Cartman squirts his blood into Kyle's mouth. Blood transfusions normally cause serious problems when not cross matched, but Cartman has the same blood type as Kyle, as stated in "Cherokee Hair Tampons." Because of this, Kyle suffered no problems from ingesting Cartman's blood.
Kyle states that Aids isn't funny even though Aids had been officially declared funny in the season six episode "Jared Has Aides".
This is the second time that Cartman has infected Kyle with something related to HIV and the AIDS virus. In the Episode 406, Cartman Joins NAMBLA, when playing Investigative Reports funtime game with Bill Curtis, Cartman gives Kyle AIDS as a card within the board game.
GOOF:The older grey hair scientist says at one point that the cash seems to prevent the HIV cells from stabilizing. This is scientific nonsense as HIV is a virus not a bacteria and therefore is not made up of cells
While Principal Victoria is explaining Cartman's situation to the teachers and the boys, you can see Mr. Adler sitting amongst them.
Butters: I just, eh. Well.. I don't know if I should be helping you make Kyle look silly.
Cartman: Butters. Helping People who have AIDS, is one of the most important things you could do.
Butters: I know, but are you sure Kyle has to be taught a lesson?
Cartman: I'm not just sure, butters. I'm H.I.V. Positive.
Butters: Oh yeah, eh. I guess that's true.
Cartman: Of all the times to get AIDS, I get it right when everyone stops giving a crap.
Liane: Just calm down honey..
Cartman: F*ck you mom! I have f*cking AIDS!
Announcer: I'm pleased to announce that there is no trace of the HIV virus in either Kyle Broflovski or Eric Cartman. Together these boys beat their illness, with nothing but each other and overcoming all odds, these two brave friends...
Kyle: Oh Stop! we are not friends! He's the one who infected me with AIDS!
Announcer: ... These two brave lovers found the cure and helped the world. And so, to honor these boys, here is: Jimmy Buffett!
Cartman: What? Oh No!
Cartman: F*ck you Jimmy Buffett! You f*ckin suck!
Butters: How're you doin' Eric? You know, I think you're a real special little guy. And even though you have AIDS, I ain't gonna act any different towards you. (Kisses Cartman's cheek)
Cartman: ...God dammit, this SUCKS ASS!!
Ticket Guy: Are you boys sure you don't have any money?
Cartman: We're not just sure..we're HIV positive.
Denmark: August 1, 2008 on TV3
Latin America: March 2, 2009 on MTV Latinoamerica
Though not a direct allusion; the way Cartman contracts HIV in this episode is similar to how British actor Denholm Elliott (Best known for his role as Marcus Brody in the Indiana Jones series) contracted the disease himself, through a accidental transfusion of blood infected with HIV. Denholm died of AIDS-related tuberculosis in 1992.
The two songs Jimmy Buffet sang at the AIDS benefit and at the AIDS cure benefit were parodies of his hit songs "Margaritaville" and "Cheeseburger in Paradise."
Cartman's hat and scarf were in reference to the movie Philadelphia in which Tom Hanks played a lawyer with AIDS.
Leave it to Beaver:
The happy music cue that is played during the transition from the hospital to the school is very similar to the one in Leave it to Beaver.
"Two brave little buddies who against all odds have journeyed across America to find a cure for AIDS; all they have is each other in a race against time." This is an allusion to the 1995 Brad Renfro film, The Cure.