Does Website virus = Sandbox?

I've been working on a client website and making steady progress with it. After a week it went from not being found to #50 for the chosen keywords.

Unfortunately the site picked up an html-script-inf virus. It was caught fairly quickly and cleaned but now the site has dropped in the rankings like a stone.

Will Google de-rank you for something like this? If they do is there any chance of recovery? Has anybody dealt with this before?

Thanks,

Chuck

they will mail you if they found a virus on your website
you can submit your site for reconsideration after removing the virus

That's unfortunate, never even though about the possibility of that.

Submit the website for reconsideration if the virus has been removed and tell them that it was not your fault and how you also got messed up due to the same. Normally it is re-indexed if it was not the webmaster's mistake.