The agency added that there is no vaccine for norovirus.
Epidemiological data shows cruise ships account for about one percent of reported norovirus cases, despite the high visibility of maritime outbreaks.
"Really, when we have these areas where people … are in really close contact, things like day care facilities, nursing homes and cruise ships, it’s more likely (to be) diagnosed, reported and brought to our attention," said Sarah R.
Michaels, assistant professor at Tulane University’s Celia Scott Weatherhead School of Public Health and Tropical Medicine.
Health authorities emphasize that the virus spreads through contaminated hands and communal surfaces in high-density environments.
"That just means that we've handled something that is contaminated and once it’s on our hands, we do all kinds of things with our hands," said Dr. Robyn F.
Chatman, a family physician in Cincinnati.
Medical professionals note that individuals recovering from norovirus can continue to shed the pathogen for up to two weeks after symptoms clear.
"People who have norovirus can shed the virus for up to two weeks after their symptoms are gone," said Dr. Joanna Turner Bisgrove, family physician and member of the AMA Council on Science and Public Health.
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The 31-cabin National Geographic Sea Bird is currently in its final year of offering expedition cruises in Southeast Alaska.
