Explore the vast range of titles available.

Cetacean brains are uniquely adapted to diving, but can be affected by diseases and exposure to toxins, triggering neurodegenerative processes that may cause stranding. Some species exhibit a significant post-reproductive lifespan (PRLS), increasing the likelihood of observing cumulative and age-related pathology. Immunohistochemistry against amyloid-β and hyperphosphorylated tau proteins is increasingly implemented to assess Alzheimer’s Disease-like neuropathology in cetaceans, but comparisons between geographically distinct populations, animals of different age groups, sex, and with concomitant pathologies are lacking. We tested 43 cetaceans’ (30 Tursiops truncatus ; 13 Stenella coeruleoalba ) parietal cortex, our most consistently archived cerebral tissue, in immunohistochemical analyses with amyloid-β oligomer 42 (Aβ-42) and hyperphosphorylated tau (pTau AT180 and AT8) antibodies. Aβ-42 antibody cross-reacted with plaques in three aged bottlenose and two aged striped dolphins, but was more often detected within neurons, glia, and blood vessels of all the dolphins. Histoscore comparisons between dolphins of different ages, sexes, and pathologies revealed significant correlations between older age, viral infections, and plaque presence. Protozoan cysts cross-reacted with Aβ-42 antibody. pTau signal was observed as single foci in neurons and neuropil in two young and two aged bottlenose dolphins. To our knowledge, this study is the first of its kind for the Mediterranean region and will help establish baseline understanding of physiological and pathological expression of proteins associated with human neurodegenerative disease in cetacean brains.

Monitoring stranded cetaceans represents a strategic method to assess their health, conservation status, and ecological role in the marine ecosystem. Efficient stranding networks and standardized protocols are essential to monitor this phenomenon and investigate its causes. This study assesses the evidence of fishery interaction on stranded cetacean carcasses found along the Italian coastline from 1986 to 2023. Evidence assessment and post-mortem investigation methods evolved over three macro-periods, from non-standardized reporting (1986–2014) to an integrated national stranding network (2015–2019), and finally to the creation of a new standardized, evidence-based diagnostic framework under the EU-funded LIFE DELFI project (LIFE18 NAT/IT/000942) (2020–2023). A total of 5355 cases were selected for this analysis. A literature review and evidence of interaction on stranded carcasses supported the categorization of findings, ranging from case history to pathological observations, allowing the assessment of temporal variation, demographic parameters, geographical distribution, and fishing gear identification. Evidence of fishery interaction was found in 12.89% of the cases (690/5355), with an annual average of 18.15 affected animals, and fishery interaction was identified as the likely cause of death in 10.32% of the cases. The most frequently reported species were Stenella coeruleoalba and Tursiops truncatus , showing significant differences in fishery interactions, particularly in relation to sex, age class, and geographical distribution. Adult male Tursiops truncatus exhibited a higher susceptibility to gillnet interaction in the Adriatic Sea. The results of this study emphasize the importance of standardized post-mortem investigations and long-term monitoring to identify risk hotspots, implement species- and region-specific mitigation strategies, and establish threshold values for cetacean conservation.

Dolphin morbillivirus (DMV) is considered an emerging threat having caused several epidemics worldwide. Only few DMV genomes are publicly available. Here, we report the use of target enrichment directly from cetacean tissues to obtain novel DMV genome sequences, with sequence comparison and phylodynamic analysis. RNA from 15 tissue samples of cetaceans stranded along the Italian and French coasts (2008–2017) was purified and processed using custom probes (by bait hybridization) for target enrichment and sequenced on Illumina MiSeq. Data were mapped against the reference genome, and the novel sequences were aligned to the available genome sequences. The alignment was then used for phylogenetic and phylogeographic analysis using MrBayes and BEAST. We herein report that target enrichment by specific capture may be a successful strategy for whole-genome sequencing of DMV directly from field samples. By this strategy, 14 complete and one partially complete genomes were obtained, with reads mapping to the virus up to 98% and coverage up to 7800X. The phylogenetic tree well discriminated the Mediterranean and the NE-Atlantic strains, circulating in the Mediterranean Sea and causing two different epidemics (2008–2015 and 2014–2017, respectively), with a limited time overlap of the two strains, sharing a common ancestor approximately in 1998.

Plastic is a polymer extremely resistant to degradation that can remain for up to hundreds or thousands of years, leading to the accumulation of massive amounts of plastic waste throughout the planet’s ecosystems. Due to exposure to various environmental factors, plastic breaks down into smaller particles named microplastics (1–5000 μm) and nanoplastics (<1 μm). Microplastics (MPs) are ubiquitous pollutants but, still, little is known about their effects on human and animal health. Herein, our aim is to investigate cytotoxicity, oxidative stress, inflammation and correlated gene modulation following exposure to polystyrene microplastics (PS-MPs) in HRT-18 and CMT-93 epithelial cell lines. After 6, 24 and 48 h PS-MPs treatment, cell viability (MTT) and oxidative stress (SOD) assays were performed; subsequently, expression changes and cytokines release were investigated by Real-Time PCR and Magnetic-beads panel Multiplex Assay, respectively. For each exposure time, a significantly increased cytotoxicity was observed in both cell lines, whereas SOD activity increased only in CMT-93 cells. Furthermore, Magnetic-beads Multiplex Assay revealed an increased release of IL-8 in HRT-18 cells’ medium, also confirmed by gene expression analysis. Results obtained suggest the presence of a pro-inflammatory pattern induced by PS-MPs treatment that could be related to the observed increase in cytotoxicity.

Brucella ceti infections have been increasingly reported in cetaceans, although a very limited characterization of Mediterranean Brucella spp. isolates has been previously reported and relatively few data exist about brucellosis among cetaceans in Italy. To address this gap, we studied 8 cases of B. ceti infection in striped dolphins (Stenella coeruleoalba) stranded along the Italian coastline from 2012 to 2018, investigated thanks to the Italian surveillance activity on stranded cetaceans. We focused on cases of stranding in eastern and western Italian seas, occurred along the Apulia (N = 6), Liguria (N = 1) and Calabria (N = 1) coastlines, through the analysis of gross and microscopic findings, the results of microbiological, biomolecular and serological investigations, as well as the detection of other relevant pathogens. The comparative genomic analysis used whole genome sequences of B. ceti from Italy paired with the publicly available complete genomes. Pathological changes consistent with B. ceti infection were detected in the central nervous system of 7 animals, showing non-suppurative meningoencephalitis. In 4 cases severe coinfections were detected, mostly involving Dolphin Morbillivirus (DMV). The severity of B. ceti-associated lesions supports the role of this microbial agent as a primary neurotropic pathogen for striped dolphins. We classified the 8 isolates into the common sequence type 26 (ST-26). Whole genome SNP analysis showed that the strains from Italy clustered into two genetically distinct clades. The first clade comprised exclusively the isolates from Ionian and Adriatic Seas, while the second one included the strain from the Ligurian Sea and those from the Catalonian coast. Plotting these clades onto the geographic map suggests a link between their phylogeny and topographical distribution. These results represent the first extensive characterization of B. ceti isolated from Italian waters reported to date and show the usefulness of WGS for understanding of the evolution of this emerging pathogen.

Zoonotically transmitted coronaviruses were responsible for Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), causing the dramatic Coronavirus Disease-2019 (CoViD-19) pandemic, which affected public health, the economy, and society on a global scale. The impact of the SARS-CoV-2 pandemic permeated into our environment and wildlife as well; in particular, concern has been raised about the viral occurrence and persistence in aquatic and marine ecosystems. The discharge of untreated wastewaters carrying infectious SARS-CoV-2 into natural water systems that are home to sea mammals may have dramatic consequences on vulnerable species. The efficient transmission of coronaviruses raises questions regarding the contributions of virus-receptor interactions. The main receptor of SARS-CoV-2 is Angiotensin Converting Enzyme-2 (ACE-2), serving as a functional receptor for the viral spike (S) protein. This study aimed, through the comparative analysis of the ACE-2 receptor with the human one, at assessing susceptibility to SARS-CoV-2 for different species of marine mammals living in Italian waters. We also determined, by means of immunohistochemistry, ACE-2 receptor localization in the lung tissue from different cetacean species, in order to provide a preliminary characterization of ACE-2 expression in the marine mammal respiratory tracts. Furthermore, to evaluate if and how Italian wastewater management and coastal exposition to extreme weather events may led to susceptible marine mammal populations being exposed to SARS-CoV-2, geomapping data were carried out and overlapped. The results showed the potential SARS-CoV-2 exposure for marine mammals inhabiting Italian coastal waters, putting them at risk when swimming and feeding in specific risk areas. Thus, we highlighted the potential hazard of the reverse zoonotic transmission of SARS-CoV-2 infection, along with its impact on marine mammals regularly inhabiting the Mediterranean Sea, while also stressing the need for appropriate action in order to prevent further damage to specific vulnerable populations.

Between 2019 and 2021, 21 bottlenose dolphins were found stranded dead along the Ligurian Pelagos Sanctuary coast (Italy). For 11 animals, out of a total of 14 recovered, the cause of death was classified as natural, anthropic, or not determined based on gross and histological pathology and ancillary testing. Hexachlorobenzene (HCB), dichlorodiphenyltrichloroethanes (DDTs), and polychlorinated biphenyls (PCBs) were examined in their blubber, and results were discussed according to their toxicological properties. All specimens showed the following trend: PCBs > DDTs >> HCB, and the levels of cancerogenic, mutagenic, and teratogenic organochlorine compounds (T-OCs) were >50% of total OCs. Immunosuppressant organochlorine compound (IS-OC) levels in 10 out of 11 animals were above 50% of the total OCs. PCB levels always exceeded the threshold of 17 mg/kg lipid weight for PCB-induced adverse health effects. The results suggest that bottlenose dolphins living in the Pelagos Sanctuary undergo a high level of exposure to pathogens and OCs, betraying the designation of the Cetacean Sanctuary and, consequently, of a region created for their conservation. Immune dysfunction and infectious disease susceptibility appear to be highly connected with high levels of OC xenobiotics. These data are useful to understand health and mortality trends in cetacean populations, as well as for developing policies for cetacean conservation and management in this important protected area of the Mediterranean.

Photobacterium damselae subsp. damselae (Pdd) is an increasingly common bacterium in post-mortem diagnostics of beached marine mammals, but little is known about its precise etiological responsibility. To estimate the prevalence of Pdd in stranded cetaceans from 2017 to 2022 on the Ligurian coast (Pelagos Sanctuary), we tested tissues from 53 stranded individuals belonging to four cetacean species. DNA extracts from cetacean tissue were screened using a polymerase chain reaction (PCR) assay targeting the Pdd ureC gene. Positive samples were screened by PCR for dly, hlyApl and hlyAch hemolysin genes, which were confirmed by sequencing. Twenty-two out of 53 (41.5%) cetaceans analyzed by PCR were confirmed for Pdd DNA in at least one tissue among those analyzed. Five of these cetaceans were positive for at least one of the hemolysin genes tested. In all Pdd-positive cetaceans, other pathogens that were considered responsible for the causa mortis of the animals were also found. The results provide new information on the spread of Pdd in cetaceans and support the thesis that Pdd might be an opportunistic agent that could contribute to worsening health conditions in subjects already compromised by other pathogens. However, further studies are needed to investigate and deepen this hypothesis.

The monitoring of stranded marine mammals represents a strategic method to assess their health, conservation status, and ecological role in the marine ecosystem. Networks worldwide track stranding events for the passive monitoring of mortality patterns, emerging and reemerging pathogens, climate change, and environmental degradation from a One Health perspective. This study summarizes pathogen prevalence data from the Italian Stranding Network (ISN) derived from post-mortem investigations on cetaceans found dead stranded along the Italian coastline between 2015 and 2020. The decomposition of the carcasses and logistics limited the post-mortem examination to 585 individuals, out of 1236 single-stranding reports. The most relevant pathogens identified were Cetacean Morbillivirus, Herpesvirus, Brucella spp., and Toxoplasma gondii, whose roles as environmental stressors are well known, despite their real impact still needing to be investigated in depth. Statistical analysis showed that age and sex seem to be positively related to the presence of pathogens. This study represents the first step in harmonizing post-mortem investigations, which is crucial for evidence-based conservation efforts. Implementing diagnostic and forensic frameworks could offer an indirect insight into the systematic monitoring of diseases to improve the identification of regional and temporal hotspots in which to target specific mitigation, management, and conservation strategies.

Toxoplasma gondii is an emerging cause of neurologic disease in cetaceans. In the present study, we combined molecular detection, microsatellite genotyping, and neuropathology in stranded striped dolphins along the coasts of Campania and Calabria (Southern Italy). During the years 2018–2023, 93 cetaceans were necropsied. Brain tissues were screened for T. gondii DNA by Real-Time PCR targeting the 529-bp repeat element; positive samples (Ct range 21–30) were genotyped using eight microsatellite markers (TUB2, W35, TgM-A, B18, B17, M33, IV.1 and XI.1) and compared with reference strains by hierarchical clustering. Histology and immunohistochemistry (IHC) for T. gondii were performed on available brains. T. gondii DNA in the brain was detected in 12/93 cetaceans; all positive cases were striped dolphins ( Stenella coeruleoalba ). Genotyping revealed two genotypes, with GII in 10/12 dolphins and GIII in 2/12. In 10 evaluable cases, lesions ranged from mild non-suppurative meningitis/meningoencephalitis to severe necrotizing encephalitis. IHC was positive in 7/10 positive cases; tissue cysts were observed in proximity to lesions in the more severely affected brains. These findings document the circulation of multiple T. gondii genotypes in pelagic dolphins from Southern Italy, supporting the land-to-sea transmission hypothesis and confirming the value of striped dolphins as sentinels of terrestrial pathogens from a One Health perspective.