Investigation Update on the ms Maasdam

Cruise Line: Holland America Line

Cruise Ship: ms Maasdam

Voyage Dates: December 23, 2011 - January 2, 2012

Number of passengers who have reported being ill during the voyage out of total number of passengers onboard: 56 of 1255 (4.46%)

Number of ill crew who have reported being ill during the voyage out of total number of crew onboard: 6 of 573 (1.05%)

Predominant symptoms: vomiting, diarrhea

Causative agent: Norovirus

Actions: In response to the outbreak, Holland America Line and the crew aboard the ship have taken the following actions:

• Increased cleaning and disinfection procedures according to their outbreak prevention and response plan,
• Made announcements to both notify passengers and encourage case reporting,
• Intensified cleaning and sanitizing of affected staterooms,
• Collected stool specimens from ill passengers and crew for submission to CDC’s Calicivirus lab,
• Made daily reports of gastrointestinal illness cases to the VSP,
• Distributed a pre-boarding health advisory to incoming passengers.

A CDC Vessel Sanitation Program environmental health officer and an epidemiologist boarded the ship on arrival in Ft. Lauderdale, FL on January 2, 2012 to conduct targeted environmental health and epidemiologic assessments and evaluate the outbreak and response activities. Ship crew conducted intensified cleaning and disinfection of staterooms occupied by those who reported their GI illness to the infirmary. Stool specimens were sent to the CDC lab for testing.