Acorns, mice and the climate pushing debilitating infection into Canada-
Ten or so years ago we were writing about brucellosis in the forerunner to this newspaper. Later when anti-wolf activists tried to scare people about worm infections we examined that issue and found there was little to worry about. In following these political disease controversies, we found that there are a number of serious diseases that people often do acquire outdoors and are related to wildlife and livestock. They are ignored to considerable degree because special interest groups can’t use them to “grind their axe.”
Lyme Disease is one of them. It is growing into a major disease as it spreads from state to state and northward.* Lyme Disease is transmitted by the deer tick which finds a host in mice especially and of secondary importance white-tailed deer.
Now a big surge northward is expected for Lyme Disease because 3 conditions are just right for it. They was a record acorn crop in 2010, followed by boom in mice in the summer of 2011. The large number of mice resulted in growth in the number of deer tick nymphs. Unfortunately for the mice at present, the record acorn crop was followed by a very poor crop, so the mice population is crashing just as a large number of derr tick nymphs are maturing and looking for the blood meal they need so to reproduce. The ticks are finding fewer easy sources (mice).
Humans will do fine though. Ticks don’t mind. This year will require special precaution. A short article in Scientific American online gives the details. Lyme Disease Pushes Northward. The spread of the tick-borne disease may result in an increase in infections. By ClimateWire and Umair Irfan
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* Lyme Disease has not spread strictly from state to adjacent state. There are a number of states, such as western Oregon, with Lyme Disease but are well away from the center of the infested area.
Comments
Stay away from man-made forest openings of ten acres of less if you can. This is the preferred habitat of the white-footed mouse, the main carrier of lyme disease. There are many orchards and other bits of failed farmland across the north country that allow for this sort of thing.
Keep out of tall grass especially. Those in old growth areas have less to worry about when under the canopy.
It does seem then that ticks are associated with disturbance rather than a stable habitat.
Cleared area, white-footed mice, whitetailed deer are all the products of disturbance.
That’s a talking point when the news begins to focus on Lyme disease this summer.
Deer ticks and their associated infections have been on the march for decades. They travel between properties on the backs of mice, to new neighborhoods on deer, and considerably greater distances on birds. The abilities of these ticks to perpetuate and thrive are linked most closely to deer abundance. The intensity of pathogen transmission does, indeed, rely upon the stability of the mouse population as well as that of that of the deer tick population. The link with prior acorn abundance is interesting, but not full embraced by others in the Lyme disease epidemiology community. Time will tell.
Regardless of the intensity of infection, readers should note that finding and promptly removing ticks (from a person or pet) can dramatically reduce risk of infection. Once the tick has been removed, have it identified. Only certain kinds of ticks can transmit the agents of Lyme disease, babesiosis and anaplasmosis. Other ticks may transmit other infections. The longer the tick is attached, the greater the risk of infection. Physical samples can be sent, or digital images uploaded, for a rapid, confidential, independent and expert evaluation. For more educational information and help with identification, visit IdentifyUS LLC.
Richard Pollack, PhD (IdentifyUS LLC)
Good site Richard.
Never use to see ticks in my area until a neighbor bulldozed parts of his property for a subdivision (removing a lot of sagebrush) Wondering if sagebrush may have been a natural toxin/barrier for ticks?
I found an article that just noted an acorn crop failure in 2004 in Massachusetts, and likely the Northeast. I checked the MA Dept. Public Health website and saw that there was a 47% increase in Lyme disease from 2004 to 2005. I think that Rick Ostfeld is spot on.
Surge might be too strong of a word. The cases of Lyme disease out in the dry western part of the country are still quite rare and usually associated with a trip back east. The ticks that transmit the disease just don’t like living around here.
http://www.aldf.com/usmap.shtml
True, the west is much, much better for lyme disease. The wetter parts of California do have it, though.