Deborah A. Fauquier

Overcoming the challenges of studying conservation physiology in large whales: a review of available methods

A description and comparison of the four major methods available for studying conservation physiology of large whales, namely analysis of faecal, respiratory vapour, and skin/blubber biopsy samples, and photographs.

Cetacean Morbillivirus: Current Knowledge and Future Directions

We review the molecular and epidemiological characteristics of cetacean morbillivirus (CeMV) and the diagnosis and pathogenesis of associated disease, with six different strains detected in cetaceans worldwide. CeMV has caused epidemics with high mortality in odontocetes in Europe, the USA and Australia. It represents a distinct species within the Morbillivirus genus. Although most CeMV strains are phylogenetically closely related, recent data indicate that morbilliviruses recovered from Indo-Pacific bottlenose dolphins (Tursiops aduncus), from Western Australia, and a Guiana dolphin (Sotalia guianensis), from Brazil, are divergent. The signaling lymphocyte activation molecule (SLAM) cell receptor for CeMV has been characterized in cetaceans. It shares higher amino acid identity with the ruminant SLAM than with the receptors of carnivores or humans, reflecting the evolutionary history of these mammalian taxa. In Delphinidae, three amino acid substitutions may result in a higher affinity for the virus. Infection is diagnosed by histology, immunohistochemistry, virus isolation, RT-PCR, and serology. Classical CeMV-associated lesions include bronchointerstitial pneumonia, encephalitis, syncytia, and lymphoid depletion associated with immunosuppression. Cetaceans that survive the acute disease may develop fatal secondary infections and chronic encephalitis. Endemically infected, gregarious odontocetes probably serve as reservoirs and vectors. Transmission likely occurs through the inhalation of aerosolized virus but mother to fetus transmission was also reported.

Adrenal Gland and Lung Lesions in Gulf of Mexico Common Bottlenose Dolphins (Tursiops truncatus) Found Dead following the Deepwater Horizon Oil Spill

A northern Gulf of Mexico (GoM) cetacean unusual mortality event (UME) involving primarily bottlenose dolphins (Tursiops truncatus) in Louisiana, Mississippi, and Alabama began in February 2010 and continued into 2014. Overlapping in time and space with this UME was the Deepwater Horizon (DWH) oil spill, which was proposed as a contributing cause of adrenal disease, lung disease, and poor health in live dolphins examined during 2011 in Barataria Bay, Louisiana. To assess potential contributing factors and causes of deaths for stranded UME dolphins from June 2010 through December 2012, lung and adrenal gland tissues were histologically evaluated from 46 fresh dead non-perinatal carcasses that stranded in Louisiana (including 22 from Barataria Bay), Mississippi, and Alabama. UME dolphins were tested for evidence of biotoxicosis, morbillivirus infection, and brucellosis. Results were compared to up to 106 fresh dead stranded dolphins from outside the UME area or prior to the DWH spill. UME dolphins were more likely to have primary bacterial pneumonia (22% compared to 2% in non-UME dolphins, P = .003) and thin adrenal cortices (33% compared to 7% in non-UME dolphins, P = .003). In 70% of UME dolphins with primary bacterial pneumonia, the condition either caused or contributed significantly to death. Brucellosis and morbillivirus infections were detected in 7% and 11% of UME dolphins, respectively, and biotoxin levels were low or below the detection limit, indicating that these were not primary causes of the current UME. The rare, life-threatening, and chronic adrenal gland and lung diseases identified in stranded UME dolphins are consistent with exposure to petroleum compounds as seen in other mammals. Exposure of dolphins to elevated petroleum compounds present in coastal GoM waters during and after the DWH oil spill is proposed as a cause of adrenal and lung disease and as a contributor to increased dolphin deaths.

Prevalence and pathology of lungworm infection in bottlenose dolphins Tursiops truncatus from southwest Florida.

Parasitism of the respiratory system is a relatively common finding in stranded cetaceans; however, no systematic investigations regarding the severity, distribution, and clinical consequences of these infections in bottlenose dolphins Tursiops truncatus have been conducted previously. The present study determined the prevalence of lungworm infections in dead stranded (n=22) and live bottlenose dolphins (n=44) from southwestern Florida, USA, during the period from 2003 to 2005. Dead stranded bottlenose dolphins were necropsied and lungs were examined visually, by palpation, and histologically for lesions consistent with verminous pneumonia. When present, nematodes were counted, measured, and identified to species based upon their morphology. Dolphin feces and blowhole swabs were collected and examined for nematode larvae. Lungworm prevalence was 77% in dead animals (n=22). The lesions in most cases were mild, chronic, and not the primary cause of death. Only 13% of dead animals examined had patent infections, with larvae present in blowhole and fecal cytology, and only 18% of animals had intact worms present at necropsy, with a geometric mean intensity of infection of 22.6 worms animal(-1). Intact worms were identified as either Halocercus lagenorhynchi or Skrjabinalius cryptocephalus. The highest prevalence of active infections was found in neonates and calves, including 1 stillborn calf. For free-ranging animals, all blowhole swabs (n=44) were negative, and fecal cytology (n=22) showed a 3% prevalence of patent infection. Findings from the present study support the theory that bottlenose dolphins can be infected transplacentally by lungworms. The impact that such infections may have on neonatal survival is unknown; however, these infections could increase neonatal mortality.

Phocine Distemper Virus: Current Knowledge and Future Directions

Phocine distemper virus (PDV) was first recognized in 1988 following a massive epidemic in harbor and grey seals in north-western Europe. Since then, the epidemiology of infection in North Atlantic and Arctic pinnipeds has been investigated. In the western North Atlantic endemic infection in harp and grey seals predates the European epidemic, with relatively small, localized mortality events occurring primarily in harbor seals. By contrast, PDV seems not to have become established in European harbor seals following the 1988 epidemic and a second event of similar magnitude and extent occurred in 2002. PDV is a distinct species within the Morbillivirus genus with minor sequence variation between outbreaks over time. There is now mounting evidence of PDV-like viruses in the North Pacific/Western Arctic with serological and molecular evidence of infection in pinnipeds and sea otters. However, despite the absence of associated mortality in the region, there is concern that the virus may infect the large Pacific harbor seal and northern elephant seal populations or the endangered Hawaiian monk seals. Here, we review the current state of knowledge on PDV with particular focus on developments in diagnostics, pathogenesis, immune response, vaccine development, phylogenetics and modeling over the past 20 years.

BREVETOXIN IN BLOOD, BIOLOGICAL FLUIDS, AND TISSUES OF SEA TURTLES NATURALLY EXPOSED TO KARENIA BREVIS BLOOMS IN CENTRAL WEST FLORIDA

Abstract:u2003 In 2005 and 2006, the central west Florida coast experienced two intense Karenia brevis red tide events lasting from February 2005 through December 2005 and August 2006 through December 2006. Strandings of sea turtles were increased in the study area with 318 turtles (n = 174, 2005; n = 144, 2006) stranding between 1 January 2005 and 31 December 2006 compared to the 12-yr average of 43 ± 23 turtles. Live turtles (n = 61) admitted for rehabilitation showed clinical signs including unresponsiveness, paresis, and circling. Testing of biological fluids and tissues for the presence of brevetoxin activity by enzyme-linked immunosorbent assay found toxin present in 93% (52 of 56) of live stranded sea turtles, and 98% (42 of 43) of dead stranded sea turtles tested. Serial plasma samples were taken from several live sea turtles during rehabilitation and toxin was cleared from the blood within 5–80 days postadmit depending upon the species tested. Among dead animals the highest brevetoxin levels were found in feces, stomach contents, and liver. The lack of significant pathological findings in the majority of animals necropsied supports toxin-related mortality.

Distribution of tissue enzymes in three species of pinnipeds

Abstract In domestic animal medicine, changes in serum enzyme levels are routinely used as diagnostic tools to detect liver disease. Hepatic disease occurs in pinnipeds, but limited data are available on the tissue distribution of serum enzymes in marine mammals. The objectives of this study were to determine the tissue distribution of seven serum enzymes in three pinniped species. Enzymes evaluated were alanine aminotransferase (ALT), aspartate aminotransferase (AST), sorbitol dehydrogenase (SDH), lactate dehydrogenase (LDH), creatine kinase (CK), alkaline phosphatase (ALP), and gamma-glutamyl transferase (GGT) in tissues from California sea lions (Zalophus californianus) (n = 5), harbor seals (Phoca vitulina) (n = 5), and northern elephant seals (Mirounga angustirostris) (n = 5) that stranded and then died at a rehabilitation center. Samples were evaluated in duplicate from liver, skeletal muscle, cardiac muscle, kidney, adrenal, spleen, pancreas, lung, lymph node, and intestine. Patterns of tissue enzyme distribution were similar in all species, with SDH activity highest in liver and kidney, CK activity highest in skeletal and cardiac muscle, ALP activity highest in adrenal, and GGT activity highest in the kidney. Aspartate aminotransferase and LDH activities were less specific, with high activity in multiple tissues. Tissue ALT activity was high in the liver of all species, but was also high in cardiac muscle (California sea lions), skeletal muscle (harbor seals), and kidney (elephant seals). These results suggest that concurrent analysis of SDH, ALT, and CK would provide high specificity and sensitivity for the detection of hepatic lesions, and allow differentiation of liver from skeletal muscle lesions in pinniped species.

DEHYDRATION AS AN EFFECTIVE TREATMENT FOR BREVETOXICOSIS IN LOGGERHEAD SEA TURTLES (CARETTA CARETTA)

Abstract:u2003 Harmful algal blooms are known to cause morbidity and mortality to a large number of marine and estuarine organisms worldwide, including fish and marine mammals, birds, and turtles. The effects of these algal blooms on marine organisms are due to the various toxins produced by the different algal species. In southwest Florida, frequent blooms of the dinoflagellate Karenia brevis, which produces neurotoxins known as brevetoxins, cause widespread fish kills and affect many marine animals. In 2005–2007, numerous sea turtles of several species underwent treatment for brevetoxicosis at the Sea Turtle Rehabilitation Hospital. In green sea turtles, Chelonia mydas, and Kemps ridley sea turtles, Lepidochelys kempii, symptoms associated with brevetoxicosis were limited to neurologic signs, such as the inability to control the head (head bobbing) and nervous twitching. For these turtles, treatment involved removing the turtles from the environment containing the toxins and providing short-term supportive care. In loggerhead sea turtles, Caretta caretta, symptoms were more generalized; thus, a similar approach was unsuccessful, as was routine treatment for general toxicosis. Loggerhead sea turtles had more extreme neurologic symptoms including coma, and other symptoms that included generalized edema, conjunctival edema, and cloacal or penile prolapse. Treatment of brevetoxicosis in loggerhead sea turtles required a therapeutic regimen that initially included dehydration and systemic antihistamine treatment followed by supportive care.

Field energetics and lung function in wild bottlenose dolphins, Tursiops truncatus, in Sarasota Bay Florida

We measured respiratory flow rates, and expired O2 in 32 (2–34 years, body mass [Mb] range: 73–291u2005kg) common bottlenose dolphins (Tursiops truncatus) during voluntary breaths on land or in water (between 2014 and 2017). The data were used to measure the resting O2 consumption rate (V˙O2, range: 0.76–9.45u2005ml O2u2005min−1u2005kg−1) and tidal volume (VT, range: 2.2–10.4u2005l) during rest. For adult dolphins, the resting VT, but not V˙O2, correlated with body mass (Mb, range: 141–291u2005kg) with an allometric mass-exponent of 0.41. These data suggest that the mass-specific VT of larger dolphins decreases considerably more than that of terrestrial mammals (mass-exponent: 1.03). The average resting sV˙O2 was similar to previously published metabolic measurements from the same species. Our data indicate that the resting metabolic rate for a 150u2005kg dolphin would be 3.9u2005ml O2u2005min−1u2005kg−1, and the metabolic rate for active animals, assuming a multiplier of 3–6, would range from 11.7 to 23.4u2005ml O2u2005min−1u2005kg−1.absbreak Our measurements provide novel data for resting energy use and respiratory physiology in wild cetaceans, which may have significant value for conservation efforts and for understanding the bioenergetic requirements of this species.

Detection of Brucella spp. in bottlenose dolphins Tursiops truncatus by a real-time PCR using blowhole swabs

Blowhole swabs are a simple and non-invasive method for collecting samples from cetaceans and can be used for screening large numbers of animals in the field. This study reports a real-time PCR assay for the detection of Brucella spp. using blowhole swab samples from bottlenose dolphins Tursiops truncatus stranded in the coastal region of Virginia, South Carolina and northern Florida, USA, between 2013 and 2015. We used real-time PCR results on lung samples from the same dolphins in order to estimate the relative sensitivity and specificity of real-time PCR of blowhole swabs. Brucella DNA was detected in lung tissue of 22% (18/81) and in blowhole swabs of 21% (17/81) of the sampled dolphins. The relative sensitivity and specificity of real-time PCR on blowhole swabs as compared to the real-time PCR on lung samples was 94% (17/18) and 100% (63/63), respectively. These results indicate that real-time PCR on blowhole swabs may be used as a non-invasive test for rapid detection of Brucella spp. in the respiratory tract of dolphins. To our knowledge, this is the first report on the use of blowhole swabs for detection of bacterial pathogens by real-time PCR in bottlenose dolphins.