What happened Shares of Carnival (NYSE: CCL) fell more than 4% on Thursday after one of its cruise ships was locked down due to fears a passenger onboard was infected with the coronavirus. Updated reports out of Italy appear to imply it could be a false alarm, but the incident, if nothing else, highlights the risk faced by Carnival and other cruise lines as the outbreak grows. So what The Costa Smeralda, a ship operated by Carnival's Costa Crociere unit, was blocked from leaving the port of Civitavecchia on Thursday after a passenger from China showed potential symptoms of the coronavirus. The woman was placed in isolation aboard the ship, and the more than 6,000 passengers on board were ordered not to leave the ship while the situation was being assessed. Image source: Carnival. Preliminary tests indicate that the illness is not the result of the coronavirus, but authorities are taking no chances. Shares of Carnival and other cruise ship lines including Royal Caribbean (NYSE: RCL), as well as airline stocks and other travel companies, have been under pressure since news of the outbreak first broke, with investors fearing that the virus at a minimum would eat into the companies' Asian operations and at worst would cause vacationers worldwide to avoid booking cruises. Regardless of whether this passenger does have coronavirus, the images of passengers mulling around on upper decks unable to deboard seem likely to resonate with potential passengers and could make a slowdown in bookings more likely. VIDEO: 🇮🇹 More than 6,000 tourists are under lockdown aboard a cruise ship in the Italian port of https://twitter.com/hashtag/Civitavecchia?src=hash&ref_src=twsrc%5Etfw!function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0],p=/^http:/.test(d.location)?'http':'https';if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src=p+"://platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs");, near Rome, after two Chinese passengers were isolated over fears they could be carrying the https://twitter.com/hashtag/coronavirus?src=hash&ref_src=twsrc%5Etfw!function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0],p=/^http:/.test(d.location)?'http':'https';if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src=p+"://platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); pic.twitter.com/rI3I8AssJq — AFP news agency (@AFP) https://twitter.com/AFP/status/1222886309565329408?ref_src=twsrc%5Etfw!function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0],p=/^http:/.test(d.location)?'http':'https';if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src=p+"://platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); Now what Carnival has suspended cruise operations from Chinese ports until at least Feb. 4, canceling nine cruises. The company has said the suspensions will cut earnings by at least $0.03 to $0.04 per share. With upwards of 5% of capacity scheduled to be deployed to China this year, a prolonged outbreak would likely have a material impact on results. Of course, we still don't know how far the coronavirus will spread or how long the outbreak will last. The outbreak certainly won't last forever, and Carnival should have the wherewithal to weather these setbacks. But given the uncertainty, it is understandable investors aren't rushing in to buy as the shares fall. 10 stocks we like better than CarnivalWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and Carnival wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of December 1, 2019 Lou Whiteman has no position in any of the stocks mentioned. The Motley Fool recommends Carnival. The Motley Fool has a disclosure policy.Source