SWINE FLU ALL THE FACTS YOU NEED TO KNOW

The outbreak of a new form of swine flu has prompted the United States and the World Health Organization to declare a public health emergency. President Obama has called the emergency a "precautionary tool," since so far the outbreak has had only limited impact in the United States. But public health officials are scrambling to determine the extent of the outbreak.

This outbreak could peter out, like a 1976 swine flu outbreak did. Or the virus could spread easily from one person to the next, sparking a pandemic in which millions of people are infected. Richard Besser, the acting CDC director, says it's too early to say if we'll see more severe disease here in the United States. "Viruses are unpredictable and variable over time," he said yesterday. "What we say and what we learn will change."

Here's the rundown on what we know so far, as well as the options for avoiding swine flu and for treating it if you get it.

How is swine flu different than seasonal influenza and bird flu?
This is a new flu bug that includes genetic segments from human, swine, and avian flu viruses. It is an influenza A H1N1 strain, named for two proteins in the bug's protein coat. H1N1 viruses often circulate without causing major outbreaks. But since this flu virus is new, people might not have immunity to it. That's why the global public health system is on alert. No one knows where this outbreak might lead.

What symptoms would tell me I have swine flu?
Swine flu symptoms are similar to the symptoms of regular seasonal flu, according to the CDC. Those include:

-Fever
-Lethargy
-Lack of appetite
-Coughing

Some people with swine flu have also reported runny nose, sore throat, nausea, vomiting, and diarrhea.

How can I tell if someone sitting next to me has swine flu?
You can't. If someone is showing the symptoms described above, it couldn't hurt to keep your distance. Jeff Duchin, chief of the communicable disease section at Public Health Seattle, says it's best to say 6 feet away from someone who has the flu because the virus spreads in droplets when people talk, cough, or sneeze. Of course, your neighbor might just have a stuffy nose caused by a mild cold or seasonal allergies.

Should I be wearing a face mask, like they're wearing in Mexico?
Not unless you're taking care of a person who's sick with swine flu or are sick yourself. Wearing masks is a popular reaction to respiratory outbreaks in parts of the world, but it's not a step that the U.S. government has recommended for the current outbreak. The CDC has an online guide to using masks and respirators to prevent flu transmission.

Is there a vaccine available for this new swine flu?
No. Developing and producing a vaccine matched to this flu virus will take several months. Anne Schuchat, director of the CDC's National Center for Immunization and Respiratory Diseases, said yesterday that a swine flu vaccine could be added to the seasonal flu vaccine now being produced for next fall, either as a replacement for one of the three strains in that vaccine or as an addition that makes it a four-strain vaccine.

What's the best way to avoid getting exposed to the swine flu virus?
For now, avoid people who are coughing or sick. The CDC also recommends hand washing to reduce the risk of flu. Though frequent hand washing hasn't specifically been proved to protect against swine flu, it does reduce the risk of respiratory infections generally.

What other things can I do to get my family prepared?
It never hurts to think about what you would do if swine flu hits your community hard, the CDC's Besser says. That may mean that schools would be closed, as has been done in Mexico. The federal government's pandemic flu website has suggestions on getting ready at home and at work. One example: Do you have enough food in the house to feed your family if you had to stay home for a week? You can also check with your employer to make sure the company has a plan in case of a flu pandemic. And you can prepare yourself for the possibility you'd have to work from home for a while.

Is it dangerous to eat pork?
No. This flu virus is spread from person to person by touching surfaces infected with the virus or by inhaling viruses from someone coughing. You can't get swine flu from eating pork.

What should I do if I or someone in my family is sick?
"Calling the doctor is never the wrong thing to do," says Mark Metursky, a professor of medicine at the University of Connecticut School of Medicine and immediate past chair of the chest infection network for the American College of Chest Physicians. You'll know you have the flu and not just a cold if you've got a fever of 102 or more, a headache, and muscle aches.

"If you have a respiratory infection with fever, don't go to work or school," says Duchin. To minimize the risk of infecting others, avoid traveling by air and taking public transportation if you have the flu.

People aren't at risk of swine flu for now, Metursky says, unless they have traveled to Mexico of are exposed to someone who has.

What medications work against swine flu?
Laboratory tests suggest this swine flu is susceptible to the antiviral drugs Tamiflu (oseltamivir) and Relenza (zanamivir). To be effective, these drugs need to be taken as soon as possible after a person has flu symptoms. "The sooner you talk to your doctor the better," Metursky says. The CDC has new recommendations for using antivirals to treat swine flu; people who are sick and have recently been to Mexico or who have been exposed to people with swine flu should speak with a doctor about whether to take an antiviral medication.

Should I stockpile Tamiflu?
The federal government doesn't recommend that people stockpile Tamiflu at home, saying it should be saved for people who are sick with influenza now. But many public health scientists have set aside some Tamiflu for themselves in the past few years because of concern about the possibility of a pandemic caused by bird flu. It's your call.

I'm not sick. Should I avoid traveling?
This might not be the wisest time to vacation in Cancun, but travel hasn't been banned by the CDC and WHO, so it's up to you. Airlines will let passengers to certain destinations re-book their trips at no cost. Check the CDC or WHO website before traveling, because the advisories could change at any time.

Why has the swine flu been deadly in Mexico but not in the U.S.?
No one knows for sure. It could be that Americans who've gotten infected had better, faster access to health care. Or it could be that the U.S. is just at an earlier stage in the outbreak, Duchin says. If that's the case, U.S. deaths could occur as the outbreak matures.

Where do I look for more news on swine flu?
The CDC's new swine flu website is a good place to start, for information both on the state of the outbreak and on how to keep your family healthy. Other good options:

-The World Health Organization is tracking swine flu cases worldwide.

-The Center for Infectious Disease Research and Policy is following swine flu, bird flu, and the possibility of a flu pandemic.

-The Infectious Diseases Society of America gears its swine flu news to doctors, but that information on treatment and avoidance is useful for individuals, too.

-The federal government's pandemic flu website provides a broad range of information on preparing for a pandemic.