Skeletal and Cardiac Rhabdomyolysis in a Live-Stranded Neonatal Bryde's Whale With Fetal Distress

Abstract

The main objective of wildlife forensic investigation is to recognize pathologic changes and cause of death. Even though it may not always be possible to determine the specific illness and/or etiology, the description and subsequent interpretation of the injuries provide an invaluable understanding of pathology in cetacean post-mortem investigations. Although pathological studies have been previously reported in various cetacean species, such descriptions of the infraorder Mysticeti remain rare. A live-stranded neonatal Bryde's whale (Balaenoptera edeni) which subsequently died soon after the stranding, was assessed by physical exam, blood examination, gross necropsy evaluation, histopathology, and immunohistochemistry. It presented with elevated serum levels of creatine kinase, cardiac troponin I, urea, and creatinine. Microscopically, we observed keratin spicules (squamous epithelial cells) and areas of atelectasis in the lungs. Acute degeneration in the myocytes and cardiomyocytes were comparable to the findings previously described in cases of capture myopathy in live-stranded cetaceans. Immunohistochemistry biomarkers such as myoglobin, fibrinogen, and troponin were analyzed. Skeletal and myocardial damage has been documented in several cetacean species. However, this is the first reported case of skeletal and cardiac rhabdomyolysis associated with live-stranding in a newborn Bryde's whale that suffered from fetal distress.

Evaluating Potential Cetacean Welfare Indicators from Video of Live Stranded Long-Finned Pilot Whales (Globicephala melas edwardii)

“…In contrast, two single stranded animals were in poor (thin) body condition, suggesting they were likely experiencing welfare compromise in the form of hunger and thirst prior to stranding. Indeed, one of these individuals was a neonate that likely stranded due to maternal–filial separation [ 72 , 73 ], suggesting that the welfare of this animal was significantly compromised at stranding. Such animals are also suggested to have low survival likelihood, and end-of-life decisions or long-term captivity are generally indicated [ 74 , 75 ].…”

Microscopic Findings in the Cardiac Muscle of Stranded Extreme Deep-Diving Cuvier's Beaked Whales (Ziphius cavirostris)

“…These morphological alterations consist of vascular changes (i.e., congestion, interstitial edema, and hemorrhages) and acute degenerative lesions (i.e., contraction band necrosis, wavy fibers, hypereosinophilia, and cytoplasm vacuolization) with a perivascular distribution, indicative of ischemia–reperfusion damage. Additionally, infiltration of inflammatory cells, myoglobin globules and fibrotic tissue are also detected in this pathology (Herráez et al, 2007, 2013; Câmara et al, 2019 a , 2019 b , 2020 a , 2020 b ; Puig-Lozano et al, 2020).…”

Cetacean Intracytoplasmic Eosinophilic Globules: A Cytomorphological, Histological, Histochemical, Immunohistochemical, and Proteomic Characterization

“…The serum albumin is not a standout marker of liver disease in marine mammals. However, in cases of dehydration and shock [e.g., under “stranding stress response” (SSR)] [ 55 , 56 , 57 , 58 , 59 , 60 ], a high level of serum albumin may be detected [ 53 ]. By contrast, alpha-globulins such as haptoglobin, lipoproteins, and antitrypsin are important markers of acute inflammatory disease in some marine mammals and may be elevated in inflammatory and infectious diseases prior to clinical signs [ 53 ].…”

“…The etiopathogenic mechanisms that could play primary roles in the IEG development in cetaceans may be associated with (a) live-stranding-related phenomena, namely severe acute passive congestion due to body compression against the substrate and SSR [ 55 , 56 , 57 , 58 , 59 , 60 ], and (b) individual factors (species, age, nutritional status, health status). The body compression at beaching results in an impeded systemic venous return and systemic venous hypertension, primarily in the caudal vena cava and peritoneal viscera.…”