The World of Zoo Medicine:
A Peek Behind the Scenes
July 2004"Five minutes to rounds," a voice echoes over the loud speaker. It is 7:40 a.m. on a Monday morning. People begin filtering into the main treatment room of the National Zoo's animal hospital as a volunteer walks through carrying a laundry basket loaded with clean pink, green, and yellow towels. Rounds—a daily meeting of the veterinarians, keepers, and technicians working at the hospital—begin promptly at 7:45.
Today nine people are present and Dr. Carlos Sanchez, the Zoo's veterinary fellow, leads the meeting. "It was a quiet weekend," he announces from his position beside the main examining table in the middle of the room. Mandara, a female lowland gorilla, was the only concern. One of her eyes was red and itchy on Sunday. A fishing cat (right) that had supportive metal pins removed from its now-healed fractured leg last week is doing well and will rest off exhibit for ten days, he reports. And eight ducks will be arriving from SeaWorld today.
A large chalkboard hanging on the wall details the week's schedule. Today's line-up includes getting cheetah blood samples, giving antibiotics to an African crane, and anesthetizing a chicken. Dr. Tabitha Viner, the head of pathology, reminds the other vets that the lab results from a poison dart frog test will be ready this afternoon. The meeting lasts about eight minutes, and afterward preparation for the day's activities begins.
Rachel Thompson, a fourth-year vet student completing a six-week rotation at the Zoo, prepares the treatment kit. Each vet has her own box, stocked the way she likes it. This one has three tiers that open up and out like a sewing kit, revealing an array of gauze, needles, syringes, catheters, gloves, collection tubes, Q-Tips, numbing medication, and emergency drugs.
Tricky Business
On average, a Zoo vet will see about eight different animals per day, doing either a visual exam, administering medications and injections, or performing a physical procedure under anesthesia. A large animal, such as an elephant in need of a foot x-ray, will have portable equipment brought to its enclosure. Smaller animals, such as a snake or chinchilla in need of a check-up, are often transported to the animal hospital. One of the most common problems a Zoo vet sees is an animal that isn't eating because it is stressed or sick.
But zoo medicine is tricky business, and there is nothing ordinary about a vet's day. Not only does the Zoo house about 390 species with different body types and systems, but it is usually hard to tell an animal is sick until it is very sick. Wild animals hide their illnesses by nature in order to conceal their weaknesses from predators, often until it is too late to turn them around. That's why "zoo medicine is based on preventative medicine," Sanchez says. The keepers and vets work closely to catch illnesses or problems as early as possible.
And just like human patients, each animal has its own personality and feelings about visiting with the doctor. The giant pandas seem to enjoy their exams, readily sticking an arm out for a blood draw or exposing a tummy for an ultrasound while happily feeding on treats from their keeper. Some, like the gorillas, associate the vets with needles or medicine, and they don't like it. They make a racket when the vets arrive and sometimes even throw a handful of poop their way. Sanchez says the primates are one of the toughest groups to treat and can be the most challenging because of their intelligence and cunning.
The vets split up the daily cases, and by 8:30 a.m. Sanchez and Thompson are off in the Zoo's mini-van to the Cheetah Conservation Station to collect blood samples from Norok, a 13-year-old male with diabetes, and Amadi, a ten-year-old male with chronic kidney failure. Cheetahs in captivity live to be much older than cheetahs in the wild and are especially prone to illnesses resulting from genetic defects due to inbreeding that occurred in the wild long ago.
Large animals like cheetahs are often treated in squeeze cages—meaning one wall of the cage can slide in to meet the other to gently restrain the animal—for their safety and the safety of the vets. Only Amadi cooperates today. To reach the top of his tail, a good place from which to draw blood, Sanchez must crawl under a cheetah-sized trap door as the keeper, Craig Saffoe, lifts the end door of the cage a crack so Amadi's tail can stick out comfortably. Using a small needle and a syringe, he collects blood and takes a sample from a lesion he spots above the tail. Thompson kneels to watch the process and places the samples in the appropriate collection tubes. The whole operation takes three people.
Treatment decisions are often a question of balance. Sick cheetahs are highly susceptible to lesions like the one spotted on Amadi. In fact, the vets sampled one of Norok's lesions earlier, discovering that a fungus was part of the problem. But most drugs used to treat fungus have some effect on the liver. And because Norok already has liver trouble, the vets faced a catch-22 of sorts. For now, they decide to leave his lesions alone while focusing on the control of his diabetes.
Next up is an East African crowned crane. It needs a course of antibiotics, but because it eats only hard, dry pellets, the medicine must be given through a tube inserted directly into its esophagus. The keeper cradles the crane in her arms as Thompson slips the tube in and massages the antibiotics down the bird's slender gray throat.
Shewa, a male Grevy's zebra, is housed next to the crane, and he needs a tooth checked. As the keeper passes treats to the zebra through the fence, Dr. Sanchez tries to take a look between munches. The gums around the tooth are a little red so the information is documented and a follow-up visual exam is scheduled.
Back at the hospital, the veterinary technicians are preparing for the chicken procedure. A white hen has a disorder called pica, meaning she compulsively eats anything around her, including pebbles, feathers, hay, and dirt. All of this debris has collected in a pouch in her esophagus called the crop, where food is normally 
stored before it is digested. But the hen's crop is now pendulous. Ellen Bronson, the zoo's clinical veterinary resident, can feel the rubble inside with a gentle squeeze.
After the hen is anesthetized, Bronson holds the hen's head down while the rest of her body is held in the air. Thompson uses saline to flush the debris out into a metal bowl, while a veterinary technician monitors the hen's vital signs. In between flushes, Sanchez uses forceps to pull out clumped pieces of stringy hay.
Someone shouts, "Pebbles, I see pebbles!" There is obvious excitement as small rocks and a goopy liquid come pouring from the hen's mouth. They want her crop cleaned out.
From exotic cat to barnyard fowl, the vets have worked hard to give each animal the best care, and it isn't even noon yet.
Cooperative Effort
It takes a lot of hands and cooperation to treat an animal. It also takes a lot of instruments that come in different sizes. For example, when an animal is put under anesthesia, a device called an endotracheal tube is inserted down the windpipe. A tube used for a female lion is about 35 inches long and one inch wide, while one for a tamarin is only about an inch long and less than a tenth of an inch wide!
In some cases, veterinary specialists are asked to come in to check an animal's eyes, teeth, or other problem areas. One veterinary dentist working with the zoo was able to complete a root canal on a pygmy marmoset, a creature that weighs a mere three and a half ounces.
All treatments are usually finished up before 1 pm. Vets use afternoons at the hospital to write up the morning's visits and to document procedures during which animals had anesthesia. Vets try to minimize their use of anesthesia, but it is often necessary to conduct a thorough physical exam. Medical doctors cannot always predict how human patients of a certain age, sex, or condition will respond to anesthesia and the same is true for vets working with zoo animals. For this reason an animal's vital signs are closely monitored and recorded throughout any procedure using anesthesia. Every change must be recorded, so a single case write-up can take up to 40 minutes. The vets also use the afternoon to examine x-rays and lab results and to discuss difficult cases.
From Pandas to Duck Ponds
At 7:45 a.m., Tuesday morning rounds begin with Dr. Bronson leading the meeting. The chicken is recovering well, although she acted lethargic with her original bandage on. She brightened up after its removal. The giant pandas will be examined today and 58 ducks living in the Zoo's duck pond will be rounded up and given de-worming medication. A sick eyelash viper is scheduled for surgery later in the morning. Dr. Bronson takes the duck pond while Dr. Sanchez heads to the Fujifilm Giant Panda Habitat.
Pandas are the only animals in the park with which the vets do not use gloves, alcohol, or electric clippers. The pandas don't like these items and the gloves and alcohol make them sneeze. Today, the vets are drawing blood so they can monitor the levels of antibodies in response to a recent canine distemper vaccine the pandas received. Tian Tian and Mei Xiang's behavioral training makes their weekly exams go smoothly, and they even seem reluctant to leave the treatment chute. Mei Xiang clamors for her turn while Tian Tian is getting checked.
Pandas respond well to visual cues and body language so Brenda Morgan, one of the pandas' keepers, kneels on a cushion in front of the treatment cage offering pieces of fruit during the procedures. Tian Tian is first and sticks his arm out through a custom-designed hole in the cage almost immediately. He knows the drill and curls his paw around a specially positioned metal bar, a posture that makes him look as if he is ready to arm wrestle. Instead, he calmly holds the bar as Dr. Sanchez draws blood.
Mei Xiang gets her blood drawn in the same way and also gets an ultrasound. When her keeper lies down outside the cage, Mei follows suit, exposing her belly for the vet. Throughout the procedure Brenda talks to Mei soothingly, telling her she is doing a "good job" and that she's being "very brave." Dr. Sanchez checks for any abnormalities and for signs of a baby. A panda's uterus is very small and is only visible for part of the year, so the weekly ultrasounds help the vets get better at detecting changes. At the end of each exam Sanchez offers Tian Tian and Mei Xiang half a pear that they readily gobble up.
During the ultrasound Dr. Sanchez gets a call on his walkie-talkie from Dr. Bronson asking if he has time to stop by the Great Ape House to check on Mandara, the lowland gorilla, while she finishes up with the ducks. The vets are in constant communication with each other, the hospital staff, and the keepers as they make their way around the park. He agrees to go.
Mandara's eye looks fine, so Dr. Sanchez is off to the Cheetah Conservation Station to check on Norok. He cooperates today and the blood collection goes off without a hitch. Back at the hospital, the treatment room is prepped for the eyelash viper's surgery and samples are taken from the snake's pancreas and gall bladder to help determine what might be wrong and to help the vets decide on the best course of treatment.
The Big Ones
Toni and Kandula, two of the Zoo's Asian elephants, are scheduled for foot x-rays Thursday morning. But for big animals like this—Toni, a 38-year-old female, weighs about 6,100 pounds while Kandula, the young male, who is almost three, weighs about 2,500—the equipment travels to them instead of the other way around. Thompson, Sanchez, and Jennifer Kodak, a veterinary technician, load up the portable x-ray, a boxy looking machine encased in bright yellow plastic, and head off after rounds.
The purpose of today's visit is to collect baseline x-rays. Captive elephants can develop a range of foot problems including arthritis, cracked toenails, or abscesses in the sole of the foot. But if the vets have baseline x-rays of the elephants' feet when they are healthy, they have a basis for comparison if they suspect any problems in the future and will be able to offer better treatment.
Toni is up first. Three of her feet were x-rayed a month ago before she got tired, so the vets are back to finish up the last foot. Using behavioral training techniques, two keepers have Toni place her right front foot on a square plate and hold it still while Dr. Sanchez snaps the x-ray. The keepers use poles to indicate what they want her to do and talk to her throughout the process, telling her she is doing a good job. When Toni gets her foot in the middle of the plate the keepers say, "steady, steady," until the x-ray is complete. Before proceeding, Jennifer drives back to the hospital to develop it. The vets want to be sure the technique worked and the film is clear before moving on.
The x-ray looks good, so Kandula is up next. In his case, the procedure is part of his behavioral training to get him used to the process of placing his foot on the plate and holding it still while the vets take an x-ray. It takes him a few tries, but he finally places his right front foot dead center.
Patients ranging from a barnyard chicken to Asian elephants are all in a week's work for the Zoo's vets, but every week is different. As Dr. Sanchez likes to say, "Our routine is not routine."
—Emily Huhn, FONZ Communications Intern
Gorilla photo by Jessie Cohen/NZP. All other photos by Nicole Popovich/FONZ.
[Editor's note: As of 2007, some of these animals are no longer at the Zoo.]
