Department of Molecular Virology and Microbiology Swine ‘09 The 2009 H1N1 Influenza Pandemic

Department of Molecular Virology and Microbiology

Swine ‘09

The 2009 H1N1 Influenza Pandemic


What is the 2009 Swine Flu?

• A new type of flu that infects people• Like regular flu, it is a respiratory disease

that causes fever, aches, coughing, runny nose, chills, and tiredness

• More likely than regular flu to cause vomiting and diarrhea

• Contagious disease that spreads from person to person through microscopic particles that enter the air from coughs and sneezes of infected people

• Caused by a new type of flu virus


What is a Flu Virus?

• Viruses are microscopic particles that contain genetic material (DNA or RNA) surrounded by a protein coating

• Viruses must infect cells to make more copies of themselves

• Flu – or influenza – viruses have RNA as their genetic material

• Flu viruses have eight pieces of RNA that hold the instructions for making more copies of itself


Why is it called “Swine” Flu?

• The flu can cause disease not only in humans, but also in animals like pigs and birds

• The new virus is made from pieces of flu viruses that infect pigs from North America, pigs from Eurasia, and pieces from human and bird flu viruses that were all mixed together

• Scientific name is Influenza A/H1N1

Eurasian North American+ + +


What does “Influenza A/H1N1” mean?

• Three types of flu viruses – A, B, and C• The “A” type is the most dangerous• Divided into subtypes based on two proteins that

spike out of the virus• H – or hemagglutinin – 16 versions, needed for

virus to enter cell• N – or neuraminidase – 9 versions, needed for

virus to leave cell• H1N1 has version 1 of “H” protein and version 1

of “N” protein• Virus with version 3 of H and version 2 of N is

called… H3N2


How are new flu viruses created?

• Two different flu viruses infect one cell and are mixed together into a new virus


How is swine flu different from regular flu?

• Regular flu viruses that occur each season undergo small genetic changes– Called drift– Reason that flu shots are needed each year

• Swine flu is an example of a pandemic flu formed when large genetic changes happen – Called shift– Produces a new virus with a new combination

of “H” and “N” proteins– People have little immunity or defense against

the new virus


What is a Pandemic?

• A disease that has spread to different areas of the world and affects many people

• Occurs when a new virus appears that can infect humans and spread easily from person to person

• Means the disease spreads in many parts of the world, not that the disease is serious for most people

• Pandemic flu usually lasts more than one season, will return again in the fall/winter


Have there been other pandemics?

• There were three flu pandemics in the last century– 1918 – most deadly

• more than 500,000 deaths in the U.S. and up to 50 million people worldwide

• Played a role in ending World War I– 1957 – about two million deaths– 1968 – about one million deaths

• H1N1 swine flu is the first pandemic of the 21st century


How fast has H1N1 swine flu spread?

• First detected in Mexico in late April, 2009• Quickly spread through North America• By June, swine flu was spreading in Europe,

South America, and Asia• Pandemic declared by the World Health

Organization on June 11• By the end of October, more than 440,000 people

in about 200 countries around the world were confirmed to have had swine flu by laboratory tests. Actual numbers are much higher.

• Estimated that millions of Americans have had swine flu


What’s the big deal about H1N1?

• New virus that never existed before so few people have protection against it

• More people will get infected with swine flu than get regular flu

• More younger people are getting infected than with regular flu

• Flu viruses are unpredictable and could change again

• Flu viruses can be deadly, especially for people with some health problems


How can I stay healthy?

• Wash your hands often with soap and water (at least 15 seconds) or hand sanitizers

• Cough and sneeze into a tissue and discard tissue into a trash can

• If no tissue is available, cough or sneeze into the inside of your elbow

• Avoid touching your eyes, nose, or mouth• Do not share food, drinks, or personal items • Stay informed about the flu situation• Follow instructions about school and other

closings


What should I do if I get the swine flu?

• Stay home from school (and the mall!) and limit your contact with other people

• Don’t panic - most people get a mild disease – like regular flu – and recover completely even without treatment

• Check with a doctor to see if treatment is advised to shorten the length of illness and reduce the chance of spreading the virus

• If you are very ill or have a medical condition (such as asthma, diabetes, heart or lung disease), contact a doctor or other health professional


Are there drugs or vaccines?

• Two drugs work against the new H1N1 swine flu – Tamiflu and Relenza

• Drugs block the action of the “N” protein • Their use is not needed for all patients, but is

likely to be used in patients at high risk• A vaccine to prevent swine flu has been

developed and tested• Limited doses of the H1N1 vaccine are

currently available; more is on the way• Priority for the H1N1 vaccine is given to high-

risk groups, including school-age children


What are scientists doing about H1N1?

• Monitoring the spread of the virus • Finding out which people are at highest

risk• Analyzing the genetic makeup of the virus

to get an idea of how dangerous the virus is or if it is changing

• Developing and testing vaccines that can safely prevent infection by H1N1

• Studying the immune responses of infected and vaccinated people


Summary

• Swine flu is caused by a new flu virus – the 2009 H1N1 virus - that never existed before

• H1N1 contains pieces from pig (swine) flu viruses• Most people do not have natural protection against the

new H1N1 virus, so many people will get infected• H1N1 has spread around the world faster than any other

virus• Most people recover completely without medicine, but

treatment can shorten the length of sickness• A vaccine is available, but supplies are limited• Maintain good hygiene and stay informed

Documents

Department of Molecular Virology and Microbiology Swine ‘09 The 2009 H1N1 Influenza Pandemic