Diagnosis and Treatment of Pannus (Chronic Superficial Keratitis) in an Aggressive California Sea Lion, Zalophus californianus
Ocular problems, mainly at the level of the cornea, are very common in pinnipeds whether in the wild or, and then even more, when held under human care. The causative agent is most of the time the environment (quality of the water, chemicals, bright light, mechanical trauma), but infectious agents, as bacteria, viruses or fungi can also be the culprits. A California sea lion, held at Nausicaa in the north of France, started to develop eye problems in 2002. It looked at first like an oedema of the cornea, then a keratitis, coupled over time with conjunctivitis. The animal was known to be potentially aggressive towards his trainers, and a lot of time was spent in protective contact training to gain access to the eyes. Over the years, the water treatment was completely reviewed and many different treatments were attempted based on culture results, pictures and advice from colleagues, but to no avail. Eventually, a complete file on his case was sent to multiple veterinary and human ophthalmologists to gather different opinions. Several people compared his case to the one of pannus--also called the chronic superficial keratitis of the German shepherd--a progressive colonisation of the cornea by granulation tissue and blood vessels. It is believed to be a derailment of the animal's immune system--which is also aggravated with exposition to UV light. No cure is possible, and the treatment consists of controlling the active phase and minimising the consequences by the lifelong daily administration of corticoids and immuno-suppressive eye drops. The trainers have worked on several protective contact techniques to be able to administrate several times a day the drops in this aggressive animal, while it is still participating in all other daily activities and training. Since the beginning of the treatment, there has been a definite positive change in his sight and aspect of the eyes.