Not the same man

latent vampirism...

Yeah, I think that's how reservoirs work, but I'm not a public health expert.

Natural reservoir - Wikipedia

(en.m.wikipedia.org)

imagine having to explain at the vampires anonymous meeting that you got it by cleaning out your bird feeder.

I think you'd have to at least have an open wound and come into contact with fresh blood since it's a bloodborn pathogen.

...do we know that? maybe vampires just have really bad dental hygiene

I think vampirism being a bloodborn pathogen is the consensus.

could be a fungal infection

Yeah, as long as it's bloodborn.

well if it's fungal it could have other methods of transmission that aren't documented due to lack of study. like you know how brazil nut allergy can be triggered through fluid exchange

Maybe. Further study is definitely needed.