Morganella morganii septicemia and concurrent renal crassicaudiasis in a Cuvier’s beaked whale (Ziphius cavirostris) stranded in Italy

Abstract

Information regarding bacterial diseases in Cuvier’s beaked whale (CBW, Ziphius cavirostris) is scattered and mostly incomplete. This report describes a case of septicemia by Morganella morganii in a juvenile male CBW with concurrent renal crassicaudiasis. The animal stranded along the Ligurian coastline (Italy) and underwent a systematic post-mortem examination to determine the cause of death. Histopathology showed lesions consistent with a septicemic infection, severe meningoencephalitis, and renal crassicaudiasis. An M. morganii alpha-hemolytic strain was isolated in pure culture from liver, lung, prescapular lymph node, spleen, hepatic and renal abscesses, and central nervous system (CNS). The antimicrobial susceptibility profile of the strain was evaluated with the minimum inhibitory concentrations (MICs) method and reduced susceptibility to Trimethoprim-Sulfamethoxazole is reported. Crassicauda sp. nematodes were retrieved from both kidneys. No other pathogens were detected by immunohistochemistry, serology, or biomolecular analyses. Toxicological investigations detected high concentrations of immunosuppressant pollutants in the blubber. The chronic parasitic infestation and the toxic effects of xenobiotics likely compromised the animal's health, predisposing it to an opportunistic bacterial infection. To our knowledge, this is the first description of M. morganii septicemia with CNS involvement in a wild cetacean.

Health Status of Stranded Common Bottlenose Dolphins (Tursiops truncatus) and Contamination by Immunotoxic Pollutants: A Threat to the Pelagos Sanctuary—Western Mediterranean Sea

“…The post-mortem investigations in stranded specimens have shown an important correlation between high levels of these pollutants and the infectious diseases that were recognized as the most likely cause of death of these marine mammals [2,27]. This evidence is particularly documented in the Pelagos Sanctuary [28][29][30][31][32][33][34][35][36], an area for the protection of cetaceans covering 87,500 km 2 and 2022 km of coast of the northwestern Mediterranean Sea, established under an international agreement between France, Italy, and the Principality of Monaco [37]. The area can be considered a biogeographically distinct sub-section of the Large Marine Ecosystem (LME) that is the Mediterranean and is characterized by markedly heterogeneous topography and hydrodynamic diversity and high levels of primary productivity related to the upwelling of nutrients, which are crucial for the presence of eight species of marine mammals on a relatively consistent basis.…”