abstract
In 2001, after a stillbirth, a female Indo-Pacific bottlenose dolphin, Tursiops aduncus, was diagnosed with parasitic mastitis by ultrasonography of the mammary glands and adjacent muscles, and parasitology of the mammary secretion1,5. The size and morphology of the parasite eggs suggested that the parasite was the nematode Crassicauda spp. Various oral antihelmintics were used, resulting only in reduction of number of eggs shed in mammary secretion. For the next several years the animal was housed in a separate pool with two other females suspected to have the same parasitic infestation.
In 2006, it was decided to allow this animal to breed. Topical treatment was undertaken, with instillation of antihelmintic drugs directly into the main lactiferous duct via the teat. Moxidectin was used initially, and trichlorphon was used subsequently. Inflammation was noted, but subsided with treatment. During one of the endoscopic procedures, the largest part of an adult female parasite was endoscopically removed, using an Olympus OES choledochofiberscope, (OD 2.8mm, operating channel 1.2 mm, equipped with a wire basket) introduced via the teat. Microscopic examination of the mammary secretion demonstrated that there were no more viable parasite eggs after that procedure.
The dolphin became gravid in October 2006. A full term live male calf resulted, but it died at four days. On gross pathology and histopathology there was no evidence of presence of the parasite in the calf. It is suspected that lactation was impaired in this female, but it is unclear whether it was due to the inflammation and fibrosis resulting from the presence of the parasite in the mammary gland and in adjacent muscles over several years, or to the inflammation associated with endoscopic instillation of the antihelmintics drugs in the central lactiferous canal. Crassicauda spp. exists as a long helminth mostly uncoiled in the main lactiferous duct, and as latent nodules in the muscles adjacent to the gland2,3,4. These muscles appear to play a role in lactation in cetaceans and participate in milk ejection4.
Parasitic mastitis is difficult to treat successfully but treatment should start as early as possible, to preserve the mammary glands functionality. Efforts should be made to diagnose parasitic mastitis in recently acquired or stranded cetaceans, and to try and assess how it affects establishment and maintenance of adequate lactation.
acknowledgements
The authors wish to thank Fiona Brook and Murray Dailey for their continued interest and contribution to this case, as well as Ocean Park clinical laboratory and marine mammal staff for their assistance.
References
1. Brook F, Rourke N, Mauroo N, Rayner C, Kinoshita R, Cheung M, Metreweli C.2002. Sonographic diagnosis of clinically silent parasitic mastitis in three Indonesian bottlenose dolphins (Tursiops aduncus). Proceedings of the 33rd Annual Conference of the International Association of Aquatic Animal Medicine, Albufeira, Portugal. p. 138.
2. Dierauf LA. 1990. Marine mammal parasitology. In: Dierauf, L.A. Handbook of marine mammal medicine: health, disease and rehabilitation. CRC press, Pp. 89-96.
3. Dailey MD. 2001. Parasitic diseases. In: Dierauf, L.A., Gulland, F.M.D. CRC handbook of marine mammal medicine. CRC Press, Pp.357-379.
4. Geraci JR, Dailey MD, St Aubin DJ. 1978, Parasitic mastitis in the Atlantic white sided dolphin, Lagenorhynchus acutus, as a probable factor in herd productivity, J. Fish. Res. Board Can., 35:1350-1355.
5. Mauroo N. 2002. Parasitic mastitis in a group of three bottlenose dolphins, Tursiops aduncus. Proceedings of the American Association of Zoo Veterinarians, Milwaukee, USA, p. 345.