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Immunoperoxidase staining of morbillivirus antigen in cytoplasm and in nuclei (arrow heads) of syncytia in a lymph node using monoclonal antibody against PDV. x 400
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Mass strandings of sperm whales (Physeter macrocephalus) are rare in the Mediterranean Sea. Nevertheless, in 2014 a pod of 7 specimens stranded alive along the Italian coast of the Central Adriatic Sea: 3 individuals died on the beach after a few hours due to internal damages induced by prolonged recumbency; the remaining 4 whales were refloated af...
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... The abundance and distribution of the fin whale population in the Northern Hemisphere (Monestiez et al. 2006;Delarue et al. 2009;Edwards et al. 2015) as well as stranding records (Jauniaux et al. 2000;Notarbartolo-de-Sciara et al. 2003;Mazzariol et al. 2012;Alstrup et al. 2013;Mazzariol 2016) are well documented. Many of the recorded strandings have been attributed to disease (crassicaudiasis and morbillivirosis), vessel strikes, fishing gear entanglement, anthropogenic ocean noise, and starvation, among other causes 1 3 (Lambertsen 1986;Jauniaux et al. 1998;Alstrup et al. 2013;Cooke 2018). ...
Fin whales (Balaenoptera physalus) can be found worldwide, in oceanic waters, though are rarely found in coastal areas of wide and shallow continental platforms such as those in the western South Atlantic Ocean. Here we report the first confirmed stranding of a B. physalus off the Atlantic coast of Tierra del Fuego (TDF), in July (austral winter) of 2016. In addition, a bibliographic review of the strandings of this species was carried out on the Argentinian coasts and especially on TDF. The animal was fresh when it was found and may have been alive at the moment of the stranding. The specimen was a physically immature female with a total length 15.8 m. No injuries or fishing gear were observed to suggest accidental entanglement or vessel collision. The specimen’s stomachs were empty except for a low-grade infestation with the trematode Ogmogaster antarcticus, but without any associated macroscopic gastric pathology. Although the necropsy was carried out within a few hours of death, we could not make an accurate diagnosis of the cause of death. However, the insufficient fat deposits indicate a bad physical condition and may have contributed to its stranding and subsequent death. This specimen represents the first confirmed stranding of this species in TDF.
... After the Mediterranean striped dolphin morbillivirus epizootic of 1990–92 (Aguilar & Raga, 1993), and following the report of an infected B. physalus in the North Sea (Jauniaux et al., 1998), it was feared that the disease might spread to fin whales in the Mediterranean. Such apprehension perhaps induced unwarranted diagnoses of exanthematic infection of fin whales in this region, following the stranding of two specimens in a 2-month period (Sept–November 1995), and the sighting of a free-swimming individual bearing reddish marks on its back, interpreted as skin eruptions (Guibourgé et al., 1996). ...
1. The ecology and status of fin whales Balaenoptera physalus in the Mediterranean Sea is reviewed. The species’ presence, morphology, distribution, movements, population structure, ecology and behaviour in this semi-enclosed marine region are summarized, and the review is complemented with original, previously unpublished data.
2. Although the total size of the fin whale population in the Mediterranean is unknown, an estimate for a portion of the western basin, where most of the whales are known to live, was approximately 3500 individuals. High whale densities, comparable to those found in rich oceanic habitats, were found in well-defined areas of high productivity. Most whales concentrate in the Ligurian-Corsican-Provençal Basin, where their presence is particularly noticeable during summer; however, neither their movement patterns throughout the region nor their seasonal cycle are clear.
3. Based on genetic studies, fin whales from the Mediterranean Sea are distinct from North Atlantic conspecifics, and may constitute a resident population, separate from those of the North Atlantic, despite the species’ historical presence in the Strait of Gibraltar. Fin whales are known to calve in the Mediterranean, with births peaking in November but occurring at lower rates throughout the year. They feed primarily on krill Meganyctiphanes norvegica which they capture by diving to depths in excess of 470 m. It is suggested that the extensive vertical migratory behaviour of its main prey may have influenced the social ecology of this population.
4. Known causes of mortality and threats, including collisions with vessels, entanglement in fishing gear, deliberate killing, disturbance, pollution and disease, are listed and discussed in view of the implementation of appropriate conservation measures to ensure the species’ survival in the region.
... Chez les cétacés, un morbillivirus a été identifié initialement chez le marsouin commun (Phocoena phocoena) (Visser et al., 1993b), un autre dans différentes espèces de dauphins (Kennedy, 1998) et finalement, chez un globicéphale (Globicephalus melas) (Taubenberger et al., 2000). Chez les grands cétacés, des lésions spécifiques associées à une infection par un morbillivirus ont été identifiées chez un rorqual commun (Balaenoptera physalus) (Jauniaux et al., 1998) mais le virus n'a pu être caractérisé (Jauniaux et al., 2000). ...
... La déplétion se caractérisait par de la lymphocytolyse, une absence de follicules lymphoïdes ou de zones paracorticales bien développées avec une infiltration importante de cellules syncytiales (Domingo et al., 1992;Lipscomb et al., 1994a;Jauniaux et al., 2000). Chez les marsouins, les cellules syncytiales n'ont pas été rapportées dans le tissu lymphoïde Kennedy et al., 1992;Kuiken et al., 1994b), bien qu'elles soient fréquentes chez les autres espèces, principalement au niveau des ganglions ( Figure 4) (Domingo et al., 1992;Duignan et al., 1992;Lipscomb et al., 1996;Schulman et al., 1997;Jauniaux et al., 1998). ...
... Les protéines H et N étant très similaires entre les différents morbillivirus, leurs séquences génomiques présentent des séquences conservées pouvant être utilisées (Dako Envision™, Dako, Denmark) ; contre-coloration à l'hématoxyline (x200). (Jauniaux et al., 1998) comme primers universels pour l'amplification de l'ARN viral (Barrett et al., 1993;Forsyth et Barrett, 1995). ...
Morbillivirus infections were described since 1988 in marine mammals including pinnipeds and cetaceans. Since, numerous outbreaks, responsible for thousands marine mammals death, as well as sporadic cases, have occurred in various populations from North Atlantic, Mediterranean Sea, Baikal Lake, Caspian Sea, and recently from northern Pacific. Clinical signs and macroscopic lesions are similar between species infected by morbillivirus and are close to those reported in dog with canine distemper. Under microscope, characteristic les ions are interstitial bronchopneumonia, lymphoid depletion and subacute encephalitis. Syncytia and inclusion bodies are frequently observed in lesions and epithelia. Lymphoid depletion promotes secondary infections by opportunistic pathogens, responsible in many cases of the animals death. Various parameters explain the high sensibility of certain population such as the species, the naive immunological status and vectors intervention for the disease.
Transmission of morbilliviruses within and among marine mammal species has been documented in a variety of marine habitats. Cetacean morbillivirus spreads between cetacean species in the aquatic environment whereas both phocine distemper virus and canine distemper virus have been associated with transmission within and between pinniped and terrestrial carnivore species in their natural habitat and at the aquatic-terrestrial interface. Periodically these viruses have caused large epizootics involving thousands of animals, due to sustained intra-species virus transmission. Social behavior of host species, marine habitat, geographical barriers and virus-host adaptations all likely contribute toward modulating virus spread. In combination with increased surveillance and whole genome sequencing, further research into ecological and host factors will be pivotal in better understanding the global transmission dynamics of marine morbilliviruses.
Dolphin morbillivirus (DMV) has been deemed as one of the most relevant threats for fin whales (Balaenoptera physalus) being responsible for a mortality outbreak in the Mediterranean Sea in the last years. Knowledge of the complete viral genome is essential to understand any structural changes that could modify virus pathogenesis and viral tissue tropism. We report the complete DMV sequence of N, P/V/C, M, F and H genes identified from a fin whale and the comparison of primary to quaternary structure of proteins between this fin whale strain and some of those isolated during the 1990–‘92 and the 2006–‘08 epidemics. Some relevant substitutions were detected, particularly Asn52Ser located on F protein and Ile21Thr on N protein. Comparing mutations found in the fin whale DMV with those occurring in viral strains of other cetacean species, some of them were proven to be the result of diversifying selection, thus allowing to speculate on their role in host adaptation and on the way they could affect the interaction between the viral attachment and fusion with the target host cells.
Both humans and wildlife are exposed to a highly complex mixture of toxic chemicals, which may include more than a hundred different chlorinated organics. Routes of exposure depend on the chemical(s) and organism(s) in question. While there will always be exceptions, broad generalisations can be made. Volatile compounds will be absorbed primarily through inhalation. Chemicals may be directly absorbed from the environment — for example, flatfish resting on contaminated sediments may absorb high levels of chemicals. Trees may be exposed to water soluble compounds in fogs or to compounds that are be washed into the soil where they may impact on the roots. The most studied compounds are the persistent and bioaccumulative organochlorines, particularly the pesticides, PCBs and dioxins. The most important route of biological exposure to these semivolatile pollutants is through food, although some humans may be subjected to higher exposure through their occupation.
Marine mammal mass strandings and large-scale mortalities have attracted considerable scientific and public attention in recent years. Investigations of the cause or causes of mass mortalities have also expanded knowledge of harmful agents capable of threatening marine mammal populations. To establish an integrated, explanatory framework for such phenomena, acceptable to all types of expertise in marine mammal science is an extraordinarily difficult task. Divergence in the interpretation of the importance of noxious effects and their interrelationships in several recent mortalities has been the rule rather than the exception. In this chapter we will (i) discuss the main causes of recent mass mortalities, and (ii) describe some recent events affecting pinnipeds and cetaceans, with special focus on those episodes in which a morbilliviral aetiology was demonstrated as a primary cause of the die-offs. The roles of other deleterious agents, such as chemical pollutants, parasites, fisheries, and noise pollution on marine mammal populations are considered in other chapters of this book.
