1,721,159 research outputs found
Tsunami and microbial pathogens
No full textThe present Letter to the Editor comments on an interesting article recently published in "Science", which deals with an unprecedented, tsunami-driven, transoceanic spread of marine organisms, following the dramatic 2011 earthquake in East Japan. Among the large number of (mainly) invertebrate species affected by the aforementioned phenomenon, special emphasis should be also placed upon microbial pathogens, some of which are known to impact the health and conservation of free-ranging cetaceans. A paradigmatic example in this direction is represented by Toxoplasma gondii, a protozoan and zoonotic agent of major concern, which may also infect striped dolphins (Stenella coeruleoalba), with subsequent development of severe brain lesions leading to stranding and death. Although a “general consensus” seems to exist on a “land-to-sea flow” as the most plausible mechanism through which T. gondii oocysts, similarly to other oro-fecally transmitted microorganisms, may gain access to the marine environment, this becomes questionable when dealing with striped dolphins and other T. gondii-susceptible species of aquatic mammals living in the open sea. In other words, how striped dolphins and other pelagic cetaceans may acquire T. gondii infection is still far from being understood. Consequently, among the different hypotheses drawn to explain this phenomenon, the existence of an “alternate” (mainly, if not exclusively) intra-marine biological protozoan’s cycle has been also hypothesized. Since “alternate” cycles of a similar nature have not been demonstrated to occur, thus far, both for T. gondii and for many other protozoan and non-protozoan agents, it would be worthwhile to investigate whether tsunamis, seaquakes, and (more in general) seawater movements may account for the dispersal into marine and oceanic ecosystems, also for very long distances, of T. gondii and other oro-fecally transmitted pathogens, along with their (vertebrate and invertebrate) hosts
Prevalence of epidermal conditions in common bottlenose dolphins (Tursiops truncatus) in the Gulf of Ambracia, western Greece
No full textBottlenose dolphins (Tursiops truncatus) of the Gulf of Ambracia are exposed to numerous growing anthropogenic impacts, rendering them more prone to cutaneous changes. The prevalence of skin conditions in this resident population was evaluated based on photo-identification. Five skin lesions previously described in other studies were considered, namely dark-fringed spots, white-fringed spots, orange patch, tattoo-like and white fin-fringe, in addition to a new particularly severe condition named as “white dots” (WD). A 37% prevalence of epidermal lesions was detected on a total of 153 dolphins. The newly identified WD was the skin condition most frequently observed (45%) in the area, showing considerable differences on its severity between individuals. From 29 dolphins affected by WD in 2012, two were severely affected throughout their 10-year photo-id records and all of them either worsened over the years, or maintained their WD condition. No cases were found in which WD resolved over time. The increasingly degraded conditions of the Gulf of Ambracia may be influencing their epidermal integrity or causing them physiological stress. The epidermal conditions here reported, in some cases very conspicuous and relatively easy to monitor over the years, might act as indicators of environmental burden
Biologically threatened dolphins and whales
No full textAmong the several threats to which free-ranging cetaceans are exposed, a number of biological noxae are believed to represent a serious hazard to their health and conservation on a global scale, with special emphasis on the Mediterranean Sea. These pathogens include viral agents such as Morbillivirus, which during the last 25 years have caused dramatic epidemics and die-offs among several aquatic mammal species and populations worldwide, as well as Herpesvirus, protozoan agents such as Toxoplasma gondii and bacterial pathogens such as Brucella spp
Cetaceans, Toxoplasma gondii and tsunami
No full textThis is a Letter to the Editor addressing an interesting paper published one year before (in 2017) in Science by Dr J.T. Carlton and coworkers
CETACEAN STRANDINGS ON THE MEDITERRANEAN COAST OF ITALY: ACTIVITIES OF THE ITALIAN CETACEAN TISSUE BANK AFTER ONE YEAR
No full textDistribution of Nitrergic Neurons in the Dorsal Root Ganglia of the Bottlenose Dolphin (Tursiops truncatus).
Full text linkDorsal root ganglia (DRGs) contain the cell bodies of primary afferent neurons that transmit sensory information from the periphery into the spinal cord. Distinct populations of DRG neurons have been characterized by a variety of different immunohistochemical markers. A subpopulation of ganglionic neurons containing neuronal nitric oxide synthase (nNOS), an enzyme known to generate nitric oxide, has been detected in a number of mammalian species. Despite previous studies, no information is known on the presence and exact distribution of nNOS-immunoreactive neurons in the DRGs of the bottlenose dolphin. In this investigation, immunoperoxidase for nNOS was used to determine the distribution and the perikaryal size of nitrergic neurons in the DRGs of this species. Double immunofluorescence protocol was used to determine the percentage of nNOS-immunoreactive (IR) neurons over the total primary afferent neurons. In addition, double immunostaining was used to verify whether there was colocalization of nNOS with substance P (SP). In all DRGs, a subpopulation of small- and medium-sized neurons (about 9%) exhibited nNOS immunoreactivity. Data analysis revealed that the majority of nNOS-IR neurons (81.3%) expressed SP. The density of nNOS-immunoreactive and nNOS/SP-double immunopositive cells was relatively constant throughout the ganglia. However, as observed in others mammals, the number of nitrergic neurons decreased in the caudalmost DRGs. Our results, in conjunction with previous observations, suggest that nNOS-IR neurons may be involved in the afferent transmission of visceral and nociceptive information as well as in the regulation of the vascular tone
"Malattia da decompressione" nei cetacei: analisi retrospettiva su 16 soggetti spiaggiati lungo le coste italiane
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