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Swine Influenza

Swine Influenza (Flu)

Swine flu is a respiratory disease of pigs caused by type A influenza viruses. These swine flu viruses regularly cause outbreaks of influenza in pigs throughout the year, but most outbreaks happen during the late fall and winter months similar to outbreaks of seasonal influenza in people. Like human influenza viruses, there are different subtypes and strains of swine flu viruses. The main swine flu viruses circulating in U.S. pigs in recent years have been H1N1, H3N2, and H1N2. Swine flu viruses can cause high levels of illness in pigs, but usually cause few deaths.

What's Happening Now

As fair season is starting in Indiana, the Indiana Department of Health is gathering information on any potential human illness associated with attending a local or state fair or animal exhibition during the 2024 summer. If you attended a local or state fair or animal exhibition and developed symptoms, please complete this survey:

Frequently Asked Questions

  • How is swine influenza spread?

    Swine flu viruses that normally circulate in pigs have caused sporadic human infections. When a flu virus that normally spreads in pigs is found in a person, it is called a “variant flu virus.” These viruses are typically found in children exposed to pigs at an agricultural event, people who raise pigs, or workers in the swine industry.

    Exposure occurs when an infected pig coughs or sneezes, and droplets containing influenza virus spread through the air. If these droplets land in your nose or mouth or are inhaled, you can become infected. There is also some evidence that you might get infected by touching something that has a virus on it and then touching your own eyes, mouth, or nose.

  • What are the signs and symptoms of swine influenza?

    Swine flu viruses usually cause mild illness; however, they can cause severe illness and are concerning because of their pandemic potential. Symptoms can include fever, lethargy (tiredness), lack of appetite, cough, runny nose, sore throat, eye irritation, nausea, vomiting, and diarrhea.  Similar to seasonal flu, serious illness resulting in hospitalization and death is possible.

  • Who is at risk for infection with swine influenza viruses?

    Similar to seasonal flu, people with certain underlying conditions such as asthma, heart disease, diabetes, kidney disease, HIV/AIDS, and cancer are at higher risk of developing serious complications from infections with swine flu viruses. Other groups at increased risk for flu complications include:

    1. Children younger than 5 years
    2. Adults 65 years and older
    3. Pregnan women
    4. People with disabilities
    5. People belonging to racial and ethnic minority groups
  • How do you protect yourself from swine influenza viruses spread from pigs?

    The best way to protect yourself from infection with swine flu is to understand your risk for exposure and take proper precautions when having contact with pigs or their environments.

    • Anyone who is at higher risk of serious flu complications should avoid contact with pigs and swine barns.
    • If unable to avoid exposure, wear a well-fitting mask that covers the nose and mouth (e.g., an N95 respirator or KN95 respirator if available, or if not available, a surgical mask).
    • Always wash your hands with soap and running water before and after exposure to pigs. Use an alcohol-based hand rub if soap and running water are unavailable.
    • Don’t take food or drink into areas with pigs; don’t eat, drink or put anything in your mouth in areas with pigs.
    • Don’t take toys, pacifiers, cups, baby bottles, strollers, or similar items into areas with pigs.
    • Avoid contact with pigs if they are sick.
    • Avoid contact with pigs or their environments if you are experiencing flu-like illness.

    IDOH  recommends seasonal influenza vaccination for people working with swine. It will not prevent infection with swine flu viruses, but it can reduce the risk of coinfection with other seasonal flu viruses.

  • Is treatment available?

    Antiviral medications are available to treat people with suspected or confirmed infection with swine flu viruses. There are different antiviral medications recommended for use in the US for treatment of influenza.

  • What should I do if I become sick after having contact with pigs or their environment?

    If you or your family members become sick with flu-like symptoms after a potential exposure, take the following actions:

    • Contact your health care provider to let them know about your symptoms and tell them that you have been around pigs. Your doctor may prescribe treatment with flu antiviral medications and may order testing to check for swine variant flu or other respiratory diseases.
    • Stay home from work and school, avoid travel, and avoid or limit contact with other people and pigs as much as possible until your doctor tells you it is safe to resume normal activities.
    • Practice good respiratory and hand hygiene including using facial tissues to cover coughs and sneezes, disposing of contaminated tissues, and washing your hands with soap and running water.
  • How are people tested for swine influenza viruses?

    Testing for swine flu viruses can only be performed at specific laboratories that are part of the Laboratory Resource Network (LRN). The Indiana Department of Health Laboratory is the only LRN laboratory in the state with the capacity to test for swine flu viruses. If a healthcare provider is considering the possibility of swine flu in a sick patient with recent exposure to pigs or their environments, they should contact IDOH Laboratory to obtain approval for submitting a test.

Information for the Public

Information for Clinicians

Fairs, Farms, and Occupational Workers

Laboratory Specimen Information

State and Federal Partner Swine Resources

Contact Information

For healthcare providers requesting approval for specimen testing at IDOH Laboratory, please call the IDOH Infectious Disease Epidemiology and Prevention Division at 317-233-7125 to obtain approval from the Influenza Coordinator or the Vector-Borne and Zoonotic Disease Epidemiologist during normal business hours (Monday - Friday, 8:15am to 4:45pm).

  • If calling after hours or on holidays, please contact the Epidemiologist On-Call (EOC) at 317-233-1325 for specimen testing approval.

For questions on specimen collection, transport, or shipment, please call the IDOH Laboratory Virology Division at 317-921-5500 during normal business hours (Monday - Friday, 8:15am to 4:45pm).

Page last reviewed/updated: October 2024