DALLAS -- The first case of Ebola diagnosed in the U.S. was confirmed Tuesday in a patient who recently traveled from Liberia to Dallas -- a sign of the far-reaching impact of the out-of-control epidemic in West Africa.
The unidentified patient was critically ill and has been in isolation at Texas Health Presbyterian Hospital since Sunday, federal health officials said.
Questions and answers on EbolaHere are answers to common questions about the Ebola virus:
How is Ebola spread?
By direct contact with an Ebola patient's blood or other bodily fluids like urine, saliva, and sweat. The highest concentration of virus is thought to be in blood, vomit and diarrhea.
Someone can also get infected by handling soiled clothing or bed sheets without protection, and then touching their nose, mouth or eyes. People can also catch the disease by eating infected bushmeat, as Ebola can sicken animals including bats, chimpanzees and antelopes. Scientist think fruit bats might be the source of the virus, but aren't certain.
What are the symptoms?
The Centers for Disease Control and Prevention says symptoms of Ebola are a fever higher than 101.5 degrees, a severe headache, muscle pain and weakness, vomiting, diarrhea, abdominal pain and unexplained bruising or bleeding. Symptoms can appear from two to 21 days after exposure, but the average is eight to 10 days. If you think you have Ebola, you should tell your doctor about your recent travel and symptoms before you go to the office or an emergency room, to help protect others.
Who is most at risk?
The most vulnerable people are health care workers and family members or others who care for the sick. Because of the deadly nature of the disease, health workers should wear protective gear, especially when handling things like contaminated syringes. Such equipment is not commonly available in Africa, and the disease isn't always quickly recognized. Symptoms are similar to other diseases like malaria and cholera.
Can Ebola spread in the air, like flu or tuberculosis?
There is no evidence Ebola can be spread in the air by sneezing or coughing. "If there was a role for airborne transmission, we'd be seeing a lot more cases and deaths by now," said Ben Neuman, a virologist at Britain's University of Reading.
Ebola is in some ways similar to the AIDS virus because it is spread through bodily fluids, according to Stephen Morse, of Columbia University's Mailman School of Public Health. Unlike those infected with HIV, those with the Ebola virus are considered infectious only when they show symptoms, which include fever, vomiting and diarrhea.
Can the spread of Ebola be stopped?
Yes, by isolating anyone with symptoms while testing is done, taking precautions while providing them medical care and tracking down anyone they were in close contact with when they got sick. Those who have had direct contact with an Ebola patient are advised to take their temperature twice a day for three weeks, the incubation period for the disease. If they show symptoms, they should then be isolated and tested.
How can I protect myself?
First and foremost, avoid traveling to areas affected by the outbreak. The CDC says U.S. citizens should avoid all nonessential travel to Guinea, Sierra Leone and Liberia. The agency also advises taking enhanced precautions if you travel to Nigeria or the Democratic Republic of Congo.
If you must travel to those areas, the CDC recommends washing your hands frequently, avoiding contact with blood and bodily fluids of other people, avoiding hospitals where Ebola patients are being treated, avoiding contact with bats or nonhuman primates, and seeking medical attention immediately if you develop a fever or other symptoms of the virus.
What's being done to prevent infected people from entering the U. S.?
Countries in West Africa are conducting exit screening. Also, the CDC says it is working with international health organizations and federal agencies to identify sick travelers. If a passenger aboard a flight exhibits symptoms, the CDC will work with the airline and health officials and conduct an investigation of exposed passengers.
How long as Ebola been around?
Ebola first appeared nearly 40 years ago. In past Ebola outbreaks, many cases have been linked to people burying their loved ones, involving ritual cleansing of the body and kissing the body. The World Health Organization recommends that only trained personnel handle the bodies of Ebola victims.
"We know how to stop Ebola," said Gregory Hartl, a WHO spokesman. "We have stopped all previous outbreaks in the past using old-fashioned methods."
"From what we've seen, there isn't any reason to think we can't stop the outbreak in West Africa using what we have done in the past."
Source: Associated Press, Centers for Disease Control and Prevention
They have begun tracking down family and friends who may have had close contact with the patient and could be at risk for becoming ill. But officials said there are no other suspected cases in Texas.
Health authorities would not reveal the patient's nationality or age. And even though they repeatedly referred to the patient as "he," they would not confirm the person's gender.
At the Centers for Disease Control and Prevention, Director Tom Frieden said the patient left Liberia on Sept. 19, arrived the next day to visit relatives and started feeling ill four or five days later. He said it was not clear how the person became infected.
There was no risk to anyone on the airplane because the patient had no symptoms at the time of the flight, Frieden said.
Ebola symptoms can include fever, muscle pain, vomiting and bleeding, and can appear as long as 21 days after exposure to the virus. The disease is not contagious until symptoms begin, and it takes close contact with bodily fluids to spread.
"The bottom line here is that I have no doubt we will control this importation, or this case of Ebola, so that it does not spread widely in this country," Frieden told a news conference.
"It is certainly possible that someone who had contact with this individual, a family member or other individual, could develop Ebola in the coming weeks," he added. "But there is no doubt in my mind that we will stop it here."
Frieden said he believed the case also marked the first time this strain of Ebola has been diagnosed outside of West Africa.
In Washington, President Barack Obama was briefed about the diagnosis in a call from Frieden, the White House said.
Four American aid workers who became infected while volunteering in West Africa have been flown back to the U.S. for treatment after they became sick. They were cared for in special isolation facilities at hospitals in Atlanta and Nebraska. Three have recovered.
Also, a U.S. doctor exposed to the virus in Sierra Leone is under observation in a similar facility at the National Institutes of Health.
The U.S. has only four such isolation units. Asked whether the Texas patient would be moved to one of those specialty facilities, Frieden said there was no need and virtually any hospital can provide the proper care and infection control.
Dr. Edward Goodman, an epidemiologist at the hospital, said the U.S. was much better prepared to handle the disease than African hospitals, which are often short of doctors, gloves, gowns and masks.
"We don't have those problems. So we're perfectly capable of taking care of this patient with no risk to other people," he said.
After arriving in the U.S. on Sept. 20, the patient began to develop symptoms on Sept. 24 and initially sought care two days later. But he was released. At the time, hospital officials did not know he had been in West Africa. He returned later as his condition worsened.
Blood tests by Texas health officials and the CDC separately confirmed an Ebola diagnosis on Tuesday.
State health officials describe the patient as seriously ill. Goodman said the patient was able to communicate and was hungry.
Asked how many people the patient may have had close contact with in that time period, Frieden said, "I think a handful is the right characterization."
The hospital is discussing if experimental treatments would be appropriate, Frieden said.
Since the summer months, U.S. health officials have been preparing for the possibility that an individual traveler could unknowingly arrive with the infection. Health authorities have advised hospitals on how to prevent the virus from spreading within their facilities.
People boarding planes in the outbreak zone are checked for fever, but that does not guarantee that an infected person won't get through.
Liberia is one of the three hardest-hit countries in the epidemic, along with Sierra Leone and Guinea.
Ebola is believed to have sickened more than 6,500 people in West Africa, and more than 3,000 deaths have been linked to the disease, according to the World Health Organization. But even those tolls are likely underestimates, partially because there aren't enough labs to test people for Ebola.
Two mobile Ebola labs staffed by American naval researchers arrived this weekend and will be operational this week, the U.S. Embassy in Monrovia said in a statement Monday. The labs will reduce the amount of time it takes to learn if a patient has Ebola from several days to a few hours.
The U.S. military also delivered equipment to build a field hospital, originally designed to treat troops in combat zones. The 25-bed clinic will be staffed by American health workers and will treat doctors and nurses who have become infected.
The U.S. is planning to build 17 other clinics in Liberia and will help train more health workers to staff them. Britain has promised to help set up 700 treatment beds in Sierra Leone, and its military will build and staff a hospital in that country. France is sending a field hospital and doctors to Guinea.