When three cases of swine flu emerged in Germany on Wednesday, the country's health minister, Ulla Schmidt, was blunt: "The development fills me with worry. None of us knows how far this will extend."
The World Health Organization on Wednesday raised its pandemic alert to Phase 5 — the second-highest level and a step away from a full-fledged pandemic.
As the virus spread deeper into Europe, the first swine flu death in the U.S. was reported in Texas, and President Obama suggested that school closings may be a necessary precaution. Earlier this week, Obama reassured Americans that federal preparations were under way to deal with a possible epidemic, adding that there was "no cause for alarm."
But alarm seemed to be the order of the day in Egypt. Authorities ordered the slaughter of 300,000 to 400,000 pigs in the country Wednesday to limit the spread of the disease, even though no cases have been reported there.
In Spain, where a handful of cases have been confirmed, Prime Minister Jose Luis Rodriguez Zapatero urged people not to panic. "We have the scientific and the therapeutic means to respond to this situation," he said.
Political leaders and public health authorities around the globe are grappling with a fundamental question as new swine flu cases are reported daily: how to address the problem but not exacerbate it.
Tone Should Be 'Scary But Tentative'
"The way to sustain credibility is to be simultaneously scary but also tentative," says Peter Sandman, a Princeton, N.J.-based risk communication consultant who has advised the World Health Organization, the U.S. government and private companies.
Jeffrey Koplan, a former director of the Centers for Disease Control and Prevention, now with Emory University, says much deliberation goes into crafting the public message during a crisis like the swine flu outbreak.
"It is a constant balancing act in which you struggle to convey a sense of risk while not inducing a public panic," Koplan says.
He says the CDC has been consistent in its language — calling it an "epidemic of concern" and stressing that it is likely to get worse.
In Mexico, where the outbreak has hit hardest, schools and other public places have been ordered closed, and restaurants in the capital have been told to serve only takeout.
The U.S. and scores of other governments have recommended to their citizens that they limit their travel to Mexico. Argentina and Cuba have banned flights to and from Mexico, though Cuba relaxed the prohibition Wednesday for flights taking people to Mexico.
Screening Travelers And Banning Pork Imports
Officials at major airports worldwide are on the lookout for travelers with flu symptoms on flights from Mexico and the U.S. In Asia, authorities have dusted off thermal scanners used during the 2003 SARS outbreak to detect passengers who may have a fever. And Russian officials have ordered planes coming from affected countries to special zones where health officials can board the aircraft and screen passengers.
Australia is requiring pilots of international flights to declare whether any passengers are displaying flu-like symptoms before the airport will grant permission to land.
British officials are advising their citizens to curtail trips to Mexico. They have also recommended that British nationals in Mexico stay put rather than risk spreading an infection that they may already have.
China and Russia, among other countries, have banned imports of pork and pork products from Mexico and U.S. states reporting cases of swine flu. Indonesia, which was hit hardest by bird flu several years ago, said it is banning all pork imports.
The Centers for Disease Control and Prevention says there is no evidence to suggest that consuming pork can spread the swine flu virus.
The U.S., the European Union, China and other countries with sophisticated public health research agencies are better able to assess threats and react appropriately, Koplan says.
"There is no interest to the public being served by telling people not to eat pork or killing pigs," Koplan says.
In Israel, where two cases of the flu have been confirmed, officials were preparing to transfer control of emergency preparations from the government's health agency to the Israeli military, which has a long history of handling national crises.
Prepare For Worst-Case Scenario
The influenza coordinator at the European Center for Disease Prevention and Control, Angus Nicoll, said governments need to be prepared.
"The pattern at the moment is that of a mild disease, but one of the things that you've got to always remember with flu and particularly potentially pandemic viruses is that they have a nasty habit of changing and even becoming nastier over time," Nicoll said. "That's why in the EU, we're working so hard to make sure that the countries are prepared if this is going to get bad."
At least one high-ranking European Union official issued an advisory earlier this week warning against travel to the United States. That prompted the State Department spokesman in Washington, D.C., to issue this tart response Tuesday: "As far as I know, there hasn't been any official notification coming from the European Union. As far as I know, that was just a personal view of the EU health commissioner."
What To Call It?
And what to call the disease?
The United States began referring to the disease Wednesday by its scientific designation — H1N1.
Israeli Deputy Health Minister Yakov Litzman, an ultra-Orthodox Jew, declared Monday that Israel would call the disease "Mexico flu" rather than swine flu, as pigs are not kosher.
Mexico's ambassador to Israel formally protested Litzman's statement. Israel's Foreign Ministry later apologized, saying Litzman was "just kidding." In any event, Litzman's call has gone unheeded and the press and the public continue to call it swine flu.
No one in Hong Kong is joking about the disease. Memories of the SARS crisis, which claimed more than 750 lives mostly in China and Hong Kong, are still fresh. Officials in Hong Kong are preparing camps to quarantine patients and have announced that all schools will be shut down if just one student falls ill with swine flu. Residents have already been lining up at pharmacies to buy face masks and medical supplies.
Chief executive Donald Tsang said Hong Kong would "rather take extra steps than lower its guard."
NPR's Lourdes Garcia-Navarro in Jerusalem, Louisa Lim in Shanghai, Jerome Socolovsky in Madrid and Eric Westervelt in Berlin contributed to this report.