Abstract

During the 1995 IAAAM conference, our group presented a report of unidentified flagellates found in the blowhole of a juvenile pygmy sperm whale (Kogia breviceps) that stranded in 1993 in New Jersey. The whale was successfully rehabilitated at the National Aquarium in Baltimore and released into the Gulf Stream off the coast of Cape Canaveral, Florida, in May 1994. Blowhole samples were obtained throughout rehabilitation by holding a petri dish over the blowhole while the animal exhaled 3-5 times. Flagellates were routinely detected in these mucus samples. Observations of Giemsa-stained specimens showed that the flagellates were characterized by a long anterior whiplash flagellum, a short trailing posterior flagellum, a long and wide undulating membrane, an oval nucleus, and a fragmented kinetoplast. The flagellates belong to the order Kinetoplastida and are believed to be a new genus, similar to, but distinct from, Cryptobia and Trypanoplasma. Flagellates were not found in the blood of the whale, suggesting that a hematophagous vector, such as those required by Trypanoplasma and Trypanosoma, is not involved in the life cycle. Transmission is probably directly from whale to whale. Since pygmy sperm whales are usually solitary, transmission probably occurs from mother to calf, and or, during mating. The flagellates could be expelled from the blowhole in an aerosol and then inhaled by the next whale, or they could be taken in with water through the mouth, then migrate past the epiglottis into the nasal cavity and up into the blowhole. The newly discovered flagellates are believed to be commensals rather than pathogenic parasites, based upon their presence in the healthy whale upon release, and their similarity to commensal kinetoplastids from fish.

Acknowledgements

We would like to express our gratitude to the Marine Animal Rescue Program and the Biological Programs Department at the National Aquarium in Baltimore for facilitating and supporting this study. We have benefited greatly from advice and comments from Professor Patrick Woo of the University of Guelph, Canada, and Professor Keith Vickerman, of the University of Glasgow, Scotland, concerning the taxonomy of the flagellate.