The Hippo with Toothache (24 page)

I HAD MIXED
emotions when a supervisor from the children's zoo—part of the Houston Zoo, where I worked as staff veterinarian—called to say that their collection of dung beetles had red spots on them. Could I come take a look? There were seven beetles, from the
Canthon
genus; they'd been collected locally in Texas. I thought to myself,
I don't do bugs; I don't know anything about insects. I guess I could go look at them at least; maybe I can do something, but what?

Like most budding veterinarians, I had a small collection of my own pets as a child, I loved science and animals—at least, most of them—and if I found an injured or sick wild creature, I'd try to take care of it. But insects and spiders had never interested me. I don't like being surprised by bugs landing on my shoulder or getting caught in my hair. I'm
actually a little afraid of them. At best, they are nice to look at—through glass.

The beetles needed to be examined, however, and it was in my job description to pay them a visit. I began by doing some research on my soon-to-be patients. The Internet (in 2000) had no information about the medical management of dung beetles, nor any reference to beetles with red spots, but I did learn that dung beetles are very interesting creatures. Sometimes called “tumblebugs,” most species are between 1 and 1½ inches long; the color of their carapace, or body, ranges from dull to shiny black. Considered environmentally beneficial and medically harmless, these beetles recycle animal feces. On a Texas ranch, they can recycle up to 80 percent of the cattle manure in a pasture, improving soil nutrient levels and structure, and supporting forage growth for the cattle to eat.

Different species of dung beetle found in other parts of the world play a similar role, ensuring a healthy environment for animals as varied as gazelles, rhinos, and elephants. Adult beetles use the liquid portion of manure for nourishment, sort of a dung Slurpee (sorry, but that's the image this fact created in my mind). Then they work in male-female pairs to roll a ball of dung away from the manure pile, and the female lays an egg in the middle of the ball. They bury it in a deep burrow. The egg develops into a larva, which then eats its way out of the dung ball and to the surface, to start the life cycle all over again.

I also got a bit distracted reading about ancient Egypt. The dung beetle was once considered sacred by the Egyptians. The beetle's behavior of rolling a huge dung ball during
the day, disappearing into a hole at night, and starting again the next day symbolized renewal and a connection to the god of the rising sun. There was also a belief that all dung beetles were male, reproducing themselves out of nothing by depositing sperm into the dung ball. Had bugs been my hobby growing up, maybe I would have known all of this.

After learning what I could, I met the children's zoo supervisor to go look at the beetles. On our way, I kept thinking—hoping—that maybe we'd find nothing wrong with them. But I soon saw that all seven dung beetles actually did have red spots and that the spots moved. They appeared to be some type of millimeter-size red insect riding around on their backs. My best guess was a mite.

At that point, I realized that the difference between a beetle and a mite confused me. Both are in the kingdom Animalia and phylum Arthropoda, which makes them generically “bugs.” They diverge from there. Mites belong to the class Arachnida, same as spiders and ticks, and dung beetles belong to the class Insecta, along with wasps, ants, grasshoppers, butterflies, other types of beetles, and—just to confuse the issue—a particular type of insect called a “true bug.” So both were bugs: the mites were arachnids and the beetles were insects.

I had plenty of questions about this case. I'd never had to work on a bug infested with bugs. Were the red bugs harmful to the beetles, or were they symbiotic bugs just hitching a ride? Would they go away on their own? Where had they come from? How would I handle these animals if I needed to?

I remembered seeing mites on other types of animals, like chiggers that bite humans and cause a rash. I'd seen little red
mites on the bodies of birds and reptiles; these are harmful to the animal because they bite and suck blood, potentially causing anemia, or passing bacteria or viruses to their hosts. But even if these beetle hitchhikers were similar to those seen on humans, birds, or reptiles, the treatment would have to be completely different. For animals infested with mites, we use commercially available insecticides—carefully. A more appropriate name for such chemicals might be “bugicides.” In this case, they would undoubtedly kill my patients as well as their red spots.

I asked more questions about the history of the zoo's beetles and the red mites: were the dung beetles behaving, eating, and moving around normally? The responses were not helpful: “We're not sure” and “They don't seem to be eating as much as before.” Given the number of red mites observed on each beetle, I decided reluctantly that this was a problem that needed taking care of. The supervisor and I discussed the situation and came up with a plan—several plans, actually.

First, we would try to change their environment. The mulch substrate for the beetles could be the source of the infestation; maybe the red mites normally live in this soil. So we brought in fresh dirt, hoping the hitchhikers would prefer it to the beetles. After a few days, we saw no difference. The beetles still had red spots, mostly congregated around the midbody, near what I would call the neck region. Next we tried freezing the soil for several days before using it. Maybe this step would kill the mites already in the substrate and reduce the numbers on the beetles. But when we placed the beetles and their red friends on the thawed-out soil, the hitchhikers still did not disappear.

Okay, on to the next step.

The conservative approach had failed. I would need to manually remove the red mites from the beetles. But this strategy presented yet another set of questions: How could I get the mites off without harming my patients or myself? If I put the dung beetles in an anesthetic chamber to anesthetize them, then removed them to work on them, would they stay asleep long enough? If I dispensed with the chamber, was there any way I could use anesthetic gas on the beetles without putting myself to sleep as well?

Since I couldn't think of a way to keep the beetles under anesthesia long enough to work on them, that option was out. I would have to contain my fear of bugs and somehow immobilize the beetles myself while I picked off the red mites.

The removal operation was scheduled for one quiet afternoon, and the dung beetles were brought up to the clinic. I didn't know how they'd react to the stress of my handling and fussing over them, so we split the beetle collection in two. One group of three would go back to the children's zoo exhibit to be the “control group”; the four others would be the “experimental manual removal group.”

The day before, I'd asked my technicians to sterilize some dirt so that it was free of all possible contamination. Even more surely than freezing, the sterilization process would kill any bacteria, fungi, or bugs that might be lingering in the soil. Once they were cleared of the red bugs, the beetles would be kept in the sterilized dirt in a clean cage at the clinic for monitoring. I'm pretty sure this was the one and only time we purposefully put dirt into our clean sterilizing unit.

Now the fun part began. What should I use to restrain these little buggers? Even if the beetles could tolerate the stress of hands-on handling, I feared my instruments or clumsiness might damage them beyond repair. We might need to modify my technique as we proceeded, depending on the results, good or bad. The supervisor and staff understood the risks. Ready to proceed, I chose a pair of large blunt-tipped forceps (surgical tweezers, about six inches long, with rounded tips) to handle the beetles, allowing me to control the pressure on the body. I chose a pair of small delicate forceps about four inches long, with pointy tips, to remove the red mites from the beetles. I set a shallow plate in front of me to serve as a catch pan in case the dung beetle fell from my grasp, or in case one of us needed a break.

The first procedure on any animal is always a learning experience. I grabbed the first beetle and it jumped! Startled, I gasped, and half rose from my chair. Everyone in the room laughed, including me, even while I thought,
Please don't jump or fly onto me
. Luckily, the first beetle didn't go far; it jumped just enough to let me know it wasn't happy with my touching it. At least it didn't fly. These beetles have large wings that enable them to move from dung pile to dung pile in the wild. (My worst fear was of a beetle flying around my treatment room, pursued by people running after it with nets.)

The next time I grabbed the beetle, I held it firmly but gently—and held my breath at the same time. Once the beetle realized I wasn't letting go, it stopped struggling, played dead, and behaved like an ideal patient throughout the rest of the procedure. I had to scout around on its small black body, peering in all the cracks and crevices for red bugs. It took about a quarter of an hour to remove all the mites.

Each of the four beetles I treated that first day handled the procedure like a champ. They were placed in the cage with the sterilized soil and kept at the clinic for a week. All survived without any obvious signs of trauma. No red mites were detected on the beetles during the observation period. A week later, the three beetles of the control group back at the children's zoo were brought to the clinic to undergo the same procedure. Again, all went well, and we put them in the sterile-environment cage with their friends from the first group.

After the keepers had disinfected their habitat cage, we returned the group of seven beetles to their original exhibit, along with a fresh batch of sterile soil. They were home again. I visited them daily for a week. So far, so good: they were behaving normally, without freeloading bugs. But a month later, I got a report that the red mites were back, although in far fewer numbers. We decided to leave them alone and just be vigilant, since the beetles appeared healthy. If the situation changed, I would intervene again.

I never found out for sure what those little red bugs were, though it's likely that they were parasitic mites. I suppose we could have sent them to a special lab for identification, but I doubt that would have changed the outcome. Generally, the mites didn't seem to be doing any harm to the beetles. Plus, my attempted treatment hadn't worked, and I doubt I would have tried anything more invasive. Any kind of chemical just seemed too dangerous for the patient.

After all the hours I spent on this case, I still knew very little about insect medicine. Did the mites make the beetles feel itchy, lethargic, or thirsty? I have no idea, and doubt I ever will.

I'm happy to say that I haven't been asked to examine or treat any of our other bugs—though that may just be a matter of time. On the other hand, the thought of spending a quiet afternoon in the clinic picking mites off dung beetles no longer bugs me.

Maryanne Tocidlowski was raised in New York State and decided to become a vet at the age of ten. She graduated from Daemen College in Buffalo, New York, as a medical technologist, and then worked in a human hospital hematology laboratory for six years before attending veterinary technician school. Dr. Tocidlowski graduated with an associate's degree in animal health technology and was then accepted to Purdue University's College of Veterinary Medicine. After her graduation in 1993, she did a one-year small animal internship at the New Haven Central Animal Hospital in Connecticut; next came a three-year residency in zoological medicine at North Carolina State University and the North Carolina Zoological Park. Dr. Tocidlowski joined the staff of the Houston Zoo in 1997 as an associate veterinarian, and became a diplomate of the American College of Zoological Medicine in 1998.

I STIFFENED WITH
anxious tension as I opened my e-mail to read the final pathology report on Brass, the red-ruffed lemur. I hoped for confirmation of the immune disease I'd suspected, or at least some sort of clue to the cause of the lemur's fatal illness. But as I scanned the report, anticipation gave way to disappointment and my questions remained unanswered. I sighed and slumped in my chair, studying the screen to review the details I'd hurried through on the first read. No, I hadn't missed anything. I sat back, replaying the case in my mind in a last-ditch search for answers to the bizarre illness.

I couldn't help feeling as if I'd failed Brass. Part of my reaction was personal. This case hit a little too close to home. I'd wanted to find an answer in the report not only to satisfy
myself but also to share it with my mom. Coincidentally, she too had been suffering from strange chronic ailments. The past few months, we'd talked over the phone every week or two about both her case and the lemur's. Where they overlapped, we'd compared clues as we tried to solve the mysteries.