Healthwise H1N1 Influenza Update

Healthwise continues to update information on H1N1 flu in the United States and Canada as part of our standard medical review process. On June 11, 2009, the World Health Organization called the flu a pandemic because it has spread to so many countries. This topic will help you understand H1N1 flu. The topic covers causes, symptoms, when to call a doctor, examinations and tests, treatment, prevention, and where to get the latest information from public health organizations.

H1N1 Influenza (Swine Flu)

What is H1N1 flu?

H1N1 flu, also called swine flu, is an infection caused by an influenza virus that infects the lungs of pigs. In some cases, the virus can also infect humans and spread from one person to another. Although there is more than one kind of swine flu, the one that concerns health workers is the H1N1 virus.

When you have swine flu, you may feel tired and achy and have a sore throat, a fever, and a cough. Most of the time, the illness is not serious. But severe cases can lead to pneumonia, serious lung problems, and death. If you have another health problem, swine flu can make it worse.

Before 2005, cases of swine flu in people were rare in the United States. But in 2009, the U.S. Centers for Disease Control and Prevention reported an outbreak of a new strain of swine flu in Mexico, the United States, and other countries. This new strain is the H1N1 virus.

Cause

H1N1 flu, also called swine flu, is caused by a virus that infects the lungs of pigs. Most of the time, swine flu viruses don't infect humans. But under some conditions, infections can start when people are exposed to pigs that have the virus, such as on a farm or at a livestock fair. After a person is infected, he or she may spread the flu to other people by coughing or sneezing.

Drops from a cough or sneeze from an infected person can move through the air. Breathing them in can make you sick. You can also get infected by touching something with the flu virus on it, such as a desk or counter, and then touching your mouth or nose.

You can't get swine flu from eating pork.

Symptoms

The symptoms of H1N1 flu, also called swine flu, are the same as regular human flu. They include:
  • Fever or shaking chills.
  • Cough.
  • Sore throat.
  • Body aches.
  • Headache.
  • Extreme tiredness (fatigue).
Some people also have vomiting and diarrhea. Most of the time, the illness is not serious. But in severe cases, swine flu can lead to pneumonia, serious lung problems, and death. If you already have a health problem, swine flu can make it worse.

If you are infected with swine flu, you can infect others 1 day before your symptoms start and up to 7 days after you get sick.

When to call a doctor

For your child

Call your doctor now or seek emergency care if your child:
  • Is having trouble breathing.
  • Has blue or gray skin.
  • Is not drinking enough fluids or has signs of dehydration.
  • Is having trouble waking up or is acting confused.
  • Is extremely irritable and cranky.
  • Had been feeling better, but now symptoms—such as fever or cough—have come back or gotten worse.
  • Has a fever with a rash.
For you

Call your doctor now or seek emergency care if you:
  • Have trouble breathing or shortness of breath.
  • Have pain or pressure in your chest or belly.
  • Suddenly feel dizzy.
  • Are acting confused.
  • Have severe or persistent vomiting.
If you think you have the symptoms of swine flu or if you have been around someone with swine flu, call your doctor or go to the Centers for Disease Control and Prevention Web site (www.cdc.gov/H1N1flu) for information on what to do.

Exams and Tests

If your doctor thinks you have H1N1 flu (also called swine flu), he or she will do a physical exam and ask you questions about your symptoms and past health.

Your doctor may also take a nasal swab to test for the virus. If this test is needed, it is usually done within the first 4 or 5 days of illness.

Treatment

If you get sick:
  • Talk to your doctor. You may need to get tested to be sure you have H1N1 flu.
  • Stay home from school or work. Try to avoid being around other people. This will reduce the risk of spreading the flu to others.
  • Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.
  • If you don't have a tissue, cover your mouth when you cough or sneeze. Use the bend in your arm, not your hands.
  • Wash your hands every time you cough or sneeze.
To treat swine flu, your doctor will prescribe an antiviral medicine such as oseltamivir (Tamiflu) or zanamivir (Relenza). These medicines can help you feel better faster and may prevent other health problems caused by the flu.

The medicines work best if you start to take them within 2 days after your symptoms start.

Prevention

There is no vaccine to protect against H1N1 flu (also called swine flu). But there are things you can do to keep from getting sick.
  • Avoid close contact with others who are sick.
  • Wash your hands often, using soap and water. Alcohol-based hand cleaners also work well.
  • Avoid touching your eyes, nose, and mouth. Germs spread this way.
  • Try not to touch surfaces that may be contaminated with the virus. Some viruses and bacteria can live for 2 hours or longer on surfaces such as doorknobs, cafeteria tables, and desks.
  • Try to stay in good general health. Get plenty of rest, eat healthy foods, and drink lots of fluids.

Latest Information About H1N1 Flu

These organizations are studying and keeping track of H1N1 flu (also called swine flu), including what is being done to prevent its spread. Their Web sites have the most up-to-date information about H1N1 flu: