"Leper at the World Series" joke

A guy with leprosy wins tickets to see the world series. But when he gets there, he has trouble finding a seat because pieces of him are
peeling and flaking off, and he's very concerned about grossing out
the other fans.
The leper wanders through the bleachers looking for a seat where his
grotesque appearance won't disturb anyone else. Finally he finds an open seat where he might be able to watch the game. He asks the man
in the adjoining seat if it would be okay to sit there.
The man answers, "Yeah. Just sit down, shut up, and watch the game."
The leper sits down and adds, "As you can see, I have leprosy. If
it disturbs you, I will move."
"It doesn't bother me. Just shut up, and watch the game."
A while later, during the fourth inning, the man suddenly vomits.
Frothy beer, hot dogs, and peanuts are splattered everywhere.
Seeing this, the leper gets up and says, "Thank you for allowing
me to sit next to you, but I can see that my appearance has caused
you to get sick. I will find another place to sit."
"It's NOT you. Just sit down, shut up, and watch the game."
So the leper sits back down. But during the sixth inning, the man begins to vomit again. This time it is projectile vomitus. A powerful blast of beer and pretzels shoots out from the man's mouth and nose until is stomach is completely emptied.
Seeing this, the leper gets up and says, "Thank you for allowing
me to sit next to you, but I can see that my appearance has caused
you to get sick. I will find another place to sit."
"Really, it's NOT you. Just sit down, shut up, and watch the game."
So the leper sits back down. But during the seventh inning, the man begins to vomit again. This time it is the dry heaves. The leper feels absolutely awful at the sight of this man suffering. And once again, the leper offers to leave.
But the man insists, "Really, it's NOT you."
So the leper asks, "Well if it's not me that is making you so sick,
that what is it?"
"It's that guy behind you. He keeps dipping his nachos in your back."