Reevaluating Global Whale Strandings: A Review of Trypanosomiasis as a Potential Cause

Whale mass strandings are enigmatic events with multifactorial causes. Conventional hypotheses include anthropogenic sonar exposure, navigational errors, and infectious diseases, yet many stranding events remain unexplained¹. Here we propose African trypanosomiasis (“sleeping sickness”) as an overlooked contributing factor. This perspective synthesizes evidence that Trypanosoma parasites, transmitted by tsetse flies and other vectors, may induce neurological dysfunction in cetaceans. We review cetacean sleep physiology (unihemispheric slow-wave sleep) and migration patterns that could expose whales to tsetse fly bites in coastal Africa. We summarize documented cases of Trypanosoma infection in marine mammals – from dolphins with meningoencephalitis in the Americas to stranded whales harboring novel trypanosomes. We outline the pathophysiology of trypanosomal CNS invasion, drawing parallels to human “sleeping sickness” where parasites crossing the blood–brain barrier cause disorientation, disturbed sleep cycles, and fatal neurologic sequelae. We propose diagnostic approaches (PCR-based postmortem screening) for stranded cetaceans and advocate for a global surveillance program. Recognizing trypanosomiasis as a potential contributor to strandings highlights a One Health perspective, linking terrestrial vector-borne diseases to marine ecosystem health and urging interdisciplinary research on this emerging hypothesis.