I am not sure that I can add too much to this thread, but there are certain environmental factors that create these types of issues. Yall hit the nail on the head when you spoke of the drought. Another issue is over-population of ruminants with in a given area and the biggest issue is climate change/shift. I am not a tree hugger or anything like that, but I will tell you that it is proven that the release of Carbon-dioxide into the atmosphere causes the climatic shifts. This is a cycle and a way Mother Nature cleans up a mess we make. Now the effects that we see are actually from China which is in their Industrialization period. Their population is released in the atmosphere but the jet stream carries it to the US. So, with warmer winters and high populations of ruminants coupled with drought you will see several outbreaks. Sorry to hear it is happening but until we figure out ways to minimize the global changes in climate we will continue to see this type of effects on our wildlife.
V/R
Mike