They’re Out Snooping to Keep You From Being Bugged
The sun hadn’t been up for long, and already the surveillance boys were itchy for action, ready to check the traps they had set the day before in a no-nonsense effort to corral the creatures of the night.
But, as he pulled on his plastic gloves and stepped out of his well-marked truck, it wasn’t the sleazy domain of street vice that Paul Damos was set upon cracking.
“We’re after rats,” he said.
Not only rats, but also mice and gnats, fleas, ticks and mosquitoes. Damos prowls the creepy, crawling underworld of vectors--the insects and rodents that carry potentially fatal diseases such as malaria, encephalitis, Lyme disease and bubonic plague.
One of six technicians with San Diego County’s Vector Control and Surveillance Division, Damos and the others regularly hit the gnarly underbrush as a rodent investigators.
They’re bug cops.
Started last year, the wandering surveillance teams have taken on the daunting task of checking and identifying fast-spreading vector populations before they have the chance to unleash any full-blown disease outbreaks.
They’re on the lookout for signs of anything resembling the malaria outbreak of 1986. With its 28 confirmed cases throughout San Diego County, it became the biggest outbreak of the disease to hit the continental United States since 1953. In 1988, the county broke its own malaria record with 30 confirmed cases.
As San Diego suburbs sprawl closer and closer to the breeding grounds of insects and rodents--the brush-covered ravines, rural streams and pristine open space--the technicians make sure the diseases of the wild aren’t brought home to suburban doorsteps.
That means forays to the brushy fields near the San Elijo and Batiquitos lagoons, the Agua Hedionda Lagoon area, Lusardi Creek near Rancho Santa Fe, the San Luis Rey and Tijuana river basins.
“We go out looking for disease,” said Jim Shoemake, a surveillance team supervisor. “We really can’t prevent it. But we can be the first alarm to warn people how to protect themselves if the disease carriers are present.”
If necessary, the county will spread leaflets in both English and Spanish explaining the dangers of a particular insect to both suburban homeowners and residents of open-air migrant encampments.
Several times each month, the bug and rodent bounty hunters set traps for wild field mice, squirrels and wood rats, looking for something called crossover. That’s when the often disease-carrying ticks and fleas carried by these rodents are picked up by more domestic rodents, such as the roof rat, that return to hole up in attics and garage rafters.
“When wild rodents start mixing with domestic rodents, we become concerned,” said Janet Ortiz, vector control and surveillance division manager. “Historically, that crossover activity has brought on diseases such as the bubonic plague, or Black Death, in the 14th Century. The disease is still around today. The good news is that it can be treated if caught early enough.”
Like some suburban Marlin Perkins, the technicians wander the undergrowth of still-wild San Diego County, trapping and then releasing rodents after they have checked for the pesky gnats and fleas that are then taken into the laboratory for further study.
And now malaria season is here. August is the primary month, experts say, when mosquitoes are most numerous.
Migrant workers, they say, are particularly susceptible to mosquito-carried diseases such as malaria because they are often unable to protect themselves from insect bites.
So, early Tuesday, Damos and his partner, Chris Wickham, hit the dusty back roads of Rancho Bernardo, ready to reap the results of the traps they had set the night before.
Late Monday afternoon, as the sun dipped toward nearby Lake Hodges, the pair set 12 mosquito traps, 15 large rodent traps and seven smaller ones in areas that have been designated as possible breeding grounds.
Their catch would be turned over to the county’s insect ecologists, who study the data and may send the specimens off for further research at a Berkeley laboratory to determine if they are disease carriers. If so, the county would determine what efforts need to be taken to warn the public to any threat.
But first came the dangerous job of emptying the traps. “You never know what’s going to be in those traps until you get right up on them,” said Ramos, a 50-year-old former commercial exterminator, as he picked his way through the bristly bushes near the Rancho Bernardo Park and Recreation Center.
The technicians also risk being bitten by a rodent or a disease-carrying mosquito. But the thing that spooks Damos most are the snakes that slither through the brush. “They scare me to death,” he said.
There was also the skunk that found its way into a trap and almost sprayed several technicians. Or the South Bay youth who brandished a gun at another technician who unknowingly surprised him as he slept in a remote patch of brush.
On Tuesday, the first trap Damos encountered hung from a tree, just where he had left it the previous afternoon. The trap consisted of a block of dry ice, a light, a fan and a collection net. At night, mosquitoes are attracted by the carbon dioxide, in the same way they are attracted by the carbon dioxide exhaled in the human breath.
The tiny light then draws them above the net, where they are sucked in the bag by the swirling motion of the fan. On this morning, about 2 dozen angry-looking mosquitoes buzzed about the tiny net.
The technicians know that only the adult mosquitoes will bite, and that they must keep their catch alive for it to be valuable for any study. So they gingerly emptied the trap, looking for the Culex tarsalis or anopheles breeds, whose bites are known to cause malaria and encephalitis, which attacks the membrane around the brain.
Nearby, they also captured two wood rats and a field mouse that had found their way into traps overnight, attracted by the barley, peanut butter and honey Graham cracker bait.
“We got us a customer here,” Damos said as he retrieved the tiny metal trap, carrying both unhappy rats to the pickup truck nearby.
There, as passing joggers looked on in curiosity, the back of the truck became a tagging and recording station as the technicians drugged the beady-eyed rodents with ether and then brushed them free of gnats, ticks and fleas.
The technicians say it is important not only to release the territorial rodents, but to replace them exactly where they found them. They let them go--even if potentially dangerous insects are discovered hiding in their fur--because the fleas and ticks left in their burrow would only move into the fur of the next resident.
“Before we started the vector control and surveillance team, we could only play catch-up with this problem,” Shoemake said. “Now, we can be more proactive, to nip situations in the bud before they become problems.”
The surveillance team was founded two years ago, after the County Board of Supervisors adopted the powers of a vector control district, authorizing workers to enter private property and increasing their funding.
Ortiz said the recent outbreaks of several diseases, including malaria and encephalitis, convinced county officials to take a more aggressive approach to the problem.
Since 1988, when the number of reported cases of malaria contracted within the county reached an all-time high of 30, the figures have dropped off to six in 1989 and one in 1990.
“Surveillance of this kind is not new in San Diego County, but in the past we could only accomplish it in certain areas and not year-round,” Ortiz said. “But now we have the resources to stay on top of this. California has a history of outbreaks of malaria and the plague. This program is a symptom of the awareness to the spread of these diseases.”
Shoemake said the work of surveillance teams has already turned over valuable information about the tick that is believed to be responsible for Lyme disease, which has surfaced in 17 cases here since 1982.
“The accepted research is that these ticks are only found at elevations above 3,000 feet,” he said. “But we’ve found them all over the place. And we’ve been able to warn park authorities and campers and hikers to the danger of their presence.”
Within the course of an hour, the technicians had harvested several traps as well as raked a nearby field for ticks using special sheets of material. They were ready to move on to the next trap site.
The two rats and mouse that were rendered unconscious with ether only a short while earlier were now scampering about their temporary cages, ready to go home. And Paul Damos was ready to take them there.
“For me, this is one satisfying job,” he said. “I get to see all kinds of beautiful areas of the county. At the same time, I have the feeling at the end of each day that I’ve done something for the people of the community. And that makes me feel good.”