There can be no argument that the incidence of tick borne diseases is exploding; Lyme, Babesiosis, Human Granulocytic Anaplasmosis, Powassan Encephalitis, and other very bad things.
https://www.cdc.gov/ticks/diseases/index.html

The why is of course dependent on one's agenda ie "it's climate change and we only have 12 more years to live" smirk
Interesting short articles suggesting that forest fragmentation with increasing populations of white-footed mouse may be part of the culprit, and we might be to blame
https://www.nsf.gov/news/special_reports/ecoinf/lyme.jsp
https://www.johnshopkinshealthreview.com...me-so-prevalent

Why Lyme is exploding a California is unclear...oh, it's climate change too! frown
https://www.ucsf.edu/news/2018/05/410401/lyme-disease-rise-expert-explains-why