The amazing western fence lizard. (Robert C. Stebbins / Houghton )
What if ticks were an endangered species? Would we preserve critical habitat for them? Fund a captive-tick breeding program? It would be hard for me, as a hiker and dog owner, to summon any sympathy for these disgusting little pests. If they were gone, would the greater environment miss them in any way?
Just a fantasy. Ticks are, of course, thriving and a new report from the U.S. Centers for Disease Control finds that they are, in fact, responsible for 10 times more Lyme disease than previously thought — 300,000 cases a year nationwide. The report has been used by the Lyme community — and I’m not talking about the town in Connecticut but people who say that the disease is intentionally underdiagnosed and undertreated — as justification for their arguments. But the study doesn’t appear to say that Lyme isn’t being diagnosed, just underreported to authorities. In fact, the researchers got their figures largely by looking at insurance claims and lab test results. Though of course with this many cases, it’s also probably that many cases of Lyme are missed. Just to complicate things, the researchers say many people are diagnosed with Lyme who don’t have it.
The CDC report might lead health authorities to accelerate the research and approval of a Lyme vaccine. Promising results were found earlier this year on one vaccine under development. That would be a popular item in prime Lyme disease territory, largely the Northeast and northern Midwest states where up to 30% of deer ticks carry the infection. Almost all cases of the disease — 96% — occur in 13 states.
California isn’t among them, and one reason for that is that we have, in a sense, our own little natural vaccine program going. In this state, nymphal ticks’ favorite host is the common western fence lizard, which has a protein in it blood that kills the bacterium responsible for Lyme. As a result, few adult ticks are carriers.
The situation is a little more complicated than it seems. A 2011 study found that reducing lizard populations appeared to reduce tick populations too — in other words, they didn’t take to other hosts very easily. But that study, though intriguing, is limited in size and scope. What happens if over time, without their favored host, evolution favors ticks that are happy to switch to, say, wood rats (which came in as second choice among ticks in the study)? So far, the lizards have kept California’s endemic Lyme disease very low, though it does exist here.
No, California is better off sticking with what nature provided us. Here’s a bumper sticker for our Lyme-riddled time: Save the lizards.
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