Well, 'close' contact with me - being in the same thread as I am, is one way to catch the typo virus.
The other way is being exposed to my typos one too many times.
Typos of mine that I do without realising it, such as 'teh' instead of 'the'.
It is quite possible you have been infected already.
Your brother had flawless typing once upon a time.
Only one typo in a hundred posts or so.
And then he met me.
Now he can go for a hundred posts, and then have twenty that are typo'd to shreds.
Well, then, I've definitely caught it. Fortunately for me, my English major degree acts as typo-repellant force field against typical typos. I can only hope to develop a booster shot in the laboratory that will protect me from atypical typos....