What's the difference between bird flu and swine flu?

setup: What’s the difference between bird flu and swine flu?

[BILL] qua pigeon qua Colonel Sam Daniels in full space suit PPE This bird died from something. He didn’t just eat too much bread. There’s a virus.

[Shakes] qua pigeon qua Rene Russo in full space suit PPE Can you sign our divorce papers, please?

[BILL] qua pigeon ((MOVES HEAD BACK AND FORTH ON NECK)) Can we do this later? I need to examine this bird? Where is my microscope?

[Shakes] [BILL], you can’t dodge this forever. Please sig-

[BILL] qua pigeon looking into microscope ((COO. COO.)) There it is!

[Shakes] Did you find something?

[BILL] I was wrong. It’s not a virus. It’s Porkidiya. If that bird, ((FLAPS WINGS WILDLY)), had sought tweetment earlier! All he needed was an oinkment.

punchline: One requires tweetment, the other an oinkment.