Responses
Sorry, I feel like this isn't the one but I got reminded of this one that I think you might enjoy http://www.mangago.zone/read-manga/emerging/mr/emerging/1/
Parasyte
No that’s not it, but that one is one of my favourites! The two of them are quite similar if I remember correctly.
Also not it, but that one is still a very good read!
It was about a disease/parasite that was like a worm or something and I think it started killing by messing with peoples’ eyes. The main characters were two police officers/detectives and one was male while the other was female.