Our monkey trap was assembled and ready. It was a frame cube of aluminum tubing and nylon mesh, big as a closet, custom built for this purpose, with a falling door controlled by a remote tripwire. You sat at a distance, you watched, you saw monkeys enter, you pulled the line—and the door came down. But don’t pull too soon. Don’t settle for the first animal that ventures inside. Part of optimal technique for trapping macaques, I’d been told, was to catch as many as possible on the first go, because these critters are smart and they learn quickly. They become trap-shy after seeing the trick worked on their comrades. So whoever holds the tripwire must be patient, waiting for just the right moment, when as many animals as possible are inside the trap.
My assignment was minor: When the door fell, I should get there immediately and lock it down with my foot, so the captured macaques couldn’t widget their way out. Gregory Engel would then do the hard part, tranquilizing them one by one with a hypodermic full of Telazol, a fast-acting veterinary anesthetic. How do you inject a hysterical monkey? In this case, by jabbing into its thigh through the mesh of the trap. Professor Mohammed Mustafa Feeroz, Engel and Jones-Engel’s principal Bangladeshi collaborator, would stand as defense. Four of Feeroz’s students would help. Defense was important because the uncaptured monkeys might charge, frantic to free their comrades. They could be a formidable platoon. Lisa Jones-Engel, chief genius of the whole project but prohibited from entering this shrine because of her gender, would be waiting in a courtyard nearby, along with several female assistants, to begin drawing blood. One, two, three: trap, tranquilize, draw. What could be simpler?
Lots of things, let me tell you, could be simpler.
The trap was baited with puffed rice and bananas. Within moments of seeing the bait placed, a few monkeys came to inspect. They climbed all over the trap, inside and out. Most of the others held back. Word seemed to pass among them, excitement rose, more animals arrived across the rooftops; there must have been a hundred, all nervously curious about our presence and tantalized by the bait. We loitered discreetly, on the steps, on the slope, looking casual and averting our eyes. Feeroz held the trip line. He had the patience of a fisherman watching a bobber jiggle. He waited, he waited, as several of the biggest macaques entered the trap to investigate. One of them, a great male with a Schwarzenegger physique and very long canines, may have been the alpha of the troop. He was bold. Greedy for his share. A few more animals entered behind him. Feeroz pulled.
The door fell, trapping Schwarzenegger plus six others, and all hell broke loose.
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Maybe it has occurred to you to wonder: sacred monkeys in an Islamic country? Bangladesh’s population is 90 percent Muslim, mostly composed of traditional Sunnis. Doesn’t Islam forbid graven images and totemism? Aren’t those monkey temples supposed to be Hindu or Buddhist?
Right enough, but with an exception: the Sufi shrines of northeastern Bangladesh, including Sylhet. Chashnipeer Majar is a Sufi site.
Sufism in the region traces back seven hundred years, to a pious invader named Hazrat Shah Jalal. It may be practiced by either Shiites or Sunnis, but it’s a more mystical, esoteric brand of Islam than mainstream Shia or Sunni observance. As the story goes, Shah Jalal came out of the west, from Mecca by way of Delhi, with his army of 360 disciples. Sylhet was a Brahmin kingdom in those years, but a kingdom of faded strength, ruled by a tribal chieftain. Shah Jalal either conquered the chieftain or (depending on which version you hear) scared him into retreat. One among Shah Jalal’s entourage was a man named Chashnipeer, a sort of wizard geologist, charged with finding just the right place for a new kingdom of Sufi believers, where the soil would match Mecca’s sacred soil. Sylhet was it. Shah Jalal and his followers settled in the region and converted much of the populace to Sufism. After a long rule, Shah Jalal died and was buried there. His mausoleum, now encompassed within a large mosque complex in a north neighborhood of the city, still attracts pilgrims from all over Bangladesh. I don’t believe it welcomes monkeys.
But other sites of worship were also established, taking their names from the lesser founding heroes. These were different from normal Islamic mosques; they were majars, shrines, implying veneration of a holy personage, whose body might be entombed (like Shah Jalal’s) on the spot. Because this recognition of saintliness can be construed as idolatry—implicitly comparing a mortal individual to God—such Sufi majars may offend against the letter of Islam as understood by Sunni or Shia. They are heterodox. You won’t find them down south in the capital, Dhaka.
Then too, in more recent times, some of the Sylhet majars underwent another stage of transformation. With macaque habitat shrinking as the landscape became farmed and urbanized, monkeys found refuge at the shrines. At first they may have stolen food or picked garbage. Gradually they became half-tame. They learned how to beg food and were accommodated, tolerated, eventually indulged, by the men who looked after those sites. Several majars, including Chashnipeer, became monkey shrines.
People arrived to worship, enjoyed seeing the macaques, gave alms, and came back again, occasionally in great number and from long distances for festivals that involved feasting and prayer. The macaques were novel. They were popular. It was a good business model, pardon my secular soul, for a religious establishment. Some pilgrims believed that if a monkey took food from your hand, your prayers would be answered. The whole arrangement might seem sacrilegious in most parts of the Islamic world, but in Sylhet it became holy tradition.
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Mustafa Feeroz is professor of zoology at Jahangirnagar University in Savar, just north of Dhaka. He’s a sweet-spirited fellow, a careful scientist, and an observant Muslim, though not a Sufi. He and Dr. Jones-Engel had of course sought permission to trap monkeys at Chashnipeer Majar, explaining their scientific purposes and their concern that no animals be harmed. That satisfied the committee in charge but not the macaques themselves, who went ballistic when they saw that we had trapped one of their honcho males and a half dozen others, including a female with an infant.
Inside the trap, the captives panicked, bouncing and scrambling across the mesh walls and ceiling. Outside the trap, about eighty other macaques came down from their tree limbs and wires and rooftops, screaming and chattering, surging around us, making moves to attack in support of the hostages. Feeroz and the students had prepared for this moment by picking up large sticks. Now they brandished those weapons, swinging, threatening, smacking the ground, shouting to drive the macaques back. I pinned the door with my foot, as instructed, so that nimble monkey fingers couldn’t unlatch it. The loose animals weren’t easily cowed. They dodged the sticks, backed off, jumped around, screeched all the more, and came forward again, like those infernal winged monkeys in The Wizard of Oz. Gregory Engel meanwhile moved to the trap with his syringe and, through the mesh, managed to jab the Schwarzenegger macaque in its thigh; in the same motion, he rammed down the plunger. It was a nifty move, somewhat outside the usual duties of a family-practice physician from Seattle.
Within a few seconds, Schwarzenegger’s ferocity started to wilt. The animal went clumsy, then limp. Lights out, for at least half an hour.
Working quickly, Engel tried to get each of the others. But it was difficult with six monkeys still ricocheting around the cage and others at his back. He poked a couple more and then reloaded his syringes with Telazol. Nobody wanted to get clawed or bitten. Grab a tail if you can! he hollered to me. Pin one against the mesh! Yeah, right. I made a lame tail-grab attempt, but I was the amateur here, and I found little zeal for exposing my hands to the flying claws and teeth of animals well known for carrying herpes B.
Somehow, within a few minutes, Engel injected all five adults in the trap. When we opened the door, one juvenile and the infant skittered away, but the others were down like drunks.
We loaded them into a duffel bag. Go, go fast, said Engel, and two students carried the bag down the staircase and then hoisted it gingerly over a wall, below which Jones-Engel stood ready to help catch the
bundle of doped monkeys. She was dressed in traditional Bangladeshi attire—a camise and salwar pants plus a veil over her shoulders, which was her usual field garb, worn in deference to local sensibilities—but now she also wore exam gloves and a surgical mask. She guided the monkey-bearers down an alley to the private courtyard, where women were welcome, where tables had been prepared, where swabs and vials and clipboards and more syringes had been laid out in readiness. The gathering of data began.
Lisa Jones-Engel is a forceful, direct person with years of experience among Asia’s nonhuman primates. She loves her subject animals but doesn’t romanticize them. As she and her assistants started drawing blood and taking oral swabs, her husband and Feeroz, followed by the male students and me, headed back to the shrine for another round of trapping. Now that we had shown our methods, and our devious intentions, it was dicey to say how the troop might behave. “If the monkeys in the last half hour have figured out their plan of attack,” Lisa commanded us, “you just retreat.”
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“Herpes B scares the shit out of people,” she told me a few days later. We had returned to Dhaka, and after another long day she and Gregory and I were sharing wee drams of Balvenie in my hotel room. Lisa was adamant. “Herpes B gets populations of monkeys shot in the head and . . .”—she had in mind the safari park culling as well as other such events—“just eradicated. Herpes B is like Ebola that way.” It’s not only frightful and potent, she meant, but profoundly misunderstood.
Herpes B and Ebola, of course, are very different sorts of bug. But she was right; there are similarities worth noting. In both cases, the virus is often lethal to humans but not nearly so consequential as it would be if not constrained by the limits of its transmissibility. It has no preternatural powers. It finds humans a dead-end host. People are ignorant about its actual properties and inclined to imagine an unreal breadth of risk. Among differences between the two, there’s this: Ebola is infamous and herpes B is largely unknown. It’s unknown, that is, unless you work in a monkey lab or run a safari park.
Killing off captive macaques is uncalled for, Lisa insisted, even in populations that might carry the virus, so long as their likelihood of passing it to a human is extremely low. And a positive test for antibodies doesn’t even prove that the virus is still present.
She mentioned a recent case, just three months earlier, in which a research colony of macaques at a university in France was condemned to extermination. Some of those individual animals were known to and studied by attentive ethologists for twenty-five years. The colony was notable for expressing some fascinating behavioral patterns. A thousand primatologists, from the International Primatological Society and other scientific groups, signed petitions challenging the logic of wholesale condemnation. “Look, don’t do this,” they argued. “You don’t really understand what these results mean.” The university council made its decision anyway and, on a Sunday in August, before the scientists and the keepers could protest further, the macaques were all killed.
However dangerous herpes B might be when infecting a person, the chances of monkey-human transmission seem to be extremely small. That’s what those research results from the Sangeh Monkey Forest in Bali suggest. Lisa and Gregory found a high prevalence of the virus among the macaques there, and a high incidence of macaque bites and scratches among the people, but no evidence of herpes B transfer. If cases do sometimes occur in Bali, they must escape medical notice, or else get taken for some other dreadful disease, such as polio, or rabies, which is a serious problem in Bali because of its prevalence among the island’s dogs. Nobody knows whether any undetected herpes B infections have come out of Sangeh. Possibly, none have.
Other data, published almost a decade earlier by a different team, support the impression that herpes B doesn’t leap readily to humans. This study looked at blood samples from 321 laboratory workers—scientists and technicians who handled live primates or else primate cells in culture. Most of those people worked with macaques. Many of them had been bitten, scratched, or splashed. Yet none of the 321 workers tested positive for exposure to herpes B. Evidently the virus is not easily transmitted, and evidently it’s not causing subtle, asymptomatic infections among people in close contact with monkeys.
The medical record notes just forty-three cases, beginning with William Brebner, in which contact between a macaque and a person led to infection. True, those forty-three infections often brought dire results. But over the same period of time, during untold thousands or millions of other such contacts—in laboratories, in the wild, from monkey temples to Petri dishes, via scratching or biting or drool or needlestick accident or splashed urine—herpes B didn’t make the monkey-human leap. Why not? Apparently this virus isn’t ready.
Another way of saying that: Ecology has provided opportunities, but evolution hasn’t yet seized them. Maybe it never will.
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The blood drawn from the macaques we trapped at Chashnipeer Majar would be screened for evidence of another virus too. Lisa Jones-Engel and her team had lately shifted their attention to this one. It’s a favorite of mine because of its lurid name: simian foamy virus. No, infected hosts don’t foam at the mouth. The “foamy” part derives from its tendency to cause cells in a host to fuse with one another, forming gigantic, nonfunctional megacells that, under a microscope, resemble bubbles of foam.
There’s actually a whole gaggle of foamy viruses, all lodged within the genus Spumavirus. Some of them infect cows, cats, and horses. They have also been found among gorillas, chimpanzees, orangutans, baboons, macaques, and other primates, in each of which they seem to be ancient infections, having coevolved with their hosts for as long as 30 million years, one species of simian foamy virus (SFV) per species of simian. Maybe that’s why, nowadays, they seem so benign. One team working in Central Africa reported evidence of SFV passing from primates that are hunted for bushmeat (mandrills, gorillas, and guenons) into people who hunt those animals. Whether SFV makes the hunters sick is another question, not addressed by that study. If it does, the effects must be slow and subtle. Then again, the HIVs are slow and subtle. And SFV, like the HIVs, is a retrovirus. Jones-Engel isn’t the only researcher who feels that simian foamy virus bears watching.
Thirty years ago, scientists believed that we humans have our own foamy virus, our own endemic version, distinct from the zoonotic foamies we may acquire while feeding rice to a sacred monkey or cutting open a gorilla with our machete. Destructive in cell cultures but apparently harmless in a living person, human foamy virus was called “a virus in search of a disease.” Later research with advanced molecular methods—most notably, genetic sequencing—showed that it was probably just a variant of the foamy virus endemic to chimpanzees. Anyway, that one isn’t what interests Lisa Jones-Engel and her husband. They’re more concerned with the versions that dwell in Asian macaques.
Like the African SFVs, those Asian viruses seem to be innocuous when they get into human hosts. During our talk in Dhaka, Lisa stated the point a little more guardedly. “There’s no known disease in nonhuman primates infected with simian foamy virus. Now when the virus jumps the species barrier to humans . . . ”—when that happens, well, it’s hard to say what may occur, because of limited data. “The number of people that we’ve had to look at so far is so small that we really can’t speak yet to whether it does cause disease in humans.” The cases observed have been too few, and the time of observation has been too short. As retroviruses, the SFVs might conceivably have a long, sneaky period of latency and slow replication within the body, before emerging from their secret lairs to wreak havoc.
For Engel and Jones-Engel, this particular line of investigation had its origin at the Sangeh temple, in Bali, where they screened for simian foamy virus as well as for herpes B. And like herpes B, simian foamy seemed to be widespread throughout the population; they found antibodies against it in most macaques tested. A common infection, then, probably passed from monkey to monkey by social contact, again like herpes
B. But how often does it spill into humans?
Besides trapping and sampling monkeys, the researchers drew blood from more than eighty people and screened those samples by the same method used for the monkeys. All the humans tested negative except one, a forty-seven-year-old Balinese farmer. This man lived near Sangeh, visited the temple often, and had been bitten once and scratched several times. No, he told them, he had never eaten a monkey. No, he did not keep a pet monkey. If the virus was in him, it must have come from those aggressive animals at the temple. In retrospect, the most notable aspect of what Jones-Engel and Engel found among their eighty-some test subjects in Bali was that only the farmer had been infected. Since then, further sampling in other Asian countries (Thailand, Nepal, and Bangladesh) has shown that simian foamy gets into humans more readily than the early results suggested.
But if it causes no known disease, so what?
Beyond the obvious point that it might cause an unknown disease, Engel and Jones-Engel have another reason for studying this virus. “It’s a marker,” Gregory told me. “We caught a marker for transmission,” Lisa echoed. What they meant is that the presence of SFV within a human population marks opportunities having occurred for cross-species infection of all kinds. If simian foamy has made the leap from a half-tame macaque to a person—to several people, maybe to thousands of people passing through sites such as Sangeh—then so could other viruses, their presence still undetected, their effects still unknown.
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