Environmental Health & Safety

Understand


In order for you to understand the risks associated with a possible flu pandemic, it is important to that you recognize the three primary types of flu and understand how they differ from each other.

Seasonal Flu
Avian "Bird" Flu
Pandemic Flu

(The below information is adapted from material gathered from the Centers for Disease Control, www.cdc.gov/flu.)

Seasonal Flu


Seasonal flu is a contagious respiratory illness caused by influenza viruses that can cause mild to severe symptoms and can sometimes lead to death, generally in the elderly or people with underlying chronic illnesses. Getting a flu vaccination each fall is the best way to prevent this illness.

During an average year in the United States:
  • 5 to 20 percent of the population gets the flu
  • over 200,000 people are hospitalized from flu complications
  • about 36,000 people die
How Flu Spreads
Flu viruses spread in respiratory droplets caused by coughing and sneezing. They usually spread from person to person, through touching something with flu viruses on it and then touching their mouth or nose sometimes infects people. Most healthy adults are infectious beginning one day before symptoms develop and up to five days after becoming sick. That means you can give someone else the flu before you know you are sick, as well as while you are sick.

Common Flu Symptoms
  • fever (usually high, greater than 100.5º Fahrenheit)
  • headache
  • extreme fatigue
  • dry cough
  • sore throat
  • runny or stuffy nose
  • muscle aches
  • occasionally stomach symptoms, such as nausea, vomiting, and diarrhea (more common in children than adults)
Certain groups-such as older people, young children, and people with certain health conditions-are at a higher risk for serious flu complications.

Flu Complications
Complications of flu can include bacterial pneumonia, dehydration, and worsening of chronic medical conditions like congestive heart failure, asthma, or diabetes. Children may get sinus problems and ear infections.

Avian "Bird" Flu


Avian (or bird) flu is caused by influenza viruses that occur naturally among wild birds. The H5N1 variant, one strain of the bird flu, is deadly to domestic fowl and can be transmitted from birds to humans, though the risk is generally low to most people. Several species of wild fowl can harbor this virus without showing signs of illness. Confirmed cases of avian flu infection in humans have been reported since 1997, and the H5N1 flu in humans can currently be found in much of Asia and has spread to Europe. There is no human immunity and no vaccine is available, however vaccine development efforts are underway.

Avian H5N1 flu in humans is currently very limited and NOT a pandemic. However, it is uncertain whether the currently circulating H5N1 virus will lead to a global disease outbreak in humans.

See www.pandemicflu.gov/#map for a map showing the nations with confirmed human cases and the number of cases.

How the Bird Flu Spreads
Close contact with infected poultry has been the primary source for human infection. Wild birds can carry the viruses without showing signs of illness, and may also be infectious to humans. The virus is quite contagious in birds, though the H5N1 virus does not infect humans easily. Close contact with sick domestic fowl or consumption of uncooked or undercooked poultry has been the usual cause of illness when people have become infected.

The spread of avian influenza viruses from one ill person to another has been reported very rarely, and transmission has not been observed to continue beyond one person. Because all influenza viruses have the ability to change, scientists are concerned that the H5N1 virus could one day easily infect humans and spread easily from one person to another.

More than half of the humans who have sought health care because of H5N1 infections with bird flu have died. It is unclear how many people have been infected but have not developed severe symptoms.


Symptoms of Bird Flu
Symptoms of bird flu in humans are typical human influenza-like symptoms (e.g., fever, cough, sore throat, and muscle aches). In addition, bird flu-specific symptoms include eye infections, pneumonia, severe respiratory diseases (such as acute respiratory distress), and other severe and life-threatening complications. Some of the symptoms are a consequence of the body's response to this particular virus.

Pandemic Flu


A pandemic is a global disease outbreak. A flu pandemic occurs when a new influenza virus emerges for which people have little or no immunity, and for which there is no vaccine. A pandemic disease spreads easily from person to person, causes serious illness, and can sweep across the country and around the world in a very short time. Currently, there is no pandemic flu, as the avian flu is not spreading among humans easily.

Pandemic Predictions
Experts at the World Health Organization (WHO) and elsewhere believe that the world is now closer to another influenza pandemic than at any time since 1968, when the last of the previous century's three pandemics occurred. WHO uses a series of six phases of pandemic alert to inform the world of the seriousness of the threat.

The world is presently in phase three: a new influenza virus (avian flu) is causing disease in humans, but is not yet spreading rapidly among humans.

No one can predict when a pandemic might occur. However, experts from around the world are watching the avian flu in Asia and Europe very closely and are preparing for the possibility that the virus may begin to spread more easily and widely from person to person.

Wherever and whenever a pandemic starts, everyone around the world is at risk. Countries might delay arrival of the virus through measures such as border closures and travel restrictions, but they cannot stop it.


Impact of a Pandemic
A pandemic may come and go in waves, each of which can last for six to eight weeks.

An especially severe influenza pandemic could lead to high levels of illness, death, social disruption, and economic loss. Everyday life would be disrupted because so many people in so many places become seriously ill at the same time. Impacts can range from school and business closings to the interruption of basic services such as public transportation and food delivery.

Health care facilities can be overwhelmed, creating a shortage of hospital staff, beds, ventilators and other supplies. The need for vaccine is likely to outstrip supply, and the supply of antiviral drugs also is likely to be inadequate early in a pandemic. Difficult decisions will need to be made regarding who gets antiviral drugs and vaccines.

Historically, the 20th century experienced three influenza pandemics:
  • 1918 influenza pandemic caused at least 675,000 U.S. deaths and up to 50 million deaths worldwide
  • 1957 influenza pandemic caused at least 70,000 U.S. deaths and 1-2 million deaths worldwide
  • 1968 influenza pandemic caused about 34,000 U.S. deaths and 700,000 deaths worldwide