(Reuters) - Wall Street's slide deepened on Monday as the rapidly spreading coronavirus forced more U.S. states into lockdown, eclipsing optimism from an aggressive policy easing by the Federal Reserve and putting the S&P 500 on pace for its worst month since World War Two.After cutting interest rates to near zero and offering to buy more Treasury bonds and mortgage-backed securities, the Fed will now lend against student loans and credit card loans, as well as back the purchase of corporate..