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Each no bigger than a poppy seed, a host of minuscule critters lurks in Northern California woodlands, loaded with bacteria capable of inflicting misery on campers, hikers and picnickers who take to the woods this spring. 

The western black-legged tick harbors the spiral-shaped bacterium that causes the dread Lyme disease, named for the Connecticut town of Old Lyme where the affliction was first recognized in the mid-1970s. 

Though the bacterium wasn’t identified until 1982, UC Berkeley professor Robert Lane says evidence now indicates the disease had been around for millennia. 

“Californians who had it in the 1800s and 1900s were misdiagnosed with rheumatoid arthritis or neurological disorders,” said Lane, who teaches in the Division of Insect Biology of UCB’s College of Natural resources. 

Lane and two other students of insect biology are the authors of a study in the current issue of the Journal of Insect Etymology. 

But where Lane is concerned, don’t call ticks insects. “They’re arachnids, eight-legged animals like spiders, scorpions and mites. And of all the arachnids, ticks are the most significant carriers of disease,” he says. 

Officially, Lyme disease strikes about 100 people a year in California, and 17,000 to 18,000 nationally. “But a lot of cases go unreported by doctors, so the actual numbers are probably several times higher.” 

While California cases are concentrated to the north of San Francisco Bay in Mendocino, Humboldt, Trinity and Lake counties, the tick is no stranger to the East Bay, 

“We’ve found them in Tilden Regional Park in the 1990s,” Lane said. “We looked in picnic areas and along the trails and found the rate of infected ticks to be very low, less than one percent to zero. We later look for nymphal ticks, which are so small they’re very hard to find, and on one trail slightly less than six percent of them carried the disease.” 

The nymphal—infant—ticks are the size of poppy seeds, between 1/25th and 1/20th of an inch long, he said. 

Lane’s been studying the critters for decades. His first job after receiving his doctorate from UCB in 1974 was looking into ticks for the state health department. Then, in 1982, Willy Burgdorfer, the discoverer of the Lyme disease organism which bears his name—B. burgorferi—invited Lane to join his team. 

Two years later, Lane joined the Berkeley faculty, where he set up a program to study the epidemiology of the disease, which he’s been doing ever since. 

Lane, graduate researcher Denise Steinlein and Jeomhee Munn, a UCB insect biology research specialist, are spreading the word about how not to catch the debilitating disease. 

They earned their expertise the old-fashioned way, by trekking into the black oak forests of southeastern Mendocino county and finding out just which behaviors produced the greatest tick exposures. 

The highest risk comes from sitting on logs in California’s hardwood forests. “We sat on logs for only five minutes at a time, and in 30 percent of the cases, it resulted in exposure to ticks,” Lane said. Second in risk was leaning against a tree, which produced tick exposure 23 percent of the time, followed by gathering firewood, which also gathered ticks in 17 percent of their trials. 

Once the nymphal tick contacts skin, its small size makes detection difficult, he said. 

Once Lyme disease was discovered, researchers found it and its close bacterial kin scattered across the temperate regions of the Northern Hemisphere, Lane said. “It’s particularly common in Central Europe.” 

Lyme disease isn’t the only tick-borne infection. The spotted fevers were known much earlier, and are caused by rickettsia bacteria. 

While pharmaceutical companies once manufactured vaccines for both Lyme disease and Rocky Mountain spotted fever, slow sales and lawsuits triggered by side effects in a small number of patients ended their production, Lane said. 

The ailments can be treated by antibiotics, with good outcomes likely when the ailments are diagnosed early, Lane said. Later diagnosis can result in ongoing affliction. 

Tick season starts in April, and the arachnids become abundant in late April and on into May. The season can extend into August in higher elevations and in more northerly latitudes. 

The creatures love leaves and moisture, although sitting in fallen leaves produced exposure in only eight percent of their trials. 

Lane said the high risk from log sitting may result from their use as favored perches by the western fence lizard, a favorite host for the ticks. The relatively high exposure rate on the Tilden Regional Park trail likely stemmed from another host, the wood rat. 

Genetic tests are most commonly used to diagnose the disorder in humans, and a new test is currently in development. 

“We really want to get the word out about risky behaviors,” Lane said, “and now’s the time to do it.” ›