Gorilla Doctors

Category: Orphaned Mountain Gorillas, Routine Health Checks | Date: Dec 17 2007 | By: admin

Bukima’s two-year old infant, Ihumure, in Titus Group (Rwanda).

What is normal? I asked myself that question a dozen times last week in connection with the Goma orphans and their continuing intestinal upsets. What is normal fecal flora for a seven- to nine-month old mountain gorilla? What should a fecal gram stain look like in a healthy infant of this species? At what age does this change to the pattern found in adult mountain gorillas? Jean Paul has run this test on free-ranging adult mountain gorillas and on the orphaned gorillas living up at Kinigi; he also has experience evaluating the results in humans. But what about mountain gorillas less than a year old?

In Susa Group (Rwanda), Ruvumu’s infant seems particularly independent and playful.

Obviously, the most direct way to find the answer to these questions is to collect samples from the field. The problem is that the mother usually consumes the feces of her infant right away, essentially as it comes out. Two weeks ago, we put out a request for infant gorilla fecal samples to the trackers (in Rwanda.) Nothing so far. During routine health checks last week, I observed several infants with their mothers, but none produced a sample that I could see, let alone collect.

Kanama’s infant in Shinda Group (Rwanda) suffered from a bout of diarrhea that resolved on its own.

We’ve tested one fecal sample from a free-ranging mountain gorilla infant during the past year—a baby with diarrhea. The infant of Kanama (Shinda Group, Rwanda) produced bright yellow, loose stools for several days, in enough quantity that trackers were able to retrieve a small sample from the ground. Our gram stain showed a huge amount of yeast, probably candida, a problem known to occur in human babies and not considered life-threatening if the baby’s immune system is strong. If needed, the treatment of choice is daily doses of oral medicine—impossible in our setting. Fortunately, the infant gorilla recovered completely.

Ituza’s 18-month old infant, Umurage, in Amahoro Group (Rwanda)

Another way to confirm a test result as normal or abnormal is to check the reference literature. We often search far and wide for such information—in books, journals, and on the Web. But even if we find published normal values for physiologic data in a given species, these must be interpreted carefully. Small sample sizes are the rule rather than the exception in zoo and wildlife medicine. Without a huge data base, it’s impossible to distinguish the slightly abnormal from normal variations. For this particular question, our searches revealed little information on fecal flora results in any great ape, and none at all for infant mountain gorillas.

Ndakasi, now approximately eight months old, in Goma, DRC.

A last resort, and one that works pretty well, is to extrapolate from reference information and first-hand experience with better known species—in this case, humans. Jean Paul has worked as a lab technician in human hospitals, and when he compares the results of fecal gram stains in people to gorillas, they are similar. Above one year of age, people and mountain gorillas have mostly gram-negative bacteria with very little yeast. In human infants less than a year old, there is a mixture of flora. In infant mountain gorillas . . . well, he’s just beginning to figure this out, with the Goma orphans as his research subjects.

Andre, veterinary technician and gorilla caretaker, with Ndeze (lap) and Ndakasi in Goma.

These questions were brewing in our minds as we continued with routine staining of the orphan fecal samples in Goma. A few days after beginning the acidophilus tablets, Ndakasi’s samples showed a significant change on the gram stain from few bacteria to many of both stain types (positive and negative), including many yeast. We saw less change in Ndeze’s sample, but figured it might just take her a few more days for the friendly flora to build up. I talked again to Drs. Caleb and Louis King at nearby Shyira Hill Hospital; they confirmed that a mixture of bacteria is normal in young human infants, and said they never treat for the yeast.

Ndeze not feeling one hundred percent from intestinal upset.

Then Ndeze surprised us and fell ill with diarrhea for the first time. Her milk intake dropped by half, though she continued to play. Her gram stain didn’t look all that different from before, so we agreed to wait and see if her system could handle a bad bug—maybe she was just now showing signs of exposure to the same bacteria that had given Ndakasi a problem. If the acidophilus was working, we hoped she wouldn’t need treatment. We did consider that the acidophilus itself might be the problem, but that didn’t really make sense. Had the orphans been in Rwanda, Jean Paul could have set up fecal cultures to be sure. But once again, the infants’ location in DRC limits our ability to do proper diagnostics.

Ndeze playing on tripod, despite intestinal upset.

The next day, Ndeze showed no improvement and had lost weight, a sign of dehydration. She continued to play, but with less vigor. Reluctantly, we began her on a course of broad spectrum antibiotics given orally—the same one we’d recently chosen for Ndakasi. Ideally, we’d wait and culture the fecal sample first before choosing an antibiotic, in order to grow the bug to identify it. But these infants have so few physical reserves that waiting for a definitive result could be disastrous. In any case, we have limited capabilities for antibiotic sensitivity testing even at the MGVP lab in Rwanda.

Ndeze much improved after a day on antibiotics.

Like Ndakasi a few weeks ago, Ndeze was much brighter after just one dose of antibiotics. This rapid recovery is much faster than we’d expect if they were suffering from a serious bacterial pathogen or a viral diarrhea. These results support our working diagnosis that their intestinal problems are not due to any particular bacteria but rather to opportunistic ones that can readily dominate their less-than-normal intestinal flora. We worry that repeated antibiotic therapy will have the same effect, by wiping out the good bacteria too. Acidophilus tablets are used for this very purpose, so the next few days will be another good test of how well this supplement works in mountain gorillas.

Ndakasi takes her mid-morning bottle from gorilla caretaker Richard.

After a week on acidophilus tablets, Ndakasi looked great—bright, strong, and active. For the first time, her 24-hour milk intake hit one liter, and her weight tipped the scale at 6 kg. Now the question is, will the bouts of diarrhea stop? In theory, if we’ve helped the orphans establish a more “normal” intestinal flora, they should have more consistent stool. Their feces may never have the same color and consistency as that of a free-ranging infant mountain gorilla, but we may find that the gram stain results are similar. This result could be as close to establishing a norm as we can get—for now. But it’s too soon to tell.

10 responses so far