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Variant Influenza Virus (Swine Flu) Symptoms

Medical Author: Benjamin C. Wedro, MD, FACEP, FAAEM
Medical Editor: Melissa Conrad Stöppler, MD

Not infrequently, there is a news report of another outbreak of swine flu, where a type of influenza A that normally infects pigs crosses over and infects a human. Actually, however, "swine flu" no longer exists, since the infection is now called a "variant influenza virus" infection. The type of virus is often named based on its genetic makeup. People remember H1N1 from the news, but there are three different variants that have been recognized in recent years: H1N1, H1N2, and H3N2.

As a reminder, many types of viruses can cause very similar symptoms that are called influenza or the flu.

Symptoms of variant influenza virus

Variant influenza virus symptoms may include all those included in a regular influenza-like disease, including

However, with the variant virus, some patients may also experience more nausea, vomiting, and diarrhea than the seasonal flu, but this is not the case for every patient. Aside from the nausea, vomiting, diarrhea, and chills, these symptoms sound similar to the symptoms of a severe cold. Whether that's all there is or whether a person will become significantly ill is difficult to predict. However, individuals with poor or altered immune systems such as infants, pregnant women, the elderly, those undergoing chemotherapy treatment, or taking medications that impair immunity are at higher risk for more severe illness.

But even healthy people can become sick. The virus spreads by aerosol droplets, meaning that secretions from an infected person can be spread into the air by coughing or sneezing. It's the close contact with an ill person that causes the disease to spread. We live in a very social society. We ride public transportation, we attend school, and we work with many people. It's sometimes hard to know whom to avoid since a person may be contagious for 24 hours before their first symptoms occur.

Fortunately, we have learned how to limit the spread and the U.S. Centers for Disease Control and Prevention (CDC) has established monitoring programs looking for the first sign that an epidemic might be on the horizon. How a community, a hospital, or an individual deals with the potential for infection will help decide how fast and how far it will spread.


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