Lyme disease risk is year-round in Northwest California, according to new study

Excerpted from the EurakAlert: (08/19/2014)

SILICON VALLEY, Calif., August 19, 2014 — Bay Area Lyme Foundation, which aims to make Lyme disease easy to diagnose and simple to cure, applauds new research published in an upcoming issue of the Elsevier peer review journal Ticks and Tick-borne Diseases. The findings show that ticks that carry Lyme disease in Northwest California are active throughout the year, making the threat of Lyme disease year-round. The research was conducted by researchers at California Department of Public Health (CDPH) Vector-borne Disease Section and University of California, Berkeley (UC-B).

“These results are critical as they offer proof that it is possible to become infected with Lyme disease in the Bay Area at any time of the year,” said Linda Giampa, Executive Director, Bay Area Lyme Foundation. “It underscores the need for residents to take precautions year-round and know the symptoms of the disease. While the threat in Northwest California is lower, it’s more constant than the Northeast USA.”

The findings suggest that the timing of peak tick activity of Western Black-legged ticks (Ixodes pacificus), which are the ticks most commonly known to carry Lyme disease in Northwest California is largely predictable and year-round. In general, tick larvae (young ticks) are active April to June, and sometimes activity extends into October, while adult ticks are active from October to May. From January to October, nymphal ticks (which are younger and smaller than adult ticks but older than larvae) become active.

Interestingly, the highest reported incidence of Lyme disease in humans in Northwest California correlate to the times when the younger, smaller ticks (nymphal I. pacificus), which are smaller than a poppy seed, are most active.

“Based on these results, tick season in Northwestern California is longer than even we expected and quite different from patterns in the Northeast USA,” said Daniel Salkeld, PhD, a Public Health Biologist formerly with the California Department of Public Health (CDPH) Vector-borne Disease Section, and currently a Research Scientist, Colorado State University. Dr. Salkeld was an author of the recent study published in a journal of the Centers for Disease Control (CDC) that found that ticks carrying the bacteria that cause Lyme disease, are widespread in the San Francisco Bay Area, which was funded by Bay Area Lyme Foundation. He is now supported by the Bay Area Lyme Foundation to continue research into the ecology of ticks and their pathogens in California.

Compounding the growing problem of Lyme disease in northwestern California is that the host animals that most commonly carry Lyme disease are also active throughout the year and often live for extended periods of time, compared to host animals in the Northeast United States. In the Northeast, few white footed mice, the host animals that most commonly carry the bacteria that causes Lyme disease in that region of the country, live through the cold winters. By contrast, the host animals that most commonly carry the bacteria that causes Lyme disease in California, western gray squirrel and dusky-footed wood rat often live longer than one year and can carry the bacteria throughout the year.

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~ by Rob on August 20, 2014.

3 Responses to “Lyme disease risk is year-round in Northwest California, according to new study”

  1. Staggering and scary; so many people remain unaware of the particulars and spread of this horrid disease. In Canada, it’s finally getting some attention, but there’s still a long way to go. Yet – there lives hope in that fact.

    • BMT,
      You’re so right. For those of us that have been afflicted for years, it seems inconceivable to fathom the millions out there that aren’t aware of the risk. Well for the moment, EBOLA will be on most people’s minds even though contracting c LD is the much greater risk.

  2. I know for a FACT the California CDC map should look like the upper US afflicted , reported cases States. California is a State in infectious disease denial. As a 57 year old Native first bitten in the mid 60s near Redding California (known bite, with classic symptoms never linked to the bite) , and thereafter about 4 or more times, I’m fairly certain I’m a “lifer” but I will never know. Might donate my body to science, AD…which is what SHOULD be done, testing post mortem. My 92 year old Dad, I also think is a “lifer”. I brought up Lyme disease possibility with his various doctors and specialsts…I was ignored, had eyes rolled at me, I was nervously giggled at. The VA doctors took notes (ah the government/military) and…not a ONE suggested taking a western blot to rule out Lyme disease. DENIAL, running scared. My Dad exposed from birth or early childhood has lost his hearing, is now blind in one eye, and has borderline dementia, yet he made it to 92, almost 93!

    I think tick infection is generational and has affected ALL my kin, and American immigrant ancestors for generations all the way back to Europe. (due to their farming lifestyle, exposure levels, land areas of occupation) Why do some people suffer so severely, others not so much? might have to do with repeated exposure, diet, genetics, ancestry.

    Post mortem testing…should become a standard in cases of dementia, severe illness, blindness, deafness, and so on. Blood and synovial and brain tissue. We are taking “secrets” to the grave. As a Native I also remember how long it took HIV/Aids to come to light,….an infectious disease should be treated like one….too late, for “Borreliosis” aka Lyme Disease, and it’s co-infections..!!I can tell you for CERTAIN, my backyard, is a TICK HAVEN. Birds, Squirrels, Rats, Deer. At least I have possums, sweeping the yard of ticks.

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