It seems like they’re linked because they are, but one didn’t cause the other, rather they are symptoms of the same thing: over population. This heightens the effect of global warming, as well as the chance that some idiot would eat some wildlife that was itself sick. I mean, in the last 20 years we’ve had about 8 diseases come from interacting with animals, because there is just too many humans. (MERS, SARS, HIV, Ebola, H5N1, Zika, Bird Flu, Swine Flu)
TL;DR: not done on purpose. Both due to over population.