Is it an Epidemic?
In the midst of a rise in reported human cases of Lyme disease, many New England infectious disease experts are calling Lyme an epidemic in this area. But what is Lyme, why is it increasing in frequency, and how can we protect ourselves and our pets? We’re going to do a series of articles to help answer some of the most frequently asked questions about this disease.
Lets talk about Lyme
Lyme was first noted in Connecticut in 1975 (in the town of Lyme…let’s not even talk about how much it would stink to have your town’s name become the name of a disease. What if the next dread disease was named after your town? Where do you live? Rabies, New Jersey.)
The bacteria causing Lyme disease is called Borrelia burgdorferi. It is what is called a “vector-borne disease” – this means that it cannot be directly transmitted from one animal to another. It has to first be transmitted via a tick (the “vector”). There are other diseases that behave in a very similar fashion to Lyme (Anaplasma, Ehrlichia, Rocky Mountain Spotted Fever), and may be passed within the same tick or different tick species.
In humans, Lyme is reportable – in theory this should mean that we have a pretty good idea of how many cases are occurring. But a lot of factors have to fall into place for this to work – so IF it is properly diagnosed and IF the attending physician is aware of this and IF they remember and IF they have time, the CDC knows about the case. For this reason we think that the reported number of cases of Lyme far underestimates the actual numbers. Here is the CDC’s incidence map of Lyme, which gives you an idea of the geographic spread.
In dogs, the geographic distribution is very similar. The cases are not reported to any centralized agency, so actual case numbers are unknown. These maps are based upon positive cases documented by one of the major diagnostic labs in the country: map of Lyme disease in dogs.
So, to recap: Lyme disease is a pretty recent discovery. It occurs nation-wide but has a much higher prevalence in the Northeast, Southeast, and Chicago area. And we think it’s occurring a LOT more in both people and dogs than current reporting shows.