Human infection with avian influenza viruses (Bird Flu)

What is H1N1?

H1N1 (also known as Swine Flu) is a powerful new strain of the influenza virus that can cause respiratory problems in humans. It was originally referred to as "Swine Flu" due to the fact that the virus is similar to influenza viruses that are found in pigs (swine). The first cases of H1N1 in humans were diagnosed in America in April of 2009. Since then, the new virus has continued to spread much like a seasonal flu virus.

According to the Centers for Disease Control, the most common ways H1N1 is spread are person-to-person contact, coughing, or touching infected surfaces and touching your face. The H1N1 virus can survive on surfaces for several hours. People who are infected can be contagious from 24 hours before exhibiting any symptoms and up to 7 days after symptoms began. The good news is that once infected, your body should produce antibodies for the virus, meaning you will only get it once.


The CDC reports that symptoms for the H1N1 virus are similar to a seasonal flu virus. Symptoms can include fever, chills, sore throat, cough, body aches and fatigue. Diarrhea and vomiting were also reported in some cases. Symptoms can last for a week or more. Severe complications such as pneumonia and respiratory failure are a concern for high risk groups (the elderly, children under 5, pregnant women, and people with suppressed immune systems or other health problems). Seek immediate medical care for children who experience any of the following symptoms:

  • Difficulty breathing or fast breathing
  • Bluish skin color
  • Dehydration
  • Extreme irritability to the point of not wanting to be held
  • Non-responsiveness
  • Flu-like symptoms that improve briefly, but return with fever and worse cough

Adults who experience the any of the following symptoms should also seek immediate medical care:

  • D1ifficulty breathing or shortness of breath
  • Chest pain or pressure
  • Confusion
  • Sudden dizziness
  • Severe or persistent vomiting
  • Flu-like symptoms that improve briefly, but return with fever and worse cough


Due to its similarity with the seasonal flu and common cold, the only way to get a definite diagnosis of H1N1 is through laboratory testing. There are several tests that can detect the virus, and some can even be done in your doctor's office. However, most people will not need a test for H1N1 because a positive result usually does not alter treatment. Diagnosis is most often made by health care providers based on the patient's report of severity and length of symptoms.

Fever Fever is rare Low grade fever is common High fever (101° or above) usually present
Cough Productive cough with mucus is common Occasional dry, hacking cough is common Persistent non-productive (dry) cough is common
Body Aches Slight body aches are common Moderate body aches are common Body aches are usually severe
Nasal Congestion Stuffy nose or runny nose is common, and usually mild to moderate Stuffy nose or runny nose is common, and can be moderate to severe Nasal congestion is extremely rare
Sore Throat Sore throat is common and can be mild to moderate Sore throat is common, and usually moderate Sore throat is rare
Headache Headache is uncommon Mild headache is common Headache is common and usually severe
Chest Congestion Chest discomfort is occasionally present can be mild to moderate Chest discomfort is usually present and is often moderate. Chest pressure and/or shortness of breath are common and usually severe
Fatigue Mild fatigue occasionally present Mild to moderate fatigue is common, lasting 1-3 days Moderate to severe fatigue lasting several days is common
Symptom Onset and Duration Symptoms develop gradually, and usually don't last more than a few days Symptoms develop gradually, and can last up to a week Rapid onset of symptoms (within 3-6 hours) is common, and usually last a week or more


The CDC recommends the following procedures for minimizing exposure to H1N1 and similar viruses:

  • WASH YOUR HANDS - Soap and water will get rid of most viruses. If you cannot wash your hands often, an alcohol-based hand sanitizer will work also.
  • DISSINFECT COMMON SURFACES - H1N1 can live on surfaces for hours. Use disinfecting sprays or wipes to kill the virus on common surfaces like countertops and door handles.
  • COVER WHEN YOU COUGH - Use a tissue to cover your mouth when you sneeze or cough. If no tissues are available, cough into your elbow or sleeve to avoid spreading germs with your hands.
  • AVOID CLOSE CONTACT - Try to stay at least 6 feet away from persons with flu symptoms. Avoid large crowds if possible.
  • AVOID TOUCHING YOUR FACE - Germs on your hands can be spread to your eyes, nose, or mouth.
  • IF YOU FEEL SICK, STAY HOME - Persons infected with H1N1 can be contagious for over a week after symptoms begin. People exhibiting flu-like symptoms should not go to work or school until the fever has been gone for 24 hours.