Actually these are old epidemics, but why now?
In England, they're having a resurgence of Rickets, caused by a lack of sunshine, brought about not by global warming, which might be expected to prevent this, but by overly protective mommies who won't let the kids out of the house without a generous soaking in SPF 10,000.
I blame overly protective mommies for the increasing number of asthma cases as well. You moms need to toss your kids outdoors early and often, with the admonition not to come back until dinner time. Let the 6-year-old be the 2-year-old's overseer. This will insure that everybody will be exposed to, or ingest their MDR of dirt, which will serve to strengthen the immune systems. Immune systems are like any other system: Use it or lose it.
Of course there are exceptions to this. There is an ongoing movement among the tinfoil-hat brigades that insists that vaccinations cause autism. Post hoc, ergo propter hoc. Still, if you put on a lab coat, your credibility goes way up with graduates of the public schools, and you get people to go along with this. Coincidentally, we have a budding outbreak of whooping cough in California. I had sort of been hoping that some sort of disease would break out that targeted people with a tenuous hold on reality, which would be devastating on the coasts, but I suppose if the contagion gets bad enough, people will start asking questions.