Please, help me! I read this years ago and now I can't find this fic.

John, Dean and Sam were on a hunt. I think Sammy got a concussion and Dean got a wound about he didn't tell because he was worried about Sammy and feeling guilty. At the hotel John told Dean to monitor Sam's breathing and left, but when John came back he found Dean asleep. So John woke Dean up, yelled something like "Sammy could stop breathing and you were sleeping!!" Dean was sent to bed and he knew that he actually needed to say something about his wound because the creature they had been hunting was kind of poisonous, but he was feeling guilty and sad so he didn't tell anything. In the morning John woke up to Sammy demanding breakfast. John's first thought: why the hell is Dean not up to take care about his brother?! He called for Dean, Sammy said that he couldn't wake Dean up. That made John worried, he came to Dean's bed and understood that something was really wrong. Then he found the wound, understood that Dean was dying and then he needed to find that creature again because they needed his blood (maybe?) for the antidote to Dean. I think that antidote information came from Bobby... but I'm not sure...

OK, maybe my vaguest request yet. (But I have faith in y'all.) The fic I'm looking for was a series, each section titled with a scientific (biological?) name - possibly various types of bacteria or disease, but I truly can't remember. Anyway, the fic was great, amazingly intelligent, aaaannnndddd - that's all I remember. Except that the writer may have been from the UK and had a background in the science related to the series titles. Can't even be sure whether it was J2 or Sam/Dean.

Please, and thank you.

Okay so Alpha!Jensen was the principal(or just a teacher) and Omega!Jared was a student, and omegas would present to an alpha and they would accept, but whenever an omega presented to Jensen he would refuse so Jared started to like seduce him kinda (but like not really) and he eventually presented around like Halloween or thanksgiving or something, and Jensen accepted and they has sex like right there. Also Jensen was friends with Jared's older brother.

Found:Temptation Comes But Once to a Man, by SloeDjinn

Link: http://archiveofourown.org/works/2201421