New Disease Increases Risk of Tick-Borne Illness in California

CONTRA COSTA MOSQUITO CONTROL 

With fall and winter brings on young active ticks, and with that the risk of disease, according to a news letter released by the Contra Costa Mosquito and Vector Control District.

"In addition to spreading Lyme disease, researchers now say ticks are also responsible for transmitting a previously unknown disease that is related to Rocky Mounted spotted fever," the release stated.

[Related: How Do You Remove a Tick?]

Rocky Mountain spotted fever is a tick-borne disease commonly found in the southeastern United States; but 2008 in California, they discovered a new tick-borne bacterium which is part of the "spotted fever family of diseases." The new bacterium was recorded in four human cases statewide, with two of those cases in Contra Costa County.

[Tips for Preventing Ticks on Your Pets]

The newsletter reads:

The Rickettsia philipii bacterium is transmitted by the Pacific Coast tick (Dermacentor occidentalis), which is one of the three primary ticks that can be found across California.

So far scientists have found ticks infected with this new bacterium in at least eight California counties.

While a small percentage of adult Pacific Coast ticks have tested positive for the disease thus far, researchers find that young nymphs are testing positive as well. This makes prevention very important because these young ticks are very small and very difficult to see. Symptoms can include fever, headache, fatigue and what appears to be a blackened scab at the site of a tick bite.

In addition to the discovery of this new form of spotted fever, California researchers also confirm that the western black-legged tick (Ixodes pacificus) which is the primary tick responsible for spreading Lyme disease in California is also capable of transmitting a newly recognized type of tick-borne relapsing fever caused by the bacterium Borrelia miyamotoi. The symptoms of this illness include a fever that comes and goes, as well as headache and muscle aches. 

As of the writing of this article, there have not been any reports of  humans infected with Borrelia miyamotoi in California, but scientists say the fact that a tick that already exists in California is capable of transmitting this disease makes it more important than ever for outdoor enthusiasts to take the risk of tick-borne illness very seriously.

Using a tick repellent, wearing light-colored long sleeve clothing that is carefully tucked in at the waist and socks, and doing a tick check after exposure to wooded or grassy areas are all important ways to prevent tick bites and reduce the risk of tick-borne illness. Pet owners should consider using a veterinarian-approved flea and tick product on pets that roam outdoors because it can reduce the chance a pet might bring an infected tick home. Pet owners should also perform tick checks on pets as another way to reduce disease risk within a home. 

Prevention is the key to reducing risk from tick-borne diseases. In Contra Costa County, only about two percent of ticks are infected with Lyme disease. With such low risk of disease, there is no guarantee that a person who is bitten by an infected tick will also become infected.

Various studies indicate that the tick must feed on a person for 2-24 hours before any disease-causing bacterium can be transferred. That is why prevention is so important. While tick-borne disease may be unlikely in our county, learn to recognize the symptoms and consult your doctor if they appear after a tick bite.

Anyone who finds a tick on a person should remove the tick by pulling gently, but firmly, with tweezers placed as close to the surface of the skin as possible. The Contra Costa Mosquito & Vector Control District does provide a free tick identification service for county residents, but does not test ticks for disease, as such tests cannot determine whether or not the tick has actually transmitted the pathogen. 

The District can provide a list of commercial laboratories that citizens may contact for tick testing should they be bitten by a tick; however at this time there are no current tests available for the newest tick-borne disease caused by Rickettsia philipii bacterium.

Ticks may be small, but they can make a big impact. Be sure to protect yourself from the old and new tick-borne diseases and remember ticks do not seek people; we enter their habitat. With a few simple precautions, outdoor enthusiasts can take an important step toward a healthy future. 

Read the letter in its entirety here.