Thirty Ebola experts who traveled recently to West Africa, including an official of the World Health Organization, have been banned from attending a New Orleans medical meeting about infectious diseases.


The Louisiana Department of Health and Hospitals warned doctors and others who returned recently from Liberia, Guinea or Sierra Leone that they should not attend the annual meeting of the American Society of Tropical Medicine and Hygiene this week in New Orleans.


In a letter to people who registered for the conference, Louisiana officials said they were trying to prevent people at the conference from infecting others with Ebola. Anyone who travels to Louisiana within three weeks of visiting West Africa will be confined to their hotel rooms, the letter says. Ebola has an incubation period of up to 21 days.


"We see no utility in you traveling to New Orleans to simply be confined to your room," says the letter, signed by Kathy Kliebert, secretary of the Department of Health and Hospitals, and Kevin Davis, director of the Governor's Office of Homeland Security and Emergency Preparedness.


The tropical medicine society says Louisiana's decision has no scientific basis. People with Ebola are not contagious until they begin to show symptoms, such as a fever, and possibly not for two to three days after that, according to an October article in the New England Journal of Medicine. That gives doctors and others plenty of time to isolate themselves, according to the report, written by the journal's editors.


In recommendations issued last month, the Centers for Disease Control and Prevention said anyone at risk for Ebola should be monitored twice a day for symptoms.


The CDC called for restricting the travel of only people at "high risk" of Ebola, such as health workers who get the blood of infected patients directly on their skin. The CDC leaves it up to state and local officials to decide whether to restrict the movements of people at "some risk," such as health workers who treated Ebola patients while wearing personal protective equipment. People at "low risk" of having Ebola — such as those who have traveled in West Africa but had no contact with patients — should be allowed to travel freely, the CDC says.


More than 4,000 experts in infectious diseases are attending the meeting, the world's largest gathering of tropical medicine specialists, to learn the latest science and share ideas for treating patients.


Losing the perspective of doctors and nurses who have served in Africa, including the WHO's Piero Olliaro, a researcher in tropical diseases, deprives others of the chance to learn from their experience, said Alan Magill, president of the American Society of Tropical Medicine and Hygiene.


A number of medical societies have spoken out against strict quarantines for physicians and nurses who have treated Ebola patients in Africa, warning that harsh restrictions could deter health workers from volunteering to help.


Olliaro, who returned from Guinea Oct. 22, said he was in that country scouting out locations for clinical trials and was not treating patients. He plans to return to West Africa to continue his work, even though that could mean another 21 days of monitoring.


"It sends a bad message" to the public about how Ebola is spread, Olliaro said. "There is a real shortage in terms of people going there. So if you are discouraging people from going, that's not good."


According to the WHO, only 22% of planned Ebola treatment beds are open, mostly because of challenges "in finding sufficient numbers of foreign medical teams." More than 13,000 people have been infected with Ebola and more than 4,800 have died. Health workers have been particularly hard hit, with 546 Ebola infections and 310 deaths.


Turning away tourism dollars doesn't help the economy of New Orleans, which is still recovering from Hurricane Katrina, said Jimmy Guidry, medical director of the Louisiana Department of Health and Hospitals. Guidry said the economic damage would have been worse if anyone with Ebola symptoms had attended the meeting. Tracing the contacts of people at such a large meeting would have been daunting, Guidry said.


"We are not trying to be difficult," Guidry said. "We are trying to protect them (attendees) and our citizens. Anyone who lives in Louisiana and goes to help in West Africa, we monitor them, so they don't go to large gatherings. We are not treating these folks who are visiting any different than we're treating our own citizens."