Western Fence Lizard (Sceloporus occidentalis). Photo courtesy of Jocelyn Knight.
There is a small lizard that lives all across the western USA that has a superpower! The lizard is the Western Fence Lizard (Sceloporus occidentalis) and the superpower is that it can kill Lyme Disease. This is not a new story, by any means, but it is a great one. It is also a reminder that there are amazing things to discover in our back yards, and that we gain amazing benefits from unlikely parts of the natural world.
So, the story is this. A person in Connecticut is about 100 times more likely to get Lyme Disease than a person in California. Why is this true? This was a puzzle for scientists and public health specialists.
Female Black-legged Deer Tick (Ixodes scapularis). Photo courtesy of Innovative Pest Management.
Many possible ideas have been examined. Is it because there are more ticks in Connecticut? No, there are lots of ticks in both states. Well, only certain species of tick can carry Lyme Disease, so maybe those species occur in Connecticut but not California. No, the species of tick, members of the genus Ixodes, occur in both states. Ok, where do the ticks get Lyme Disease from, maybe the reservoir for the disease is only found on the east coast, but not the west. Nope, the disease is commonly found in many species of mammal, deer particularly, and these animals are found all across North America. Well, maybe people in the two states are not getting bitten at the same rates for some reason. No, the numbers of bits per 100,000 individuals is about the same. But, for some reason, when a person is bitten by a tick in California they very rarely get Lyme Disease.
It turns out that this is because most ticks in California (and I am talking about the members of the genus Ixodes that can carry Lyme Disease, here) don’t actually carry Lyme Disease very often. They can, but they generally don’t.
An entomologist at the University of California, Berkeley (Robert Lane, Ph.D.) figured out why they don’t back in the late 1990s. It turns out that one of the common hosts of ticks in the western USA are Western Fence Lizards and Western Fence Lizard blood contains a protein that kills the Lyme Disease causing organism (a bacteria called Borrelia). In lab tests, Borrelia bacteria that was placed in mouse blood would survived for about three days, but Borrelia bacteria that was place in Western Fence Lizard blood died in one hour! (On a bit of a side note, when I was a kid my family and I actually did some field collecting for this project. When we went hiking in the east bay hills, we would save the ticks we found on ourselves or the dog and take them in to UCB.)
So what happens is that any time a tick bites a Western Fence Lizard, the blood that the tick drinks kills off all the Borrelia in its system. If that tick then goes on to bite you, it has no Borrelia to pass on to you and you do not get Lyme Disease. Pretty cool, right? One of the big, unanswered questions is what protein, exactly, in Western Fence Lizard blood is so lethal to Borrelia?
So, next time you see a Western Fence Lizard say thanks for the Lyme Disease protection. The next time you find a tick on you, don’t panic because it probably has been drinking blood from a Western Fence Lizard and so has no Lyme Disease to give you, unless you are back east in which case you should probably watch for possible Lyme Disease symptoms.
abirdingnaturalist 
This information is NOT true and contributes to unnecessary chronic illness for many people, which is nothing short of cruel. To say there is no Lyme disease from ticks in California prevents people from seeking treatment early, which is the ONLY way to not be left with debilitating symptoms. Lyme has been found in tick collections in 2016 at Folsom lake, and is well known to exist on the coast, as well as other areas in the state. Some areas are more prevalent than others, but it exists. I know people who have sought treatment for YEARS for the horrific symptoms caused by Lyme, who finally get tested and are positive. Lyme disease is horrible, I know first hand how this bacteria destroys your life if treated after long term exposure. You can also die from Lyme carditis, and neuro Lyme. Bad info to say don’t worry if bitten.
Hi Peggy,
I am sorry if got the wrong impression from my piece, but nowhere do I say that there is no Lyme disease in California. I do say that it people in California are very unlikely to contract Lyme disease, as the numbers of ticks that are actually carrying the Borrelia in California are very small. That is true.
I also say that if a person is bitten by an Ixodes tick, they should not panic. That is also true, as they are in very little danger of contracting Lyme disease. I do not say that there is no danger at all. Near the beginning of my piece, I say that rates of Lyme disease are something like 100 times higher in Connecticut than they are in California. That statement alone, which is also true, acknowledges that there are Lyme disease rates in California, just that they are not panic worthy rates.
Of course, it is terrible for anyone who contracts Lyme disease, but there is, to the best of my knowledge, no false information in this post.
Sincerely,
Aaron
https://www.google.com/amp/sacramento.cbslocal.com/2012/01/26/placer-county-warns-residents-about-ticks-with-lyme-disease/amp/
https://www.lymedisease.org/touched-lyme-hikers-think-twice-sitting-rocks/
Aaron, your information regarding the western fence lizard is interesting, however California has been varied climate and terrain. There are pockets with higher incidences of Lyme than in other areas and the state can’t be lumped into one category with equal exposures. My biggest issue with the article is where you say if you are bitten by a tick you only need to worry if you live in Connecticut. Awareness needs to be a priority in all states, including California. Many people are suffering in California due to misinformation and poorly trained doctors. I personally am aware of several. Are you aware that ticks carry other bacterial Co infections? These can also cause serious illness if not treated. Everyone bitten by a tick needs to have the tick tested and be alert for symptoms of Lyme. They should not have a false sense of security because they don’t live on the east coast.
Hi Peggy,
To take your comments in order…
I never say that exposure is equal across California. What I say is that California, as a whole, has lower incidents of Lyme Disease than states in other parts of the county.
That is true.
I do not say that Connecticut is the only state that has Lyme disease. And while I agree that awareness should be advocated for in all states, some perspective is also appropriate. If someone is bitten by an Ixodes tick in California the odds are very low that they will get Lyme disease.
That is also true.
Of course ticks can carry numerous potential infectious agents. I did not title my post ‘Lizards, Ticks, and Disease’; I titled it ‘Lizards, Ticks, and Lyme.’ That is because I am only discussing the fascinating relationship between Lizards, Ticks, and Lyme.
That relationship is also true.
Now to respond to the links you provided. The one from CBS Sacramento clearly states that eight ticks tested positive for Lyme in Placer county. That is all. Eight ticks. I like those odds. Next time I go hiking in Sacramento County (which I do a lot), I am not going to be too worried about contracting Lyme disease.
As to the Touched by Lyme site that you sent, I have other issues. It is not so much the information, but the presentation.
Statements like, “The ticks were only tested for the pathogens associated with Lyme disease—Borrelia burgdorferi and Borrelia miyamotoi. (Who knows what nasty co-infections might be lurking in them as well?)” Really only serves to invite people’s imaginations down a dark and scary path. Not necessarily a true or accurate path, just one that gets a strong knee-jerk reaction. It has a whiff of fear mongering to it.
Beyond that, statements such as, “And where did they find the most nymphs? ROCKS! In fact, one researcher found 34 nymphs on one rock alone.” and “Specific data hasn’t been released yet, but one slide shown at the meeting indicated 22 different spots where infected nymphal ticks were found within a swath about 400 yards long. All within sight of a residential house and swimming pool.” show clear bias.
How many times were 34 nymphs on a single rock? What numbers were other researchers finding? What was the average number of nymphs found on any given rock? And the same can be said of those 22 infected ticks found along the 400 yard swath. The simple fact that specific data has not been released makes it clear that a conclusion drawn the data available so far may very well be inaccurate.
And pointing out that the 400 yard swath was within sight of houses and pools is again going for the knee-jerk sensationalism.
One part of the Touched by Lyme site that I do like is the canine map that they link to (http://www.dogsandticks.com/diseases_in_your_area.php) which clearly shows that California (while having some hotspot areas) has much lower Lyme disease rates than pretty much all of New England and parts of the mid-west.
Should we all be careful? Sure. But there is only a small amount of danger of Lyme disease from ticks in California.
And that is true as well.
Sincerely,
Aaron
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