Q&A: Understanding Swine Flu

-What is swine flu?

Swine influenza is a respiratory disease of pigs caused by type A influenza viruses. The classical swine flu virus was first isolated from a pig in 1930.

People rarely get swine flu and if they do, transmission from person to person is usually very limited. However the CDC has determined that the H1N1 strain of the virus, which is causing the current outbreak of cases, is contagious and is spreading from human to human. The H1N1 strain is unusual because it has acquired genes from swine, bird, and human influenza virus.

-What are the signs and symptoms of swine flu in people?

The symptoms of swine flu in people are similar to the symptoms of regular human flu, including fever, body aches, runny nose, sore throat, nausea, or vomiting or diarrhea. Like seasonal flu, swine flu may cause a worsening of pre-existing chronic medical conditions.

Some cases of swine flu have led to severe illness, including pneumonia and respiratory failure, and death in some cases.

Urgent medical care may be needed if an adult is experiencing difficulty breathing, pain or pressure in the chest or abdomen, sudden dizziness, confusion or severe and persistent vomiting.

In children, urgent care may be needed if the child has quickened or troubled breathing, bluish skin color, fever with a rash, is not drinking enough fluids, not waking up or interacting, or if the child has flu symptoms that improve, but then return with more severity.

-How does swine flu spread?

Spread of the H1N1 swine influenza virus is thought to be happening in the same way that seasonal flu spreads, from person to person through coughing or sneezing. Droplets from a cough or sneeze of an infected person carry the disease through the air. Touching objects that have the flu virus on them, then touching the mouth, nose or eyes can also cause transmission.

Infected people can pass the disease onto others one day before symptoms develop and up to seven or more days after becoming sick.

Eating pork or pork products has not been linked to the spread of swine flu. The CDC's Web site states that swine influenza viruses are not transmitted by food.

-Have there been past cases of swine flu in humans?

According to the CDC, the agency has received reports of approximately one human swine influenza virus infection every one to two years in the U.S., but from December 2005 through February 2009, 12 cases of human infection with swine influenza have been reported.

-What can be done to prevent getting sick?

The CDC has announced that existing flu vaccines are not effective on the H1N1 swine influenza virus. However, precautions should be taken similarly to guarding against other strains of flu to avoid infection. Washing hands often with soap and water is important, as well as avoiding close contact with people who are sick and touching surfaces that could be contaminated.

If individuals cover their nose and mouth with a tissue when they cough or sneeze that can help curb the spread. If a person is sick with influenza, CDC recommends that he or she stay home from work or school and limit contact with others.

-What medications are available to treat swine flu?

Laboratory testing has found the swine influenza A H1N1 virus is susceptible to the prescription antiviral drugs oseltamivir and zanamivir.

These drugs fight against the flu by keeping flu viruses from reproducing in the body and can make the illness milder and prevent serious complications.

-Is a vaccine being created for this strain of swine flu?

The CDC is creating what is called a "seed stock" for this strain of swine flu, which is a stock of the virus that would be used to make a vaccine if that decision is made. CDC Director Richard Besser told members of the press on April 27 that discussions were still ongoing and no decision had been made as to whether a vaccine for the H1N1 strain should be created.

Thomas Inglesby, deputy director for the Center for Biosecurity at the University of Pittsburg Medical Center said Monday the CDC is moving towards creating a prototype vaccine.

-What might account for the more deadly nature of the virus in Mexico, versus the cases seen in the U.S.?

CDC Director Richard Besser said on April 27 that the cause for the different disease spectrums, or differences in the severity of the disease, in the two countries is not known yet and is being investigated.

Some public health experts have suggested that the death rate among those infected in Mexico is not as high as it seems because there may have been many more milder cases of the strain of swine flu that have not been reported or confirmed.

-Should the WHO decide to increase its pandemic alert level, would that change health recommendations in the United States?

CDC Director Richard Besser said a change in the pandemic alert level would not change the CDC's response to the disease. Besser said, "Our actions are based on what is taking place in out country and in our communities...we are acting aggressively and whether they go from a phase three to a phase four would not change anything that we are currently doing."

-What is a flu pandemic?

Flu pandemics occur when a strain of the flu virus mutates into a new form that people have no natural immunity to and can spread from human to human. The most severe flu pandemic on record was the 1918 Spanish Flu, which killed as many as 50 million people around the world.

--What's the difference between an outbreak, an epidemic and a pandemic?

An outbreak is a sudden increase in the numbers of a particular illness. An epidemic is a disease that spreads rapidly and widely in a localized region or country. A pandemic is a worldwide outbreak of disease, typically affecting millions of people.

Sources: Centers for Disease Control, World Health Organization, Associated Press, NPR