- Italy orders businesses to close, tightening its lockdown.
- Stocks plunge in the absence of clear plans from world leaders.
- This is a global pandemic, the W.H.O. says.
- Washington, Kentucky, New York and other states move toward stronger measures.
- “It is going to get worse,” a leading American scientist says.
- Labs see new supply shortages as testing demand soars.
- The N.C.A.A. bars fans from March Madness.