The threat that germs can present ranges anywhere from minor to catastrophic.

Many germs can make us mildly uncomfortable with the common cold, allergy sniffles, or the stomach flu. While our immune systems are generally equipped to combat them in relatively short order to get us quickly back on our feet, these mild diseases are still not fun, and they can disrupt the flow of our lives.

But even these garden-variety germs can threaten the life of anyone whose immune system is compromised by youth, old age or illness, and every effort should be made to prevent spreading them.

At the other end of the spectrum are very potent germs that few of us are equipped to fight off — some examples are West Nile Virus, SARS, and Bird Flu. Not only do they represent a serious threat to us individually, they are highly contagious and represent the potential for pandemic illness.