Dark Banquet (25 page)

She went on to explain that, in all likelihood, these sprays not only killed the roaches but also had a positive effect on bed bug control.

“But roach control is different nowadays,” she said. “In many instances, they use poison baits instead of spraying. And since bed bugs only feed on blood, roach or ant baits are ineffective.”
^*115

According to Andy Linares, “Those older sprays offered additional protection because they would actually vaporize and redeposit themselves onto areas adjacent to where they'd been sprayed initially.”

One of the things
everyone
seemed to agree on is that “bug bombs” are a
terrible
idea for dealing with bed bugs.

“They're one of the worst things you can do,” said Dr. Gangloff-Kaufmann.

“You might kill some individuals, but you'll send others into voids and sheltered areas—and possibly into your neighbor's apartment,” warned Gil Bloom. “And with bug bombs, most of the bugs won't get a lethal dose anyway.”

“It'll just irritate them and get them to move around a bit,” Lou Sorkin told me as we sat in his museum office.

I asked the entomologist if there were any other reasons why bed bug treatments themselves had become part of the problem.

“Well, for one, in New York State, you can't do a preventative treatment on a building, which means that, by law, you can't treat a place for bed bugs until there's a reported infestation.”

“How come?”

Lou hesitated, and I could tell that he was a bit uncomfortable answering this particular question. But after some wheedling on my part, I was able to determine that the reasons for banning preemptive strikes against bed bugs (as well as certain pesticides) were more politically based than scientific.

“Hey, politicians have to keep their constituents happy,” Lou quipped.

I decided to leave it at that, suddenly remembering Lou's earlier offer to have me feed his bed bug colony.

I nodded toward the canning jar. “So how
do
you feed those guys, anyway?”

“Simple,” he said. “You just invert the jar and hold it against your arm for five minutes or so.”

As I watched, Lou rolled up his shirtsleeve. I couldn't help noticing that there were several circular patches of red skin on his forearm and that each was the exact size and shape of the mesh-covered hole in the jar lid.

“That's really…neat,” I sputtered.

“The welts don't really itch that much,” he said. “And, anyway, I'm used to it.”

He must have seen me staring at his arm. “Sometimes I guess I let them feed a little too long,” he said with a shrug.

Ticks: the foulest and nastiest creatures that be.

—Pliny the Elder

That which is not good for the beehive cannot be good for the bees.

—Marcus Aurelius
(Meditations)

8.

OF MITES AND MEN

T
he first time I visited Trinidad in August 1991, I brought along one pair of long, cotton field pants and five pairs of shorts. I figured, Hey, it's hot there every day. Who needs long pants?

On subsequent visits to the country, or any other tropical locale I happened to be working in, I'd bring
one
pair of shorts, reserved for walking around town (if there was a town) and
five
pairs of long pants.

The reason for the drastic wardrobe revision can be summed up in one word:
chiggers.
As I found out, the easiest way to experience these tiny parasites firsthand is to wear short pants (and sandals) while walking through any grassy or wooded area. Unfortunately, that's exactly how I encountered them as I hiked the forest trails behind the PAX Guest House where I was staying.

It hadn't seemed like a bad idea—at least initially. It was probably about 90°F with humidity to match and I'd snuck away from my lab work, thinking that a walk under a canopy of green might cool things down a bit.

The hike itself was uneventful and in that regard it was entirely different from my evening treks through the forest. Missing were the night sounds—layer upon layer of chirps, buzzes, and clicks, all of them set against the incessant drone of mosquitoes. With each nighttime walk in the rain forest came a growing awareness that the trees themselves were alive and covered with life, and this awareness brought with it a mild claustrophobia that was impossible to describe and never entirely went away.

But now, in the blast furnace of midafternoon, the forest was silent. Nothing moved.

Soon enough, I headed back to PAX, convinced that any creatures worth seeing were also smart enough not to be out and about in such wretched conditions.

After getting buzzed in past the front door, I was confronted by Gerard, the guesthouse manager. Gerard runs on the low side of the “Aunt Rose Height Scale,” but he is a force of nature. Wildly funny and incredibly bright, he and his wonderful Dutch wife Oda run the mountaintop landmark as if they were born for the job. Gerard's only real personality flaw is that he hates bats (which is rather unfortunate for him since there are probably thirty species patrolling the rain forest right outside his back door).

“And where have you been, young man?” Gerard inquired, his voice rising to a pitch that threatened to crack my sunglasses. (Gerard refers to all males younger than the age of eighty-eight as “young man,” and on a recent return trip to PAX, my wife Janet and grad student Maria were disappointed to learn that Gerard had been calling them
both
“sugar plum.”)

“Just taking a walk,” I said, trying not to drip on the exquisitely polished wooden floor.

Gerard shot me a look as if I'd said I'd been out munching road kill. “Whatever,” he said, throwing me a good-natured but dismissive wave before hurrying past—presumably in search of more intelligent company.

The next day I awoke to find that not all of the forest creatures had been inactive during my ill-advised walk. Looking down, I could see a band of itchy, red dots circumnavigating my waist like Magellan's diaper rash.

After taking a hot shower, I slathered on some calamine lotion, but strangely, the itching just got worse so that by that evening I had run through the entire bottle, exhibiting all the self-control of an addict on hot pink liquid crack.

Embarrassed, I decided to keep my new red belt a secret.

“I hear you picked up a few chigger bites,” my graduate adviser and mentor John Hermanson mentioned over breakfast the following day.

Great,
I thought. It must have been my question about whether calamine lotion came in a five-gallon drum.

“Yeah, no problem,” I said, with as much nonchalance as I could muster. “I'm feeling a lot better.”

“That's good,” he said, returning his attention to a plateful of eggs. “Because they'll probably arrest you if you keep rubbing against the table like that.”

Over the next few days, the rash actually got worse, as did my desire to scratch the angry welts that had developed. I tried to get creative, imagining how I'd deal with this if I'd been stranded on an island somewhere. I found that by hooking my thumbs into my belt buckle and imitating some old twist meister, I could scratch all of my chigger bites simultaneously. Almost as important, I learned that I could avoid bites altogether by wearing lightweight long pants with the cuffs tucked into my boots. And as for protecting my upper body, I found that an ultralight, long-sleeved shirt added the finishing touch to a relatively chigger-resistant field outfit. The key bit of knowledge, though, was
not
to go wandering around the forest or scrub during the hottest, most humid part of the day.

Doing some investigative work, I determined that the itching and redness I'd been suffering through was a type of dermatitis called thrombidiosus and that I'd been lucky the problem hadn't stuck around for ten days instead of five or six. I was also lucky that the chiggers in Trinidad weren't transmitting some sort of nasty, trip-ending bacterial infection. Had I been trekking through the brush in Southeast Asia or the South Pacific, I would have run the risk of contracting “scrub typhus” from chiggers such as
Leptothrombidium akamushi.
The Japanese first described this tiny arthropod over two thousand years ago (
akamushi
is Japanese for something akin to “dangerous bug”) but although
Leptothrombidium akamushi
isn't a bug, or even an insect for that matter, its bite can transmit a potentially lethal bacterium to humans.

Initially, the bacterium
Orientia tsutsugamushi
is inoculated into the skin of a host through a chigger bite or contact with the chigger's feces. It then spreads through the host's bloodstream where it invades the endothelium, the flattened layer of cells that compose the inner lining of vertebrate blood vessels.
Orientia
(a close relative of
Rickettsia rickettsii,
the bacterium responsible for Rocky Mountain spotted fever) gains access to the endothelial cells' interior in a rather dodgy way, and in doing so, it pulls off a microscopic version of the famous Trojan horse trick. Phagocytosed by the host cells,
Orientia
is packaged inside enzyme-filled death baggies called phagosomes. But instead of waiting around to be lysed (or “sliced up,” for those of you who skipped the blood chapter), the bacterium thwarts the host's defenses by escaping its membrane-bound prison to take up residence in the cells' gel-like cytoplasm. There,
Orientia
multiplies rapidly by a form of asexual reproduction called binary fission.
^*116
Soon the bacteria-packed host cells burst, sending millions of new pathogens to infect new endothelial cells downstream.

During World War II, Allied forces in Southeast Asia and the South Pacific were ravaged by a number of chigger-and tick-borne diseases. Of these, scrub typhus became the most common as well as the most deadly. Sometimes described as mite-borne rickettsia (the rod-shaped bacterium was formerly known as
Rickettsia tsutsugamushi
), scrub typhus is characterized by high fever, muscle pain, painfully swollen lymph nodes, delirium, and a severe rash. If left untreated or treated too late, scrub typhus can cause encephalitis, circulatory failure, and even death.

In a pattern that's become familiar to those studying arthropod-transmitted diseases, rodents and not humans were the preferred host of the pathogen-carrying chigger. In the Pacific theater of World War II, rat, vole, and field mouse populations exploded owing to the massive influx of troops, the garbage they produced, and the filthy conditions they endured. As a result, human chigger bites became more and more frequent, until scrub typhus reached epidemic levels. With no specific treatment available during the early 1940s, the disease killed more soldiers in the Burma-India-China theater of operations than any other infectious disease.
^*117
So serious was the scrub typhus problem that in some of the scientific literature from the 1950s, the chigger responsible for transmitting the disease was described in terms usually reserved for human enemies:

All along the Papuan coast and adjacent islands Akamushi continued its ambush tactics against American troops. Invariably combat troops in most of the engagements of the island-hopping road to Tokyo sought the ever-present cover afforded by the tall kunai grass where Akamushi waited in hiding.

(Emory C. Cushing,
History of Entomology in World War II,
80–81)

Not surprisingly, the death toll from scrub typhus generated increased concern about the parasite causing the disease, and this concern led to an intense period of research that ushered in the modern science of acarology (i.e., the study of chiggers, mites, and ticks). Eventually, antibiotics like tetracycline, doxycycline, and chloramphenicol became effective treatments for scrub typhus and other acarid-transmitted diseases.

As with other bacterial pathogens, antibiotic resistance is becoming more of a problem. In parts of northern Thailand, for example, doxycycline-resistant and chloramphenicol-resistant strains of
Orientia tsutsugamushi
have evolved, and as a result, 15 percent of patients who contract scrub typhus die from the disease. This type of antibacterial resistance can be attributed to several factors: the tremendous rate at which bacteria multiply, the high rate of bacterial mutation, and the misuse of antibiotics.

In that regard, one of the most common ways that antibiotics are misused occurs when a prescribed antibiotic regimen is abandoned, usually once a patient feels better. Few people, in fact, seem to realize the danger posed when they decide to stop their antibiotic treatment before it's complete—and here's why. Think of a hypothetical population of 1,000 microbes inside a person who has been instructed to take an antibiotic for seven days. Discounting bacterial reproduction for a moment (since this is a model), let's say the antibiotic kills 900 microbes by day five and 990 by day six. If the patient were then to stop taking the antibiotic after day six, which microbes would be left alive? The ten survivors who were the most resistant to the antibiotic in the first place.
Now
factor in bacterial reproduction—and as these surviving microbes begin to multiply, each new generation will have the same antibiotic resistance exhibited by the ten original survivors.
^*118

Now that we've seen some of the nasty effects of chiggers it's time to figure out just what they are. The short answer is that they're the parasitic juvenile stages of some mite species.
^†119

And what about ticks?

Like chiggers, their story has become an extremely important one because of the pathogens they transmit through their bites. Starting in the mid-1970s, there has been growing concern in the United States and elsewhere over tick-transmitted diseases—especially Lyme disease and Rocky Mountain spotted fever.