Swine Flu (Swine Influenza A [H1N1 and H3N2v] Virus)

  • Medical Author:
    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

  • Medical Editor: Melissa Conrad Stöppler, MD
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

View Slideshows

What to Do if You Think You Have H1N1 Swine Flu Virus

If you've got fever, cough, or one of the other symptoms of the flu, you may be wondering if you have contracted the H1N1 swine flu virus. The reality is that it isn't possible to know unless specialized testing is ordered, and for uncomplicated cases of the flu in non-hospitalized patients, routine testing for the H1N1 virus is not being carried out.

Quick GuideCommon Respiratory Illnesses

Common Respiratory Illnesses

Swine flu (H1N1 and H3N2v influenza virus) facts

  • Swine flu is a respiratory disease caused by influenza viruses that infect the respiratory tract of pigs and result in a barking cough, decreased appetite, nasal secretions, and listless behavior; the virus can be transmitted to humans.
  • Swine flu viruses may mutate (change) so that they are easily transmissible among humans.
  • The 2009 swine flu outbreak (pandemic) was due to infection with the H1N1 virus and was first observed in Mexico.
  • Symptoms of swine flu in humans are similar to most influenza infections: fever (100 F or greater), cough, nasal secretions, fatigue, and headache.
  • The incubation period for the disease is about one to four days.
  • Swine flu is contagious about one day before symptoms develop to about five to seven days after symptoms develop; some patients may be contagious for a longer time span.
  • The disease lasts about three to seven days with more serious infections lasting about nine to 10 days.
  • Vaccination is the best way to prevent or reduce the chances of becoming infected with influenza viruses.
  • Primary-care specialists, pediatricians, and emergency-medicine doctors usually treat the disease, but other specialists may be consulted if the flu is severe and/or complicated.
  • Two antiviral agents, zanamivir (Relenza) and oseltamivir (Tamiflu), have been reported to help prevent or reduce the effects of swine flu if taken within 48 hours of the onset of symptoms.
  • There are various methods listed in this article to help individuals from getting the flu.
  • Home remedies are available, but patients should check with their doctors before use; over-the-counter medications may help reduce symptoms.
  • The most serious complication of the flu is pneumonia.

What is the swine flu?

Swine flu (swine influenza) is a respiratory disease caused by viruses (influenza viruses) that infect the respiratory tract of pigs, resulting in nasal secretions, a barking cough, decreased appetite, and listless behavior. Swine flu produces most of the same symptoms in pigs as human flu produces in people. Swine flu can last about one to two weeks in pigs that survive. Swine influenza virus was first isolated from pigs in 1930 in the U.S. and has been recognized by pork producers and veterinarians to cause infections in pigs worldwide. In a number of instances, people have developed the swine flu infection when they are closely associated with pigs (for example, farmers, pork processors), and likewise, pig populations have occasionally been infected with the human flu infection. In most instances, the cross-species infections (swine virus to man; human flu virus to pigs) have remained in local areas and have not caused national or worldwide infections in either pigs or humans. Unfortunately, this cross-species situation with influenza viruses has had the potential to change. Investigators decided the 2009 so-called "swine flu" strain, first seen in Mexico, should be termed novel H1N1 flu since it was mainly found infecting people and exhibits two main surface antigens, H1 (hemagglutinin type 1) and N1 (neuraminidase type1). The eight RNA strands from novel H1N1 flu have one strand derived from human flu strains, two from avian (bird) strains, and five from swine strains.

How is swine flu transmitted? Is swine flu contagious?

Swine flu is transmitted from person to person by inhalation or ingestion of droplets containing virus from people sneezing or coughing; it is not transmitted by eating cooked pork products. The newest swine flu virus that has caused swine flu is influenza A H3N2v (commonly termed H3N2v) that began as an outbreak in 2011. The "v" in the name means the virus is a variant that normally infects only pigs but has begun to infect humans. There have been small outbreaks of H1N1 since the pandemic; a recent one is in India where at least three people have died.

Medically Reviewed by a Doctor on 3/18/2016

Subscribe to MedicineNet's Newsletters

Get the latest health and medical information delivered direct to your inbox!

By clicking Submit, I agree to the MedicineNet's Terms & Conditions & Privacy Policy and understand that I may opt out of MedicineNet's subscriptions at any time.

VIEW PATIENT COMMENTS
  • Swine Flu - Concerns and Risks

    Are you concerned about contracting swine flu? Has it affected your travel plans?

    Post View 32 Comments
  • Swine Flu - Symptoms and Signs

    What symptoms and signs did you experience with swine flu?

    Post View 7 Comments
  • Swine Flu - Treatment

    What treatment did you receive for swine flu?

    Post View 1 Comment

Health Solutions From Our Sponsors