Zalophus californianus

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Kathleen M. Colegrove - One of the best experts on this subject based on the ideXlab platform.

  • complex virome in a mesenteric lymph node from a californian sea lion Zalophus californianus with polyserositis and steatitis
    Viruses, 2020
    Co-Authors: Eda Altan, Martha A Delaney, Elizabeth A Wheeler, Kathleen M. Colegrove, Xutao Deng, Yanpeng Li
    Abstract:

    An emaciated subadult free-ranging California sea lion (Csl or Zalophus californianus) 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.

  • polyphasic rhabdomyositis in california sea lions Zalophus californianus pathology and potential causes
    Veterinary Pathology, 2019
    Co-Authors: Mauricio Seguel, Cara L Field, Kathleen M. Colegrove, Sophie Whoriskey, Tenaya Norris, Padraig J Duignan
    Abstract:

    A myositis syndrome has been recognized for more than a decade in California sea lions (CSLs; Zalophus californianus) but a detailed description of the lesions and potential causes of this condition is lacking. The tissues of 136 stranded CSLs with rhabdomyositis were examined. Rhabdomyositis was considered incidental in 67% (91/136) of the CSLs, and a factor contributing to the animal stranding (significant rhabdomyositis) in 33% (45/136). Of the 91 cases with incidental rhabdomyositis, lesions consisted of a few small foci of lymphohistiocytic inflammation. Of the 45 cases with significant rhabdomyositis, 28 (62%) also presented with major comorbidities such as leptospirosis (2 animals) and domoic acid toxicosis (6 animals), whereas 17 (38%) had severe polyphasic rhabdomyositis as the only major disease process associated with mortality. In these animals, most striated muscles had multiple white streaks and diffuse atrophy. Microscopically, there was myofiber necrosis surrounded by lymphocytes and histiocytes admixed with areas of myofiber regeneration, and/or moderate to severe rhabdomyocyte atrophy usually adjacent to intact Sarcocystis neurona cysts. At the interface of affected and normal muscle, occasional T lymphocytes infiltrated the sarcoplasm of intact myocytes, and occasional myofibers expressed MHCII proteins in the sarcoplasm. S. neurona antibody titers and cyst burden were higher in animals with significant polymyositis antibody titers of (26125 ± 2164, 4.5 ± 1.2 cysts per section) and active myonecrosis than animals with incidental rhabdomyositis antibody titers of (7612 ± 1042, 1.7 ± 0.82 cysts per section). The presented findings suggest that S. neurona infection and immune-mediated mechanisms could be associated with significant polyphasic rhabdomyositis in CSLs.

  • Supplemental Material, DS1_VET_10.1177_0300985819829526 - Polyphasic Rhabdomyositis in California Sea Lions (Zalophus californianus): Pathology and Potential Causes
    2019
    Co-Authors: Mauricio Seguel, Kathleen M. Colegrove, Cara Field, Sophie Whoriskey, Tenaya Norris, Padraig J Duignan
    Abstract:

    Supplemental Material, DS1_VET_10.1177_0300985819829526 for Polyphasic Rhabdomyositis in California Sea Lions (Zalophus californianus): Pathology and Potential Causes by Mauricio Seguel, Kathleen M. Colegrove, Cara Field, Sophie Whoriskey, Tenaya Norris and Padraig Duignan in Veterinary Pathology

  • prevalence of urogenital carcinoma in stranded california sea lions Zalophus californianus from 2005 15
    Journal of Wildlife Diseases, 2018
    Co-Authors: Ailsa J Hall, Kathleen M. Colegrove, James F. X. Wellehan, Padraig J Duignan, Alissa C Deming, Frances M. D. Gulland
    Abstract:

    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.

  • hypervirulent klebsiella pneumoniae in california sea lions Zalophus californianus pathologic findings in natural infections
    Veterinary Pathology, 2017
    Co-Authors: Mauricio Seguel, Shawn P. Johnson, Nicole L. Gottdenker, Kathleen M. Colegrove, Carsten Struve, Elizabeth W Howerth
    Abstract:

    Tissues of stranded California sea lions ( Zalophus californianus) naturally infected with a hyperviruluent strain of Klebsiella pneumoniae were examined by histopathology and immunohistochemistry against the K. pneumoniae K2 capsular antigen. In 7 of 8 animals, there was severe purulent bronchopneumonia, sometimes complicated by fibrinonecrotizing pleuritis with pyothorax. In affected areas of lung, large numbers of degenerate neutrophils and macrophages were admixed with rare large extracellular and intracellular gram-negative bacilli surrounded by a prominent capsule. Through serotyping, polymerase chain reaction, sequencing, and immunohistochemistry, these bacteria were confirmed to be a K2 serotype of K. pneumoniae. The same bacteria were identified through double immunolabeling within macrophages in blood vessels, lymph nodes, spleen, and liver. Intact K. pneumoniae were identified on epithelial surfaces of the nasopharyngeal, tracheal, and small intestine mucosae and within distal renal tubules. Our findings indicate that hypervirulent K. pneumoniae causes severe respiratory disease and intrahistiocytic bacteremia in California sea lions.

Frances M. D. Gulland - One of the best experts on this subject based on the ideXlab platform.

  • proteomic analysis of urine from california sea lions Zalophus californianus a resource for urinary biomarker discovery
    Journal of Proteome Research, 2018
    Co-Authors: Benjamin A Neely, Frances M. D. Gulland, Katherine C Prager, Alison M Bland, Christine Fontaine, Michael G Janech
    Abstract:

    Urinary markers for the assessment of kidney diseases in wild animals are limited, in part, due to the lack of urinary proteome data, especially for marine mammals. One of the most prevalent kidney diseases in marine mammals is caused by Leptospira interrogans, which is the second most common etiology linked to stranding of California sea lions (Zalophus californianus). Urine proteins from 11 sea lions with leptospirosis kidney disease and eight sea lions without leptospirosis or kidney disease were analyzed using shotgun proteomics. In total, 2694 protein groups were identified, and 316 were differentially abundant between groups. Major urine proteins in sea lions were similar to major urine proteins in dogs and humans except for the preponderance of resistin, lysozyme C, and PDZ domain containing 1, which appear to be over-represented. Previously reported urine protein markers of kidney injury in humans and animals were also identified. Notably, neutrophil gelatinase-associated lipocalin, osteopontin, a...

  • proteomic analysis of urine from california sea lions Zalophus californianus a resource for urinary biomarker discovery
    bioRxiv, 2018
    Co-Authors: Benjamin A Neely, Frances M. D. Gulland, Katherine C Prager, Alison M Bland, Christine Fontaine, Michael G Janech
    Abstract:

    Urinary markers for the assessment of kidney diseases in wild animals are limited, in part, due to the lack of urinary proteome data, especially for marine mammals. One of the most prevalent kidney diseases in marine mammals is caused by Leptospira interrogans, which is the second most common etiology linked to stranding of California sea lions (Zalophus californianus). Urine proteins from eleven sea lions with leptospirosis kidney disease and eight sea lions without leptospirosis or kidney disease were analyzed using shotgun proteomics. In total, 2694 protein groups were identified and 316 were differentially abundant between groups. Major urine proteins in sea lions were similar to major urine proteins in dogs and humans except for the preponderance of resistin, lysozyme C, and PDZ domain containing 1, which appear to be over-represented. Previously reported urine protein markers of kidney injury in humans and animals were also identified. Notably, neutrophil gelatinase-associated lipocalin, osteopontin, and epidermal fatty acid binding protein were elevated over 20-fold in the leptospirosis-infected sea lions. Consistent with leptospirosis infection in rodents, urinary proteins associated with the renin-angiotensin system were depressed, including neprilysin. This study represents a foundation from which to explore the clinical use of urinary protein markers in California sea lions.

  • prevalence of urogenital carcinoma in stranded california sea lions Zalophus californianus from 2005 15
    Journal of Wildlife Diseases, 2018
    Co-Authors: Ailsa J Hall, Kathleen M. Colegrove, James F. X. Wellehan, Padraig J Duignan, Alissa C Deming, Frances M. D. Gulland
    Abstract:

    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.

  • no evidence for clonal transmission of urogenital carcinoma in california sea lions Zalophus californianus
    Wellcome Open Research, 2017
    Co-Authors: Maire Ni Leathlobhair, Frances M. D. Gulland, Elizabeth P Murchison
    Abstract:

    Urogenital carcinoma is a highly metastatic cancer affecting California sea lions ( Zalophus californianus). 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.

  • No evidence for clonal transmission of urogenital carcinoma in California sea lions (Zalophus californianus) [version 1; referees: 2 approved]
    Wellcome, 2017
    Co-Authors: Maire Ni Leathlobhair, Frances M. D. Gulland, Elizabeth P Murchison
    Abstract:

    Urogenital carcinoma is a highly metastatic cancer affecting California sea lions (Zalophus californianus). 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

Sharon R. Melin - One of the best experts on this subject based on the ideXlab platform.

  • accuracy and precision of age determination using growth layer groups for california sea lions Zalophus californianus with known ages
    Marine Mammal Science, 2019
    Co-Authors: Lauren Rust, Sharon R. Melin, Kerri Danil, Brent A Wilkerson
    Abstract:

    Age determination from counts of growth layer groups (GLGs) in tooth dentine is a common method for aging marine mammals. Using known-aged animals, we validated this method for acid etched teeth of California sea lions (CSLs), Zalophus californianus. Between 1991 and 2013, the upper left canine (n = 33) was collected opportunistically during necropsy from animals tagged or branded as pups that later died. Overall, 55%-61% of age estimates by GLG counting were within 1 yr of the known-age in the sample of 1-30-yr-old CSLs. Accuracy of age estimates was found to be dependent on age of the CSLs, however. 71%-79% of age estimates were within 1 yr of the known-age in CSLs <10 yr old. These findings support the validity of counting GLGs to estimate age for CSLs <10 yr old to within 1 yr of accuracy.

  • age and sex specific survival of california sea lions Zalophus californianus at san miguel island california
    Marine Mammal Science, 2017
    Co-Authors: Robert L Delong, Sharon R. Melin, Anthony J Orr, Jeffrey L Laake, Patricia A Morris, Jeffrey D Harris
    Abstract:

    We conducted a mark-recapture study of California sea lions (Zalophus californianus) using pups branded on San Miguel Island, California, from 1987 to 2014, and annual resightings from 1990 to 2015. We used the Burnham model (Burnham 1993), an extension of the Cormack-Jolly-Seber mark-recapture model, which includes recoveries of dead animals, to analyze age, sex, and annual patterns in survival. Generally, females had higher survival than males. For female pups, the average annual survival was 0.600 and for male pups it was 0.574. Yearling survival was 0.758 and 0.757 for females and males, respectively. Peak annual survival was at age 5 and was 0.952 for females and 0.931 for males. Pups with larger mass at branding had higher survival as pups and yearlings, but the effect was relative within each cohort because of large between-cohort variability in survival. Annual variability in sea surface temperature (SST) affected survival. For each 1°C increase in SST, the odds of survival decreased by nearly 50% for pups and yearlings; negative SST anomalies yielded higher survival. Annual variation in male survival was partly explained by leptospirosis outbreaks. Our study provides a unique view of one demographic parameter that contributed to the successful recovery of the California sea lion population.

  • the effects of el nino on the foraging behavior of lactating california sea lions Zalophus californianus californianus during the nonbreeding season
    Canadian Journal of Zoology, 2008
    Co-Authors: Sharon R. Melin, R L Delong, Donald B Siniff
    Abstract:

    We compared the nonbreeding-season foraging behavior of lactating California sea lions (Zalophus californianus californianus (Lesson, 1828)) at San Miguel Island, California, during El Nino conditions in 1993 and non-El Nino conditions in 1996. Lactating females were instrumented with satellite-linked time–depth recorders between January and March in 1993 (n = 6) and 1996 (n = 10) and data were collected through May in each year. Females foraged northwest of the colony, up to 367 km from it and 230 km from the California coast. Mean dive depths ranged from 19.5 to 279.3 m, but most females achieved dives deeper than 400 m. Most females fed exclusively in the offshore habitat, traveled farther from the colony, spent more time traveling, made deeper and longer dives, and terminated lactation earlier during the 1993 El Nino. The results suggest that prey were concentrated in the offshore habitat and located farther from the colony and deeper in the water column during El Nino. Females did not change their fo...

  • an immunogenetic basis for the high prevalence of urogenital cancer in a free ranging population of california sea lions Zalophus californianus
    Immunogenetics, 2005
    Co-Authors: Lizabeth Bowen, Robert L Delong, Sharon R. Melin, Linda J. Lowenstine, Frances M. D. Gulland, Brian Aldridge, Elizabeth L Buckles, Jeffrey L Stott, Michael L Johnson
    Abstract:

    In response to an unprecedented prevalence of cancer recently identified in free-ranging populations of California sea lions [(CSL) (Zalophus californianus], we examined the role of the immunologically important major histocompatibility (MHC) genes in this disease epidemic. Associations between MHC genes and cancer have been well established in humans, but have never before been investigated in wildlife. Using a previously developed technique employing sequence-specific primer-based PCR with intercalating dye technology, MHC genotypes were examined from 27 cancer-positive and 22 cancer-negative CSL stranded along the California coastline. Analyses elucidated an underlying immunogenetic component to the high prevalence of urogenital cancer in sea lions. Furthermore, these results demonstrate the functional relevance of CSL class II MHC by revealing a non-random nature of cancer susceptibility associated with the presence of specific genes.

  • comparative biology of uncinaria spp in the california sea lion Zalophus californianus and the northern fur seal callorhinus ursinus in california
    Journal of Parasitology, 2000
    Co-Authors: Sharon R. Melin
    Abstract:

    Studies on several aspects of the life cycle of hookworms (Uncinaria spp.) in the California sea lion (Zalophus californianus) and northern fur seal (Callorhinus ursinus) were conducted on material collected on San Miguel Island (SMI), California and at The Marine Mammal Center, Sausalito, California in 1997, 1998, and 1999. Examination of Z. californianus intestines for adult hookworms and feces for eggs revealed that longevity of these parasites in pups is about 6–8 mo, and infections are probably not present in older sea lions. Parasitic third-stage larvae (L3) were recovered from the ventral abdominal tissue of Z. californianus, suggesting transmammary transmission. Callorhinus ursinus pups had no hookworm eggs in their feces or adult worms (except for 1 probable contaminant) in their intestines in the fall and early winter, revealing that adult Uncinaria spp. are spontaneously lost at <3 mo of age of the pups. Sand samples from rookeries, used by both Z. californianus and C. ursinus, on SMI were nega...

Robert L Delong - One of the best experts on this subject based on the ideXlab platform.

  • age and sex specific survival of california sea lions Zalophus californianus at san miguel island california
    Marine Mammal Science, 2017
    Co-Authors: Robert L Delong, Sharon R. Melin, Anthony J Orr, Jeffrey L Laake, Patricia A Morris, Jeffrey D Harris
    Abstract:

    We conducted a mark-recapture study of California sea lions (Zalophus californianus) using pups branded on San Miguel Island, California, from 1987 to 2014, and annual resightings from 1990 to 2015. We used the Burnham model (Burnham 1993), an extension of the Cormack-Jolly-Seber mark-recapture model, which includes recoveries of dead animals, to analyze age, sex, and annual patterns in survival. Generally, females had higher survival than males. For female pups, the average annual survival was 0.600 and for male pups it was 0.574. Yearling survival was 0.758 and 0.757 for females and males, respectively. Peak annual survival was at age 5 and was 0.952 for females and 0.931 for males. Pups with larger mass at branding had higher survival as pups and yearlings, but the effect was relative within each cohort because of large between-cohort variability in survival. Annual variability in sea surface temperature (SST) affected survival. For each 1°C increase in SST, the odds of survival decreased by nearly 50% for pups and yearlings; negative SST anomalies yielded higher survival. Annual variation in male survival was partly explained by leptospirosis outbreaks. Our study provides a unique view of one demographic parameter that contributed to the successful recovery of the California sea lion population.

  • ontogenetic dietary information of the california sea lion Zalophus californianus assessed using stable isotope analysis
    Marine Mammal Science, 2012
    Co-Authors: Seth D Newsome, Jeffrey L Laake, Glenn R Vanblaricom, Robert L Delong
    Abstract:

    We used stable carbon ( 13 C) and nitrogen ( 15 N) isotopes to examine ontogenetic dietary changes in 289 California sea lions (Zalophus californianus )a t San Miguel Island, California during 2004–2007. Tissues analyzed included fur, red

  • the role of domoic acid in abortion and premature parturition of california sea lions Zalophus californianus on san miguel island california
    Journal of Wildlife Diseases, 2009
    Co-Authors: T Zabka, Robert L Delong, Elizabeth Wheeler, Mary W. Silver, Sibel Bargu, Tracey Goldstein, Gina M Ylitalo, Tod A Leighfield
    Abstract:

    Domoic acid is a glutaminergic neurotoxin produced by marine algae such as Pseudo-nitzschia australis. California sea lions (Zalophus californianus) ingest the toxin when foraging on planktivorous fish. Adult females comprise 60% of stranded animals admitted for rehabilitation due to acute domoic acid toxicosis and commonly suffer from reproductive failure, including abortions and premature live births. Domoic acid has been shown to cross the placenta exposing the fetus to the toxin. To determine whether domoic acid was playing a role in reproductive failure in sea lion rookeries, 67 aborted and live-born premature pups were sampled on San Miguel Island in 2005 and 2006 to investigate the causes for reproductive failure. Analyses included domoic acid, contaminant and infectious disease testing, and histologic examination. Pseudo-nitzschia spp. were present both in the environment and in sea lion feces, and domoic acid was detected in the sea lion feces and in 17% of pup samples tested. Histopathologic fin...

  • an immunogenetic basis for the high prevalence of urogenital cancer in a free ranging population of california sea lions Zalophus californianus
    Immunogenetics, 2005
    Co-Authors: Lizabeth Bowen, Robert L Delong, Sharon R. Melin, Linda J. Lowenstine, Frances M. D. Gulland, Brian Aldridge, Elizabeth L Buckles, Jeffrey L Stott, Michael L Johnson
    Abstract:

    In response to an unprecedented prevalence of cancer recently identified in free-ranging populations of California sea lions [(CSL) (Zalophus californianus], we examined the role of the immunologically important major histocompatibility (MHC) genes in this disease epidemic. Associations between MHC genes and cancer have been well established in humans, but have never before been investigated in wildlife. Using a previously developed technique employing sequence-specific primer-based PCR with intercalating dye technology, MHC genotypes were examined from 27 cancer-positive and 22 cancer-negative CSL stranded along the California coastline. Analyses elucidated an underlying immunogenetic component to the high prevalence of urogenital cancer in sea lions. Furthermore, these results demonstrate the functional relevance of CSL class II MHC by revealing a non-random nature of cancer susceptibility associated with the presence of specific genes.

  • penetration of the small intestine of a california sea lion Zalophus californianus pup by adult hookworms uncinaria spp
    Parasitology Research, 2004
    Co-Authors: E T Lyons, Robert L Delong, R R Zink
    Abstract:

    During a study on the mortality of California sea lion (Zalophus californianus) pups born on San Miguel Island, California in 2002, two adult female hookworms (Uncinaria spp) were found penetrating the serosal surface of the intestinal wall and protruding into the peritoneal cavity of one pup. Documentation and a description of this unexpected finding and associated lesions are presented here. Also, adult hookworms were found in the peritoneal fluid of two other dead Z. californianus pups.

Tracey Goldstein - One of the best experts on this subject based on the ideXlab platform.

  • Isolation of a novel adenovirus from California sea lions Zalophus californianus.
    Diseases of Aquatic Organisms, 2011
    Co-Authors: Tracey Goldstein, Kathleen M. Colegrove, M. Hanson, Frances M. D. Gulland
    Abstract:

    Viral hepatitis associated with adenoviral infection has been reported in California sea lions Zalophus californianus admitted to rehabilitation centers along the California coast since the 1970s. Canine adenovirus 1 (CAdV-1) causes viral hepatitis in dogs and infects a number of wildlife species. Attempts to isolate the virus from previous sea lion hepatitis cases were unsuccessful, but as the hepatitis had morphologic features resembling canine infectious hepatitis, and since the virus has a wide host range, it was thought that perhaps the etiologic agent was CAdV-1. Here, we identify a novel adenovirus in 2 stranded California sea lions and associate the infection with viral hepatitis and endothelial cell infection. Phylogenetic analysis confirmed the classification of the sea lion adeno - virus in the Mastadenovirus genus with the most similarity to tree shrew adenovirus 1 (TSAdV-1, 77%). However, as the sea lion adenovirus appeared to be equally distant from the other Mastadeno - virus species based on phylogenetic analysis, results indicate that it represents an independent lineage and species. Although sequences from this novel virus, otarine adenovirus 1 (OtAdV-1), show some similarity to CAdV-1 and 2, it is clearly distinct and likely the cause of the viral hepatitis in the stranded California sea lions.

  • the role of domoic acid in abortion and premature parturition of california sea lions Zalophus californianus on san miguel island california
    Journal of Wildlife Diseases, 2009
    Co-Authors: T Zabka, Robert L Delong, Elizabeth Wheeler, Mary W. Silver, Sibel Bargu, Tracey Goldstein, Gina M Ylitalo, Tod A Leighfield
    Abstract:

    Domoic acid is a glutaminergic neurotoxin produced by marine algae such as Pseudo-nitzschia australis. California sea lions (Zalophus californianus) ingest the toxin when foraging on planktivorous fish. Adult females comprise 60% of stranded animals admitted for rehabilitation due to acute domoic acid toxicosis and commonly suffer from reproductive failure, including abortions and premature live births. Domoic acid has been shown to cross the placenta exposing the fetus to the toxin. To determine whether domoic acid was playing a role in reproductive failure in sea lion rookeries, 67 aborted and live-born premature pups were sampled on San Miguel Island in 2005 and 2006 to investigate the causes for reproductive failure. Analyses included domoic acid, contaminant and infectious disease testing, and histologic examination. Pseudo-nitzschia spp. were present both in the environment and in sea lion feces, and domoic acid was detected in the sea lion feces and in 17% of pup samples tested. Histopathologic fin...

  • novel symptomatology and changing epidemiology of domoic acid toxicosis in california sea lions Zalophus californianus an increasing risk to marine mammal health
    Proceedings of The Royal Society B: Biological Sciences, 2008
    Co-Authors: T Zabka, Jonna A K Mazet, Mary W. Silver, Sibel Bargu, Tracey Goldstein, Kathleen M. Colegrove, Gregg W Langlois, F Van Dolah
    Abstract:

    Harmful algal blooms are increasing worldwide, including those of Pseudo-nitzschia spp. producing domoic acid off the California coast. This neurotoxin was first shown to cause mortality of marine mammals in 1998. A decade of monitoring California sea lion (Zalophus californianus) health since then has indicated that changes in the symptomatology and epidemiology of domoic acid toxicosis in this species are associated with the increase in toxigenic blooms. Two separate clinical syndromes now exist: acute domoic acid toxicosis as has been previously documented, and a second novel neurological syndrome characterized by epilepsy described here associated with chronic consequences of previous sub-lethal exposure to the toxin. This study indicates that domoic acid causes chronic damage to California sea lions and that these health effects are increasing.