New research underway on Lyme-infected ticks

06/01/2017

Lyme disease is often considered an East Coast problem, but ticks in California also carry the bacteria, Borrelia burgdorferi, that causes the disease, if at lower rates—and late spring is when Californians are most likely to get infected. 

“It’s endemic in Marin for sure,” said Dan Salkeld, a professor at Colorado State University who researches ticks and Lyme. “We’re definitely in peak season right now.” 

Lyme disease can spur a rash, fevers, headaches and exhaustion. If left untreated—which experts believe it often is—joints and the nervous system can also suffer, according to the Centers for Disease Control. The agency reports that Lyme is the fastest-growing vector-borne infectious disease in the country.

Most cases in California are reported in the north; Marin ranks 11th of 58 counties for rates of confirmed Lyme, with Mendocino topping the list. According to a report from the California Department of Public Health, 98 cases were confirmed in California in 2015. Nationally, there are roughly 30,000 cases reported annually, though the C.D.C believes the real number of cases is closer to 300,000. 

Bringing awareness to the fact that Lyme disease exists in California is critical, said Linda Giampa, president of the Bay Area Lyme Foundation. She said the nonprofit, based in Portola Valley, started in 2012 because physicians who didn’t realize the disease existed in the state were misdiagnosing patients. 

Now the group is funding research projects across the country. “Our goal is to find a cure for the disease,” Ms. Giampa said.

Research in the past couple of years has revealed more detailed information about Lyme and the species that carries it on the West Coast—the western black-legged tick—in the Bay Area. 

A study conducted in 2014 by Dr. Salkeld and the California Department of Public Health in Napa, Sonoma, San Mateo and Marin Counties found that young ticks, called nymphs, can be active for longer than previous research in Mendocino had indicated. 

Though Dr. Salkeld found that nymphs were the most active between April and June, they can be active from January to October. 

That information is important because nymphs are more likely than adults are to pass on the disease. Partly that’s because of their size: though adults are often compared to the size of a sesame seed, nymphs are closer in size to a poppy seed.  “The danger is that they will bite you and you won’t even notice,” Dr. Salkeld said. 

The longer an infected tick feeds on a person, the more likely it is to pass on the disease. Most cases require a tick feeding on a person for 36 to 48 hours. 

Nymphs are also more likely to carry the Lyme bacteria, which ticks acquire from host animals like mice and lizards. 

In 2015, the Marin/Sonoma Mosquito Vector Control District found that 8.1 percent of nymphs tested in Marin carried Lyme, compared to only 2.4 percent of adults.

And more information will be coming soon, specifically about the presence of the Lyme bacteria on the Point Reyes peninsula. 

Dr. Salkeld is in the midst of analyzing ticks he collected last year in Point Reyes, as well as other areas like the Headlands and Olompali. One of his goals is to compare the presence of the bacteria in different environments, such as wooded areas and chaparral.

The Bay Area Lyme Foundation is also conducting a citizen science project. In early 2016, it called on people to send in ticks for free testing. The group expected to receive 1,400 samples, but ended up with about 10,000 from 49 states. Thirty percent came from California. 

The group plans to publish a heat map of the United States sometime this year.

The foundation is still accepting ticks for the free testing. “We’re going to compare 2016 to 2017,” Ms. Giampa said.

In the meantime, the Marin/Sonoma Mosquito Vector Control District encourages people to use a tick repellant and avoid contact with nymph habitat—leaf litter, logs and tree trunks, in particular. You can tumble clothes in a dryer for 10 minutes to kill ticks, and always check yourself carefully after possible exposure, especially in the areas ticks are often found: the groin, armpits and scalp.

But for many, the bite that brings Lyme will go unnoticed. 

Dylan Flynn, an Inverness resident, grew up roaming outdoors in San Anselmo, where ticks were a constant. Later, working as a facilities manager at Slide Ranch, he also may have gotten a bite. 

It was there, at the ranch, that his symptoms first appeared—though it was not readily clear what was causing them. 

In 2012, Mr. Flynn’s right knee swelled up “like a grapefruit,” as he put it. He thought he had torn something, and an M.R.I. showed that he did have a torn meniscus. 

After months of aching and swelling that was so bad he was on crutches at times, Mr. Flynn went in for surgery. But the surgeon said things didn’t add up—the pain and swelling didn’t match the level of the tear—and took a sample of fluid from the knee. “He said, ‘There is something strange going on here,’” Mr. Flynn said.

The surgeon ordered a titer test, which can detect antibodies produced by the immune system in response to Lyme. Luckily for him, Mr. Flynn said, the test showed a clear case of Lyme (it often doesn’t) and he had no trouble getting treatment. 

After he took two rounds of antibiotics, Mr. Flynn’s symptoms finally cleared up. The damage to his knees is permanent, however, and blood tests are unable to show whether the disease is still alive inside him. 

“I’ve felt good for about four years, but I always wonder, when things come up, if it’s a Lyme symptom or a symptom of any number of things,” he said.

Mr. Flynn learned a lot about Lyme in the last several years. People’s views on it are wildly divergent, from government conspiracy theories to the belief that eating Western fence lizards can cure you. 

The blood of those lizards, often called blue-bellies, contains something that neutralizes the Lyme bacteria, Dr. Salkeld, the researcher, said. 

“No one is absolutely sure what that factor is, but if an infected tick feeds on a western fence lizard, then the [Lyme bacteria is] destroyed,” he said. “And lizards feed a lot of ticks. It’s one of the reasons that Lyme is rarer in California than it is in the Northeast.”