It may have looked like a penguin foot spa – but it was so much more.
On a cold winter morning, Purple the penguin lay back comfortably asleep in a cozy clinic room with each foot resting in a little tub of liquid. But this wasn’t just a foot soak. The little bird was about to get the second round of a cutting-edge treatment for his foot lesions – a photodynamic laser therapy that Point Defiance Zoo & Aquarium has also used successfully on skin cancers in other animals.
But for the penguin flock, it was a first. And it did include a long foot soak.
“Okay, are we ready?” asked Dr. Kadie Anderson, zoo veterinarian.
After anesthetizing Purple (Point Defiance penguins are named after their colored ID armbands) and checking his heart and lungs, she’d prepared two small containers full of a white lipid and the drug 5-ALA, which penetrates skin to render unhealthy tissue more sensitive to laser light. (The fatty lipid is for greater absorption.)
Then, as Anderson set a 20-minute timer, she and senior staff biologist Amanda Shaffer each lifted one webby penguin foot, gently folded it forward and set it into the white liquid to soak.
“We use laser therapy a lot,very successfully, on other conditions like arthritis and wounds to promote healing,” explained Anderson, as veterinary technician Sara Dunleavy prepped the laser probes, intern veterinarian Dr. Lauren Mulreany helped Purple breathe through an endotracheal tube, and everyone waited for the timer to finish. “But this technique is pretty new, and this is the first time we’ve used it on our birds. We learned about its use in penguins from veterinarians in Brazil, and we worked with our veterinary oncologist to adapt their technique for a different drug. It’s exciting.”
This version of photodynamic therapy (PDT) uses a higher wave frequency than the regular healing one: 630nm compared to 445. It’s particularly effective thanks to the photosensitivity soaking drug, which enables the veterinary team to target precise areas to kill unhealthy tissue. It’s much less invasive than overall treatments like chemotherapy, and has been proved more effective than antibiotics in healing infections like Purple’s.
The treatment needs repeating every three weeks. This is the second round for Purple, and already his infections have reduced by a few millimeters. Fellow penguin Blue – waiting patiently in a nearby crate – is getting treatment for a single foot.
PDT has also helped other animals around the zoo: Hanako the elephant, who has cancer on one foot and was patient enough to soak it regularly for PDT, and Drake the meerkat, whose foot was saved from squamous cell carcinoma.
With a loud beep the timer went off, and Anderson and Shaffer lifted Purple’s feet out of the tubs. Everyone put on protective glasses. Then, holding one silver probe each, Shaffer and Dunleavy pointed the red beams at the infection sites. (The zoo’s vet team had the laser machine customized for two probes to minimize the time Hanako had to hold her foot still.)
Feathers dry and softly ruffled, Purple slumbered on, chest rising and falling and eyes peacefully shut.
After exactly six minutes, the probes were put away and the team took a couple of chest x-rays to check Purple’s lungs. Then Mulreany reversed the anesthesia and Shaffer lifted a sleepy Purple into a standing position.
“Come on, buddy!” she called softly, massaging his neck and stroking his back. “Time to wake up!”
As Purple slowly opened his eyes to stand on his own, Shaffer walked to the crate and reached in for Blue.
Time for another foot soak.