The title from the first book made sense when Mac (not a direct quote) says she felt like she was gripped by a Darkfever since coming to Ireland. She could feel the Dark forces even before she knew what was going on. And as she is drawn into the Dark side of Dublin looking for the Sinsar Dubh, she becomes more aware of it.
I think that in the second book, there will be more bloodshed hence the title Bloodfever, since there were (dont remember the exact descriptive number used) a lot of Unseelie that entered from the dolmen at the end of Dark Fever.
I dont know why but I really dont see JB as a Vampire, but i could be totally wrong. I see him more as either fae, Druid,or maybe a mix of both, but that is hopeful thinking.
