Pathological features of the Florida manatee cold stress syndrome

The Florida manatee (Trichechus manatus latirostris) is an endangered marine mammal species found primarily in south-eastern coastal waters of the United States. Chronic exposure to cold water produces a cascade of clinical signs and disease processes termed the manatee cold stress syndrome (CSS). No definitive pathological studies have been performed to characterize CSS or define its pathophysiological mechanisms. In this study, pathological features of CSS were characterized in 12 manatees and based on these findings, pathogenic mechanisms were postulated. All age and sex categories were aVected by CSS, except the neonatal age category. Emaciation, fat store depletion, serous fat atrophy, lymphoid depletion, epidermal hyperplasia, pustular dermatitis, enterocolitis, and myocardial degeneration were consistent lesions of CSS. These data indicate that CSS is a complex multifactorial disease process that involves compromise to metabolic, nutritional, and immunologic homeostasis and culminates in secondary opportunistic and idiopathic diseases. Treatment for CSS in rescued manatees should address these complex clinical issues. Additionally, these findings are critical for developing future management strategies for this species due to the disappearance or sporadic availability of human-made sources of warm water that manatees habituate to during the winter months.