Visiting Veterinarian : When vets have to treat unexpected pets
With the winter doldrums setting in, I flip through stacks of veterinary journals, searching for inspiration for a column. Here's an interesting tidbit about a pilot whale that beached in the Florida Keys.
While recuperating at SeaWorld, it developed scoliosis — curvature of the spine. The whale was transferred to the Cetacean Rehabilitation Facility where veterinarians fitted it with a custom-made orthopedic brace that can gradually be adjusted to straighten the spine and tail. Imagine that.
Below the whale blurb is an item entitled "Wisconsin Vet Treats Alligators." I guess I should stop complaining about working with pit bulls.
I give up on journals and start scanning veterinary conference proceedings. Aha. The American Association of Zoo Veterinarians. Surely there will be something unusual there.
Hhmm. Chelonian Shell Repair. That's fixing tortoise shells. I scan the article. Epoxy, drills, screws. I yawn. How about Macropod Medicine? That's wallabies and kangaroos. Interesting, but it makes me too sad, thinking of our friends who just moved back to Australia. I wipe away a tear.
Then, at the very bottom of the Table of Contents, there it is. Spiders. Seriously. An article entitle "Spider Medicine" by Trevor T. Zachariah, D.V.M., M.S. from Brevard Zoo in Melbourne, Florida. It's all about tarantulas.
Now I know people keep tarantulas as pets, but it hadn't really occurred to me that they go to the veterinarian. I read on. Here's what I learned.
All spiders belong to the Class Arachnida, Order Aranae. Tarantulas belong to the family Theraphosidae which is divided into two groups based on geographical location — Old World and New World. The names for many species are surprisingly poetic — Mexican Redknee, Chilean Rose, King Baboon, Greenbottle Blue, Pink Zebra Beauty, Goliath Birdeaters. Almost makes you want to own one, doesn't it?
If I ever have to examine a tarantula, I should know about their anatomy. The body is comprised of two parts. The prosima (or cephalothorax) contains venom glands, some digestive tract, lots of muscles, and what passes for a brain. Six legs attach there, including those ones with the fangs, which can be up to an inch long.
Eight tiny eyes are on the top, though apparently tarantulas have very poor eyesight. The back half of the body is the opisthosoma (or abdomen) and contains heart, more digestive tract, lungs, sexual organs, silk glands, and excretory system. The last pair of legs attach there.
If I want to pick Charlotte up, the author suggests pinching gently between the second and third pair of legs. Uh huh. Wearing gloves is recommended. Other methods of physical restraint include coaxing her into a clear glass or plastic container, or stretching clear plastic wrap over the body. Spider anesthesia has not been well studied, but there are anecdotal reports of using gas inhalation anesthetics successfully.
What if I pick up Charlotte and she bites me? The deadliness of tarantula venom has been highly overrated. There are no confirmed reports of fatalities from tarantula bites. Not one. That's not to say a bite won't hurt. The fangs may be large enough to cause a significant wound and secondary bacterial infection is a frequent complication... but that's true of cat bites as well. Rarely, people experience more serious effects including swelling, joint stiffness, muscle cramps, even temporary paralysis. But not death.
New World tarantulas have another defense mechanism to keep in mind — tiny irritating hairs on their backs that they kick off with their hind legs and send flying at their enemy. Called urticating hairs, these cause inflammation and intense itching that may last two weeks.
What tarantula maladies should I be familiar with? Dysecdysis. That's improper or incomplete molting and can lead to injury, deformation, even death. If Charlotte doesn't shed her old skin within 24 hours, glycerin or soap solution can be used to lubricate the old exoskeleton so it can be gently removed. In some instances, it might actually need to be cut off.
Traumatic injuries occur most frequently if Charlotte falls or is dropped from a height greater than her leg span. If she breaks a leg, the recommended treatment is amputation. The author advises grasping the broken leg close to the body with hemostats and giving a sharp tug upward. As long as the spider is not anesthetized, this will result in "autotomy," the voluntarily shedding of the limb that occurs when an invertebrate is injured or attacked.
Tarantulas then have the capacity to regenerate a new limb. Other exoskeleton injuries have been treated with varying success using tissue glue, adhesives, sealants, and sutures. Tarantulas need a small pool of standing water to drink, or they may get dehydrated.
Dehydration can be treated by placing the spider in a shallow dish of water, making sure her lungs are not submerged, or syringing water by hand into the oral opening... wherever that is. If necessary, sterile saline solution may be administered by injection directly into the heart or abdominal cavity.
What about parasites? A serious nematode infection of tarantulas has been identified in Europe, but not here. Mite infestations occur, but it is unclear whether these cause any problems other than cosmetic ones. They can be treated by frequent cage cleaning and wiping Charlotte with a damp cloth. Captive New World tarantulas may develop bald patches from excessive flicking of urticating hairs in response to stress.
Treatment is to find and eliminate whatever is bothering Charlotte. Nix the cat crouched outside her cage. Turn down the heavy metal music.
Finally, there is the sad task of end of life issues. For Charlotte, the main point is to be sure she is actually, well, dead. Tarantulas normally lie on their backs when shedding their old exoskeleton. She's not dead. She's molting. Don't disturb her. Her new exoskeleton is very fragile at first. A truly dead tarantula will typically be right side up, legs curled underneath, and have a "somewhat shriveled overall appearance." It helps to know these things... in case anyone ever brings a pet tarantula to my office.