Ships are breeding grounds for disease-causing viruses, and one of the most common of these is the notorious Norwalk virus, or norovirus.

''You need to be careful [on board],'' says Jean Fleming, a registered nurse who is clinical director of infection prevention for Nice-Pak Products, which makes sanitary wipes. ``You can get norovirus and MRSA (a common staph strain) from high-touch surfaces such as handrails, elevator buttons, door knobs and computer keyboards.''

Her advice:

• Wash your hands frequently.

• Carry hand sanitizing wipes with you. She says wipes are better than gels.

• Wash your hands before eating.