The Centers for Disease Control and Prevention (CDC) has extended its no-sail order potentially cancelling cruises because of the coronavirus until early July.

The order issued late last week covers all overnight vessels with passenger and crew totals of 250 or more which affects some of the smaller U.S.-flag ships as well as the foreign-flag behemoths operating in “international, interstate, or intrastate waterways” subject to U.S. jurisdiction.

Cruise lines have already stopped cruising or postponed start and restart dates.

“Cruise ship travel markedly increases the risk and impact of the Covid-19 disease outbreak within the U.S.,” CDC said. The order extends for another 100 days or until the virus is no longer considered a public health emergency. The March 14 order was for 30 days.

“The measures we are taking today to stop the spread of Covid-19 are necessary to protect Americans,” CDC Director Robert Redfield said in a statement.

Approximately 100 cruise ships remain at sea off the East, West and Gulf coasts with nearly 80,000 crew onboard, CDC said. Additionally, it “is aware of 20 cruise ships at port or anchorage in the United States with known or suspected Covid-19 infection among the crew who remain onboard.”

The order requires cruise lines to develop a comprehensive plan approved by CDC and the Coast Guard to address the coronavirus outbreak through “maritime-focused solutions” including a response with limited reliance on government support.

U.S.-flag American Cruise Lines (ACL), the largest U.S.-flag overnight operator with 12 ships on inland and coastal waters, suspended cruises through May 31. It is on schedule to debut the third in its modern riverboat series, American Jazz, later this year in New Orleans.

ACL’s ships “are all under 190 passengers, but we have suspended all cruise operations for the safety of our guests and crew,” the company said. “As we have for over 30 years, American will continue to make all decisions in accordance with the best interests of those who travel with us.”

U.S.-flag American Queen Steamboat Co., with three overnight vessels, has suspended operations through May 16. A fourth vessel, American Countess, was to be christened in New Orleans early this month.

The trade group Cruise Lines International Association (CLIA) said CDC was singling out the industry “which has been proactive in its escalation of health and sanitation protocols” and was one of the first to voluntarily suspend operations. “The fact is cruising is neither the source or cause of the virus or its spread” and comparable land-based businesses don’t have the same reporting requirements.

Dale DuPont has been a correspondent for WorkBoat since 1998. She has worked at daily and weekly newspapers in Texas, Maryland, and most recently as a business writer and editor at The Miami Herald, covering the cruise, marine and other industries. She and her husband once owned a weekly newspaper in Cooperstown, N.Y., across the alley from the Baseball Hall of Fame. A South Florida resident, she enjoys sailing on Biscayne Bay, except in hurricane season.