Lyme disease is under-reported in animals in Montana (and everywhere), as it is in people. But, interestingly enough dogs are routinely tested and treated in areas where people are not. Many people have treated their dog for Lyme disease where I live, which is why it catches many people off guard to hear that the CDC still claims that Lyme disease has not and cannot be contracted by humans here.
The number of reported cases each year in Montana on the CDC’s Lyme disease reporting table is no longer zero, but there is an asterisk and a note that all Montana cases were contracted elsewhere. This is primarily because current diagnosis guidelines (initially intended only for reporting purposes, but now erroneously used diagnostically) would preclude a patient who contracted Lyme here from being considered for potentially having Lyme disease in the first place (since they did not travel, which is poor logic that keeps any of us as from being documented as the “first” Montana-contracted case).
If you piece together information available from state and federal health agencies, you will read the claim that Montana does not have deer ticks (but wouldn’t you think they have supporting data to display?), followed by claims that only deer ticks transmit Lyme to humans (which is refuted by peer reviewed studies) and that the species of ticks that transmit Lyme to dogs can’t transmit Lyme to humans (which is not supported by fact and is also directly refuted by peer reviewed studies).
Even though drastically under-reported in dogs, as for people, hundreds of canine Lyme disease cases have been confirmed in my area (hard to say a number based on their key, and this is 2007 to present). The shaded area (Flathead County) on the map for my zip code (59912) includes the drainage where I was bitten (due east of the red pin on the map) and all of the districts I work on….so that my “office” for the past decade or so has been roughly half of this shaded area.
I also stumbled across this article, about a dog recovering from Lyme in the town where I live.
Another data base with a somewhat better interface (also allows you to see sample size and positive cases by state and county):