Ticks, Lizards and Lyme Disease

A blacklegged tick (Ixodes scapularis) questing with legs reaching as it waits for a host to pass by. (Centers for Disease Control and Prevention)

Hikers beware. According to the latest April 2012 issue of Veterinary Practice News, we may be in for an unusually abundant tick season and therefore a greater chance at contracting some hideous tick-borne disease.

“An unseasonably warm U.S. winter not only has meant non-stop tick-sightings, it could mean a boom in the parasite population this springor sooner, parasitologists say. This correlates with a higher prevalence of tick-borne diseases in dogs and humans.”

Ticks, the parasitic scourge of the forest. I wonder how many ticks I’ve plucked from my skin and swept from my clothing through the years. Loads. While walking trails I’m constantly feeling my beltline for these detestable vermin, where they routinely accumulate. Once in awhile, I’ll spot them clung to the ends of grass along a trail questing with their legs outspread and waiting to hitch onto passing animals for a feeding.

It amazes me, and it seems uncanny, how many times I’ve woken at night, and in the dark confines of my tent felt around with my finger tips, and extracted one of the tiny buggers from my body before it chewed its way into my flesh to suck my blood. The last tick bite I suffered a couple of months ago left behind a two-inch in diameter red, sore rash for nearly a week. I still have a small purplish-red spot at the site of the bite, which occurred within inches of, uh, well, let us say some sensitive male equipment. It was one of the worst reactions I’ve had thus far.

Scanning electron micrograph of tick mouthparts (University of California, Davis). The center serrated rod is what the tick pierces into the flesh of the host to suck its blood. Not only do the serrations make the parasite harder to remove, but most hard ticks secrete a cement-like substance from their salivary glands that effectively glues them in place while feeding.

Ticks are vectors for numerous affections one of which is the painful, debilitating Lyme disease. It’s caused by a type of bacterium and is found in North America, Europe and northern Asia. The disease took its name in America from the Connecticut town of Old Lyme, which is near where it was first found in the United States.

In one study, fifty percent of adult ticks tested in the northeastern United States carried Lyme disease, while in California the rate was remarkably less with only 1.3 percent of tested adult ticks carrying the disease. In California there exists a rather neat phenomenon that occurs between ticks and lizards, which is thought to dramatically lower the rate of Lyme disease found among adult ticks in the state. Western fence lizards unwittingly rid ticks of the disease causing bacteria.

Engorged ticks feeding on a western fence lizard or “blue belly.”

Forty-nine species of ticks are found in California. Among those, two in particular are considered the main vectors of Lyme disease, the deer tick and Western black-legged tick (Ixodes scapularis and Ixodes pacificus). These particular parasites are known as three host ticks, which means they feed on three hosts during their life cycle. They feed mostly on lizards and rodents during their subadult stage and larger mammals when mature.

During the first feeding as a nymph, if hosted by a Western fence lizard, all the Lyme disease causing bacteria will be killed. The lizard’s blood effectively rids the tick of the bacteria it harbors.

“The lizard’s blood contains a substance – probably a heat-sensitive protein – that kills the Lyme disease spirochete, a kind of bacterium,” Robert Lane, professor of insect biology, was quoted as saying in the Berkeleyan, a newspaper for the staff and faculty at University of California, Berkeley. The blood-borne protein transfers from the lizard to the tick and, working through the tick’s system, permanently cleanses the parasite of the disease causing bacteria.

Even when bitten by a tick carrying Lyme, people may be able to avoid contracting the disease by removing the parasite quickly. According to the CDC:

“If you remove a tick quickly (within 24 hours) you can greatly reduce your chances of getting Lyme disease. It takes some time for the Lyme disease-causing bacteria to move from the tick to the host. The longer the tick is attached, the greater the risk of acquiring disease from it.”

Ben Edlund’s cartoon creation, The Tick.

Bibliography:

Lizard May Act as Lyme Disease Panacea, Kathleen Scalise, Public Affairs, April 29, 1998

Ticks Commonly Encountered in California, Larisa Vredevoe, Ph.D, Department of Entomology, University of California, Davis


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13 Responses to Ticks, Lizards and Lyme Disease

  1. Yet another reason to love lizards! Great post!

  2. beechcreekproject says:

    Informative post. Never knew lizards got ticks. One of the only things I dislike about hiking here in Oklahoma and Arkansas is the ticks. After a long day of hiking, it’s home for a shower and tick inspection. I got lucky today and found none. Not so lucky last week when I had several that had to removed after getting home from hiking. Safe hiking to you and hopefully you will stay tick free.

  3. trailblogs says:

    Reblogged this on trailblogs and commented:
    Great information on scourge of the forest!

  4. Pam says:

    That is really interesting! I saw ticks once lined up along a trail at Elkhorn Slough (north of Monterey). When I was driving home I felt one crawling in my clothing. I about drove off the road trying to fling it off of me!

  5. EMW says:

    Well, I can’t resist this. Here now is an appearance by the spiral villain who causes all the trouble (to engage in a bit of anthropomorphic excess), my old friend Borrelia burgdorferi: http://www.flickr.com/photos/95019575@N00/7033791695/
    I once worked in a building where the floors where painted white and all corners were smooth and rounded so escaped ticks could not hide.

  6. J M Naszady says:

    I have had a few close encounters of the tick kind. Yuck. Thanks for the informative post!

  7. Coyote Dave says:

    I was on Santa Rosa Island during the first weekend of March where on a 3-hour day hike up Water Canyon I removed close to 50 ticks from my clothing and body. One of the buggers dug in and left a similar mark and the scab still persists a month later. I pondered at the end of my day hike if the recent eradication of deer and elk has left them without their main food source and exacerbated the tick problem.

  8. Nico says:

    Interesting tidbit of info about the western fence lizards and their ability to strip ticks of their lyme disease carrying capacities. Didn’t know about that.

    I got bit early this year… January. Poking around off trail up around the rock band along Hurricane Deck. Didn’t find the tick until I got home. Pulled him off but the little red scar is still there. Wasn’t expecting ticks to be out that early in the year; I tend to think of them as more of a spring phenomenon.

    Worst tick encounter ever was probably last spring up in Big Sur. Did a quick overnighter on a brushy trail that hadn’t been hiked for at least a week prior. My poor pup and I were constantly having to stop and do a major tick check/removal exercise. Bixby got the worst of it being in front and being at grass level. I’d estimate I pulled over 100 off him over the course of the hike on day 1 and probably 40 off me. Nasty little things. Luckily (as far as ticks go) the overnight and next morning rain seemed to send all the ticks off to hide (at least temporarily) and we were able to get out without anymore hitch hikers.

  9. You would creep me out tonight. Now I’ll be thinking that ticks are crawling over me while I’m sleeping….

  10. Very informative. I’ve had to remove some of these little creatures from my dogs but fortunately not from me. Thanks for the scoop!

  11. Loren McFarland says:

    I picked up a tick at Los Cruces and within 3 hours he was so attached his bite actually hurt. Even when I saw him in the mirror it was so red ( with the tick in the middle) that I mistook it for a branch stabbing wound. It was quite difficult to pull him off. Here is a link to the CDC on how to properly remove ticks. http://www.cdc.gov/lyme/removal/index.html

  12. Carol says:

    Got a tick recently at Will Rogers State Historic Park, probably while pulling down some German Ivy. Due to another injury nearby, and difficult-to-see location, didn’t realize it was a tick for over three days; Drat! Mouthpart stayed in while trying (as recommended) to pull it out, so went to the Doctor next day. After being stabbed with increasingly sharper forceps, he admitted defeat, said it didn’t matter anyhow, and gave me a prescription for a one-dose antibiotic. The pill cost $1.17, the Doctor visit was $197. No rash resulted, and within a couple of weeks the mouthpart had worked its way out. A month later there’s still a purple disc about 1/4 inch in diameter at the bite site. Within a day or two of the bite, it was very painful, so if you have a very painful area, check for a tick. Very few cases of Lyme Disease are reported from California, so I’m hopeful that the proactive antibiotic will work if my tick wasn’t deactivated by a Fence Lizard.
    Thanks for the link to the CDC site; they have lots of good information.

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