The Centers For Disease Control (CDC) recommends the use of NIOSH approved N95 face masks when entering a room containing an Avian bird flu patient.
Here are the symptoms of Avian bird flu in humans according to the CDC:
"Symptoms have ranged from typical flu-like symptoms (fever, cough, sore throat and muscle aches) to eye infections, pneumonia, severe respiratory diseases (such as acute respiratory distress), and other severe and life-threatening complications."
The death rate of the reported cases of Bird Flu, so far, is more than 50%.
For biological terrorist attacks, United States Senator Bill Frist, a physician and public health expert, recommended in his recent book, "When Every Moment Counts," that people should have face masks rated "N95" or better for each family member.
Because the face mask is fluid resistant, it also aids in reducing the potential exposure of the wearer to blood and other body fluids. Also effective against smoke and dust. It is not effective against aerosols containing oil.
There is no published data on the length of time the mask is effective for the wearer. Health Canada recommends masks should be changed if they become wet, interfere with breathing, are damaged, or visibly soiled. The face masks should be carefully thrown away immediately after using. Do not touch the outside of the mask because you might contaminate your fingers. Remove it by using only the straps.
People who are sick with a communicable disease should wear face masks without the exhalation valve to help prevent transmission of the disease to other people.
Do not use this mask for filtering gases or vapors, including those present in paint spraying operations, oil aerosols, asbestos or sandblasting. This respirator does not supply oxygen.
