Posts Tagged ‘Five-lined Skink’

A few years ago, I wrote a post called Lizards, Ticks, and Lyme. It explained how Western Fence Lizards (Sceloporus occidentalis) have a blood protein that kills the bacteria that causes Lyme Disease, and this is one of the major explanations of why Lyme Disease is so much less common in the Western USA.

Well, new research (see references at the end) has added a really intriguing facet to the Tick-Lizard-Lyme story. This new research focuses on the southeastern USA. The southeast is another area where Lyme Disease rates are very low. But why? The southeastern USA has populations of Black-legged Ticks (members of the genus: Ixodes), which are the ticks that can carry Lyme Disease. The region has the mammal species such as deer and mice that act as reservoirs for Lyme Disease. People in the southwest get bitten by ticks, just like other parts of the country. So why is Lye Disease so much more common in the northeastern USA than the southeastern?

Well, once again, it looks like we can thank lizards. Skinks are a group of smooth-scaled rather lovely looking lizards and they are one of the preferred hosts for ticks in the southeastern USA. In the northeastern USA mice are the much more common host to ticks. And this sets up a roadblock for Lyme Disease in the southeast because skinks have been shown to be really bad transmitters of Lyme Disease. Mice, on the other hand, have been shown to be very effective transmitters of Lyme Disease.

A Southeastern Five-lined Skink (Photo credit: Animal Spot)

It is not yet known if the stinks blood contains proteins that actually kill the Lyme Disease-causing bacteria, or it there is something else about skinks that reduces transmission rates, but this difference in host does help to explain why Lyme Disease rates are so much lower in the southeastern USA as compared to the northeastern USA.

So, fence lizards and skinks both contribute to reducing Lyme Disease in the areas where these lizards are found. Pretty fascinating stuff! I am very much looking forward to learning more about this subject as more research is done. Do other lizard species also reduce the occurrences of Lyme Disease? Does skink blood kill the bacteria that causes Lyme Disease? What is the blood protein that the fence lizards produce that kills the bacteria, and can it be synthesized? So many questions!

I hope you follow this story, and are as intrigued by it as I am. I will certainly write more as more is discovered.

Here are some sources for further reading: a Science News article, and an SF Gate article.

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