Explaining jokes is always lame, but sometimes necessary it seems ;) Putin as many of you probably know, is a true 100% man that is not afraid of anything. Here we can see he's saddled his most dangerous foe yet - the ebola virus.
You're welcome :)

Putin rides viruses and doesn't afraid of anything.

So, is there an actual punchline, or is the joke just how manly Putin is supposed to be?

Explaining jokes part 2
the punchline is Putin riding the virus. He's done so many manly and awesome stuff before, it's only natural he's looking for more dangerous challenges.
It gave me a chuckle ;)

wut
need moar context