Personally, I think it's all the coyotes fault.
Deer overpopulation is a major factor, you can also blame global warming.I also wonder why now there are so many. Back in the stone age when I was a kid, we never heard of ticks in this area. They started popping up around 25 or so years ago.
http://healthypets.mercola.com/sites/healthypets/archive/2013/06/14/tick-borne-illness.aspxVery cold winters spanning several months have traditionally killed off tick populations in the U.S. Ticks are hardy creatures. It takes lengthy periods of low temperatures around 10°F to accomplish a winter kill of tick populations. If daytime temperatures reach 40°F, even if it’s much colder overnight, ticks can remain active. In the last 20 years or so, winter weather across the country has grown milder. As a result, ticks once found only in the southern states have moved north. Even snowfall doesn’t insure a tick die-off, because ticks can survive under a blanket of snow. And there are species of ticks, like the black-legged tick, that actually thrive in cold weather.
Another huge factor in the spread of ticks is wildlife. Birds, coyotes and deer transport ticks from one location to another, and once they are dropped off in a new area, smaller animals like mice, chipmunks and shrews move them around in the new location.
Conservation programs have dramatically increased populations of white-tailed deer in the U.S. In addition, coyote populations have also seen huge increases in the last few decades. Coyotes prey on the red fox, and the red fox preys on rodents that harbor infectious ticks. Where coyotes are present, red fox are not, and tick populations flourish.