Retrospective Review of Routine Mycobacterial Screening in a Captive Collection of Atlantic Bottlenose Dolphins (Tursiops truncatus)
American Association of Zoo Veterinarians Conference 2010
Leigh Ann Clayton1, DVM, DABVP; Jessica B. Hammack; Catherine A. Hadfield, MA, VetMB1

1National Aquarium, Baltimore, MD, USA; 2Class of 2010, College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA, USA


Non-tuberculous mycobacteriosis has been reported in cetaceans.1-5 Normal results of acid-fast cytology and mycobacterial cultures from cetaceans are not well established and some have theorized that the aquatic environment may increase the risk of false positive test results. In 2004, an adult male Atlantic bottlenose dolphin (Tursiops truncatus) at the National Aquarium was evaluated for respiratory disease. Non-tuberculous mycobacteriosis was initially suspected when beaded, gram-positive rods were identified on diagnostic samples from respiratory secretions and gastric fluid. The bacteria appeared morphologically similar to non-tuberculous mycobacteria routinely identified in fish mycobacteriosis cases. Acid-fast stained cytology, culture/PCR testing, and histopathology subsequently supported a diagnosis of pulmonary Mycobacterium abscessus infection.3

Screening of fluid and tissue samples from the remaining population was instituted. Samples were collected during routine quarterly health exams or as part of diagnostic evaluations. All animals were managed in an indoor, artificial saltwater system with ozone disinfection.

Between October 1, 2004 and December 31, 2009, 913 acid-fast cytology and 74 mycobacterial culture samples were evaluated from 13 animals. Acid fast stained cytology samples were 99% negative (904/913) and 1% positive (9/913). Culture samples were 95.9% negative (71/74) and 4.1% positive (3/74). M. abscessus, M. aurum/neoaurum, and M. neoarum/lacticola were identified on positive cultures. Cytology and culture results were overwhelmingly negative for acid-fast positive organisms and mycobacteria. Positive results were sporadically identified, not repeatable, and primarily consistent with environmental contamination. Repeatable, positive results on either test are considered abnormal and additional follow-up would be warranted.


The authors would like to thank the Clinical Pathology Laboratory and Marine Mammal staff at the National Aquarium for their participation in this work.

Literature Cited

1.  Bowenkamp K.E., S. Frasca Jr., A. Draghi 2nd, G.J. Tsongalis, C. Koerting, L. Hinckley, S. De Guise, R.J. Montali, C.E. Goertz, D.J. St. Aubin, and J.L. Dunn. 2001. Mycobacterium marinum dermatitis and panniculitis with chronic pleuritis in a captive white whale (Delphinapterus leucas) with aortic rupture. J. Vet. Diagn. Invest. 13:524–530.

2.  Calle P.P., C. McClave, G. Kramer, K. Lyashchenko, R. Greenwald, L. Heifets, C. Peloquin, M. Hiatt, and J.R. White. 2007. Fatal Mycobacterium abscessus infection in a beluga whale (Delphinapterus leucas). Abst. IAAAM 38th Annual Conference Proceedings, Lake Buena Vista, Florida. 196–198.

3.  Hadfield CA, Whitaker BR, Clayton LA, Stamper A . 2005. Mycobacterium abscessus infection in an Atlantic bottlenose dolphin (Tursiops truncatus). Abst. IAAAM 36th Annual Conference Proceedings, Seward, AL. 49.

4.  Morick D., M. Kik, J. de Beer, A.G.M. van der Zanden, and D.J. Houwers. 2008. Isolation of Mycobacterium mageritense from the lung of a harbor porpoise (Phocoena phocoena) with severe granulomatous lesions. J. Wildl. Dis. 44:999–1001.

5.  Wünschmann A., A. Armien, N.B. Harris, B.A. Brown-Elliot, R.J. Wallace, J. Rasmussen, M. Willette, and T. Wolf. 2008. Disseminated panniculitis in a bottlenose dolphin (Turiops truncatus) due to Mycobacterium chelonae infection. J. Zoo Wildl. Med. 39:412–420.


Speaker Information
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Leigh Ann Clayton, DVM, DABVP (Avian)
National Aquarium
Baltimore, MD, USA

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