Abstract

Pneumonia is considered the most common disease in both wild and captive bottlenose dolphins. Unlike terrestrial mammals, dolphins do not have upper airway filters or turbinate to filter the air. They have a great breathing efficiency, which can exchange 75–90% of air in the lung within one-third of a second.^1,2 With the specific respiratory mechanisms, the incidence of getting bronchopneumonia is highly increased because of rapid and deep breathing. There are several bacterial pathogens associated with pneumonia in dolphins, genera Pseudomonas was included.^3,4 Bacterial pneumonia could be secondary to other causes such as viral infections, other systemic diseases, immune suppression, high sporulation and dust from the environment.⁵ In this case, viral infection cannot be proved, and the bronchopneumonia was not detected in other dolphins sharing the same environment. The reduced level of immunity is therefore suspected to be the reason for infection.

An approximately 15 year old, female captive Pacific Bottlenose Dolphin (Tursiops truncatus gilli) was raised in Far-glory Ocean Park in Taiwan since July 2004. In July, 2013, the patient was coughing, having fever and anorexic. Blowhole cultures revealed heavy growth of Pseudomonas aeruginosa, blood work revealed inflammatory reaction. Antibiotic treatment was given according to the result of the drug sensitivity test of P. aeruginosa. After a month of treatment, the inflammation transiently decreased. However, the logging behavior, fever, increased respiratory rate, coughing and anorexia were observed repeatedly. So further examinations were conducted. In November, 2013, a mass (5.1 x 5.8 cm) was found on the surface of the right lung via thoracic ultrasound examination even though the thoracic x-ray image was normal. P. aeruginosa was isolated from the mucus-like white and sticky bilateral bronchoalveolar lavages. Systemic antibiotic administration and nebulizing treatment had been conducted for almost 3 months. (Table 1) The patient`s appetite and energy went back to normal after the period of treatment. The size of the abscess decreased (2.5 x 2.7 cm) and the blood work revealed normal levels of inflammatory indicators except for eosinophilia. We have not found the cause of eosinophilia yet and the individual is still being monitored carefully and routinely. Until now, there were no significant abnormal findings from the ultrasound and bronchoscopic examinations.

Table 1

Acknowledgements

The authors would like to thank the veterinarians who have been in charge of this case, Dr. Meng-Da Lee, Mario Jian and Jing-Yun Lee, and all other Far-glory Ocean Park members who supported and devoted in this case.

* Presenting author

Literature Cited

1.  Irving L, Scholander PF, Grinnell SW. The respiration of the porpoise, Tursiops truncatus. J Cell Comp Physiol. 1941;17:145–168.

2.  Ridgway SH, Scronce BL, Kanwisher J. Respiration and deep diving in the bottlenose porpoise. Science. 1969;166:1651–1654.

3.  Avalos-Tèllez R, Suárez-Güemes F, Carrillo-Casas EM, Hernández-Castro R. Bacteria and yeast normal microbiota from respiratory tract and genital area of bottlenose dolphins (Tursiops truncatus). In: Méndez-Vilas A, ed. Current Research, Technology and Education Topics in Applied Microbiology and Microbial Biotechnology. Badajoz: Formatex Research Center; 2010:666–673.

4.  Venn-Watson S, Daniels R, Smith C. Thirty year retrospective evaluation of pneumonia in a bottlenose dolphin Tursiops truncatus population. Dis Aquat Organ. 2012;99:237–242.

5.  Venn-Watson S, Smith CR, Jensen ED. Primary bacterial pathogens in bottlenose dolphins Tursiops truncatus: needles in haystacks of commensal and environmental microbes. Dis Aquat Organ. 2008;79:87–93.