The latest norovirus outbreak aboard the Princess Cruises' Crown Princess has infected 172 people, according to the U.S. Centers for Disease Control and Prevention.

At least 158 of 3,009 passengers and 14 of 1,160 crew members came down with the virus aboard the Crown Princess during a 28-day cruise that docked in Los Angeles on Sunday.

This ship had sailed from Los Angeles to Hawaii and Tahiti.

Are cruise ships floating petri dishes?

Onboard rapid norovirus testing resulted in positive results of the virus, the CDC investigation update confirmed.

Cruise ship mishaps 10 photos

Cruise ship mishaps 10 photos

More than 200 passengers and crew became ill with possible norovirus on Royal Caribbean's Grandeur of the Seas during a cruise that started January 24.

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Cruise ship mishaps 10 photos

During a fall 2014 sailing, 158 passengers and 14 crew members became ill with norovirus on Princess Cruises' Crown Princess. The ship's passengers were also sickened during an April 2014 sailing.

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Cruise ship mishaps 10 photos

A federal judge ruled Carnival Cruise Lines liable and responsible for the engine fire that left the ill-fated Triumph cruise adrift in the Gulf of Mexico in February 2013. More than 4,200 passengers endured power outages, overflowing toilets and food shortages.

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Cruise ship mishaps 10 photos

A norovirus outbreak aboard Princess Cruises' Caribbean Princess sickened 181 passengers and 11 crew members during a late January 2014 sailing.

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Cruise ship mishaps 10 photos

Nearly 700 crew and passengers fell ill aboard Royal Caribbean's Explorer of the Seas in January 2014. It is the highest number of sick people reported on any cruise ship in two decades, according to the Centers for Disease Control and Prevention.

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Cruise ship mishaps 10 photos

In 2013, the Silver Shadow, run by Silversea Cruises, failed a CDC health inspection over concerns about hiding food in crew cabins.

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Cruise ship mishaps 10 photos

On Memorial Day 2013, a fire aboard Royal Caribbean's Grandeur of the Seas cut short a seven-day cruise to Port Canaveral, Florida, and the Bahamas. The ship changed its course and sailed under its own power to Freeport in the Bahamas.

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Cruise ship mishaps 10 photos

The Carnival Dream, shown here at its North American debut in November 2009, lost power in March 2013, and some of its toilets stopped working temporarily. For a time, no one was allowed to get off the vessel, docked at Philipsburg, St. Maarten, in the eastern Caribbean.

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Cruise ship mishaps 10 photos

During a surprise visit in August 2012, CDC inspectors found multiple sanitation violations on the Holland America ship ms Veendam (shown here in March 2012). The CDC found enough violations, including brown liquid dripping on clean dishes and a fly on the buffet, to give the Veendam a failing grade.

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Cruise ship mishaps 10 photos

A fire in the Carnival Splendor engine room in November 2010 crippled the cruise ship, stranding passengers off the coast of Mexico for several days without air conditioning or hot showers.

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EXPAND GALLERY

"Over the last few days, the ship began seeing an increased number of gastrointestinal illnesses, caused by norovirus (commonly referred to as the stomach flu)," said Princess Cruises spokeswoman Susan Lomax, via email. "In response, we have enacted our stringent disinfecting protocols developed in conjunction with the U.S. Centers for Disease Control (CDC), which includes an extensive deep cleaning of the ship and the terminal in Los Angeles on Sunday before the ship embarks on its next voyage."

The CDC statement confirmed the ship has implemented CDC sanitation procedures to slow the disease's spread. The cruise line also made announcements to notify onboard passengers of the outbreak, encouraging hand hygiene and case reporting. Passengers about to board the ship were also supposed to be notified.

At least 122 of 3,161 passengers and 30 of 1,176 crew members aboard the Crown Princess were sickened on an April sailing, according to the CDC. The federal agency blamed norovirus and E. Coli for the outbreak.

Norovirus is known for being quite contagious. It causes nausea, vomiting and diarrhea and is believed to have infected passengers on a number of cruise ships this year.

"As it is the cold and flu season, when the stomach flu circulates on land, we encourage all of our guests to be diligent in following the widely accepted practices of frequent hand washing with soap and water and the use of hand sanitizers," said Lomax.

Is your cruise safe?

In February, 114 passengers and 10 crew members took ill on the Holland America cruise ship MS Veendam during a weeklong voyage.

In January, more than 600 people on cruise ships sailing in the Caribbean fell ill from the virus, the CDC reported.

How the Navy avoids norovirus

Norovirus infects many people on land, but health officials track it on cruise ships, leading to more frequent reporting of cases, the CDC said.

It is passed in person-to-person contact and can spread more easily in closed quarters.