330, 3.5, and <0.1 ng g⁻¹ lw in harbor seal (P. vitulina) pups. Two additional flame retardants, pentabromoethylbenzene (PBEB) and 1,2-bis(2,4,6 tribromophenoxy)ethane (BTBPE) were detected in sediments but with less frequency and at lower concentrations (median concentrations of 0.01 and 0.02 ng g⁻¹ dw, respectively) compared to the other flame retardants. PBEB was also detected in each of the adult harbor seals and in 83% of the pups (median concentrations 0.2 and 0.07 ng g⁻¹ lw, respectively). The flame retardants hexabromobenzene (HBB), decabromodiphenyl ethane (DBDPE), bis(2-ethylhexyl) tetrabromophthalate (TBPH), and 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB), were not detected in sediments and BTBPE, HBB and TBB were not detected in wildlife samples. Elevated concentrations of some flame retardants were likely associated with urbanization and Bay hydrodynamics. Compared to other locations, concentrations of PBDEs in Bay wildlife were comparable or higher, while concentrations of the alternatives were generally lower. This study is the first to determine concentrations of PBDE replacement products and other flame retardants in San Francisco Bay, providing some of the first data on the food web occurrence of these flame retardants in a North American urbanized estuary.
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http://dx.doi.org/10.1016/j.envint.2012.06.005DOI Listing
October 2012

Serum profiling by MALDI-TOF mass spectrometry as a diagnostic tool for domoic acid toxicosis in California sea lions.

Proteome Sci 2012 Mar 19;10(1):18. Epub 2012 Mar 19.

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

Background: There are currently no reliable markers of acute domoic acid toxicosis (DAT) for California sea lions. We investigated whether patterns of serum peptides could diagnose acute DAT. Serum peptides were analyzed by MALDI-TOF mass spectrometry from 107 sea lions (acute DAT n = 34; non-DAT n = 73). Artificial neural networks (ANN) were trained using MALDI-TOF data. Individual peaks and neural networks were qualified using an independent test set (n = 20).

Results: No single peak was a good classifier of acute DAT, and ANN models were the best predictors of acute DAT. Performance measures for a single median ANN were: sensitivity, 100%; specificity, 60%; positive predictive value, 71%; negative predictive value, 100%. When 101 ANNs were combined and allowed to vote for the outcome, the performance measures were: sensitivity, 30%; specificity, 100%; positive predictive value, 100%; negative predictive value, 59%.

Conclusions: These results suggest that MALDI-TOF peptide profiling and neural networks can perform either as a highly sensitive (100% negative predictive value) or a highly specific (100% positive predictive value) diagnostic tool for acute DAT. This also suggests that machine learning directed by populations of predictive models offer the ability to modulate the predictive effort into a specific type of error.
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http://dx.doi.org/10.1186/1477-5956-10-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3338078PMC
March 2012

Perfluoroalkyl compounds (PFCs) in wildlife from an urban estuary.

J Environ Monit 2012 Jan 2;14(1):146-54. Epub 2011 Dec 2.

San Francisco Estuary Institute, 4911 Central Avenue, Richmond, CA 94804, USA.

Previous research has documented the bioaccumulation of perfluoroalkyl compounds (PFCs) in apex predators in remote locations but few studies have evaluated urban estuaries. To assess the importance of PFCs in San Francisco Bay, two apex predators in the San Francisco Bay, double-crested cormorants (Phalacrocorax auritus) and Pacific harbor seals (Phoca vitulina richardii), were sampled. Prey fish (Atherinops affinis and Menidia audens) were also evaluated to better understand potential sources of PFCs to the foodweb. Perfluorooctane sulfonate (PFOS) was the primary PFC detected in cormorant eggs, small fish and harbor seal serum. PFOS detected in San Francisco Bay seal serum was typically an order of magnitude higher than those at the reference site. PFOS concentrations were highest in seals and cormorant eggs from the highly urbanized southern portion of the Bay. PFOS in eggs from the southern part of the Bay remained relatively constant between 2006 and 2009 despite the phase-out of perfluorosulfonyl-based compounds nationally. In addition, these levels exceed the avian predicted no effects concentration of 1.0 μg mL(-1). Concentrations of the remaining PFCs measured were substantially lower than those of PFOS.
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http://dx.doi.org/10.1039/c1em10609kDOI Listing
January 2012

Geography and stage of development affect persistent organic pollutants in stranded and wild-caught harbor seal pups from central California.

Sci Total Environ 2011 Aug;409(18):3537-47

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

Persistent organic pollutants have been associated with disease susceptibility and decreased immunity in marine mammals. Concentrations of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), polybrominated diphenyl ethers (PBDEs), chlordanes (CHLDs), and hexachlorocyclohexane isomers (HCHs) were evaluated in terms of stage of development and likely exposure routes (in utero, suckling, fasting) in the blubber of 202 stranded and wild-caught, primarily young of the year (n=177), harbor seals (Phoca vitulina) in the central California coast. This is the first report of HCH concentrations in the blubber of California seals. Lipid normalized concentrations ranged from 200 to 330,000 ng/g for sum PCBs, 320-1,500,000 ng/g for sum DDTs, 23-63,000 ng/g for sum PBDEs, 29-29,000 ng/g for sum CHLDs, and 2-780 ng/g for sum HCHs. The highest concentrations were observed in harbor seal pups that suckled in the wild and then lost mass during the post-weaning fast. Among the pups sampled in the wild and those released from rehabilitation, there were no differences in mass, blubber depth, or percent lipid although contaminant concentrations were significantly higher in the pups which nursed in the wild. When geographic differences were evaluated in a subset of newborn animals collected near their birth locations, the ratio of sum DDTs to sum PCBs was significantly greater in samples from an area with agricultural inputs (Monterey), than one with industrial inputs (San Francisco Bay). A principal components analysis distinguished between seals from San Francisco Bay and Monterey Bay based on specific PCB and PBDE congeners and DDT metabolites. These data illustrate the important influence of life stage, nutritional status, and location on blubber contaminant levels, and thus the need to consider these factors when interpreting single sample measurements in marine mammals.
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http://dx.doi.org/10.1016/j.scitotenv.2011.05.047DOI Listing
August 2011

Congenital neuroglial heterotopia in a neonatal harbor seal (Phoca vitulina richardsi ) with evidence of recent exposure to polycyclic aromatic hydrocarbons.

J Wildl Dis 2011 Jan;47(1):246-54

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

A male neonatal Pacific harbor seal (Phoca vitulina richardsi) stranded off the coast of California, USA, was presented for rehabilitation with numerous partially haired, soft tissue masses around the mouth and in the oropharynx. Because of the extent of the lesions, the seal was humanely euthanized. Histologically, the masses consisted of subepithelial connective tissue and subcutis expanded by a proliferation of streams and bundles of spindle to stellate cells. Morphology of these cells suggested a neural origin, which was confirmed by positive immunohistochemistry for two neural markers, S-100 protein and glial fibrillary acidic protein, so the masses were diagnosed as neuroglial heterotopia. Heterotopic neuroglial tissue is a rare lesion comprised of benign mature neural tissue in an ectopic location with no connection to the central nervous system. Results of polycyclic aromatic hydrocarbon (PAH) metabolite analysis of bile indicated recent exposure to a petroleum source. Although fetal exposure to PAHs in utero can cause neurotoxicity and affect normal embryonic development, it is unknown whether gestational exposure occurred in this case.
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http://dx.doi.org/10.7589/0090-3558-47.1.246DOI Listing
January 2011

Hematology and serum chemistry in stranded and wild-caught harbor seals in central California: reference intervals, predictors of survival, and parameters affecting blood variables.

J Wildl Dis 2010 Oct;46(4):1172-84

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

Blood was collected from stranded harbor seal (Phoca vitulina) pups at admission (n=64) and release (n=45) from rehabilitation in 2007 and 2008 and from wild-caught harbor seal pups, subadults, and adults (n=110) in 2004, 2007, and 2008. Blood values measured at the time of admission were not predictive of survival during rehabilitation. Mass was associated with survival until release, and all pups that died weighed less than 10 kg at the time of admission. Döhle bodies were observed in leukocytes from 15% to 22% of the pups in rehabilitation, but not in the wild pups. Thresholds (95% confidence intervals) among wild pups were less than those in the released pups for leukocytes, neutrophils, total cholesterol, alanine aminotransferase (ALT), glucose, phosphorus, sodium, potassium, total protein, albumin, and globulin; thresholds were greater in wild pups than in released pups for hemoglobin (HGB), hematocrit (HCT), and glucose. Thresholds among released pups were less than those in wild pups for HGB, HCT, mean cell volume, chloride, and creatine kinase; thresholds among released pups were greater than those in wild pups for neutrophils, platelets, total cholesterol, triglycerides, ALT, aspartate aminotransferase, sorbitol dehydrogenase, bilirubin, phosphorus, potassium, total protein, and albumin. Age, girth, and geographic location affected the blood variables from wild-caught pups; age class, geographic location, sex, and body condition affected the blood variables of wild-caught, subadult and adult harbor seals.
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http://dx.doi.org/10.7589/0090-3558-46.4.1172DOI Listing
October 2010

Cyclical changes in seroprevalence of leptospirosis in California sea lions: endemic and epidemic disease in one host species?

BMC Infect Dis 2007 Nov 6;7:125. Epub 2007 Nov 6.

Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, USA.

Background: Leptospirosis is a zoonotic disease infecting a broad range of mammalian hosts, and is re-emerging globally. California sea lions (Zalophus californianus) have experienced recurrent outbreaks of leptospirosis since 1970, but it is unknown whether the pathogen persists in the sea lion population or is introduced repeatedly from external reservoirs.

Methods: We analyzed serum samples collected over an 11-year period from 1344 California sea lions that stranded alive on the California coast, using the microscopic agglutination test (MAT) for antibodies to Leptospira interrogans serovar Pomona. We evaluated seroprevalence among yearlings as a measure of incidence in the population, and characterized antibody persistence times based on temporal changes in the distribution of titer scores. We conducted multinomial logistic regression to determine individual risk factors for seropositivity with high and low titers.

Results: The serosurvey revealed cyclical patterns in seroprevalence to L. interrogans serovar Pomona, with 4-5 year periodicity and peak seroprevalence above 50%. Seroprevalence in yearling sea lions was an accurate index of exposure among all age classses, and indicated on-going exposure to leptospires in non-outbreak years. Analysis of titer decay rates showed that some individuals probably maintain high titers for more than a year following exposure.

Conclusion: This study presents results of an unprecedented long-term serosurveillance program in marine mammals. Our results suggest that leptospirosis is endemic in California sea lions, but also causes periodic epidemics of acute disease. The findings call into question the classical dichotomy between maintenance hosts of leptospirosis, which experience chronic but largely asymptomatic infections, and accidental hosts, which suffer acute illness or death as a result of disease spillover from reservoir species.
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http://dx.doi.org/10.1186/1471-2334-7-125DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2186333PMC
November 2007

Transplacental transfer of organochlorines in California sea lions (Zalophus californianus).

Environ Toxicol Chem 2007 Jan;26(1):37-44

The Marine Mammal Center, 1065 Fort Cronkhite, Sausalito, California 94965, USA.

The transplacental transfer of organochlorines (OCs) in California sea lions (Zalophus californianus) was investigated by analyzing blubber samples from 20 female sea lions and their fetuses during the last trimester of pregnancy. A rapid, high-performance liquid chromatographic, photodiode-array method was used to measure blubber concentrations of polychlorinated biphenyls (PCBs), including dioxin-like congeners, as well as DDTs and hexachlorobenzene. Summed values of PCBs (sigmaPCBs), of DDTs (sigmaDDTs), and of PCB toxic equivalents (sigmaPCB TEQs) were calculated from these data. The ratios of mean blubber concentrations of fetal sigmaPCBs to maternal blubber concentrations of sigmaPCBs were 0.45 by wet weight and 0.97 by lipid weight, but these ratios varied widely among mother-fetus pairs. Mean ratios of fetal sigmaDDTs to maternal sigmaDDTs were 0.53 by wet weight and 1.12 by lipid weight. Fetuses were classified into two age groups, based on date of recovery, to examine differences in OC transfer because of gestational age. Fetal to maternal ratios for individual PCB congeners, DDT compounds, and sigmaPCBs, sigmaDDTs, and sigmaPCB TEQs were lower among premature compared with late-term fetuses. These ratios increased for both groups as the logarithmic n-octanol/water partition coefficient (log Kow) for each compound decreased. Linear predictions for sigmaPCB and sigmaDDT concentrations in fetal blubber could be obtained using the sigmaPCB and sigmaDDT concentrations in maternal blubber, maternal and fetal blubber lipid content, maternal mass, and maternal age. Fetal TEQ was explained by maternal TEQ and maternal age. The ability to predict contaminant concentrations in fetal blubber from maternal parameters is important for developing risk assessment models for marine mammals.
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http://dx.doi.org/10.1897/05-609r.1DOI Listing
January 2007

Age-prevalence of Otarine Herpesvirus-1, a tumor-associated virus, and possibility of its sexual transmission in California sea lions.

Vet Microbiol 2007 Feb 12;120(1-2):1-8. Epub 2006 Oct 12.

Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA.

Otarine Herpesvirus-1 (OtHV-1) is a gammaherpesvirus routinely detected in urogenital tumor tissues of adult sea lions dying during rehabilitation, To investigate the epidemiology of this virus and guide the development of a mathematical model of its role in the multifactorial etiology of cancer in California sea lions, polymerase chain reaction (PCR) amplification of an OtHV-1 specific fragment of the DNA polymerase gene was used to look for evidence of OtHV-1 infection in urogenital and pharyngeal swabs and peripheral blood mononuclear cells (PBMC) of sea lions of different ages. Samples were also examined from pregnant females and their late term in utero or aborted fetuses to investigate potential for vertical transmission. Prevalence of infection in 72 adult females was 22%, whereas it was 46% in 52 adult males, and was significantly lower in 120 juvenile animals (6%). OtHV-1 DNA was most often detected in the lower reproductive tract of the adult animals, especially the males, and rarely in the pharynx or urogenital tract of juvenile animals. These data suggest sexual transmission may an important route of transmission. Additional studies are required to confirm this mode of transmission. Additionally, the virus was detected in a single prematurely born pup, suggesting the possibility of perinatal transmission. No indication of a PBMC associated viremia was evident in adults using standard PCR or in juveniles using standard and real time PCR.
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http://dx.doi.org/10.1016/j.vetmic.2006.10.002DOI Listing
February 2007

Otarine Herpesvirus-1, not papillomavirus, is associated with endemic tumours in California sea lions (Zalophus californianus).

J Comp Pathol 2006 Nov 10;135(4):183-9. Epub 2006 Oct 10.

Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, One Shields Drive, University of California, Davis, CA 95616, USA.

The purpose of this study was to determine if Otarine Herpesvirus-1 (OtHV-1) is associated with the presence of urogenital carcinomas in California sea lions. Polymerase chain reaction (PCR) analysis with primers specific for OtHV-1 was used to compare the prevalence of OtHV-1 infection in 15 sea lions affected by urogenital carcinoma with that of age-matched and juvenile tumour-free animals, and animals with tumours of non-urogenital origin. The herpesvirus was more prevalent (100%) and more widespread in the 15 animals with urogenital carcinoma than in 25 control animals, and was most often found in the urogenital tissue (vagina and prostate) and in the draining lymph nodes. Moreover, OtHV-1 DNA was not found in any juvenile animal, or in the neoplastic tissues of animals with non-urogenital tumours. Papillomavirus-specific PCR analysis of urogenital carcinoma tissues detected papillomavirus sequences in only one carcinomatous tissue. Further studies are needed to determine if OtHV-1 contributes to oncogenesis in the California sea lion; these data show, however, that OtHV-1 is associated with urogenital carcinomas, is preferentially present in urogenital tissues, and may be sexually transmitted. Papillomaviruses, which are known to contribute to urogenital tumours in other species, did not appear to be associated with the sea lion carcinomas.
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http://dx.doi.org/10.1016/j.jcpa.2006.06.007DOI Listing
November 2006
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