Catching up on Catch-22

Catch-22 is a Red Bellied Cooter that came to the NMLC back in May, 2010 as a 9-month old hatchling. Originally part of the State’s turtle head-start program at another facility, Catch was not able to be released with the rest of his “classmates”. At the head-start turn-in event Catch was observed have a fungus like growth on his shell. He was also lethargic and minimally responsive. The state biologists turned Catch over to the NMLC and tasked us with determining what the shell fungus was, the potential for harm to a wild population, and the best way to treat it.

One of the first things we do for every marine animal rehab patient is take radiographs (x-rays). Upon examining Catch’s x-rays, we noticed a white curved line that looked like a scratch on the film. Subsequent x-ray views showed this line was actually a staple. Somehow, at his previous facility, Catch had eaten a staple! Dr. Williams considered surgery, but this would have been dangerous for then 131.7-gram Catch. Instead, we tube-fed Catch a slurry of lettuce and oil, and within a couple days he defecated the staple. Immediately, Catch began moving more readily in his habitat; that staple must have been painful! Thankfully, the staple must have passed through Catch’s system without causing damage because we never noticed any further symptoms. We then turned to addressing the shell fungus.

When Catch was originally admitted he was treated with a topical medication for several months, which didn’t seem to have any effect on the fungal growth. The decision was made to allow the fungus to grow without treatment in an effort to collect a clean sample that could be identified in a fungal lab. With a specific identification to the species level we could test the fungus’ sensitivity to different medications and then prescribe the best treatment for Catch. After a year and a half of sample collections and working with multiple fungal labs including Cornell University and The Texas A&M Fungal Lab, we still don’t know exactly what type of fungus Catch has.

Why is it so hard to identify his fungus? The first problem is  heavy bacterial contamination (despite collection by sterile techniques). Mixed species are very hard to isolate by PCR. As it stands, Catch-22 suffers only from a disease of cosmetic morbidity (It only seems to be affecting the surface, not causing a deeper infection).

The first set of results from a DNA biopsy revealed a Trichosporon, which  can affect the keratin in human hair shafts.  The treatment for people is shaving off the affected hair, but obviously removing Catch’s shell is not a option! Trichosporonosis in humans mostly affects immuno-compromised individuals, and Zoonotic reports are scarce. We don’t believe that  Catch-22 is at risk for systemic disease, but we felt further investigation was warranted in this fungal infection of the shell on an endangered species.

Using a carapace culture, a second lab reported Chrysosporium anamorph of a fungi closely related to Aphanoascus species (91% homology), but this is insufficient to confirm the genus identification. This sample also had heavy contamination with a mixed bacterial population, and Fusarium solani. Chrysosporium anamorph was too far off for a definitive match. The yeast was sub-cultured and sent to the Texas fungal lab for growth characteristics and to confirm ID, but they failed to grow a definitive form of the yeast. Even without a definitive identification we decided to try and move forward with fungal sensitivity testing to determine the best course of treatment, but all attempts including a thick suspension failed to grow in a suitable fashion.

All of these unsuccessful attempts to identify and verify the identification of Catch’s fungus have taken some time. Catch missed a release window in the summer of 2011, and without treatment we were getting concerned about his potential as a release candidate if we do not eliminate the fungus before the end of summer 2012. The decision was made to move forward with treatment on Catch in an effort to complete his rehabilitation this year. The good news is that the infection has remained superficial without specific treatment, and has even subsided in it’s intensity.

After some literature review and consultation with other veterinarians, two forms of treatment were selected to tackle Catch’s unsightly shell fungus; one topical and one oral.  The oral treatment is itraconizol which is often used by humans for nail fungus. Catch receives this treatment for 7 days, then gets a break for 21 days. During the break periods, blood samples are collected and analyzed to ensure that there are no complications. Fungal medications – unlike antibiotics – tend to take a long time to show results and can cause harmful complications to organs such as the liver. Catch is currently on his third round of Itraconozol treatments and so far has not experienced any negative side effects.

The second form of treatment is a nail lacquer called Curanail with an active ingredient of Amorolfine. These two treatments act separately and but in a synergistic manner. Since we could not find any evidence of the Curanail being used on reptiles, we decided to run an experiment. We are currently treating half of Catch’s carapace with the lacquer and leaving half without. We hope this will help us determine the effectiveness of both treatments. Keep an eye on our website and Facebook pages for updates from Dr. Williams’ Rounds Notes.

We are making every effort to have Catch fungus free and releasable by the summer. With any luck he will be joining the cooters from the 2011-2012 headstart class as they venture out into the wild at the end of May.