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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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This article deals with Central Nervous System (CNS) disorders of marine mammals as putative neuropathology and neuropathogenesis models for their human and, to some extent, their animal "counterparts" in a dual "One Health" and "Translational Medicine" perspective. Within this challenging context, special emphasis is placed upon Alzheimer's disease (AD), provided that AD-like pathological changes have been reported in the brain tissue of stranded cetacean specimens belonging to different Odontocete species. Further examples of potential comparative pathology interest are represented by viral infections and, in particular, by "Subacute Sclerosing Panencephalitis" (SSPE), a rare neurologic sequela in patients infected with Measles virus (MeV). Indeed, Cetacean morbillivirus (CeMV)-infected striped dolphins (Stenella coeruleoalba) may also develop a "brain-only" form of CeMV infection, sharing neuropathological similarities with SSPE. Within this framework, the global threat of the A(H5N1) avian influenza virus is another major concern issue, with a severe meningoencephalitis occurring in affected pinnipeds and cetaceans, similarly to what is seen in human beings. Finally, the role of Brucella ceti-infected, neurobrucellosis-affected cetaceans as putative neuropathology and neuropathogenesis models for their human disease counterparts is also analyzed and discussed. Notwithstanding the above, much more work is needed before drawing the conclusion marine mammal CNS disorders mirror their human "analogues". [ABSTRACT FROM AUTHOR]

The genus Morbillivirus comprises several lympho-epithelio-neurotropic, highly pathogenic RNA viruses of domestic and wild vertebrates, including aquatic mammals. Among them, cetacean morbillivirus (CeMV) has been responsible since the 1980s for [...]

Fin whales (Balaenoptera physalus) living in the Mediterranean Sea belong to a population that is part of the Atlantic stock (1). For feeding purposes, these whales tend to concentrate in [...]