A cruise ship carrying at least 77 people with flu-like symptoms on board is on its way to Fort Lauderdale, Fla., according to a statement from the cruise line. The ship, MS Zaandam, intends to arrive in Fort Lauderdale on Monday, March 30 but cruise line Holland America notes that “plans are still being finalized.”

Holland America Line said in a statement emailed to TIME that, as of Tuesday, at least 30 guests and 47 crew on the Zaandam have reported to the ship’s medical center with influenza-like symptoms.

More than 1,800 people are on board the vessel, including 1,243 guests and 586 crew members.

Holland America Line said in the statement that “since it is flu season, and COVID-19 testing is not available on board, it is difficult to determine the cause of these elevated cases at this time.” In the absence of clear information about who may or may not be infected with the COVID-19 virus, Holland America says it is taking several precautions. Among them: all ill people have been isolated, and their close contacts were also placed in quarantine, the cruise line said.

The Zaandam isn’t the only ship with sick people on board that plans to dock in Florida. Two Costa Cruises ships, with only crew members on board, are trying to dock at Port Miami on Thursday after at least 30 individuals were reported as having flu-like symptoms, a company spokesperson said. Roger Frizzell, a spokesperson for Carnival Corporation, which owns Costa Cruises, told TIME in an emailed statement on Thursday afternoon that “at this point,” the Magica and the Favolosa do not have official clearance to enter from the port of Miami” but they are “attempting to return to port.”

At least six people on the Favolosa and two individuals on the Magica tested positive for COVID-19 in recent weeks after disembarking from the ships in mid-March, according to the Miami Herald. Both ships were in the middle of voyages when major cruise lines announced they would halt operations because of the coronavirus pandemic, the Herald notes.

Guests on Holland America’s Zaandam have been asked to remain in their rooms “out of an abundance of caution,” the cruise line said, noting that Zaandam is following protocols developed with the U.S. Centers for Disease Control and Prevention. Passengers and crew have also been provided with complimentary telephone counseling services, according to the company.

“All ports along Zaandam’s route are closed to cruise ships,” the statement says. Holland America said it sent a second ship — MS Rotterdam — to assist Zaandam and “provide extra supplies, staff, COVID-19 test kits and other support as needed.” Rotterdam left Puerto Vallarta, Mexico, at 3 p.m. local time on Sunday and should meet Zaandam on Thursday evening off the coast of Panama, the cruise line said.

Zaandam left Buenos Aires, Argentina on March 7 on a trip that was supposed to end in San Antonio, Chile on March 21 — but that route was disrupted over coronavirus concerns. Holland America announced on March 13 that it would suspend its global cruise operations for 30 days “due to the continued port closures and travel restrictions surrounding COVID-19 and in an abundance of caution.”

The plan was to end current cruises “as quickly as possible and return guests home.” But Zaandam was not granted permission for guests to disembark in Punta Arenas, Chile, despite previous confirmations that they could, the cruise line said. The vessel instead sailed to Valparaiso, Chile, “where it remained at anchor March 20-21 while taking on provisions and fuel, including regular medications for those that needed them.” It left Valparaiso on March 21.

The CDC has advised all Americans to avoid taking cruises in guidance published on March 8 in an effort to contain the coronavirus outbreak. Older adults and travelers with underlying health issues, such as heart disease, chronic lung disease, diabetes and other conditions that cause suppression of the immune system, should in particular avoid getting on cruise ships, the CDC says.

Write to Sanya Mansoor at sanya.mansoor@time.com.