Thirty year retrospective evaluation of pneumonia in a bottlenose dolphin Tursiops truncatus population

Expression and basic biochemical characteristics of recombinant surfactant protein D of bottlenose dolphin (Tursiopstruncatus)

We previously identified surfactant protein D (SP-D) in the bottlenose dolphin Tursiops truncatus as a unique evolutionary factor of the cetacean pulmonary immune system. In this short report, recombinant SP-D of bottlenose dolphin (dSP-D) was synthesized in mammalian cells, and its properties were analyzed in vitro. The recombinant proteins were purified using Ni-carrier or Co-carrier. Sodium dodecyl sulfate poly-acrylamide gel electrophoresis and western blotting revealed a 50 kDa major band with minor secondary bands. Enzyme-linked immunosorbent assay-like methods revealed that recombinant dSP-D bonded to gram-positive and gram-negative bacterial walls. Our findings suggest the clinical usefulness of dSP-D for cetacean pneumonia.

An update on the development of a bottlenose dolphin, Tursiops truncatus, immune reagent toolkit

There are extensive immunological reagents available for laboratory rodents and humans. However, for veterinary species there is a need for expansion of immunological toolkits, with this especially evident for marine mammals, such as cetaceans. In addition to their use in a research setting, immune assays could be employed to monitor the health status of cetaceans and serve as an adjunct to available diagnostic tests. Such development of specific and sensitive immune assays will enhance the proper care and stewardship of wild and managed cetacean populations. Our goal is to provide immune reagents and immune assays for the research community, clinicians, and others involved in care of bottlenose dolphins. This review will provide an update on our development of a bottlenose dolphin immunological toolkit. The future availability and continued development of these reagents is critical for improving wild and managed bottlenose dolphin population health through enhanced assessment of their responses to alterations in the marine environment, including pathogens, and improve our ability to monitor their status following vaccination.

Survey of selected viral agents (herpesvirus, adenovirus and hepatitis E virus) in liver and lung samples of cetaceans, Brazil

Hepatic and pulmonary lesions are common in cetaceans, despite their poorly understood viral etiology. Herpesviruses (HV), adenoviruses (AdV) and hepatitis E virus (HEV) are emerging agents in cetaceans, associated with liver and/or pulmonary damage in mammals. We isolated and molecularly tested DNA for HV and AdV (n = 218 individuals; 187 liver and 108 lung samples) and RNA for HEV (n = 147 animals; 147 liver samples) from six cetacean families. All animals stranded or were bycaught in Brazil between 2001 and 2021. Positive-animals were analyzed by histopathology. Statistical analyses assessed if the prevalence of viral infection could be associated with the variables: species, family, habitat, region, sex, and age group. All samples were negative for AdV and HEV. Overall, 8.7% (19/218) of the cetaceans were HV-positive (4.8% [9/187] liver and 11.1% [12/108] lung), without HV-associated lesions. HV-prevalence was statistically significant higher in Pontoporiidae (19.2%, 10/52) when compared to Delphinidae (4.1%, 5/121), and in southeastern (17.1%, 13/76)-the most industrialized Brazilian region-when compared to the northeastern region (2.4%, 3/126). This study broadens the herpesvirus host range in cetaceans, including its description in pygmy sperm whales (Kogia breviceps) and humpback whales (Megaptera novaeangliae). Further studies must elucidate herpesvirus drivers in cetaceans.

Evaluation of the safety and efficacy of fecal microbiota transplantations in bottlenose dolphins (Tursiops truncatus) using metagenomic sequencing

AIMS

Gastrointestinal disease is a leading cause of morbidity in bottlenose dolphins (Tursiops truncatus) under managed care. Fecal microbiota transplantation (FMT) holds promise as a therapeutic tool to restore gut microbiota without antibiotic use. This prospective clinical study aimed to develop a screening protocol for FMT donors to ensure safety, determine an effective FMT administration protocol for managed dolphins, and evaluate the efficacy of FMTs in four recipient dolphins.

METHODS AND RESULTS

Comprehensive health monitoring was performed on donor and recipient dolphins. Fecal samples were collected before, during, and after FMT therapy. Screening of donor and recipient fecal samples was accomplished by in-house and reference lab diagnostic tests. Shotgun metagenomics was used for sequencing. Following FMT treatment, all four recipient communities experienced engraftment of novel microbial species from donor communities. Engraftment coincided with resolution of clinical signs and a sustained increase in alpha diversity.

CONCLUSION

The donor screening protocol proved to be safe in this study and no adverse effects were observed in four recipient dolphins. Treatment coincided with improvement in clinical signs.

The Ecology of Non-Candida Yeasts and Dimorphic Fungi in Cetaceans: From Pathogenicity to Environmental and Global Health Implications

Cetaceans, which are integral to marine ecosystems, face escalating anthropogenic threats, including climate change and pollution, positioning them as critical sentinel species for ocean and human health. This review explores the neglected realm of non-Candida yeasts in cetaceans, addressing the gaps in the understanding of their prevalence, pathogenicity, and environmental impacts. By examining identified species such as Cryptococcus spp., Paracoccidioides spp., and several dimorphic fungi, this review emphasizes global prevalence, epidemiology and ecology, pathogenicity, and potential zoonotic implications. It also discusses the fine line between yeast commensalism and pathogenicity by considering environmental influences such as pollution, climate shifts, and immune suppression. Environmental impact discussions delve into how rising ocean temperatures and pollution can modify yeast mycobiota, potentially affecting marine host health and broader ecosystem dynamics. The cetacean's unique physiology and ecological niches are considered, highlighting potential impacts on behaviors, reproductive success, and survival rates. Identifying crucial knowledge gaps, the review calls for intensified research efforts, employing advanced molecular techniques to unravel the cetacean mycobiome. Systematic studies on yeast diversity, antifungal susceptibility, and their influence on environmental and ecosystem health are proposed, and the balance between commensal and pathogenic species emphasizes the significance of the One Health approach. In conclusion, as marine mammals face unprecedented challenges, unveiling non-Candida yeasts in cetaceans emerges as a critical endeavor with far-reaching implications for the conservation of marine ecosystems and for both animal and human public health.

Accumulation of endogenous free radicals is required to induce titan-like cell formation in Cryptococcus neoformans

IMPORTANCE

Cryptococcus neoformans is an excellent model to investigate fungal pathogenesis. This yeast can produce "titan cells," which are cells of an abnormally larger size that contribute to the persistence of the yeast in the host. In this work, we have used a new approach to characterize them by identifying drugs that inhibit this process. We have used a repurposing off-patent drug library, combined with an automatic method to image and analyze fungal cell size. In this way, we have identified many compounds that inhibit this transition. Interestingly, several compounds were antioxidants, allowing us to confirm that endogenous ROS and mitochondrial changes are important for titan cell formation. This work provides new evidence of the mechanisms required for titanization. Furthermore, the future characterization of the inhibitory mechanisms of the identified compounds by the scientific community will contribute to better understand the role of titan cells in virulence.

Bronchial Tree System Analysis of Live Beluga Whale (Delphinapterus leucas) Using Bronchoscopy

Cetaceans, including beluga whales (Delphinapterus leucas), have high morbidity and mortality rates due to bacterial or fungal lower respiratory infections. Bronchoalveolar lavage fluid (BALF) collection by bronchoscopy is beneficial for detecting pathogenic microorganisms in the lower respiratory tract. Efficient and safe bronchoscopy requires characterizing the bronchial tree systems of beluga whales, as no reports exist on bronchial length and bifurcation. In this study, bronchoscopy was performed on five captive beluga whales (9-44 years old) to detect bronchial length and bifurcation. The lengths from the blowhole to the scope impassable points due to the minimized bronchi diameters of the left principal bronchus (LPB), right principal bronchus (RPB), and tracheal bronchus (TB) were 110-155, 110-150, and 80-110 cm, respectively, and were correlated with the body length. Bronchoscopy identified more than 10, 10, and 6 bifurcated bronchi from the LPB, RPB, and TB, respectively. This is the first report to clarify the differences in bronchial tree systems between beluga whales and other cetaceans, as well as the differences for each individual beluga whale. These results could be useful for obtaining BALF via bronchoscopy to detect pathogenic microorganisms causing infections in the lower respiratory tract of beluga whales.

Establishment and characterization of a novel lung cell line derived from the common bottlenose dolphin

Cetaceans are specialized marine mammals with a unique respiratory system adapted for diving behavior. Furthermore, respiratory diseases are commonly observed in these mammals. Nevertheless, much of their respiratory physiology remains unknown due to the limited supply and poor quality of their biological samples for research. In this study, we established a novel lung cell line, dLu, derived from the common bottlenose dolphin (Tursiops truncatus), which can prove useful in cetacean research, including for understanding the pathogenesis of respiratory diseases in cetaceans. The cells were cultured in a simple medium consisting of Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum. The morphology of the cells was fibroblast-like. dLu was produced by transfecting the simian virus 40 large T antigen into primary cultured cells. Although dLu exhibited approximately 80 cell divisions, it was unable to achieve complete immortalization, as the cells stopped proliferating beyond this number. dLu cells expressed toll-like receptor 3 but not toll-like receptor 4. Immunostimulation with poly(I:C) altered the gene expressions of interferon beta 1 and tumor necrosis factor alpha in dLu cells. In summary, dLu established in this study is a novel cetacean cell resource that can be easily cultured and is a useful in vitro tool in cetacean research, particularly for studying host immune responses in the lungs.

MORBIDITY AND MORTALITY PATTERNS OF INDIAN RIVER LAGOON COMMON BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS TRUNCATUS) 2002-2020

Mortality patterns in cetaceans are critical to understanding population health. Common bottlenose dolphins (Tursiops truncatus truncatus) inhabiting the Indian River Lagoon (IRL), Florida have been subjected to four unusual mortality events (UMEs), highlighting the need to evaluate morbidity and mortality patterns. Complete gross examinations were conducted on 392 stranded dolphins and histopathological analyses were conducted for 178 animals (2002-2020). The probable causes of mortality were grouped by etiologic category: degenerative, metabolic, nutritional, inflammatory (infectious and noninfectious disease), and trauma. Probable cause of mortality was determined in 57% (223/392) of cases. Inflammatory disease (infectious/noninfectious) and trauma were the most common. Inflammatory disease accounted for 41% of cases (91/223), with the lungs (pneumonia) most commonly affected. Trauma accounted for 36% of strandings (80/223). The majority of trauma cases were due to anthropogenic activities (entanglement, fishing gear or other debris ingestion, and propeller strikes), accounting for 58% of trauma cases (46/80). Natural trauma (prey-associated esophageal obstruction or asphyxiation, shark bites, and stingray interactions) accounted for 12% of all cases (26/223), and trauma of undetermined origin was identified in 4% of cases (8/223). Starvation or inanition (nutritional) were the probable cause of mortality in 17% of cases and peaked during the 2013 UME (61% of cases). Degenerative and metabolic etiologies accounted for 5% of cases. This study represents the most comprehensive evaluation of morbidity and mortality patterns in IRL dolphins. Because IRL dolphins are routinely exposed to anthropogenic threats and have endured multiple UMEs, these baseline data are critical to the conservation and management of this population.

A Review of Circumpolar Arctic Marine Mammal Health-A Call to Action in a Time of Rapid Environmental Change

The impacts of climate change on the health of marine mammals are increasingly being recognised. Given the rapid rate of environmental change in the Arctic, the potential ramifications on the health of marine mammals in this region are a particular concern. There are eleven endemic Arctic marine mammal species (AMMs) comprising three cetaceans, seven pinnipeds, and the polar bear (Ursus maritimus). All of these species are dependent on sea ice for survival, particularly those requiring ice for breeding. As air and water temperatures increase, additional species previously non-resident in Arctic waters are extending their ranges northward, leading to greater species overlaps and a concomitant increased risk of disease transmission. In this study, we review the literature documenting disease presence in Arctic marine mammals to understand the current causes of morbidity and mortality in these species and forecast future disease issues. Our review highlights potential pathogen occurrence in a changing Arctic environment, discussing surveillance methods for 35 specific pathogens, identifying risk factors associated with these diseases, as well as making recommendations for future monitoring for emerging pathogens. Several of the pathogens discussed have the potential to cause unusual mortality events in AMMs. Brucella, morbillivirus, influenza A virus, and Toxoplasma gondii are all of concern, particularly with the relative naivety of the immune systems of endemic Arctic species. There is a clear need for increased surveillance to understand baseline disease levels and address the gravity of the predicted impacts of climate change on marine mammal species.

An evolutionary medicine perspective on the cetacean pulmonary immune system - The first identification of SP-D and LBP in the bottlenose dolphin (Tursiops truncatus)

Evolutionary medicine expresses the present status of biomolecules affected by past evolutionary events. To clarify the whole picture of cetacean pneumonia, which is a major threat to cetaceans, their pulmonary immune system should be studied from the perspective of evolutionary medicine. In this in silico study, we focused on cetacean surfactant protein D (SP-D) and lipopolysaccharide-binding protein (LBP) as two representative molecules of the cetacean pulmonary immune system. Sequencing and analyzing SP-D and LBP in the bottlenose dolphin (Tursiops truncatus) lung and liver tissue collected post-mortem elucidated not only basic physicochemical properties but also their evolutionary background. This is the first study to report the sequences and expression of SP-D and LBP in the bottlenose dolphin. Besides, our findings also suggest the direction of an evolutionary arms race in the cetacean pulmonary immune system. These results have important positive implications for cetacean clinical medicine.

Erysipelas in a stranded common bottlenose dolphin: first report in a South American odontocete

Erysipelas is a zoonotic disease caused by Erysipelothrix rhusiopathiae. In cetaceans, this disease has two main clinical forms: a cutaneous one, grossly characterized by rhomboid lesions, and a septicemic and often fatal form. Erysipelas is considered an important cause of morbidity and mortality in captive cetaceans; however, information in free-ranging cetaceans is limited. An adult common bottlenose dolphin (Tursiops truncatus) was found dead and in advanced autolysis in Paraíba state, northeastern Brazil, on July 19th, 2020. Upon gross examination, 80% of the body surface presented disseminated rhomboid cutaneous lesions ranging from 4 to 6 cm-width, characterized by well-defined edges and occasional ulceration, consistent with erysipelas. Additionally, anthropic-made postmortem linear cuts and partial mechanical removal of the flank musculature were noted. Skin samples were collected for histopathologic and molecular analyses. Microscopically, it was possible to observe multifocal dermatitis with vasculitis. Erysipelothrix sp. was detected by PCR. Despite previous reports of human consumption of cetacean meat in northeastern Brazil, the observed marks and advanced carcass autolysis suggested that the animal was most likely used as bait for fishing instead of human intake. This case highlights the value of postmortem examination and PCR even in poorly preserved cadavers and contributes to the understanding of the epidemiology of cutaneous erysipelas in free-ranging cetaceans (first report in an odontocete from the Southern Hemisphere). Due to the zoonotic potential of certain Erysipelothrix species (i.e., E. rhusiopathiae), active public health policies are required to inform field professionals and the general public about the health threats associated with marine mammal manipulation and consumption.

Bacterial microbiomes from mucus and breath of southern resident killer whales (Orcinus orca)

Opportunities to assess odontocete health are restricted due to their limited time at the surface, relatively quick movements and large geographic ranges. For endangered populations such as the southern resident killer whales (SKRWs) of the northeast Pacific Ocean, taking advantage of non-invasive samples such as expelled mucus and exhaled breath is appealing. Over the past 12 years, such samples were collected, providing a chance to analyse and assess their bacterial microbiomes using amplicon sequencing. Based on operational taxonomic units, microbiome communities from SRKW and transient killer whales showed little overlap between mucus, breath and seawater from SRKW habitats and six bacterial phyla were prominent in expelled mucus but not in seawater. Mollicutes and Fusobacteria were common and abundant in mucus, but not in breath or seawater, suggesting these bacterial classes may be normal constituents of the SRKW microbiome. Out of 134 bacterial families detected, 24 were unique to breath and mucus, including higher abundances of Burkholderiaceae, Moraxellaceae and Chitinophagaceae. Although there were multiple bacterial genera in breath or mucus that include pathogenic species (e.g. Campylobacter, Hemophilus, Treponema), the presence of these bacteria is not necessarily evidence of disease or infection. Future emphasis on genotyping mucus samples to the individual animal will allow further assessment in the context of that animal's history, including body condition index and prior contaminants burden. This study is the first to examine expelled mucus from cetaceans for microbiomes and demonstrates the value of analysing these types of non-invasive samples.

Chronic nonchylous lymphatic pleural effusion in a bottlenose dolphin (Tursiops truncatus)

CASE DESCRIPTION

A 19-year-old male bottlenose dolphin (Tursiops truncatus) presented with inappetence and avoidant behavior.

CLINICAL FINDINGS

Ultrasound revealed a large-volume left-sided pleural effusion, which was consistent with chronic nonchylous lymphatic effusion and mild chronic hemorrhage by cytology. Computed tomography identified ipsilateral rib fractures, atelectasis, nodular pleuritis, marginal lymph node enlargement, and suspected dilation of the thoracic duct and internal thoracic veins. Fifteen lipids were significantly higher in serum of the dolphin as compared with controls (n = 3) using nontargeted lipidomics.

TREATMENT AND OUTCOME

A series of thoracentesis procedures were performed. Follow-up CT demonstrated marked reduction in pleural effusion with persistence of thoracic duct dilation and mass-like areas of pleural thickening. Ultrasonographic resolution of pleural effusion occurred 14 months after presentation; however, recrudescence was noted 5 months later. Over a total of 24 months, 21.52 L of pleural effusion was removed. Despite the presence of pleural effusion, the patient was clinically stable during this time and quality of life was considered good on the basis of continuous animal welfare evaluations. Humane euthanasia was elected following acute clinical decline 27 months after initial diagnosis. Necropsy confirmed severe pleural effusion, chronic severe pleural fibrosis with chronic hemorrhage, and mediastinal fibrosis with entrapped lymph nodes and thymic tissue.

CLINICAL RELEVANCE

Pleuritis and effusion were suspected sequelae of previous rib fractures. To our knowledge, this is the first report of nonchylous lymphatic pleural effusion with repeated pleural drainage and diagnostic imaging for clinical management in a bottlenose dolphin.

A Preliminary Comparison on Faecal Microbiomes of Free-Ranging Large Baleen (Balaenoptera musculus, B. physalus, B. borealis) and Toothed (Physeter macrocephalus) Whales

Large baleen and toothed whales play crucial ecological roles in oceans; nonetheless, very little is known about their intestinal microbiomes. Based on striking differences in natural history and thus in feeding behaviours, it can be expected that intestinal microbiomes of large baleen whales and toothed whales are different. To test this hypothesis, the phylogenetic composition of faecal microbiomes was investigated by a 16S rRNA gene amplicon sequence-based approach for Bacteria and Archaea. Faecal samples from free-ranging large whales collected off the Azores Archipelago (Portugal) were used, comprising 13 individual baleen whales (one sei, two blue and ten fin whales) and four sperm whales. The phylogenetic composition of the Bacteria faecal microbiomes of baleen and toothed whales showed no significant differences at the phylum level. However, significant differences were detected at the family and genus levels. Most abundant phyla were Firmicutes, Bacteroidetes, Proteobacteria, Tenericutes and Spirochaeta. Few highly abundant bacterial genera were identified as key taxa with a high contribution to differences among baleen and toothed whales microbiomes. Only few archaeal sequences were detected, primarily Methanomassiliicoccales representing potential methanogenic Archaea. This is the first study that directly compares the faecal bacterial and archaeal microbiomes of free-ranging baleen and toothed whales which represent the two parvorders of Cetacea which members are fully aquatic large mammals which were evolutionary split millions of years ago.

RESPIRATORY CHANGES IN STRANDED BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS)

Lung function (breath duration, respiratory flow [V̇], and tidal volume [V_T]), and end-expiratory O₂ were measured in 19 adult bottlenose dolphins (Tursiops spp.) while at rest in water or beached for up to 10 min. The results show that inspiratory V_T, expiratory V_T, or inspiratory V̇ did not differ on land or in water. The average expiratory V̇ for all dolphins on land decreased by 16%, and the expiratory and total breath durations increased by 5% and 4%, respectively, compared with in water. There were temporal changes observed during beaching, where expired and inspired V_T and inspired V̇ decreased by 13%, 16%, and 9%, respectively, after 10 min on land. These data suggest that dolphins compensate for the effect of gravity by adjusting respiration to maintain alveolar ventilation and gas exchange, but during extended durations, the increased work of breathing may impede ventilation and gas exchange. Continuous monitoring of lung function and gas exchange may help prevent long-term damage during out-of-water medical procedures, optimize animal transport conditions, and improve survival during stranding events.

Streptococcal Infections in Marine Mammals

Marine mammals are sentinels for the marine ecosystem and threatened by numerous factors including infectious diseases. One of the most frequently isolated bacteria are beta-hemolytic streptococci. However, knowledge on ecology and epidemiology of streptococcal species in marine mammals is very limited. This review summarizes published reports on streptococcal species, which have been detected in marine mammals. Furthermore, we discuss streptococcal transmission between and adaptation to their marine mammalian hosts. We conclude that streptococci colonize and/or infect marine mammals very frequently, but in many cases, streptococci isolated from marine mammals have not been further identified. How these bacteria disseminate and adapt to their specific niches can only be speculated due to the lack of respective research. Considering the relevance of pathogenic streptococci for marine mammals as part of the marine ecosystem, it seems that they have been neglected and should receive scientific interest in the future.

Highly abundant core taxa in the blow within and across captive bottlenose dolphins provide evidence for a temporally stable airway microbiota

Background

The analysis of blow microbiota has been proposed as a biomarker for respiratory health analysis in cetaceans. Yet, we lack crucial knowledge on the long-term stability of the blow microbiota and its potential changes during disease. Research in humans and mice have provided evidence that respiratory disease is accompanied by a shift in microbial communities of the airways. We investigate here the stability of the community composition of the blow microbiota for 13 captive bottlenose dolphins over eight months including both sick and healthy individuals. We used barcoded tag sequencing of the bacterial 16S rRNA gene. Four of the dolphins experienced distinct medical conditions and received systemic antimicrobial treatment during the study.

Results

We showed that each dolphin harboured a unique community of zero-radius operational taxonomic units (zOTUs) that was present throughout the entire sampling period (‘intra-core’). Although for most dolphins there was significant variation over time, overall the intra-core accounted for an average of 73% of relative abundance of the blow microbiota. In addition, the dolphins shared between 8 and 66 zOTUs on any of the sampling occasions (‘inter-core’), accounting for a relative abundance between 17 and 41% of any dolphin’s airway microbiota. The majority of the intra-core and all of the inter-core zOTUs in this study are commonly found in captive and free-ranging dolphins and have previously been reported from several different body sites. While we did not find a clear effect of microbial treatment on blow microbiota, age and sex of the dolphins did have such an effect.

Conclusions

The airways of dolphins were colonized by an individual intra-core ‘signature’ that varied in abundance relative to more temporary bacteria. We speculate that the intra-core bacteria interact with the immune response of the respiratory tract and support its function. This study provides the first evidence of individual-specific airway microbiota in cetaceans that is stable over eight months.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-020-02076-z.

Pneumonia in endangered aquatic mammals and the need for developing low-coverage vaccination for their management and conservation

Anthropogenic activities can lead to several devastating effects on the environment. The pollutants, which include the discharge of effluents, runoffs in the form of different lethal and sub-lethal concentrations of pesticides, heavy metals, and other contaminants, can harm exposed fauna and flora. The aquatic environment is the ultimate destination for many pollutants which negatively affect aquatic biodiversity and even can cause a species to become extinct. A pollutant can directly affect the behavior of an animal, disrupt cellular systems, and impair the immune system. This harm can be reduced and even mitigated by adopting proper approaches for the conservation of the target biota. Among aquatic organisms, cetaceans, such as the Yangtze finless porpoise, Irrawaddy dolphin, Ganges River dolphin, Amazon River dolphin, and Indus River dolphin, are at a higher risk of extinction because of lack of knowledge and research, and thus insufficient information with respect to their conservation status, management, and policies. Pneumonia is one of the leading causes of mass mortalities of cetaceans. This article reviews the limited research reported on stress and pneumonia induced by pollution, stress-induced pneumonia and immunosuppression, pneumonia-caused mass mortalities of aquatic mammals, and vaccination in wildlife with a specific focus on aquatic mammals, the role of genomics in vaccine development and vaccination, and the major challenges in vaccine development for biodiversity conservation.

Respiratory microbiota of humpback whales may be reduced in diversity and richness the longer they fast

Humpback whales endure several months of fasting while undertaking one of the longest annual migrations of any mammal, which depletes the whales’ energy stores and likely compromises their physiological state. Airway microbiota are linked to respiratory health in mammals. To illuminate the dynamics of airway microbiota in a physiologically challenged mammal, we investigated the bacterial communities in the blow of East Australian humpback whales at two stages of their migration: at the beginning (n = 20) and several months into their migration (n = 20), using barcoded tag sequencing of the bacterial 16S rRNA gene. We show that early in the fasting the whale blow samples had a higher diversity and richness combined with a larger number of core taxa and a different bacterial composition than later in the fasting. This study provides some evidence that the rich blow microbiota at the beginning of their fasting might reflect the whales’ uncompromised physiology and that changes in the microbiota occur during the whales’ migration.

Basic principles of the virulence of Cryptococcus

Among fungal pathogens, Cryptococcus neoformans has gained great importance among the scientific community of several reasons. This fungus is the causative agent of cryptococcosis, a disease mainly associated to HIV immunosuppression and characterized by the appearance of meningoencephalitis. Cryptococcal meningitis is responsible for hundreds of thousands of deaths every year. Research of the pathogenesis and virulence mechanisms of this pathogen has focused on three main different areas: Adaptation to the host environment (nutrients, pH, and free radicals), mechanism of immune evasion (which include phenotypic variations and the ability to behave as a facultative intracellular pathogen), and production of virulence factors. Cryptococcus neoformans has two phenotypic characteristics, the capsule and synthesis of melanin that have a profound effect in the virulence of the yeast because they both have protective effects and induce host damage as virulence factors. Finally, the mechanisms that result in dissemination and brain invasion are also of key importance to understand cryptococcal disease. In this review, I will provide a brief overview of the main mechanisms that makes C. neoformans a pathogen in susceptible patients.

Abbreviations: RNS: reactive nitrogen species; BBB: brain blood barrier; GXM: glucuronoxylomannan; GXMGal: glucuronoxylomannogalactan

Pulmonary function testing as a diagnostic tool to assess respiratory health in bottlenose dolphins Tursiops truncatus

Pulmonary function testing was performed in 3 bottlenose dolphins Tursiops truncatus (1 female and 2 males) under managed care during a 2 yr period to assess whether these data provide diagnostic information about respiratory health. Pulmonary radiographs and standard clinical testing were used to evaluate the pulmonary health of each dolphin. The female dolphin (F1) had evidence of chronic pulmonary fibrosis, and 1 male (M2) developed pneumonia during the study. Pulmonary function data were collected from maximal respiratory efforts in water and from spontaneous breaths while beached. From these data, the flow-volume relationship, the flow measured between 25 and 75% of the expired vital capacity (mid forced expiratory flow, FEF25%-75%), and the percent of the vital capacity (VC) at the peak expiratory flow (%VCPEF), were evaluated and compared with the diagnostic assessment. For maximal respiratory manoeuvres in water, there were no differences in FEF25%-75% or %VCPEF, and the flow-volume relationship showed a consistent pattern for F1. Additionally, FEF25%-75% and %VCPEF decreased by 27 and 52%, respectively, and the flow-volume relationship showed clear flow limitations with emerging disease in M2. While spontaneously breathing on land, M2 also showed a 49% decrease in %VCPEF and changes in the flow-volume relationship, indicating flow limitations following the development of pneumonia. Based on these preliminary results, we suggest that pulmonary function testing should be given more attention as a non-invasive and possibly adjunctive diagnostic tool to evaluate lung health of dolphins under managed care and in the wild.

Health Assessments of Common Bottlenose Dolphins (Tursiops truncatus): Past, Present, and Potential Conservation Applications

The common bottlenose dolphin (Tursiops truncatus) is a global marine mammal species for which some populations, due to their coastal accessibility, have been monitored diligently by scientists for decades. Health assessment examinations have developed a comprehensive knowledge base of dolphin biology, population structure, and environmental or anthropogenic stressors affecting their dynamics. Bottlenose dolphin health assessments initially started as stock assessments prior to acquisition. Over the last four decades, health assessments have evolved into essential conservation management tools of free-ranging dolphin populations. Baseline data enable comparison of stressors between geographic locations and associated changes in individual and population health status. In addition, long-term monitoring provides opportunities for insights into population shifts over time, with retrospective application of novel diagnostic tests on archived samples. Expanding scientific knowledge enables effective long-term conservation management strategies by facilitating informed decision making and improving social understanding of the anthropogenic effects. The ability to use bottlenose dolphins as a model for studying marine mammal health has been pivotal in our understanding of anthropogenic effects on multiple marine mammal species. Future studies aim to build on current knowledge to influence management decisions and species conservation. This paper reviews the historical approaches to dolphin health assessments, present day achievements, and development of future conservation goals.

Effect of temperature and cell concentration on dolphin (Tursiops truncatus) spermatozoa quality evaluated at different days of refrigeration

The use of cryopreserved dolphin spermatozoa facilitates the exchange of genetic material between aquatic parks and makes spermatozoa accessible to laboratories for studies to further our understanding of marine mammal reproduction. Sperm cryopreservation in the bottlenose dolphin (Tursiops truncatus) has been developed for the exchange of gametes within the ex situ population. The aim of this study was to develop an effective method for refrigeration of bottlenose dolphin spermatozoa diluted in a commercial extender (BTS). In Experiment 1, the effect of temperature (5 compared with 15 °C) on sperm quality was evaluated during 7 days of storage at 100 × 10⁶ spermatozoa/ml. In Experiment 2, the effect of the storage concentration (100 × 10⁶ compared with 20 × 10⁶ spermatozoa/ml) on sperm quality was assessed during 7 days of storage at 5 °C. In Experiment 1, total motility (including % of rapid sperm) was greater at 5 than 15 °C. When the effect of storage concentration was evaluated (Experiment 2), total motility and ALH were greater at the higher storage concentration (100 × 10⁶ spermatozoa/ml). For both experiments, values for viability, acrosome integrity, and normal morphology variables were consistent throughout the 7 days of refrigeration. In Experiment 3, a microbiological study was performed to evaluate the effect of the refrigeration temperature and days of storage on bacterial growth. The results of microbiological analysis indicated there was Staphylococcus aureus in some samples, however, there was no effect of temperature or days of refrigeration. In conclusion, bottlenose dolphin semen can be refrigerated for a short to medium period of storage and there is maintenance of functionality of sperm when stored at 100 × 10⁶ spermatozoa/ml at 5 °C.

ESTABLISHING MARGINAL LYMPH NODE ULTRASONOGRAPHIC CHARACTERISTICS IN HEALTHY BOTTLENOSE DOLPHINS ( TURSIOPS TRUNCATUS)

Pulmonary disease has been well documented in wild and managed dolphin populations. The marginal lymph nodes of the dolphin thorax provide lymphatic drainage to the lungs and can indicate pulmonary disease. This study standardized a technique for rapid, efficient, and thorough ultrasonographic evaluation of the marginal lymph nodes in bottlenose dolphins ( Tursiops truncatus). Thoracic ultrasonography was performed on 29 clinically healthy adult bottlenose dolphins. Reference intervals for lymph node dimensions and ultrasonographic characteristics of marginal lymph nodes were determined from four transducer orientations: longitudinal, transverse, oblique, and an orientation optimized to the ultrasonographer's eye. The relationship between lymph node dimensions and dolphin age, sex, length, weight, origin, and management setting (pool versus ocean enclosure) were also evaluated. The mean marginal lymph nodes measured 5.26 cm in length (SD = 1.10 cm, minimum = 3.04 cm, maximum = 7.61 cm, reference interval [10th to 90th percentiles per node dimension] 3.78-6.55 cm) and 3.72 cm in depth (SD = 0.59 cm, minimum = 2.64, maximum = 5.38 cm, reference interval 2.98-4.50 cm). Sex, dolphin length, weight, and management setting had no effect on lymph node dimensions. Dolphins >30 yr of age had longer node lengths than dolphins 5-10 yr old. Node dimensions did differ between dolphins from various origins. Most commonly, the lymph node was found to be hyperechoic relative to surrounding soft tissues (98%) and to have irregular caudal borders (84%), ill-defined deep borders (83%), flat superficial border (67%), triangular or rounded triangle shape (59%), irregular cranial border (55%), and moderate heterogeneity (34%). The data reported in this study serve as a baseline reference that may contribute to earlier detection of pleural and pulmonary disease of managed and wild cetacean populations.

Leukopenia induced by micafungin in a bottlenose dolphin (Tursiops truncatus): a case report

A bottlenose dolphin (Tursiops truncatus) housed in the Port of Nagoya Public Aquarium (PNPA) presented with symptomatic pneumonia caused by Aspergillus fumigatus. The dolphin was treated with micafungin. On days 2 and 11 after the first administration of micafungin, results from a physical examination and laboratory test indicated a decline of body temperature (BT) and leukopenia, with lowest BT, white blood cells (WBCs), and segmented neutrophils (SEGs) of 34.2°C, 600 cells/µl, and 67 cells/µl, respectively. BT, WBCs, and SEGs returned to normal range after administration of granulocyte colony stimulating factor (G-CSF). To the best of our knowledge, this is the first report of micafungin-induced decline of BT and leukopenia that was successfully treated with G-CSF in a bottlenose dolphin.

Immune Response of Galleria mellonella against Human Fungal Pathogens

In many aspects, the immune response against pathogens in insects is similar to the innate immunity in mammals. This has caused a strong interest in the scientific community for the use of this model in research of host⁻pathogen interactions. In recent years, the use of Galleria mellonella larvae, an insect belonging to the Lepidoptera order, has emerged as an excellent model to study the virulence of human pathogens. It is a model that offers many advantages; for example, it is easy to handle and establish in every laboratory, the larvae have a low cost, and they tolerate a wide range of temperatures, including human temperature 37 °C. The immune response of G. mellonella is innate and is divided into a cellular component (hemocytes) and humoral component (antimicrobial peptides, lytic enzymes, and peptides and melanin) that work together against different intruders. It has been shown that the immune response of this insect has a great specificity and has the ability to distinguish between different classes of microorganisms. In this review, we delve into the different components of the innate immune response of Galleria mellonella, and how these components manifest in the infection of fungal pathogens including Candida albicans, Aspergillus fumigatus, Cryptococcus neoformans, and Histoplasma capsulatum.

Hybrids and hybridization in the Cryptococcus neoformans and Cryptococcus gattii species complexes

The basidiomycetous yeasts of the Cryptococcus neoformans and Cryptococcus gattii species complexes (CNSC and CGSC respectively) are the causative agents of cryptococcosis, a set of life-threatening diseases affecting the central nervous system, lungs, skin, and other body sites of humans and other mammals. Both the CNSC and CGSC can be subdivided into varieties, serotypes, molecular types, and lineages based on structural variations, molecular characteristics and genetic sequences. Hybridization between the haploid lineages within and between the two species complexes is known to occur in natural and clinical settings, giving rise to intraspecific and interspecific diploid/aneuploid hybrid strains. Since their initial discovery in 1977, cryptococcal hybrids have been increasingly discovered in both clinical and environmental settings with over 30% of all cryptococcal infections in some regions of Europe being caused by hybrid strains. This review summarizes the major findings to date on cryptococcal hybrids, including their possible origins, prevalence, genomic profiles and phenotypic characteristics. Our analyses suggest that CNSC and CGSC can be an excellent model system for studying fungal hybridization.

Retrospective pathological survey of pulmonary disease in free-ranging Amazon river dolphin Inia geoffrensis and tucuxi Sotalia fluviatilis

The Amazon river dolphin Inia geoffrensis and tucuxi Sotalia fluviatilis are classified as Data Deficient species. Despite very limited knowledge on health and disease aspects of these species, the main threats to their conservation include incidental mortality in fishing gear, population fragmentation, habitat loss and environmental pollution. It is also suggested that underlying diseases may contribute to their mortality rates. Herein, we retrospectively describe gross and microscopic pulmonary lesions in free-ranging I. geoffrensis (n = 24) and S. fluviatilis (n = 28) found dead. Nearly 85% of the examined animals presented some kind of primary lung disease, wherein the main etiological diagnoses were verminous pneumonia by Halocercus brasiliensis (25%), bacterial pneumonia (25%) and a single case of meconium aspiration syndrome (1.9%). An etiology was not determined in 36.5% (19/52) of animals. These results indicate a high incidence of pulmonary pathology in these species, raising concerns about population impacts and potential zoonotic implications in some instances. These data may provide a scientific basis for future medical and conservation efforts focused on Amazonian dolphins.

Positive selection in coding regions and motif duplication in regulatory regions of bottlenose dolphin MHC class II genes

The vertebrate immune response is mediated through highly adaptive, quickly evolving cell surface receptors, the major histocompatibility complex (MHC). MHC molecules bind and present a diverse array of pathogenic molecules and trigger a cascade of defenses. Use of MHC variation as a marker for population health has also evolved quickly following advances in sequencing methods. We applied a combination of traditional and next generation sequencing methodology to characterize coding (peptide binding region) and regulatory (proximal promoter) sequence variation in MHC Class II DQA and DQB genes between estuarine and coastal populations of the bottlenose dolphin, Tursiops truncatus, an apex predator whose health status is indicative of anthropogenic impacts on the ecosystem. The coding regions had 10 alleles each at DQA and DQB; the promoters had 6 and 7 alleles at DQA and DQB, respectively with variation within key regulatory motifs. Positive selection was observed for the coding regions of both genes while both coding and promoter regions exhibited geographic differences in allele composition that likely indicates diversifying selection across habitats. Most notable was the discovery of a complete duplication of a 14-bp T-box motif in the DQA promoter. Four class II promoter regions (DQA, DQB, DRA, DRB) were characterized in species from four cetacean families (Delphinidae, Monodontidae, Lipotidae, and Physeteridae) and revealed substantial promoter structural diversity across this order. Peptide binding regions may not be the only source of adaptive potential within cetacean MHC for responding to pathogenic threats. These findings are the first analysis of cetacean MHC regulatory motifs, which may divulge unique immunogenetic strategies among cetaceans and reveal how MHC transcriptional control continues to evolve. The combined MHC regulatory and coding data provide new genetic context for distinct vulnerability profiles between coastal and estuarine populations, which are key concerns for health and risk management.

Structure of Lung-Mimetic Multilamellar Bodies with Lipid Compositions Relevant in Pneumonia

The hierarchical assembly of lipids, as modulated by composition and environment, plays a significant role in the function of biological membranes and a myriad of diseases. Elevated concentrations of calcium ions and cardiolipin (CL), an anionic tetra-alkyl lipid found in mitochondria and some bacterial cell membranes, have been implicated in pneumonia recently. However, their impact on the physicochemical properties of lipid assemblies in lungs and how it impairs alveoli function is still unknown. We use small- and wide-angle X-ray scattering (S/WAXS) and solid-state nuclear magnetic resonance (ssNMR) to probe the structure and dynamics of lung-mimetic multilamellar bodies (MLBs) in the presence of Ca²⁺ and CL. We conjecture that CL overexpressed in the hypophase of alveoli strongly affects the structure of lung-lipid bilayers and their stacking in the MLBs. Specifically, S/WAXS data revealed that CL induces significant shrinkage of the water-layer separating the concentric bilayers in multilamellar aggregates. ssNMR measurements indicate that this interbilayer tightening is due to undulation repulsion damping as CL renders the glycerol backbone of the membranes significantly more static. In addition to MLB dehydration, CL promotes intrabilayer phase separation into saturated-rich and unsaturated-rich lipid domains that couple across multiple layers. Expectedly, addition of Ca²⁺ screens the electrostatic repulsion between negatively charged lung membranes. However, when CL is present, addition of Ca²⁺ results in an apparent interbilayer expansion likely due to local structural defects. Combining S/WAXS and ssNMR on systems with compositions pertinent to healthy and unhealthy lung membranes, we propose how alteration of the physiochemical properties of MLBs can critically impact the breathing cycle.

An Overview of Sex Bias in C. neoformans Infections

Cryptococcosis, a fungal disease arising from the etiologic agent Cryptococcus neoformans, sickens a quarter of a million people annually, resulting in over 180,000 deaths. Interestingly, males are affected by cryptococcosis more frequently than females, a phenomenon observed for more than a half century. This disparity is seen in both HIV− (~3M:1F) and HIV⁺ (~8M:2F) populations of cryptococcal patients. In humans, male sex is considered a pre-disposing risk factor for cryptococcosis and males suffering from the disease have more severe symptoms and poorer outcomes. There are numerous observational, clinical and epidemiological studies documenting the male disadvantage in C. neoformans but with no further explanation of cause or mechanism. Despite being commonly acknowledged, little primary research has been conducted elucidating the reasons for these differences. The research that has been conducted, however, suggests sex hormones are a likely cause. Given that the sex difference is both prevalent and accepted by many researchers in the field, it is surprising that more is not known. This review highlights the data regarding differences in sexual dimorphism in C. neoformans infections and suggests future directions to close the research gap in this area.

Cryptococcal pathogenic mechanisms: a dangerous trip from the environment to the brain

Cryptococcus neoformans is an opportunistic pathogenic yeast that causes serious infections, most commonly of the central nervous system (CNS). C. neoformans is mainly found in the environment and acquired by inhalation. It could be metaphorically imagined that cryptococcal disease is a "journey" for the microorganism that starts in the environment, where this yeast loads its suitcase with virulence traits. C. neoformans first encounters the infected mammalian host in the lungs, a site in which it must choose the right elements from its "virulence suitcase" to survive the pulmonary immune response. However, the lung is often only the first stop in this journey, and in some individuals the fungal trip continues to the brain. To enter the brain, C. neoformans must "open" the main barrier that protects this organ, the blood brain barrier (BBB). Once in the brain, C. neoformans expresses a distinct set of protective attributes that confers a strong neurotropism and the ability to cause brain colonisation. In summary, C. neoformans is a unique fungal pathogen as shown in its ability to survive in the face of multiple stress factors and to express virulence factors that contribute to the development of disease.

Development and testing of species-specific ELISA assays to measure IFN-γ and TNF-α in bottlenose dolphins (Tursiops truncatus)

Monitoring the immune status of cetaceans is important for a variety of health conditions. Assays to quantify cytokines, especially pro-inflammatory cytokines, could be employed, in addition to currently available diagnostic assays, to screen for alterations in the health status of an animal. Though a number of immunological assays are readily available for humans and mice, specific assays for many veterinary species, including cetaceans such as bottlenose dolphins (Tursiops truncatus), are more limited. Herein, we describe the development of IFN-gamma (IFN-γ) and TNF-alpha (TNF-α) enzyme-linked immunosorbent assays (ELISAs) specific to bottlenose dolphins. Utilizing these assays, we monitored the immune status of bottlenose dolphins from a managed population over a period of eleven months. The ELISA assays developed for bottlenose dolphins were used to measure IFN-γ and TNF-α in serum or in culture supernatants from peripheral blood mononuclear cells (PBMCs) stimulated with varying concentrations of mitogens concanavalin A (ConA) or phytohemagglutinin (PHA). Induction of TNF-α in PBMC cultures was consistently highest with 1 μg/mL ConA, while 1 μg/mL PHA induced the highest secretion of IFN-γ. Serum levels of TNF-α and IFN-γ remained relatively constant for each animal over the time period examined. CBC and plasma chemistry variables measured concurrently in the bottlenose dolphins were then examined as independent predictors of cytokine levels. We found these clinical variables were more likely to predict linear changes in serum IFN-γ and TNF-α levels compared to concentrations of these cytokines in mitogen-stimulated PBMC culture supernatants. Cytokine assays developed will be of substantial benefit in monitoring bottlenose dolphin health as an adjunct to currently available diagnostic tests.

Extensive Core Microbiome in Drone-Captured Whale Blow Supports a Framework for Health Monitoring

The pulmonary system is a common site for bacterial infections in cetaceans, but very little is known about their respiratory microbiome. We used a small, unmanned hexacopter to collect exhaled breath condensate (blow) from two geographically distinct populations of apparently healthy humpback whales (Megaptera novaeangliae), sampled in the Massachusetts coastal waters off Cape Cod (n = 17) and coastal waters around Vancouver Island (n = 9). Bacterial and archaeal small-subunit rRNA genes were amplified and sequenced from blow samples, including many of sparse volume, as well as seawater and other controls, to characterize the associated microbial community. The blow microbiomes were distinct from the seawater microbiomes and included 25 phylogenetically diverse bacteria common to all sampled whales. This core assemblage comprised on average 36% of the microbiome, making it one of the more consistent animal microbiomes studied to date. The closest phylogenetic relatives of 20 of these core microbes were previously detected in marine mammals, suggesting that this core microbiome assemblage is specialized for marine mammals and may indicate a healthy, noninfected pulmonary system. Pathogen screening was conducted on the microbiomes at the genus level, which showed that all blow and few seawater microbiomes contained relatives of bacterial pathogens; no known cetacean respiratory pathogens were detected in the blow. Overall, the discovery of a shared large core microbiome in humpback whales is an important advancement for health and disease monitoring of this species and of other large whales. IMPORTANCE The conservation and management of large whales rely in part upon health monitoring of individuals and populations, and methods generally necessitate invasive sampling. Here, we used a small, unmanned hexacopter drone to noninvasively fly above humpback whales from two populations, capture their exhaled breath (blow), and examine the associated microbiome. In the first extensive examination of the large-whale blow microbiome, we present surprising results about the discovery of a large core microbiome that was shared across individual whales from geographically separated populations in two ocean basins. We suggest that this core microbiome, in addition to other microbiome characteristics, could be a useful feature for health monitoring of large whales worldwide.

Optimal marine mammal welfare under human care: Current efforts and future directions

Marine mammals include cetaceans, pinnipeds, sirenians, sea otters and polar bears, many of which are charismatic and popular species commonly kept under human care in zoos and aquaria. However, in comparison with their fully terrestrial counterparts their welfare has been less intensively studied, and their partial or full reliance on the aquatic environment leads to unique welfare challenges. In this paper we attempt to collate and review the research undertaken thus far on marine mammal welfare, and identify the most important gaps in knowledge. We use 'best practice case studies' to highlight examples of research promoting optimal welfare, include suggestions for future directions of research efforts, and make recommendations to strive for optimal welfare, where it is currently lacking, above and beyond minimum legislation and guidelines. Our review of the current literature shows that recently there have been positive forward strides in marine mammal welfare assessment, but fundamental research is still required to validate positive and negative indicators of welfare in marine mammals. Across all marine mammals, more research is required on the dimensions and complexity of pools and land areas necessary for optimal welfare, and the impact of staff absence for most of the 24-h day, as standard working hours are usually between 0900 and 1700.

Pulmonary carcinoma with metastasis in a long-finned pilot whale (Globicephala melas)

Background

Lung cancer is the most commonly diagnosed neoplasm in humans, however this does not apply to other animal species. Living in an aquatic environment the respiratory system of cetaceans had to undergo unique adaptations in order to them to survive and cope with totally different respiratory pathogens and potentially carcinogens from those affecting humans.

Case presentation

This article discusses not only macroscopical, histopathological and immunohistochemical features of a pulmonary carcinoma with disseminated metastases in a long-finned pilot whale (Globicephala melas), as well as the immunohistochemical analysis performed on various tissues of cetaceans belonging to the genus Globicephala. On the necropsy examination of the carcass, multiple pulmonary nodules and generalised thoracic lymphadenomegaly were noted. Histologically, a malignant epithelial neoplasia was identified in the lung, thoracic lymph nodes, and adrenal gland. Immunohistochemical analysis revealed a pulmonary carcinoma. Vasculogenic mimicry and epithelial-to-mesenchymal transition phenotype, as suggested by cytomorphological and immunohistochemical characteristics, were observed.

Conclusions

A diagnosis of metastatic pulmonary carcinoma was determined, which to the author’s knowledge, appears to be not previously recorded in long-finned pilot whale species. This is also the first report of vasculogenic mimicry and epithelial-to-mesenchymal transition event in a spontaneous cancer from a cetacean species.

Reproductive outcome and survival of common bottlenose dolphins sampled in Barataria Bay, Louisiana, USA, following the Deepwater Horizon oil spill

Common bottlenose dolphins (Tursiops truncatus) inhabit bays, sounds and estuaries across the Gulf of Mexico. Following the Deepwater Horizon oil spill, studies were initiated to assess potential effects on these ecologically important apex predators. A previous study reported disease conditions, including lung disease and impaired stress response, for 32 dolphins that were temporarily captured and given health assessments in Barataria Bay, Louisiana, USA. Ten of the sampled dolphins were determined to be pregnant, with expected due dates the following spring or summer. Here, we report findings after 47 months of follow-up monitoring of those sampled dolphins. Only 20% (95% CI: 2.50–55.6%) of the pregnant dolphins produced viable calves, as compared with a previously reported pregnancy success rate of 83% in a reference population. Fifty-seven per cent of pregnant females that did not successfully produce a calf had been previously diagnosed with moderate–severe lung disease. In addition, the estimated annual survival rate of the sampled cohort was low (86.8%, 95% CI: 80.0–92.7%) as compared with survival rates of 95.1% and 96.2% from two other previously studied bottlenose dolphin populations. Our findings confirm low reproductive success and high mortality in dolphins from a heavily oiled estuary when compared with other populations. Follow-up studies are needed to better understand the potential recovery of dolphins in Barataria Bay and, by extension, other Gulf coastal regions impacted by the spill.

Streptococcal infections in cats: ABCD guidelines on prevention and management

OVERVIEW

Streptococcus canis is most prevalent in cats, but recently S equi subsp zooepidemicus has been recognised as an emerging feline pathogen.

S CANIS INFECTION

S canis is considered part of the commensal mucosal microflora of the oral cavity, upper respiratory tract, genital organs and perianal region in cats. The prevalence of infection is higher in cats housed in groups; and, for example, there may be a high rate of vaginal carriage in young queens in breeding catteries. A wide spectrum of clinical disease is seen, encompassing neonatal septicaemia, upper respiratory tract disease, abscesses, pneumonia, osteomyelitis, polyarthritis, urogenital infections, septicaemia, sinusitis and meningitis.

S EQUI SUBSP ZOOEPIDEMICUS INFECTION

S equi subsp zooepidemicus is found in a wide range of species including cats. It was traditionally assumed that this bacterium played no role in disease of cats, but it is now considered a cause of respiratory disease with bronchopneumonia and pneumonia, as well as meningoencephalitis, often with a fatal course. Close confinement of cats, such as in shelters, appears to be a major risk factor. As horses are common carriers of this bacterium, contact with horses is a potential source of infection. Additionally, the possibility of indirect transmission needs to be considered.

DIAGNOSIS

Streptococci can be detected by conventional culture techniques from swabs, bronchoalveolar lavage fluid or organ samples. Also real-time PCR can be used, and is more sensitive than culture.

TREATMENT

In suspected cases, treatment with broad-spectrum antibiotics should be initiated as soon as possible and, if appropriate, adapted to the results of culture and sensitivity tests.

Renal lesions in cetaceans from Brazil

This study reports the occurrence of renal lesions in cetaceans from the coast of Brazil subjected to necropsy examination between 1996 and 2011. The animals (n = 192) were by-caught in fishing nets, were found dead on beaches or died despite attempted rehabilitation. Kidney samples were evaluated grossly and microscopically and, depending on the histopathological findings, immunohistochemical and ultrastructural analyses were conducted. Due to autolysis, a diagnosis was reached in only 128 animals, of which 82 (64.1%) had kidney lesions. Cystic renal disease was the most common lesion observed in 34 cases (26.6%) and these were classified as simple cysts in eight cases (6.3%), polycystic kidney disease in one rough-toothed dolphin (Steno bredanensis), secondary glomerulocystic disease in 16 cases (12.5%) and primary glomerulocystic disease in nine cases (7%). Other lesions included membranous glomerulonephritis (28 cases; 21.9%), membranoproliferative glomerulonephritis (20 cases; 15.6%), lymphoplasmacytic interstitial nephritis (21 cases; 16.4%), lipidosis (19 cases; 14.8%), glomerulosclerosis (8 cases; 6.3%) and pyogranulomatous nephritis(five cases; 3.9%); two of the later were associated with the migration of nematode larvae. Additionally, tubular adenoma was identified in a Franciscana (Pontoporia blainvillei). The pathological implications of these lesions are discussed according the cause of death, age or sex of the animals. Furthermore, the lesions were compared with those of other marine and terrestrial mammals, including man.

Computed tomography and cross-sectional anatomy of the thorax of the live bottlenose dolphin (Tursiops truncatus)

Pulmonary disease is one of the leading causes of cetacean morbidity and mortality in the wild and in managed collections. The purpose of this study was to present the computed tomographic (CT) appearance of the thorax of the live bottlenose dolphin (Tursiops truncatus) out-of-water and to describe the technical and logistical parameters involved in CT image acquisition in this species. Six thoracic CT evaluations of four conscious adult bottlenose dolphins were performed between April 2007 and May 2012. Animals were trained to slide out of the water onto foam pads and were transported in covered trucks to a human CT facility. Under light sedation, animals were secured in sternal recumbency for acquisition of CT data. Non-contrast helical images were obtained during an end-inspiratory breath hold. Diagnostic, high quality images were obtained in all cases. Respiratory motion was largely insignificant due to the species' apneustic respiratory pattern. CT findings characteristic of this species include the presence of a bronchus trachealis, absence of lung lobation, cranial cervical extension of the lung, lack of conspicuity of intrathoracic lymph nodes, and presence of retia mirabilia. Dorsoventral narrowing of the heart relative to the thorax was seen in all animals and is suspected to be an artifact of gravity loading. Diagnostic thoracic computed tomography of live cetaceans is feasible and likely to prove clinically valuable. A detailed series of cross-sectional reference images is provided.

Identification of Lactobacillus strains with probiotic features from the bottlenose dolphin (Tursiops truncatus)

Aims

In order to develop complementary health management strategies for marine mammals, we used culture-based and culture-independent approaches to identify gastrointestinal lactobacilli of the common bottlenose dolphin, Tursiops truncatus.

Methods and Results

We screened 307 bacterial isolates from oral and rectal swabs, milk and gastric fluid, collected from 38 dolphins in the U.S. Navy Marine Mammal Program, for potentially beneficial features. We focused our search on lactobacilli and evaluated their ability to modulate TNF secretion by host cells and inhibit growth of pathogens. We recovered Lactobacillus salivarius strains which secreted factors that stimulated TNF production by human monocytoid cells. These Lact. salivarius isolates inhibited growth of selected marine mammal and human bacterial pathogens. In addition, we identified a novel Lactobacillus species by culture and direct sequencing with 96·3% 16S rDNA sequence similarity to Lactobacillus ceti.

Conclusions

Dolphin-derived Lact. salivarius isolates possess features making them candidate probiotics for clinical studies in marine mammals.

Significance and Impact of the Study

This is the first study to isolate lactobacilli from dolphins, including a novel Lactobacillus species and a new strain of Lact. salivarius, with potential for veterinary probiotic applications. The isolation and identification of novel Lactobacillus spp. and other indigenous microbes from bottlenose dolphins will enable the study of the biology of symbiotic members of the dolphin microbiota and facilitate the understanding of the microbiomes of these unique animals.

Pulmonary ultrasound findings in a bottlenose dolphin Tursiops truncatus population

Lung disease is common among wild and managed populations of bottlenose dolphins Tursiops truncatus. The purpose of the study was to apply standardized techniques to the ultrasound evaluation of dolphin lungs, and to identify normal and abnormal sonographic findings associated with pleuropulmonary diseases. During a 5 yr period (2005 to 2010), 498 non-cardiac thoracic ultrasound exams were performed on bottlenose dolphins at the Navy Marine Mammal Program in San Diego, California, USA. Exams were conducted as part of routine physical exams, diagnostic workups, and disease monitoring. In the majority of routine exams, no abnormal pleural or pulmonary findings were detected with ultrasound. Abnormal findings were typically detected during non-routine exams to identify and track disease progression or resolution; therefore, abnormal results are overrepresented in the study. In order of decreasing prevalence, abnormal sonographic findings included evidence of alveolar-interstitial syndrome, pleural effusion, pulmonary masses, and pulmonary consolidation. Of these findings, alveolar-interstitial syndrome was generally nonspecific as it represented several possible disease states. Pairing ultrasound findings with clinical signs was critical to determine relevance. Pleural effusion, pulmonary masses, and pulmonary consolidation were relatively straightforward to diagnose and interpret. Further diagnostics were performed to obtain definitive diagnoses when appropriate, specifically ultrasound-guided thoracocentesis, fine needle aspirates, and lung biopsies, as well as radiographs and computed tomography (CT) exams. Occasionally, post mortem gross necropsy and histopathology data were available to provide confirmation of diagnoses. Thoracic ultrasound was determined to be a valuable diagnostic tool for detecting pleural and pulmonary diseases in dolphins.