Gross and histopathologic diagnoses from North Atlantic right whale Eubalaena glacialis mortalities between 2003 and 2018.

Seventy mortalities of North Atlantic right whales Eubalaena glacialis (NARW) were documented between 2003 and 2018 from Florida, USA, to the Gulf of St. Lawrence, Canada. These included 29 adults, 14 juveniles, 10 calves, and 17 of unknown age class. Females represented 65.5% (19/29) of known-sex adults. Fourteen cases had photos only; 56 carcasses received external examinations, 44 of which were also necropsied. Cause of death was determined in 43 cases, of which 38 (88.4%) were due to anthropogenic trauma: 22 (57.9%) from entanglement, and 16 (42.1%) from vessel strike. Gross and histopathologic lesions associated with entanglement were often severe and included deep lacerations caused by constricting line wraps around the flippers, flukes, and head/mouth; baleen plate mutilation; chronic extensive bone lesions from impinging line, and traumatic scoliosis resulting in compromised mobility in a calf. Chronically entangled whales were often in poor body condition and had increased cyamid burden, reflecting compromised health. Vessel strike blunt force injuries included skull and vertebral fractures, blubber and muscle contusions, and large blood clots. Propeller-induced wounds often caused extensive damage to blubber, muscle, viscera, and bone. Overall prevalence of NARW entanglement mortalities increased from 21% (1970-2002) to 51% during this study period. This demonstrates that despite mitigation efforts, entanglements and vessel strikes continue to inflict profound physical trauma and suffering on individual NARWs. These cumulative mortalities are also unsustainable at the population level, so urgent and aggressive intervention is needed to end anthropogenic mortality in this critically endangered species.

Deadly diving? Physiological and behavioural management of decompression stress in diving mammals.

Decompression sickness (DCS; 'the bends') is a disease associated with gas uptake at pressure. The basic pathology and cause are relatively well known to human divers. Breath-hold diving marine mammals were thought to be relatively immune to DCS owing to multiple anatomical, physiological and behavioural adaptations that reduce nitrogen gas (N(2)) loading during dives. However, recent observations have shown that gas bubbles may form and tissue injury may occur in marine mammals under certain circumstances. Gas kinetic models based on measured time-depth profiles further suggest the potential occurrence of high blood and tissue N(2) tensions. We review evidence for gas-bubble incidence in marine mammal tissues and discuss the theory behind gas loading and bubble formation. We suggest that diving mammals vary their physiological responses according to multiple stressors, and that the perspective on marine mammal diving physiology should change from simply minimizing N(2) loading to management of the N(2) load. This suggests several avenues for further study, ranging from the effects of gas bubbles at molecular, cellular and organ function levels, to comparative studies relating the presence/absence of gas bubbles to diving behaviour. Technological advances in imaging and remote instrumentation are likely to advance this field in coming years.

Tissue distribution of phocine herpesvirus-1 (PhHV-1) in infected harbour seals (Phoca vitulina) from the central Californian coast and a comparison of diagnostic methods.

The polymerase chain reaction (PCR) was used to determine the tissue distribution of phocine herpesvirus-1 (PhHV-1) DNA in 20 stranded Pacific harbour seals (17 pups and three seals older than one year) that died during rehabilitation. The aim was to begin to define stages of infection and to investigate the relation between the presence of PhHV-1 in tissues, histological lesions and serology. PhHV-1 DNA was detected in a wide range of tissues from 10/17 pups and 3/3 subadults or adults. Different clinical patterns emerged from the examination of ante- and post-mortem samples. These patterns probably represented pups with active PhHV-1 infection, pups recovering from infection, and older harbour seals with chronic, reactivated infection. As PhHV-1 DNA was detected in tissues in the absence of typical histological lesions in seven seals and in the absence of PhHV-1 specific antibodies in four seals, it is clear that both histological examination and serology underestimate the presence of infection. These results showed that infection can occur in the absence of obvious disease and that seroconversion may be associated with clinical recovery.

Discovery of a Novel Hepatovirus (Phopivirus of Seals) Related to Human Hepatitis A Virus.

UNLABELLED: Describing the viral diversity of wildlife can provide interesting and useful insights into the natural history of established human pathogens. In this study, we describe a previously unknown picornavirus in harbor seals (tentatively named phopivirus) that is related to human hepatitis A virus (HAV). We show that phopivirus shares several genetic and phenotypic characteristics with HAV, including phylogenetic relatedness across the genome, a specific and seemingly quiescent tropism for hepatocytes, structural conservation in a key functional region of the type III internal ribosomal entry site (IRES), and a codon usage bias consistent with that of HAV. IMPORTANCE: Hepatitis A virus (HAV) is an important viral hepatitis in humans because of the substantial number of cases each year in regions with low socioeconomic status. The origin of HAV is unknown, and no nonprimate HAV-like viruses have been described. Here, we describe the discovery of an HAV-like virus in seals. This finding suggests that the diversity and evolutionary history of these viruses might be far greater than previously thought and may provide insight into the origin and pathogenicity of HAV.

Low level lead neurotoxicity in a pregnant guinea pigs model: neuroglial enzyme activities and brain trace metal concentrations.

Specific activities of the astroglial marker glutamine synthetase (GS), and the oligodendroglial marker glycerol-3-phosphate dehydrogenase (GPDH) were measured in the spinal cord of fetal guinea pigs and their dams following chronic exposure to low levels of lead (Pb) during gestation. In addition, the effects of Pb on intracellular trace metals (Cu, Fe, Zn) were measured in the blood, cerebellum and forebrain. Aminolevulinic acid dehydratase (ALAD) and zinc protoporphyrin IX (ZPP) were measured in order to monitor established parameters of Pb-exposure. Pregnant guinea pigs were orally administered 0, 5.5 or 11 mg Pb/kg body weight for 30 or 40 days commencing on day 22 of gestation. Blood Pb levels produced in dams and fetuses were at or near the currently identified "no effect" levels for children (10-30 micrograms/dl). These Pb blood levels produced a significant (P less than 0.05) dose-dependent decrease in GS and GPDH activity in the dams and fetuses. Fe and Zn concentrations in blood, cerebellum and forebrain of both dams and fetuses were significantly (P less than 0.05) decreased in a dose-dependent manner. However, Cu concentrations in the blood, cerebellum and forebrain were decreased in the dams but increased in the fetuses in a dose-dependent fashion. The alteration of trace metal concentrations is a proposed mechanism of Pb neurotoxicity. Blood ALAD activity was significantly (P less than 0.05) decreased and ZPP levels were significantly (P less than 0.05) increased, as expected in Pb-exposed animals. This study presents the first biochemical evidence for the alteration of neuroglial function at low levels of Pb exposure and focuses attention on the fetus as an important Pb target.

Lead toxicity in neuroglia.

In this article we evaluate evidence that neuroglia (astroglia and oligodendroglia) are primary targets for lead toxicity in the central nervous system or mediate its pathogenesis. An integrated overview of morphologic and biochemical evidence from clinical cases, experimental animals, and cell culture models is attempted. Our review encompasses both high-level lead exposure that produces lead encephalopathy and low-level lead exposure that is associated with cognitive deficits. We also discuss the selection of toxicologically relevant lead doses for cell culture studies. The evidence is compelling that both astroglia and oligodendroglia respond directly or indirectly to lead exposure in ways that could impair brain function. However, at this time more is understood about the responses of astroglia than those of oligodendroglia. Though oligodendroglia appear sensitive to lead in cell culture, as measured by loss of viability and enzyme activity, it is not clear whether their responses to Pb exposure in vivo are primary or secondary to other tissue and cell damage. Astroglia show a definitive primary response in vivo and in vitro to high-level lead exposure, the uptake and storage of Pb intracellularly, possibly by Pb- binding macromolecules. Astroglia also exhibit reactive gliosis, but probably as a secondary response to other tissue damage by high lead levels. The hypothesis that astroglia serve a protective function in the brain by acting as a lead depot in encephalopathy is well supported by several whole animal and cell culture studies. In addition, alterations of glutamine synthetase activity, which have been reported in the astroglia of animals chronically exposed to low levels of lead, bear further investigation.

Morphological alterations of neurons and astrocytes in guinea pigs exposed to low levels of inorganic lead.

Both astrocytes and neurons potentially undergo structural and functional alterations in the brains of animals exposed to low levels of lead (Pb). No morphometric studies of astrocytes have been reported to date in animals in low Pb exposure. In the present study, morphometric measurements of astrocytes and pyramidal neurons in the frontoparietal cortex were made in guinea pigs exposed postnatally (5 or 10 days) or prenatally (gestational day 22 to birth) to low Pb levels. Although few significant effects of Pb treatment were detected by the rigorous statistical model applied, a recurring trend was noted for postnatal Pb treatment to increase astrocyte maximum diameter (dmax). In addition, prenatal Pb treatment was associated with increased apical and basal dendritic length, increased total apical dendrites per cell and an increased basal branching complexity in neurons.

Influence of life-history parameters on organochlorine concentrations in free-ranging killer whales (Orcinus orca) from Prince William Sound, AK.

Certain populations of killer whales (Orcinus orca) have been extensively studied over the past 30 years, including populations that use Puget Sound, WA, the inside waters of British Columbia, Southeastern Alaska and Kenai Fjords/Prince William Sound, Alaska. Two eco-types of killer whales, 'transient' and 'resident', occur in all of these regions. These eco-types are genetically distinct and differ in various aspects of morphology, vocalization patterns, diet and habitat use. Various genetic and photo-identification studies of eastern North Pacific killer whales have provided information on the male-female composition of most of these resident pods and transient groups, as well as the approximate ages, reproductive status and putative recruitment order (birth order) of the individual whales. Biopsy blubber samples of free-ranging resident and transient killer whales from the Kenai Fjords/Prince William Sound, AK region were acquired during the 1994-1999 field seasons and analyzed for selected organochlorines (OCs), including dioxin-like CB congeners and DDTs. Concentrations of OCs in transient killer whales (marine mammal-eating) were much higher than those found in resident animals (fish-eating) apparently due to differences in diets of these two killer whale eco-types. Certain life-history parameters such as sex, age and reproductive status also influenced the concentrations of OCs in the Alaskan killer whales. Reproductive female whales contained much lower levels of OCs than sexually immature whales or mature male animals in the same age class likely due to transfer of OCs from the female to her offspring during gestation and lactation. Recruitment order also influenced the concentrations of OCs in the Alaskan killer whales. In adult male residents, first-recruited whales contained much higher OC concentrations than those measured in non-first-recruited (e.g. second recruited, third recruited) resident animals in the same age group. This study provides baseline OC data for free ranging Alaskan killer whales for which there is little contaminant information.

Specimen banking of marine organisms in the United States: current status and long-term prospective.

A major part of the activities conducted over the last decade by the National Biomonitoring Specimen Bank (NBSB) has involved the archival of marine specimens collected by ongoing environmental monitoring programs. These archived specimens include bivalves, marine sediments, and fish tissues collected by the National Status and Trends and the Exxon Valdez Oil Spill Damage Assessment programs, and marine mammal tissues collected by the Marine Mammal Health and Stranding, Response Program and the Alaska Marine Mammal Tissue Archival Project. In addition to supporting these programs, the specimens have been used to investigate circumpolar patterns of chlorinated hydrocarbon concentrations, genetic separation of marine animal stocks, baseline levels of essential and nonessential elements in marine mammals, and the potential risk to human consumers in the Arctic from anthropogenic contaminants found in local subsistence foods. The NBSB specimens represent a resource that has the potential for addressing future issues of marine environmental quality and ecosystem changes through retrospective analysis; however, an ecosystem-based food web approach would maximize this potential. The current status of the NBSB activities related to the banking of marine organisms is presented and discussed, the long-term prospective of these activities is presented, and the importance of an ecosystem-based food web monitoring approach to the value of specimen banking is discussed.

Preliminary study of the ultrasonographic diagnosis of pregnancy and fetal development in the dog.

A total of 18 dogs were examined by ultrasound during their gestation period. At gestational day 7, a uterus indicative of possible pregnancy was observed. At gestational day 10, the embryo was observed. Fetal and cardiac activities appeared at 28 days. Rapid increases of the crown-rump length and biparietal diameter occurred between the 5th and the 6th weeks of gestation and of the body diameter between the 4th and 5th weeks and again between the 6th and the 7th weeks of gestation.

Emergence of fatal avian influenza in New England harbor seals.

UNLABELLED: From September to December 2011, 162 New England harbor seals died in an outbreak of pneumonia. Sequence analysis of postmortem samples revealed the presence of an avian H3N8 influenza A virus, similar to a virus circulating in North American waterfowl since at least 2002 but with mutations that indicate recent adaption to mammalian hosts. These include a D701N mutation in the viral PB2 protein, previously reported in highly pathogenic H5N1 avian influenza viruses infecting people. Lectin staining and agglutination assays indicated the presence of the avian-preferred SAα-2,3 and mammalian SAα-2,6 receptors in seal respiratory tract, and the ability of the virus to agglutinate erythrocytes bearing either the SAα-2,3 or the SAα-2,6 receptor. The emergence of this A/harbor seal/Massachusetts/1/2011 virus may herald the appearance of an H3N8 influenza clade with potential for persistence and cross-species transmission. IMPORTANCE: The emergence of new strains of influenza virus is always of great public concern, especially when the infection of a new mammalian host has the potential to result in a widespread outbreak of disease. Here we report the emergence of an avian influenza virus (H3N8) in New England harbor seals which caused an outbreak of pneumonia and contributed to a U.S. federally recognized unusual mortality event (UME). This outbreak is particularly significant, not only because of the disease it caused in seals but also because the virus has naturally acquired mutations that are known to increase transmissibility and virulence in mammals. Monitoring the spillover and adaptation of avian viruses in mammalian species is critically important if we are to understand the factors that lead to both epizootic and zoonotic emergence.

Toxicology of carbaryl and aldicarb on brain and limb cultures of chick embryos.

A variety of carbamates have been developed since the 1960s for use as broad-spectrum insecticides. An easy and inexpensive in vitro assay using chick-embryo derived cells was examined for its capability to screen and test the toxicity of these compounds. Chick embryo brain and limb bud cultures were treated with different concentrations of either carbaryl or aldicarb with or without activation (+/- S-9) for 5 days. Viability and cytotoxicity using the neutral red assay, and carbamate effects on cell migration and colony spread were measured. S-9 decreased the effects of carbaryl and aldicarb on brain cell cytotoxicity at exposures of 15-60 ppm and 40-200 ppm, respectively, as indicated by increased concentrations of neutral red. Viability of brain cell cultures was not altered by aldicarb, but was decreased by carbaryl plus S-9 in concentrations of greater than 40 ppm. In limb cultures, carbaryl without S-9 was significantly toxic at 8-25 ppm, but only concentrations of greater than 25 ppm of carbaryl plus S-9 significantly affected cytotoxicity. In contrast, aldicarb without S-9 caused no effect on limb cell cytotoxicity at concentrations of 40-200 ppm, but aldicarb plus S-9 significantly reduced cellular cytotoxicity at concentrations of greater than 160 ppm. Carbaryl +/- S-9 decreased the spread of both brain and limb colonies; aldicarb +/- S-9 caused a significant increase in the spread of the brain but not limb colonies.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of a 48 hour continuous intravenous infusion of CGS 13080-primagrel, a selective thromboxane synthetase inhibitor, on the perinatal and early postnatal period in the guinea pig.

CGS 13080, imidazo[1,5-a]pyridine-5-hexanoic acid, was evaluated for perinatal and postnatal effects in third trimester pregnant guinea pigs and their offspring. The compound was administered via 48 hour continuous intravenous infusion to a group of pregnant guinea pigs (n = 16) at a dose of 3 mg/kg/hr starting on gestational day 52 (via chronically implanted indwelling jugular venous cannulas). A saline control group (n = 12) received equivalent volumes of normal saline 0.5 ml/kg/hr throughout the dosing period. A third group (surgery-sham, n = 16) was subjected to cannulation but not infused. A gross examination of each dam and piglets was conducted at necropsy on day 5 of lactation. The neonatal brains and all gross lesions (maternal and neonatal) were removed and fixed for histopathological examination. Compound-related clinical signs were noted in dams during the dosing phase of gestation. Six guinea pigs developed cephalic lymphatic swelling during the infusion. This observation may be correlated to the reported redistribution of fluid volume to the thorax of guinea pigs given intravenous injections of CGS 13080. There were no compound-induced effects on labor, delivery, or any of the examined reproductive parameters. There were no compound-related clinical signs, or effects on survival, body weight and developmental parameters in the F1 generation. Histopathological examination of the brains and other organs did not reveal any compound-related abnormalities. Based on these results, it was concluded that CGS 13080 did not elicit adverse perinatal and postnatal effects in guinea pigs.

Interaction of lead and zinc in cultured astroglia.

Astroglia take up lead (Pb) in vivo and in vitro. In view of the fact that zinc affects both tissue deposition of Pb and clinical signs of Pb intoxication, the present study was carried out to test the effects of various Zn levels on lead toxicity in astroglia. Primary cultures of astroglia from 1- to 3-day-old neonatal rats were divided into three groups and cultured in Waymouth's 752/l medium with 0, 1, or 2 microM ZnCl2. Each group was further divided into two subgroups which were treated with either 0, 29.9, or 32.5 mumol of Pb acetate. Cultures were assayed for viability and metal content after 1 and 3 days of continuous exposure to Pb (designated days 1 and 3) as well as 10, 17, and 24 days after the initiation of a 3-day exposure to Pb. The Trypan blue dye exclusion viability assay showed no significant differences between controls and Pb-treated groups except on day 3, at which time the 0 and 2 microM Zn groups treated with Pb had reduced viability. 3H-Leucine incorporation into acid-precipitable proteins (cpm/micrograms protein) was unaffected by Pb or Zn except on days 1 and 17, when cultures given 2 microM Zn and no Pb showed increased incorporation. Pb-treated cultures showed a reduction in cell number which was partially offset in a dose-dependent manner by the presence of Zn in the medium but not enough to mask completely the reduction caused by Pb. Pb produced the following effects on intracellular trace metal concentrations: (1) increased intracellular [Pb]. (2) increased intracellular [Fe], (3) increased intracellular [Cu], and increased intracellular [Zn]. By day 24, intracellular Cu concentrations were normal, but intracellular [Zn] and [Pb] remained elevated in all Pb-treated subgroups. Furthermore, intracellular Fe levels remained increased in the Pb-treated subgroup cultured with 0 microM Zn. Zinc showed a protective effect by (1) reducing intracellular Pb levels and (2) delaying or preventing the Pb-induced increase in intracellular [Fe] and [Zn] but not the increase in intracellular [Cu]. These effects became more pronounced with increasing extracellular Zn concentrations, although intracellular Zn levels did not increase in response to extracellular levels. Increased dietary zinc in rats is known to reduce Pb accumulation in organs. Our results extend this observation to cells in culture and, furthermore, suggest that the Pb-Zn interaction is complex and not simply a substitution of Pb by Zn at the point of absorption through the plasma membrane.

Thermoregulation of the intra-abdominal testes of the bottlenose dolphin (Tursiops truncatus) during exercise.

Dolphins possess a vascular countercurrent heat exchanger (CCHE) that functions to cool their intra-abdominal testes. Spermatic arteries in the posterior abdomen are juxtaposed to veins returning cooled blood from the surfaces of the dorsal fin and tail flukes. In this study, we investigated the effect of exercise on CCHE function in the bottlenose dolphin. The CCHE flanks a region of the bowel in the posterior abdomen and influences colonic temperatures. A rectal probe housing a linear array of seven copper-constantan thermocouples was designed to measure colonic temperatures simultaneously at positions anterior to, within and posterior to the region of the colon flanked by the CCHE. Immediately after vigorous swimming, temperatures at the CCHE decreased relative to resting and pre-swim values: post-swim temperatures at the CCHE were maximally 0.5 degrees C cooler than pre-swim temperatures. These data suggest that the CCHE has an increased ability to cool the arterial blood supply to the testes when the dolphin is swimming. This ability could offset the increased thermal load on the testes is an exercising dolphin. To the best of our knowledge, this is the first report of deep body cooling in an exercising mammal that is not undertaking a dive.

Ridogrel improves maternal/fetal homeostasis in an ovine model of pregnancy-induced hypertension.

The effects of ridogrel (a thromboxane synthetase inhibitor/endoperoxide receptor antagonist) were assessed in an ovine model of pregnancy-induced hypertension. Maternal serum prostacyclin and thromboxane levels were quanitiated using RIA, and maternal and neonatal coagulation status was assessed. Pregnancy and neonatal outcome were recorded. Ridogrel, (E)-5-[[[3-pyridinyl)[3-(trifluoromethyl)phenyl]methylen]amin++ +] oxy]pentanoic acid, was administered in one bolus dose at 0.1 or 1.0 mg/kg IV, three hours following the onset of a 27 hour magnesium sulfate infusion given hypertensive ewes to prevent maternal seizures. At both doses, ridogrel improved neonatal outcome (0% neonatal mortality in each ridogrel group versus 67% neonatal mortality in the magnesium sulfate group), and ridogrel at 0.1 mg/kg IV normalized birth weights. Abnormalities of maternal platelet function (abnormal or no response to collagen), occurring during the ovine syndrome, resolved following ridogrel treatment. Ridogrel's effects on maternal and neonatal coagulation were more dramatic at the 0.1 mg/kg IV dose. Ridogrel appeared to be beneficial in this model of pregnancy-induced hypertension.

Elemental composition of liver and kidney tissues of rough-toothed dolphins (Steno bredanensis).

On December 14, 1997, 62 rough-toothed dolphins (Steno bredanensis) stranded on Cape San Blas, on the Florida coast of the Gulf of Mexico. Approximately 30 animals died either on the beach or in rehabilitation facilities. Two were successfully rehabilitated and released. Liver, kidney, blubber, and muscle tissues were collected from 15 animals that died on the beach. Portions of the liver and kidney from each dolphin were analyzed using instrumental neutron activation analysis and inductively coupled plasma mass spectrometry to determine mass fractions of 37 elements. Levels of several electrolytes (Na, Cl, K, Br, Rb, I, Cs) and of the essential trace elements Fe, Cu, and Zn in both tissues were similar to those found in other Odontoceti. Mass fractions of Ca ranged from 60 mg/kg to 1,200 mg/kg (wet mass basis), indicating significant inhomogeneity in the kidney tissues of several animals. Necropsy reports noted that the kidneys of many of these animals contained fibrous nodules. The measured Ca inhomogeneity may be due to mineralization of the fibrous kidney tissue. Hepatic levels of Hg and Se were at the high end of the ranges generally found in livers of other Odontoceti and were slightly higher in animals with fibrous kidneys than in the others. Mass fractions of Se, Ag, and Hg in liver tissues increased with the size and age of the animals indicating accumulation of these elements in the liver with age. Results also indicate that Se and Hg accumulate in rough-toothed dolphin kidney. Accumulation of these elements with age has been reported commonly for marine mammals and other species.

Mortality of sea lions along the central California coast linked to a toxic diatom bloom.

Over 400 California sea lions (Zalophus californianus) died and many others displayed signs of neurological dysfunction along the central California coast during May and June 1998. A bloom of Pseudo-nitzschia australis (diatom) was observed in the Monterey Bay region during the same period. This bloom was associated with production of domoic acid (DA), a neurotoxin that was also detected in planktivorous fish, including the northern anchovy (Engraulis mordax), and in sea lion body fluids. These and other concurrent observations demonstrate the trophic transfer of DA resulting in marine mammal mortality. In contrast to fish, blue mussels (Mytilus edulus) collected during the DA outbreak contained no DA or only trace amounts. Such findings reveal that monitoring of mussel toxicity alone does not necessarily provide adequate warning of DA entering the food web at levels sufficient to harm marine wildlife and perhaps humans.