A pandemic is a global disease outbreak. Public health officials are monitoring a particular strain of avian influenza virus (or bird flu), called H5N1, that is believed to have pandemic potential, according to the World Health Organization (WHO).

"A pandemic occurs," according to WHO, "when a new influenza virus emerges and starts spreading as easily as normal influenza — by coughing and sneezing. Because the virus is new, the human immune system will have no pre-existing immunity. This makes it likely that people who contract pandemic influenza will experience more serious disease than that caused by normal influenza."

Avian H5N1's pandemic potential: H5N1 is currently not a human influenza; it is not easily transmissible from person to person, and human infections with H5N1 viruses are rare. If this particular bird flu mutates into a strain contagious among people, H5N1 will be a new human influenza virus.

It's important to remember that while it is possible, it is by no means certain that H5N1 will mutate into a human influenza.

Learn more about pandemic flu and UCSD's efforts to prepare for that possibility — or other emerging diseases with pandemic potential. Read:

• Pandemic Influenza: FAQ
• UCSD Pandemic / Epidemic Response Initiative

Precautions you can take: Practicing good health habits is your best defense against the spread of flu. The U.S. Food and Drug Administration has approved the first vaccine for humans that may provide early limited protection against the current known strain of the H5N1 virus. The vaccine will not be sold commercially, but has been included in the federal government's National Stockpile for distribution by public health officials if needed.

• See Protecting Yourself from Pandemic Influenza for best practices to avoid contracting or spreading padnemic influenza.

Find more information about pandemic flu and avian influenza at the links below:

• Avian Influenza (Bird Flu), Centers for Disease Control and Prevention (CDC)
• Flu: Pandemic/Bird (PDF), County of San Diego
• Flu: What's the Difference?, County of San Diego
• Stopping the Spread of Germs at Home, Work & School, CDC
• Ten Things You Need to Know About Pandemic Influenza, World Health Organization (WHO)
• Travelers' Health (CDC)
• University of California contributions to understanding and containing the spread of avian influenza

If you are a UCSD employee and have questions about pandemic/ epidemic preparedness planning at UCSD, contact Emergency Services, (858) 534-1064 or 534-3823.