The Toxic Effects of Environmental Domoic Acid Exposure on Humans and Marine Wildlife.

Biotoxins produced by harmful algal blooms (HABs) are a substantial global threat to ocean and human health. Domoic acid (DA) is one such biotoxin whose negative impacts are forecasted to increase with climate change and coastal development. This manuscript serves as a review of DA toxicosis after environmental exposure in humans and wildlife, including an introduction to HAB toxins, the history of DA toxicosis, DA production, toxicokinetic properties of DA, susceptibility, clinical signs, DA detection methods and other diagnostic tests, time course of toxicosis, treatment, prognostics, and recommendations for future research.

Evaluation of Two Serologic Tests for Rapid Detection of Anti-Leptospira Antibodies in California Sea Lions (Zalophus californianus).

Leptospirosis is a bacterial zoonosis impacting wild and domestic animals globally. Leptospira interrogans serovar Pomona is endemic in free-ranging California sea lions (CSLs; Zalophus californianus), and leptospirosis is frequently diagnosed in stranded CSLs. Serum microscopic agglutination test (MAT) is a commonly performed diagnostic assay, and CSLs with clinical disease have reliably elevated MAT titers.

Comparative pharmacokinetics of a single oral dose of meloxicam in the California sea lion (Zalophus californianus) and Pacific harbor seal (Phoca vitulina richardii).

Pharmacokinetics studies have investigated meloxicam, a non-steroidal anti-inflammatory drug, dosing strategies in a wide variety of non-domestic animals; however, there is no prior study examining well-founded dosing for pinnipeds. To develop dosing protocols, pharmacokinetic information is needed, with an examination of differences between pinniped species. Apparently, healthy California sea lions (Zalophus californianus: CSL; n = 13) and Pacific harbor seals (Phoca vitulina richardii: PHS; n = 17) that had completed rehabilitation were enrolled into a population-based pharmacokinetic study.

Identification of Candidate Protein Biomarkers Associated with Domoic Acid Toxicosis in Cerebrospinal Fluid of California Sea Lions ().

Since 1998, California sea lion () stranding events associated with domoic acid toxicosis (DAT) have consistently increased. Outside of direct measurement of domoic acid in bodily fluids at the time of stranding, there are no practical nonlethal clinical tests for the diagnosis of DAT that can be utilized in a rehabilitation facility. Proteomics analysis was conducted to discover candidate protein markers of DAT using cerebrospinal fluid from stranded California sea lions with acute DAT ( = 8), chronic DAT ( = 19), or without DAT ( = 13).

The symptomatology and diagnosis of domoic acid toxicosis in stranded California sea lions (): a review and evaluation of 20 years of cases to guide prognosis.

Introduction: Domoic acid (DA) is a glutaminergic excitatory neurotoxin that causes the morbidity and mortality of California sea lions (Zalophus californianus; CSL) and other marine mammals due to a suite of effects mostly on the nervous and cardiac systems. Between 1998 and 2019, 11,737 live-stranded CSL were admitted to The Marine Mammal Center (TMMC; Sausalito, CA, USA), over 2,000 of which were intoxicated by DA. A plethora of clinical research has been performed over the past 20 years to characterize the range of toxic effects of DA exposure on CSLs, generating the largest dataset on the effects of natural exposure to this toxin in wildlife.

RETROSPECTIVE REVIEW OF PROPOFOL ANESTHESIA IN MULTIPLE ELASMOBRANCH SPECIES AT GEORGIA AQUARIUM, 2010-2022.

General anesthesia is often required in elasmobranch species for medical procedures. A variety of anesthetic drugs have been administered to elasmobranchs with wide variability in efficacy and safety. A retrospective review of 47 anesthetic procedures using IV propofol in eight different elasmobranch species at the Georgia Aquarium from 2010 to 2022 was performed.

Xenotransplantation of porcine progenitor cells in an epileptic California sea lion (Zalophus californianus): illustrative case.

Background: Domoic acid (DA) is a naturally occurring neurotoxin harmful to marine animals and humans. California sea lions exposed to DA in prey during algal blooms along the Pacific coast exhibit significant neurological symptoms, including epilepsy with hippocampal atrophy.

Observations: Here the authors describe a xenotransplantation procedure to deliver interneuron progenitor cells into the damaged hippocampus of an epileptic sea lion with suspected DA toxicosis.

Cannabinoid receptor 1-labeled boutons in the sclerotic dentate gyrus of epileptic sea lions.

Pathology in the dentate gyrus, including sclerosis, is a hallmark of temporal lobe epilepsy, and reduced inhibition to dentate granule cells may contribute to epileptogenesis. The perisomatic-targeting axonal boutons of parvalbumin-expressing interneurons decrease in proportion with granule cells in temporal lobe epilepsy. In contrast, dendrite-targeting axonal boutons of somatostatin-expressing interneurons sprout exuberantly in temporal lobe epilepsy.

Diffuse large B cell lymphoma and a novel gammaherpesvirus in northern elephant seals Mirounga angustirostris.

Two emaciated male northern elephant seal (NES) Mirounga angustirostris pups were admitted to The Marine Mammal Center (Sausalito, California, USA) and treated for malnutrition. Complete blood counts showed a progressive moderate to marked leukocytosis characterized by a predominance of large monomorphic mononuclear cells of probable lymphoid origin, frequently with flower-shaped nuclei. Both seals were euthanized due to suspected lymphoid neoplasia.

Fetal mercury concentrations in central California Pacific harbor seals: Associated drivers and outcomes.

Mercury (Hg) is a well-known toxicant in wildlife and humans. High total Hg concentrations ([THg]) have been reported in central California harbor seals Phoca vitulina richardii. We evaluated the effects of presence/absence of early natal coat (lanugo), year (2012 to 2017), sex, stranding location, and trophic ecology (ẟC and ẟN values) on hair [THg] along coastal central California.

CLINICAL AND MICROBIOLOGICAL CHARACTERIZATION OF LYMPH NODE ABSCESSATION IN PUP AND YEARLING CALIFORNIA SEA LIONS () UNDERGOING REHABILITATION IN A MARINE MAMMAL CENTER.

Severe focal to multifocal abscessation of the axillary and inguinal lymph nodes is an important cause of morbidity and mortality in stranded pup and yearling California sea lions (; CSLs) at The Marine Mammal Center (TMMC). A retrospective case review was conducted of all pup and yearling CSLs with axillary and/or inguinal lymph node abscesses admitted to this California rehabilitation center between January 2015 and December 2019 ( = 162). Clinical data and cultured isolates were evaluated to (1) characterize the clinical syndrome, (2) report isolated pathogens, and (3) investigate factors associated with clinical outcome (survival to release versus death).

Genetics and pathology associated with Klebsiella pneumoniae and Klebsiella spp. isolates from North American Pacific coastal marine mammals.

Southern sea otters (SSO: Enhydra lutris nereis) are a federally-listed threatened subspecies found almost exclusively in California, USA. Despite their zoonotic potential and lack of host specificity, K. pneumoniae and Klebsiella spp.

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

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.

THE USE OF EPHEDRINE TO TREAT ANESTHESIA-ASSOCIATED HYPOTENSION IN PINNIPEDS.

Hypotension is a common adverse effect of general anesthesia that has historically been difficult to measure in pinniped species due to technical challenges. A retrospective case review found seven pinniped cases that demonstrated anesthesia-associated hypotension diagnosed by direct blood pressure measurements during general anesthesia at The Marine Mammal Center (Sausalito, CA) between 2017 and 2019. Cases included five California sea lions (CSL: ), one Hawaiian monk seal (HMS: ), and one northern elephant seal (NES: ).

OPTIMIZATION OF FECAL FLOTATIONS IN MARINE PARASITOLOGY AND DETERMINATION OF THE SPECIFIC GRAVITY OF HELMINTH EGGS IN PINNIPEDS.

Recent studies have sought to optimize the fecal flotation procedure to improve the detection of helminth eggs in terrestrial domestic species. It is unclear, however, whether these efforts in optimization are applicable to parasite species of marine environments, and verification of veterinary diagnostic procedures is clinically important. It was hypothesized that the eggs belonging to the parasites of pinnipeds would have different specific gravities (SpG) than those belonging to terrestrial hosts.

PHARMACOKINETICS OF SUBCUTANEOUS ALPHA LIPOIC ACID, A PROPOSED THERAPEUTIC AID FOR DOMOIC ACID INTOXICATION IN CALIFORNIA SEA LIONS ().

Domoic acid (DA) is a potent neurotoxin produced by certain marine algae that can cause neurologic and cardiac dysfunction by activating glutamate receptors. Glutamate receptor overexcitation results in continuous cellular activation, oxidative damage, and cell death. DA toxicosis causes disorientation and seizures, and antiseizure medications are the primary treatment.

Use of potassium chloride for low-residue euthanasia of anesthetized California sea lions () and northern elephant seals () with life-threatening injury or disease.

Objective: To demonstrate the efficacy of potassium chloride (KCl) for low-residue euthanasia of anesthetized pinnipeds in field settings for which carcass retrieval for disposal is not feasible.

Animals: Stranded, free-ranging California sea lions (CSLs; ; n = 17) and northern elephant seals (NESs; ; 6) with life-threatening injury or disease between May and August 2020.

Procedures: Each animal was anesthetized and then received a lethal dose of KCl solution administered by IV or intracardiac injection.

Exploration of serum cardiac troponin I as a biomarker of cardiomyopathy in southern sea otters .

Objective: To compare serum cardiac troponin I (cTnI) concentrations between sea otters with and without cardiomyopathy and describe 2 cases of cardiomyopathy with different etiologies.

Animals: 25 free-ranging southern sea otters with (n = 14; cases) and without (11; controls) cardiomyopathy and 17 healthy managed southern sea otters from aquariums or rehabilitation centers (controls).

Procedures: Serum cTnI concentration was measured in live sea otters.

TRANSTHORACIC ECHOCARDIOGRAPHIC EVALUATION AND SERUM CARDIAC TROPONIN VALUES IN ANESTHETIZED HEALTHY FEMALE SOUTHERN SEA OTTERS ().

Information about antemortem cardiac evaluation in sea otters () is limited, despite well-established clinical care and rehabilitation procedures and a reported elevated risk of cardiac disease for this species. Serum cardiac troponin I (cTnI) concentration and echocardiographic assessment are two ways of screening for and diagnosing cardiac disease. However, no baseline data or reference intervals for either evaluation are published for sea otters.

CLASSIFICATION AND REGRESSION TREE ANALYSIS FOR PREDICTING PROGNOSIS IN WILDLIFE REHABILITATION: A CASE STUDY OF LEPTOSPIROSIS IN CALIFORNIA SEA LIONS ().

The spirochete bacterium serovar Pomona is enzootic to California sea lions (CSL; ) and causes periodic epizootics. Leptospirosis in CSL is associated with a high fatality rate in rehabilitation. Evidence-based tools for estimating prognosis and guiding early euthanasia of animals with a low probability of survival are critical to reducing the severity and duration of animal suffering.

Occurrence of Mycoplasmas in Galapagos Sea Lions (Zalophus wollebaeki) and their Association with Other Respiratory Pathogens.

During the 2018 breeding season, an outbreak of respiratory disease occurred among Galapagos sea lions (Zalophus wollebaeki) that inhabit rookeries near urban areas with introduced fauna such as dogs and cats. Several sea lions had nasal discharge and respiratory distress and were in poor body condition. Eighteen sea lions were captured for a general health assessment including collection of blood for serology and nasal discharge for culture and PCR.

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

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.

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

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.

Plasma concentrations of itraconazole following a single oral dose in juvenile California sea lions (Zalophus californianus).

The objective of this study was to establish a single-dose pharmacokinetic profile for orally administered itraconazole in California sea lions (Zalophus californianus). Twenty healthy rehabilitated juvenile California sea lions were included in this study. Itraconazole capsules were administered orally with food at a target dose of 5-10 mg/kg.

Treatment of Canine Tooth Fractures in the Northern Elephant Seal ( Mirounga angustirostris): Three Cases.

The Marine Mammal Center (TMMC) in Sausalito, California, rescues, rehabilitates, and releases hundreds of stranded northern elephant seals ( Mirounga angustirostris) each year. Common causes for stranding include maternal separation, malnutrition, and trauma. Causes of trauma include shark bites, conspecific interactions, and anthropogenic factors.