The deadline for entries has passed, but here is the October 2009 case.

You are a marine mammal expert and are called to SeaWorld of Orlando to investigate problems they are having with a few of their bottle-nosed dolphins housed in a contact pool in the middle of the park.

The two affected animals, one adult male and one adult female, are grouped with three other animals (all females). They are housed in a 100,145 gallon, oval, artificial salt water pool which is partially covered by a large, sun-impermeable canopy. The public has direct contact with these animals during normal park hours (10 am to 4 pm). The water systems filter is working correctly but is due for a substrate change within the next three months.

The diet of these dolphins follows that of most of the other cetaceans in the park. This includes frozen and thawed herring, mackerel, capelin and squid. Vitamin B and E are supplemented in these fish daily to compensate for any loss during the freezing process which may occur.

Below is a picture taken of the dorsal thoracic region of the male dolphin showcasing the skin lesions both he and the affected female are exhibiting:

These lesions have been present for almost 2 months and have not resolved; they seem to be getting larger and spreading over the body. These two affected animals are showing no other clinical signs except the skin lesions seen above.

No other dolphins in the park (housed in other pools) are showing signs similar to this. However, approximately a week a half ago, a 3 year old, female, beluga whale, housed in a different pool that does not share the same water supply or filter, died. Necropsy showed signs of sepsis with petechial and ecchymotic hemorrhages covering internal viscera, mesentery, and mucosal surfaces. Histopath results are still pending.

You talk to the caretaker of these dolphins for a long time, asking multiple questions. He and one other person are the only people who take care of these dolphins. Besides these animals, they also work at the penguinarium taking care of many types of penguins and shorebirds. They have no contact with any other cetacean in the park.

While talking with him, you notice strange rashes on his arms. You query him about them. He replies that they showed up about 2 weeks ago, itch, and are painful. He has not gone to a doctor to have them looked at though. A picture of the caretaker’s arm is shown below.

Since you have somewhat of an idea (from other history information) of what is going on with these dolphins, you take a skin scraping for cytology. Below is a photomicrograph of the bacteria you find on skin scraping examination at the on site park veterinary hospital. You identify these bacteria as gram positive bacilli arranged as single units or short to medium sized chains.

Because you are such a great marine mammal veterinary expert, you immediately know the cause of the lesions seen. You also speculate that you know what the beluga whale died of as well. You send a sample swab of the lesions away for culture and sensitivity. A day later results come back and they are exactly as you had predicted…

Questions To Answer:

1. What is the etiological agent causing these skin lesions in the dolphins? Is there a link to the death of the beluga whale as well?
2. What should be done regarding the spread of this organism among other cetaceans in the park? In other words, how might have both the dolphins and beluga whale been infected? What should be done to monitor the situation and decrease chances of the disease occurring in other park cetaceans?
3. What kind of antibiotics should be used to treat the affected dolphins?
4. Is there a connection between the dolphin skin lesions and the rash on the caretaker’s arm? Why is this important?
5. What other domestic species are affected by the infectious agent cultured?
6. Describe the pathogenesis of the lesions seen on the skin of these dolphins.

The deadline for entries has passed. Please check back for the November case soon.