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By Jeff Mason and Roberta Rampton
WASHINGTON, Oct 17 (Reuters) - President Barack Obama appointed a former White House adviser as Ebola "czar" on Friday and named officials to bolster the response to the disease in Texas, the center of U.S. Ebola cases, as the death toll in three West African nations topped 4,500.
The White House appointments came as Obama faced criticism from some lawmakers over his administration's efforts to contain the hemorrhagic virus and as widening Ebola fears kept a U.S. cruise ship out of a Mexican port.
Obama appointed Ron Klain, a lawyer who had served as chief of staff to Vice Presidents Joe Biden and Al Gore, to oversee the U.S. Ebola response.
The White House also said it would send senior personnel to Dallas to help federal, state and local officials there trying to identify and monitor people who came in contact with three people who caught the disease.
The three include Thomas Eric Duncan, the first person diagnosed with the disease in the United States, and two nurses who were on the team of health workers caring for Duncan until his death last week.
Obama met with health and national security aides and "underscored that the domestic response to Ebola cases must be seamless at all levels," the White House said in a statement.
It was the third consecutive day that Obama had convened officials to discuss what has become a major political issue for his Democratic administration ahead of mid-term elections next month.
The officials will include a Federal Emergency Management Agency coordinator, Kevin Hannes, and a White House liaison, Adrian Saenz, a presidential aide. Governor Rick Perry has named Texas emergency management chief W. Nim Kidd to coordinate the state Ebola effort, the White House said.
Authorities said a Texas health worker, who was not ill but may have had contact with specimens from the patient, was quarantined on a cruise ship that departed on Sunday from Galveston, Texas.
The Carnival Magic, operated by Carnival Corp unit Carnival Cruise Lines, skipped a planned stop in Cozumel, Mexico, because of delays getting permission to dock from Mexican authorities, the cruise line said. The ship was scheduled to return to Galveston on Sunday.
A Mexican port authority official said the ship was denied clearance to avoid any possible risk from Ebola.
The countries worst hit by Ebola have been Guinea, Liberia and Sierra Leone, where the disease has killed 4,546 since the outbreak started in March, an updated tally from the World Health Organization shows.
That marked a sharp increase from late July, when fewer than 730 people had died from the disease in West Africa. The virus is spread through direct contact with bodily fluids from an infected person.
The toll on the worst-hit countries has gone beyond the illness, because of disruptions to farming and marketing. The World Food Program said food prices in Guinea, Liberia and Sierra Leone had risen an average of 24 percent, forcing some families to cut back to one meal a day.
The White House appointments and the Mexican cruise ship incident highlighted anxiety over the threat from Ebola, even though the three Dallas cases are the only ones diagnosed in the United States.
Klain replaces U.S. Centers for Disease Control and Prevention director Thomas Frieden as the new public face of the government's response to Ebola. The CDC chief was strongly criticized for his handling of the situation in Dallas.
Republicans were quick to criticize Klain, who is seen as a political operative.
"Leave it to President Obama to put a liberal political activist in charge of the administration's Ebola response," Representative John Fleming, a Louisiana medical doctor, said in a statement.
Frieden told a congressional hearing this week that some protective equipment used by health care workers exposed some parts of the skin.
Given those concerns and the fact that two nurses got Ebola at the hospital, the CDC "very soon" will put out new guidelines on putting on and taking off protective gowns, masks, gloves and other gear, CDC spokeswoman Barbara Reynolds said.
Illustrating the public worry in the United States, the Pentagon confirmed an Ebola scare when a woman who recently traveled to Africa vomited after getting off a bus headed to a Marine Corps ceremony.
In a statement, Virginia health officials said Ebola had been ruled out as the cause of the woman's illness.
Klain was appointed the day after U.S. lawmakers, in a congressional hearing, criticized the administration's handling of Ebola. Some called for a ban on travel from West Africa, as other politicians have in recent weeks.
The White House said on Friday that Obama was willing to "keep an open mind" about a travel ban, but it was not being considered.
In a sign the disease can be beaten, the World Health Organization said the West African country of Senegal was now Ebola-free, although still vulnerable.
The CDC has said it is expanding its search for people who may have been exposed to Amber Vinson, one of the nurses who treated Duncan, to include passengers on a flight she made to Cleveland, Ohio, in addition to those on her Monday return trip to Texas. Vinson went to Ohio over the weekend on Frontier Airlines while running a slight fever.
One of the 48 people who had the earliest contact or possible contact with Duncan has come out of quarantine after showing no symptoms for 21 days of monitoring, a Dallas County official said. The man was the first to get the all-clear.
There is no cure for Ebola. But U.S. health officials have asked three advanced biology laboratories to submit plans for producing the experimental Ebola drug ZMapp, when supplies ran out after it was given to medical workers who contracted the disease in West Africa.
Australian biotech firm CSL Ltd said it was working on a plasma product to treat Ebola following a request from the Bill & Melinda Gates Foundation, part of a growing commercial response to the outbreak.
Additional reporting by Doina Chiacu, Ian Simpson, Mohammad Zargham, Frances Kerry and Jeff Mason in Washington, Jonathan Kaminsky in New Orleans, Curtis Skinner in San Francisco, Simon Gardner and Ana Isabel Martinez in Mexico City; Writing by Jim Loney, Ian Simpson and Tom Brown; Editing by Jonathan Oatis, Grant McCool, Frances Kerry and Robert Birsel