See:
NPR SciFri: Tick Talk: Lyme Disease Under The Microscope
Vancouver Sun: B.C. must act to combat Lyme 'disease explosion,' scientist says
The most common explanation is that warmer winters lead to better survivability and hence a growing range for the disease. I took CDC data from 2001 - 2010 to show the change in reported Lyme disease cases from 2001 - 2010:
The NYT reports on a new study indicating a plausible relationship between coyotes and foxes and Lyme disease carrying white footed mice: Predators, Prey and Lyme Disease
The hypothesis is with coyotes expanding east they are displacing foxes. And since mice are a main component in the fox diet this change in the top predator is contributing to a decline in mice mortality and this leads to more cases of Lyme disease because there are more mice.
Why are coyotes expanding their range to the Eastern U.S.?
[NatGeo: Coyotes Now at Home in Eastern U.S.]
Prior to 1850 coyotes lived in the plains and western U.S.
[via NWF]
While the wolf was top predator for most of the United States
[via NPS]
(the lack of wolves in the southeast United States could be due to this being part of the historical range of Mountain Lions)
Wolves and foxes occupy different niches in the ecological ladder and are able to coexist in a shared habitat whereas coyotes occupy the range between these Canids hence wolves/coyotes and coyotes/foxes compete with each other for the same food with the smaller species the loser in these interactions. By extirpating wolves from their historic range beginning around 1850 humans set the stage for the expansion of coyotes. As coyotes became the top predators the fox populations declined. As this happened the population of the favorite foods of wolves and foxes exploded (deer and mice). As these former prey populations have grown so have their ability to be disease vectors.
The Inter-connectedness of Things
Therefore, the killing of wolves has likely led to a potential lyme disease epidemic.
An unbalanced ecosystem missing its top predator is nudged by the perturbation of climate chaos; and the result is an explosion in cases of Lyme disease.
"The Earth isn't fragile; we are"
