Two cruise ships that were on trips to the Caribbean were forced to make an early return to homeport in Fort Lauderdale, South Florida, following the outbreak of the norovirus, which is a highly contagious stomach flu virus.

The Princess Cruise Lines said about 140 of 3,103 passengers and 18 of 1,168 crew members aboard the Crown Princess have come down with the illness.

However, it said about 81 of 3,133 passengers and nine of 1,186 crew members have been affected on the other vessel, the Ruby Princess.

Norovirus, which triggers gastroenteritis, is spread easily by person-to-person contact, especially through items they touch, such as food in buffets, and by water and food contaminated by human waste.

Princess Cruise Lines says will undergo disinfection.