No, you cannot cancel your upcoming cruise because there was recently an outbreak of Norovirus on the ship.
Unfortunately, fear of contracting Norovirus is not a covered reason to cancel on standard travel insurance. Fear of traveling is never a covered unless you have the Cancel For Any Reason upgrade on your policy.
Cancel For Any Reason is a limited benefit that allows you to cancel for reasons not typically covered, but requires that you cancel at least 2-3 days prior to your scheduled departure and will only reimburse 75% of your trip cost.
If you contract Norovirus before your trip, you can be covered to cancel. If you get sick with Norovirus while on your trip, you can be covered under Emergency Medical, Trip Interruption and Medical Evacuation benefits.