Friday, December 5, 2008

Lyme Disease

I do not have it. Let me get this out there right away.

However, if any of you are like my friend KM who lists ticks as one of her top items of fear, you might want to skip this one.

My friend from good old Historical Victorian Brookville, SM, recently suffered her own special bout with Karma. In a trip to Boston to visit a friend a month or so ago, SM and said friend decided to go skydiving. It is estimated that SM may have spent as much as five whole minutes in the grass upon landing from skydiving. She then wandered over and sat on a bench for an additional potential 30-40 minutes watching others. Under the bench, there was also grass type coverage albeit much shorter than the landing area. Over the next few days, she would suffer fevers and rashes and, thinking it was a spider bite, would visit a clinic where she would later learn she is now the proud parent of lyme disease. They caught it in time in that she is not suffering mental effects from the disease but she can look forward to doctor's visits in the future.

Now, I am not a statistician by any stretch of the word but I have to point out how slim the odds are for having spent 45 minutes in a grassy area in Boston and aquiring lyme disease.

Ticks are typically found in woodsy areas. So let's assume in a given area with a typical tick population that SM could encounter at most 11% of the population during her five minutes in high grass and at most another 8% in the low grass area. So SM could have been exposed to 19% of a given tick population in an area.

Ticks have a three feeding two year life cycle. Egg, larvae, and nymph each take several days. Googling "define several" results in: more than 2 or 3 but not more than many. Doing the same for many results in: 11 or more. Therefore, each cycle above is appx. 4-10 days. So for 1.4% of the tick's life it is a nypmh. Now, 70% of all lyme disease cases are from nymphs. So for the other 690 days of a tick's life, it only has a 30% chance of giving my friend lyme disease. As many as 50% of ticks in a high lyme disease area could carry the disease....

SO... 97% chance that a tick during it's lifetime is CAPABLE of carrying lyme disease and a contact rate of 9.5% due to the fact that only 50% of ALL ticks DO carry lyme disease. Now, 9.2% of ticks that she contacted do have lyme disease. Now take the above graph and the lesser likelihood of contraction in October and November coupled with the fact that 40% of 20,000 cases (the average annual number of lyme disease cases and divide by the weighted average. So with my office mate Matt doing some math on his sprinkler calculator...

Well, the odds are that SM is a victim of knowing me and receiving some of my bad karma.


Kimberly Magrini said...

i'm am extremely glad you changed your font to green.

i am also extremely disturbed by this post.

Kentucky said...

one time when I went camping I woke up to find 3 ticks attached to my face. I did not get Lyme's disease.

I am sorry for your friend, glad she caught it in time, though!