In Blue Velvet (1986) Dorothy says these words to Jeffrey Beaumon after making love to him:
I have your disease in me now.
I am thinking disease means related to STD. Am I thinking correct?
It's meant to be intentionally ambiguous. The Director, David Lynch, left it undefined so that people could relate to it more. It means what you want it to mean. It does not specifically mean an STI. It could mean love.
Regarding the sentence "He put his disease in me." in Blue Velvet:
"Just the word disease used in that way – it's so beautiful just to leave it abstract. Once it becomes specific it's no longer true to a lot of people. Where if it's abstract there could be some truth to it for everybody."
-"Lynch on Lynch", the ticket into the world of David Lynch edited by Chris Rodley.