Ticks looking for blood on California beaches: Is Lyme Disease A Rising Risk: Millions of people enjoy hanging out on California beaches during the warmer months. Ticks also transmit Lyme disease. And the risk of the disease is rising.
It was found during four years of fieldwork in California's San Francisco Bay Area and nearby wine country which implicated almost 3,000 western black-legged creatures. The frequency of these ticks surprised tick biologists and experts, in part because it was unclear which animals they spread. Their preferred mammal host, the western grey squirrel, does not visit the seaside grasslands. How ticks survive, feed and reproduce in coastal areas remains a mystery, said Dan Salkeld, a ecologist at Colorado State University in Fort Collins who conducted the study.
The research has not yet been published but it is important for assessing whether Lyme disease, a tick-borne infection, is on the rise in the Bay Area. Linda Giampa, president of the Bay Area Lyme Foundation said she has little doubt that the disease is having a major impact. The number of ticks is increasing everywhere, Giampa said.
But others, including Salkeld, said it was difficult to determine long-term trends. Looking for patterns in human cases over the years is not simply due to annual fluctuations; the picture is complicated by climate change, changes in awareness and surveillance of Lyme disease, et cetera, he said. It is also difficult to determine a specific trajectory of human cases.
In contrast, surveys in Mendocino, Sonoma, Napa, Marin, Santa Clara, Santa Cruz and Monterey counties show a 4% incidence of the bacteria that causes Lyme disease in ticks in woodlands, grassland, beaches and scrub land. And California has a much lower incidence of disease-transmitting ticks than other parts of the country, especially on the East Coast, where about half of all ticks are carriers.
"I know where it is," Giampa said, citing an ongoing study her organization is funding in Southern California. The hotspots are Malibu, Manhattan Beach and Newport Beach.
Early symptoms of the disease include fever, chills, fatigue, muscle pain and swollen lymph nodes. Left untreated, Lyme disease can lead to arthritis, swollen joints, facial paralysis, heart irregularities, encephalitis and nerve pain. The disease can be treated with standard antibiotics.
The Centers for Disease Control and Prevention estimates that about 476,000 people develop Lyme disease each year. Most cases occur in the Northeast, the Mid-Atlantic and the upper Midwest.
It is common for East Coast doctors to prescribe antibiotics to patients reporting tick bites. But in California, it has not been investigated or found, and recognition is lagging behind. California's Giampas group is trying to make up the difference by funding research like Salkelds to better understand the behavior and ecology of western black-legged ticks, and by studying the occurrence of Lyme-causing bacteria in ticks.
The organization sponsored a citizen science study in which people across the country collected ticks and sent them to a laboratory in Arizona for analysis. Between 2016 and 2018 the team examined more than 21,000 ticks from 49 states and found ticks in 24 states able to harbor Lyme disease, including previously unknown populations of western black-legged ticks and deer ticks, the most common hosts in the East and Upper Midwest. Seemay Chou, a biochemist at the University of San Francisco, is working together with Salkeld and others to study other diseases in ticks, including viruses.
"We are trying to promote other microbes in ticks in the Northern California region to detect and detect tick-borne diseases. As the tick footprint expands, it is crucial to know the footprints of infectious ticks, according to the researchers, who advocate a specific slang term to describe arachnids looking for blood and food.
Richard Ostfeld, an ecologist at the Cary Institute for Ecosystem Studies in Millbrook, New York, says humans have created an environment in which ticks and their hosts can thrive. On the east coast, where Ostfeld most does his research, the mouse is an ideal host for deer ticks because deer ticks love the suburbs. But on the West Coast, black-legged ticks prefer lizards and squirrels, and new research suggests there are unidentified hosts that populate beaches and scrub. Ostfeld and Salkeld say lizards are unlikely to be among them because they carry biological agents that neutralize bacteria.
Ostfeld says he wouldn't be surprised to find ticks in the ocean, but notes that ticks prefer moist, moist environments. Other researchers say they have heard anecdotal reports that ticks have become more common in the state during the current drought. But beyond that, Salkeld says, he knows nothing.