2009 Swine Flu Infections in Humans

What is Swine Influenza?

Swine flu is an influenza virus that causes an upper respiratory illness, and occasionally death, in pigs. It is an Influenza A virus. There are three main types of Influenza A viruses: human, pig (swine) and bird (avian) type.  Swine flu does not usually affect humans, but if the strain mutates, it may be capable of infecting humans.  Humans can then spread the infection to other humans.  Most outbreaks of swine flu occur in the fall and winter, around the same time human influenza infections occur.

Influenza viruses can be further broken down into different subtypes based on N and H antigens. H stands for hemagglutinin  and N stands for neuramindase.  These are specific viral molecules found on a particular strain of influenza virus. There are 16 different hemagglutinin subtypes and 9 different neuraminidase subtypes that define different strains.  The current type of swine flu is type H1N1.

Influenza vaccines are developed to fight certain strains of human influenza.  The flu shot does not protect against swine or bird flu.

What about Outbreaks of Swine Flu?

Occasional outbreaks of swine flu have occurred in the past (Fort Dix, New Jersey in 1976).   An outbreak is currently occurring in Mexico and New York City.  I lived in Wisconsin when there was an outbreak of swine flu in pigs in 1988.  A pregnant woman who was exposed to pigs at a county fair contracted swine flu and died.  There was evidence that health care workers who cared for this patient developed mild cases of swine flu. Other people exposed to the pigs developed mild infections and recovered.

Usually, there is a single case of human swine flu every one to two years.  However, there have been twelve cases of reported swine flu between December 2005 and February 2009.

Swine flu cannot be contracted by eating pork. Cooking pork to an internal temperature of 160 degrees Fahrenheit kills bacteria and viruses, including swine influenza.

What are the Symptoms of Swine Flu?

Symptoms of swine flu are similar to human influenza:  fever, cough, bodyaches, feeling ill,  Other symptoms associated with swine flu include diarrhea, vomiting, sore throat and runny nose.  When people ill with influenza cough and sneeze, respiratory droplets can spread the infection to others.  If you touch a surface contaminated with swine (or human) influenza, and then touch your eyes or nose, you can spread the infection.  Therefore, hand washing is very important.  If you have a fever and upper respiratory illness, it is better to stay home and recover, rather than spread infections to others.

If you have an upper respiratory infection, you should cough or sneeze in a tissue or your elbow, not your hand.  Then you should wash your hands or use alcohol gel if soap and water are not available.

Pregnant women, the elderly and infants are most likely to have severe influenza infections.

How can human infections with swine influenza be diagnosed?

To diagnose swine influenza A infection, a nasal swab or washing is sent to the Centers for Disease Control (CDC) for identification.  There are rapid tests to detect Influenza A and B, but it is unclear how sensitive these rapid tests are for the diagnosis of swine strains of influenza.  Swine flu is most likely to be detected if tested within the first four to five days of symptoms in adults, and withing the first ten days in children.

What medications are available to treat swine flu infections in humans?

Amantadine, rimantadine, oseltamivir and zanamivir (taken nasally) are the four drugs licensed for use for the treatment and prevention of influenza.  The current H1N1 strain of swine flu is resistant to amantadine and rimantadine. These medications can be used in children over the age of one year.

Where Have Swine Flu Cases been Detected?

The Centers for Disease Control Provides up to the minute information and recommendations regarding swine flu.  Remain calm!

U.S. Human Cases of Swine Flu Infection
(As of April 28, 2009, 11:00 AM ET)
State # of laboratory
confirmed cases
California 10 cases
Kansas 2 cases
New York City 45 cases
Ohio 1 case
Texas 6 cases
TOTAL COUNT 64 cases

International Human Cases of Swine Flu Infection
See: World Health OrganizationExternal Web Site Policy.

Last edited by Dr.Vee on April 29, 2009

4 thoughts on “2009 Swine Flu Infections in Humans

  1. Thanks for letting me know about those sites Nutmeg123. It is scary, but not reason to panic!! Fortunately, knowldge helps in this situation. We can go to the doctor with any of the fever, bodyaches, cough symptoms, be tested, and be treated early if this infection spreads. Fortuanately, still few cases in America. And knowing how to avoid infection (handwashing, staying at least 6 feet away from someone with upper respiratory symptoms) is important.
    Thanks again for your comment.
    Dr. Vee

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