Search

Recent studies describe the use of UAVs in collecting blow samples from large whales to analyze the microbial and viral community in exhaled air. Unfortunately, attempts to collect blow from small cetaceans have not been successful due to their swimming and diving behavior. In order to overcome these limitations, in this study we investigated the application of a specific sampling tool attached to a UAV to analyze the blow from small cetaceans and their respiratory microbiome. Preliminary trials to set up the sampling tool were conducted on a group of 6 bottlenose dolphins (Tursiops truncatus) under human care, housed at Acquario di Genova, with approximately 1 meter distance between the blowing animal and the tool to obtain suitable samples. The same sampling kit, suspended via a 2 meter rope assembled on a waterproof UAV, flying 3 meters above the animals, was used to sample the blows of 5 wild bottlenose dolphins in the Gulf of Ambracia (Greece) and a sperm whale (Physeter macrocephalus) in the southern Tyrrhenian Sea (Italy), to investigate whether this experimental assembly also works for large whale sampling. In order to distinguish between blow-associated microbes and seawater microbes, we pooled 5 seawater samples from the same area where blow samples' collection were carried out. The the respiratory microbiota was assessed by using the V3-V4 region of the 16S rRNA gene via Illumina Amplicon Sequencing. The pooled water samples contained more bacterial taxa than the blow samples of both wild animals and the sequenced dolphin maintained under human care. The composition of the bacterial community differed between the water samples and between the blow samples of wild cetaceans and that under human care, but these differences may have been mediated by different microbial communities between seawater and aquarium water. The sperm whale's respiratory microbiome was more similar to the results obtained from wild bottlenose dolphins. Although the number of samples used in this study was limited and sampling and analyses were impaired by several limitations, the results are rather encouraging, as shown by the evident microbial differences between seawater and blow samples, confirmed also by the meta-analysis carried out comparing our results with those obtained in previous studies. Collecting exhaled air from small cetaceans using drones is a challenging process, both logistically and technically. The success in obtaining samples from small cetacean blow in this study in comparison to previous studies is likely due to the distance the sampling kit is suspended from the drone, which reduced the likelihood that the turbulence of the drone propeller interfered with successfully sampling blow, suggested as a factor leading to poor success in previous studies., Competing Interests: Costa Edutainment spa provided support in the form of salaries for one author [EE]. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

The aim of this study was to evaluate the expression of Major histocompatibility complex (MHC) class I chain-related protein A (MICA) in fibroblast cell cultures of cetaceans (skin biopsies of free-ranging specimens and skin samples of freshly stranded cetaceans) by an immunofluorescence technique and to outline possible variations in MICA expression linked to different ecological and biological factors, while also investigating MICA expression after in vitro treatments with different contaminants. Free-ranging or stranded specimens of cetaceans were sampled in the Sea of Cortez (Mexico) ( Balaenoptera edeni, Delphinus capensis , and Orcinus orca ) and in the Mediterranean Sea ( Balaenoptera physalus, Physeter macrocephalus, Tursiops truncatus , and Stenella coeruleoalba ). Cell cultures were treated with an OC mixture, flame retardants, PAHs, MeHg, and BPA. The three species from the Sea of Cortez showed higher basal activity of MICA and lower levels of DDTs and PCBs than the Mediterranean species. A Pearson's linear coefficient equal to -0.45 also confirmed this tendency to have high levels of MICA and low total OC levels. Treatment of cultured fibroblasts with different contaminants mostly resulted in the upregulation of MICA protein expression by at least one treatment dose; downregulation was also found in some species or treatments. MICA alteration indicates a state of stress of the organism and a modification of the immune system's response and can be proposed as a non-invasive immunological marker that can be measured in skin biopsy samples, thus offering a good alternative to blood measurements.

Immunology of marine mammals is a relatively understudied field and its monitoring plays an important role in the individual and group management of these animals, along with an increasing value as an environmental health indicator. This study was aimed at implementing the knowledge on the immune response in cetaceans stranded along the Italian coastline to provide a baseline useful for assessing the immune status of bottlenose ( Tursiops truncatus ) and striped ( Stenella coeruleoalba ) dolphins. In particular, since the Mediterranean Sea is considered a heavily polluted basin, a comparison with animals living in open waters such as the Atlantic Ocean was made. Formalin-fixed, paraffin-embedded spleen, thymus, and lymph node tissues from 16 animals stranded along Italian and 11 cetaceans from the Canary Island shores were sampled within 48 h from death. Information regarding stranding sites, gender, and age as well as virologic, microbiological, and parasitological investigations, and the cause and/or the death mechanism were also collected in order to carry out statistical analyses. Selected tissues were routinely stained with hematoxylin-eosin (H&E) and with immunohistochemical techniques (IHC). For IHC analysis, anti-human CD5 monoclonal mouse antibody to identify T lymphocytes, CD20 monoclonal mouse antibody for the identification of mature B lymphocytes and HLA-DR antigen (alpha-chain) monoclonal mouse antibody for the identification of the major histocompatibility complex type II were previously validated for both species by Western-blotting technique. T -test method applied to quantitative evaluation of IHC positive cells showed a significant relationship between the number of (expression) of CD20 stained lymphocytes and normal and hypoplastic lymph nodes, respectively. No other significant correlations were noticed. Analyses for organochlorines (OC) compounds were performed in animals (n°5) having frozen blubber tissue available. A simple linear regression was calculated to predict if the amount of OCs could influence the number of inflammatory cell subpopulations and a moderate negative correlation was found between the presence of high quantity of contaminants and the number of T lymphocytes. Future analysis should be aimed to understand the effect of the major immunomodulatory pathogens on sub-populations of B and T cells.

Cetacean morbillivirus (CeMV) is a major natural cause of morbidity and mortality in cetaceans worldwide and results in epidemic and endemic fatalities. The pathogenesis of CeMV has not been fully elucidated, and questions remain regarding tissue tropism and the mechanisms of immunosuppression. We compared the histopathologic and viral immunohistochemical features in molecularly confirmed CeMV-infected Guiana dolphins (Sotalia guianensis) from the Southwestern Atlantic (Brazil) and striped dolphins (Stenella coeruleoalba) and bottlenose dolphins (Tursiops truncatus) from the Northeast-Central Atlantic (Canary Islands, Spain) and the Western Mediterranean Sea (Italy). Major emphasis was placed on the central nervous system (CNS), including neuroanatomical distribution of lesions, and the lymphoid system and lung were also examined. Eleven Guiana dolphins, 13 striped dolphins, and 3 bottlenose dolphins were selected by defined criteria. CeMV infections showed a remarkable neurotropism in striped dolphins and bottlenose dolphins, while this was a rare feature in CeMV-infected Guiana dolphins. Neuroanatomical distribution of lesions in dolphins stranded in the Canary Islands revealed a consistent involvement of the cerebrum, thalamus, and cerebellum, followed by caudal brainstem and spinal cord. In most cases, Guiana dolphins had more severe lung lesions. The lymphoid system was involved in all three species, with consistent lymphoid depletion. Multinucleate giant cells/syncytia and characteristic viral inclusion bodies were variably observed in these organs. Overall, there was widespread lymphohistiocytic, epithelial, and neuronal/neuroglial viral antigen immunolabeling with some individual, host species, and CeMV strain differences. Preexisting and opportunistic infections were common, particularly endoparasitism, followed by bacterial, fungal, and viral infections. These results contribute to understanding CeMV infections in susceptible cetacean hosts in relation to factors such as CeMV strains and geographic locations, thereby establishing the basis for future neuro- and immunopathological comparative investigations., Competing Interests: The authors have declared that no competing interests exist.

Cetacean morbillivirus (CeMV) has emerged as the pathogen that poses the greatest risk of triggering epizootics in cetacean populations worldwide, and has a high propensity for interspecies transmission, including sporadic infection of seals. In this study, we investigated the evolutionary history of CeMV by deep sequencing wild-type viruses from tissue samples representing cetacean species with different spatiotemporal origins. Bayesian phylogeographic analysis generated an estimated evolutionary rate of 2.34 × 10 -4 nucleotide substitutions/site/year and showed that CeMV evolutionary dynamics are neither host-restricted nor location-restricted. Moreover, the dolphin morbillivirus strain of CeMV has undergone purifying selection without evidence of species-specific mutations. Cell-to-cell fusion and growth kinetics assays demonstrated that CeMV can use both dolphin and seal CD150 as a cellular receptor. Thus, it appears that CeMV can readily spread among multiple cetacean populations and may pose an additional spillover risk to seals.

Between 2007 and 2014, 83 cetaceans were found stranded along the Ligurian coast of Italy, in the Pelagos Sanctuary, the largest marine protected area in the Mediterranean basin. Forty-nine (59%) were submitted to complete or partial necropsy, depending on the conservation status of the carcass. Based on gross and histological pathology and ancillary testing, the cause of death was determined and categorized as anthropogenic or natural (i.e., nonanthropogenic) in origin for 33 animals (67%) and of undetermined origin in the remaining 16 (33%). Natural causes of death, accompanied by either poor or good nutritional status, were attributed to 29 animals (59%), whereas four (8%) were diagnosed with an anthropogenic cause of death, consisting of interaction with fishing activities. Infectious and noninfectious disease was the most common cause of death, involving 29 cetaceans (59%). These data are valuable for understanding health and mortality trends in cetacean populations and can provide information for establishing policies for cetacean conservation and management in such an important protected area of the Mediterranean basin.

This study reports the results of seroepidemiological investigations carried out against Morbillivirus, Toxoplasma gondii and Brucella spp. on blood serum samples collected from 70 cetacean specimens found stranded along the Italian coastline between 1998 and 2014. A total number of 23 serum samples (32.8%) obtained from Stenella coeruleoalba, Tursiops truncatus, Balaenoptera physalus and Globicephala melas harboured anti-Morbillivirus neutralizing antibodies. Ten sera (16%) collected from S. coeruleoalba and T. truncatus were found positive against T. gondii, while no antibodies against Brucella spp. were found. These data reveal that stranded cetaceans provide a unique opportunity for monitoring the health status of free-ranging animals living in the Mediterranean Sea, in order to investigate the level of exposure of cetacean populations to selected infectious agents representing a serious threat for aquatic mammals., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

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.

An unusual mortality event involving cetaceans, mainly striped dolphins Stenella coeruleoalba (Meyen, 1833), occurred along the Tyrrhenian Sea coast of Italy during the first 3 mo of 2013. Based on post-mortem analyses carried out according to body condition on 66 dolphins (54% of stranded animals), several hypotheses to explain the causes of this mortality event were proposed. Although no definitive conclusions can be drawn, dolphin morbillivirus was deemed the most likely cause, although other infectious agents (including Photobacterium damselae damselae and herpesvirus) or environmental factors may also have contributed to this recent mortality event.

Morbilliviruses, such as Cetacean morbillivirus (CeMV) or Phocine distemper virus (PDV), represent a growing threat for marine mammals on both hemispheres. Because free-ranging animal populations strongly rely on natural resistance mechanisms, innate immunity-related genes and virus cell entry receptor genes may represent key factors involved in susceptibility to CeMV in Cetaceans. Using the next generation sequencing technology, we have sequenced 11 candidate genes in two model species, Stenella coeruleoalba and Phocoena phocoena. Suitable single nucleotide polymorphism markers of potential functional importance, located in genes coding for basigin ( BSG, CD147), the signaling lymphocyte activating molecule ( SLAMF1), the poliovirus-related receptor-4 ( NECTIN4, PVRL4), toll-like receptors 3, 7, 8 ( TLR3, TLR7, TLR8), natural resistance-associated macrophage protein ( SLC11A1) and natural cytotoxicity triggering receptor 1 ( NCR1), were identified in each model species, along with MHC-DQB haplotypes unique for each species. This set of molecular markers represents a potentially useful tool for studying host genetic variation and susceptibility to morbillivirus infection in Cetaceans as well as for studying functionally important genetic diversity of selected Cetacean populations. [ABSTRACT FROM AUTHOR]