Monday, May 6, 2013

Rocky Mountain Wood Ticks and Lyme, or something like it

The Rocky Mountain Wood tick is present in Montana.  I read in March that that the RM wood tick is one of the vectors of lyme disease. If this is true or could be true, it is even stronger support that the CDC should drop the diagnostic criteria that patients must have traveled to endemic states so we can start getting real statistics for lyme contracted in Montana. 

This may not sound different than earlier posts, but I've seen since then that the Montana Fish, Wildlife and Parks website had been updated and I had never seen this link (  

I'm pretty certain when I've looked in the past, it said that tick species that carry lyme (usually only black legged ticks are named, but that seems to be changing) are not present in Montana.  It now shows pictures of Rocky Mountain wood ticks.  I first read it to say that they are one of the vectors for lyme disease, but it doesn't say that directly (the other link above does).  Still, kudos to FWP (either for updating the page or for having a better page to start with than I thought they did).  They clearly state at the top of the page that ticks are responsible for a list of diseases in people in Montana; the list includes lyme disease. 

That's still extremely helpful information, either way.  The FWP page doesn't state directly that RM wood ticks carry lyme, but they refer to black legged ticks as the primary lyme vector (rather than the only one) and appropriately do not seem to be ruling out the presence of lyme or the presence of black legged ticks (not yet known to occur here---it seems worth further investigating the range of the western black legged tick, which is only approximately known).

Most of the sites I've found so far don't list wood ticks as lyme disease vectors, but they are listed as vectors for multiple co-infections and other diseases.  Wood ticks are the identified vector for the 'lyme like' disease that has been found in Montana that I've read articles about in the past (written by and/or about cases noted by state epedimiologist Dr. Damrow (I think he has left the sate)).

We have a few species of wood ticks (Ixodes spp.) and dog ticks (Ixodes and Rhipicephalus spp.) and cooley and relapsing fever ticks (Argasidae spp.) which are all vectors for diseases we can catch. Deer ticks (Ixodes spp.) are black legged ticks that undisputedly carry lyme disease.  

Montana doctors insist we do not have any black legged species, but we aren't really looking hard enough to support their absence.  We have wood ticks (soft bodied) which are so far mostly not thought to transmit lyme, but vets are finding and treating lyme in dogs after wood tick bites and some scientists see them as a possible lyme vector.  There is agreement that Rocky Mtn Wood ticks (present here) carry a 'lyme like' disease and other tick born illnesses.  Migratory birds and mammals, lack of large enough scale survey efforts, climate change, and proximity to mapped Pacific tick ranges make it hard to accept that we really know what species we do or don't have here.  I'm not convinced that no ticks in Montana carry lyme disease.

I'm convinced that plenty of people in Montana have lyme; I'm not convinced they all got it somewhere else.

I'm not convinced that Rocky mtn wood ticks carry lyme, but I'm not fully convinced they don't.

But a person can only search for so long in one night, and this person has lyme disease and is going to bed.


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