(Swine Influenza A [H1N1 and H3N2v] Virus)
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.
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.
- Swine flu (H1N1 and H3N2v influenza virus) facts
- What is the swine flu?
- What causes swine flu?
- Why is swine flu now infecting humans?
- What are the symptoms of swine flu?
- How is swine flu diagnosed?
- What is the treatment for swine flu?
- What is the history of swine flu in humans?
- What are the risk factors for swine flu?
- Can swine flu be prevented with a vaccine?
- Can swine flu be prevented if the swine flu vaccine (or other flu strain vaccines) is not readily available?
- Was swine flu (H1N1) a cause of an epidemic or pandemic in the 2009-2010 flu season?
- What is the prognosis (outlook) and complications for patients who get swine flu?
- What is the latest news about swine flu?
- Where can I find more information about swine flu (H1N1 and H3N2v)?
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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.
- Vaccination is the best way to prevent or reduce the chances of becoming infected with influenza viruses.
- 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.
- 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.
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.
Next: What causes swine flu?
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