Abstract

Corneal ulceration commonly affects marine mammals, and corneal defects may develop secondary bacterial or fungal infections.¹ Scarring is a common sequela, which can affect vision if sufficiently severe.² Novel therapies are desired to decrease healing time and reduce residual corneal damage. Adipose-derived stem cells (ASC) assist in the regeneration of tissues and wound healing.³ In dolphins, ASCs have been isolated and differentiated into multiple cell lineages, suggesting that they may have similar regenerative capabilities as in other mammalian species.^4,5 Strong periocular muscles cause a marked blepharospastic response in dolphins, which can make frequent topical medication difficult.⁶ Subconjunctival administration of stem cells or medications form a localized depot, which may allow for long-term sustained drug delivery.⁷

In October 2012, three of six bottlenose dolphins developed corneal opacities during a transport, which progressed to keratomycosis caused by Candida albicans in two animals. Due to the severity of the lesions in one animal, an 11-year-old female, aggressive medical management was employed. Anesthetic block of the auriculopalpebral and frontal nerves were employed to address blepharospasm, providing partial visualization of the corneas. Subconjunctival injections of ASCs, platelet-rich-plasma, and voriconazole were employed at different timepoints throughout treatment. Subconjunctival injections of ASCs, platelet-rich plasma, and voriconazole were employed at different time points throughout treatment. Depot therapy was combined with topical and oral antifungals, antibiotics, anti-inflammatories and pain medication for 52 days, at which point blepharospasm had resolved and the corneal lesions were regressing. At present, only faint corneal opacities remain bilaterally and do not appear to affect vision. Following this transport, the U.S. Navy Marine Mammal Program implemented several changes to improve animal care and reduce the risk of occurrence of this type of injury, including improving methods for cleaning, disinfecting, and storing transport equipment; improving methods for in-flight water filtration and treatment; new animal sling design and construction; and closer scrutiny of water used during animal transports originating from outside the United States. This report characterizes the first use of auriculopalpebral and frontal nerve blocks, ASCs and subconjunctival injections for treatment of corneal trauma and infection in dolphins, which may aid the clinician in treating complex cetacean ocular pathology.

Acknowledgements

The authors wish to thank Dr. Bob Harman and Dr. Shawn Johnson for development of the stem cell protocols, as well as the veterinary technicians, trainers, and staff at the National Marine Mammal Foundation and the U.S. Navy Marine Mammal Program for their care of the animals in this report.

Literature Cited

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