Plague arrived in the Western Hemisphere in 1900 by way of San Francisco, carried there by ships from Asia. Within a decade, the disease had jumped from the city's Norway rats into California's wild rodent population. It soon spread across Nevada, Utah, Arizona, Colorado and New Mexico, eventually appearing in West Texas.
The last big U.S. plague epidemic was in Los Angeles during 1924-25, when 40 people contracted the disease. Only two survived. With the advent of antibiotics, plague has become a treatable disease, but it is still a serious one.
In humans, the onset of plague usually is signaled by headache, sudden high fever, nausea and muscle aches. If treatment begins too late, it can kill from within a few days to a few weeks.
The most common form of plague is known as bubonic because buboes form on the body of the victim. These tender, swollen lymph nodes, if left untreated, form blackened, horribly painful abscesses that may split open. About half the victims would die if the condition is left untreated.
Should the bacteria reach the lungs, the disease is known as pneumonic plague, which is both more lethal and more contagious.
With the sun soaring overhead, plague detectives Brown and Reynolds unload the tools of their trade--metal traps to live-capture rodents, a flexible plumber's snake, a wad of white flannel squares, sealing plastic bags--then set off in search of burrows.
The surroundings are classic New Mexico: bushy pinon and juniper trees surrounded by blue-green rabbitbrush and native grasses. It's prime plague country because ground-dwelling rodents love the seeds and nuts produced by the trees.
The pair target an adobe barn, where they find a tunnel beneath the structure's concrete slab.
"Looking at the size of it, it says 'rock squirrel' to me," Brown says, getting down on all fours to inspect it. "There's a cobweb over the front, so it hasn't been used for a while."
He attaches a flannel square to an alligator clip at the end of his plumber's snake, lies on his belly and threads the snake into the hole. "We've found rattlesnakes in our burrows before," Brown remarks matter-of-factly.
He and Reynolds give up on the barn and skitter down the steep banks of a nearby arroyo, a deep scar cut by erosion. Shaded from the gathering heat by leafy cottonwood trees, they bushwhack through some undergrowth in search of burrows, gingerly slipping between the strands of a barbed-wire fence.
Brown threads a cloth flag into a likely-looking hole, nearly nabbing a flea, but it hops off. Reynolds meanwhile spots another burrow some distance away, and this time Brown is successful. "Here we go, got one--hot damn!" he exclaims as he stuffs the flannel into a bag.
The fleas are sent to a Centers for Disease Control laboratory in Fort Collins, Colo. Scientists there grind up the insects and inject the resulting flea puree into lab animals to see if they develop plague, a process that can take several weeks. Blood and tissue samples from dead or sick animals are analyzed at the state laboratory in Albuquerque, yielding a quicker result.
With 125,000 square miles to cover, Brown and Reynolds have found no foolproof way of establishing where a person or pet might have gotten the disease. Often, as in Ole's case, they come up empty-handed.
"It is sometimes like looking for a needle in a haystack," Brown concedes.
To control the disease, they can dust burrows with a potent flea-killer called Pyraperm 455, but the most effective method is education. From kindergartens to college classrooms, the pair lecture on reducing the plague risk, urging people to clear their property of woodpiles, junked cars or other likely hiding places for rodents.
A morning's sleuthing behind them, Brown and Reynolds pack up for the two-hour drive to a ranch up north where three squirrels have died from plague.
Reynolds says she seldom worries about catching plague because she's rarely bitten by fleas.
On the other hand, Brown--whose face is punctuated with tiny scars from flea bites--sometimes takes a course of tetracycline to ward off infection.
"They seem to really like Ted," Reynolds says. "Ted gets bitten a lot."