So: what’s your state’s Lyme Disease history? What do you mean, you don’t know? If you’re worried about the illness (and well you should be), then learning the incidence of local Lyme Disease cases in recent years should be one of your first steps toward protecting yourself.

Warning Sign "Tick Infested Area"

Lyme Disease History is more prevalent in some states

There was a time when it was actually pretty tough to investigate the prevalence of Lyme Disease — or most other illnesses, for that matter. But thanks to the rise of the Internet, it’s a snap these days.

Your First Stop

While we disagree with the Centers for Disease Control about some aspects of LD and its pervasiveness, the CDC does an excellent job of keeping track of reported cases. That’s why your first stop should be at their site, where they track Lyme Disease reports by month, year, state, age, gender, and even symptom.

There are all kinds of charts, tables, Q&A’s, and reports about LD on this site, as well as maps. Like this one, which graphically illustrates cases for the entire United States for the year 2009 (the latest year for which complete data is available).

This is a very basic map, but as you can see, the cases cluster heavily in the northeast and Great Lakes regions. No surprises there.

Here are cases charted by state from 1995 on through 2008.

Note that physicians are reporting more and more LD cases each year, probably because it’s becoming easier for them to recognize the disease.

The LDA Map

The Lyme Disease Association has kindly compiled CDC data from 1990-2008 into a case map for the entire time period, which the CDC hasn’t. You can see the LDA map here. If you click on individual states, you’ll get little pop-ups that list out the cases by year, along with the 18-year total for each state.

This is an excellent map to use with the CDC sources listed above, since it gives you the most up-to-date history possible. In addition, the LDA site also has maps plotting cases by year and incidence (per 100,000 population), though these aren’t clickable by state.

Going to the Dogs

As you’re probably aware, LD can also strike dogs and cats. Apparently no one has mapped out the problem for cats, since it seems to affect them fairly rarely, but there is a very good dog Lyme map available for the U.S. and Canada.

Note that this map tracks LD co-infections as well as LD itself. As one individual has pointed out on the MedHelp site, it seems that veterinarians have a better grasp of LD and its co-infections than the human medical community does. Apparently vets are more willing to work together on the issue.

Note also that you can click on the map to drill down to the county or division level, which you can’t do with the human case maps.

Yeah, So?

Why are we even bothering with a canine LD map here? Because there remains the possibility that, despite medical doubts, people can get LD from the same ticks that bite dogs, not just the Ixodes scapularis and pacificus populations known to infect humans. Who can be sure at this point?

And note that some areas that have very low human LD infection rates (and no native Ixodes scapularis and pacificus populations) have high levels of canine LD, most notably Colorado.

Better safe than sorry, as the saying goes. Even if there’s only a vague possibility of infection, you should be aware of your state’s Lyme Disease history, human and otherwise.