Years ago I read about the hantavirus. It was mainly in the south west(New Mexico and I think Arizona)perhaps a few other nearby states. It seems the mice that carry it have found their way into California. The very hot weather may have driven them there. When I read about it then,it was rare,and seemed to die out. I think we may see a lot more(The west Nile virus) for one,and it may be our climate changes will alter habitats and insect populations may grow larger. There is(at least on the east coast a fungus that has greatly reduced the bat population here) another fungus is killing many species of frogs. It might turn into a cascading effect with our animal population.
We have invasive species that have no natural predators and are becoming problematic(kinda like the Rabbits did down under).
Check out this site and some explanation of what is happening even though the title is a bit tree hugger sounding,it does make its point. Title "apocalypse-now"
http://www.piquenewsmagazine.com/whistler/apocalypse-now/Content?oid=2316760 A quote from the story. "Aquatic and terrestrial ecosystems are on the edge globally. As evidenced by a preponderance of lethal, once-rare fungal diseases in organisms as diverse as coral, trees, frogs and bats — fungi that co-evolved with these organisms for millennia and only recently become pathogenic — the proverbial shit has hit the fan."