Wednesday, February 15, 2017

Why Don't Ticks Get Lyme Disease - Science

There's quite a bit of fear of ticks / Lyme Disease and with good reason since it's an evil malady with lots of bad consequences but, in retrospect, there's an obvious question:  why don't ticks get it.  The question is obvious now since the researchers have just asked it but doesn't it seem someone should have thought about this some while ago.  Well, it's easy to criticize so shall we review what they found.  (Science Daily:  Researchers unravel how ticks protect themselves from Lyme bacteria and other microbes)


Scientists had long assumed that the tick immune system works similarly to that of flies and mosquitoes. But ticks, which have existed on the planet for between 120 million and 443 million years, have taken an entirely different path.

Credit: © Vitalii Hulai / Fotolia

- SD

So there's a bloody great picture of one of the most disgusting and reviled creatures on the planet just in case you never saw one before.  Note:  feel free to use that as wallpaper on your computer for your future edification.


For hundreds of millions of years, ticks have survived on Earth by sucking blood from their victims for days, often leaving behind terrible diseases as a thank-you note. But no one has ever looked at why ticks, themselves, are able to survive while harboring bacteria, viruses and parasites. Now, for the first time, scientists have decoded how the ingenious tick immune system fights a myriad of microbes.

- SD

How do you like anthropomorphization so far.  There's nothing 'ingenious' in a tick's immune system but it's highly-effective in preventing this type of infection.  If you reverse the context, our immune systems must be stupid so continue that thinking as you will but maybe let's get to the science of it.


Dana Shaw, PhD, the lead author on the study and a Research Fellow in Dr. Pedra's laboratory, first noticed that ticks were missing crucial genes for a proper immune response.  This observation led to the discovery of an entirely new pathway that recognizes three distinct bacteria: the Lyme disease agent, Borrelia burgdorferi, and two others that cause rickettsial illnesses, Anaplasma phagocytophilum and Anaplasma marginale.  After identifying components of the immune system, Dr. Shaw was able to block the tick immune response with a molecular technique named RNA interference.  She also over-activated the ticks' immune system to get rid of bacteria even more efficiently.  "It's really amazing what one can do in science these days. I am very fortunate to lead such talented and driven scientists in my laboratory and to work with great colleagues at Maryland and elsewhere" says Prof. Pedra.

- SD

Maybe the plan of attack surprises you since it came as a curve to me.  The objective in this science wasn't to transplant any tick immunity to humans to make us safe from infection by Lyme Disease but rather she sought to break that immunity pathway in the ticks so the diseases they spread will kill them too and, presumably, wipe out the problem.

As always, the interested student is invited ... maybe you think you have a better idea so have a go at the article and see where it may lead you.


Note:  pick up with the Great Circle of Life if you like since ticks serve some vital purpose even when we loathe how they do it.  If we wipe them out altogether, there will be consequences.

Ed:  now you go doom and gloom?

Nah, it's common sense.  Mosquitos spread malaria but they also pollinate flowers; it's all the Great Circle of Life.  Ticks probably make my skin crawl more than anything else on the planet but wiping them out is almost certainly a bad idea so what other moves are there.

See above about the interested student.

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