The National Academies: What You Need To Know About Infectious Disease

The National Academies

What You Need To Know About Infectious Disease


Chickenpox is a highly contagious virus characterized by itchy blister-like sores all over the body. It is caused by the varicella-zoster virus, part of the herpesvirus family. Most cases of chickenpox appear in children under the age of 10. The disease can be spread through physical contact with someone with the illness or through airborne germs spread by sneezing and coughing. Although chickenpox used to be a common illness of childhood, it has become much less prevalent since the vaccine was introduced.

The rash appears 10 to 21 days after the individual comes in contact with the disease. Before then, typical symptoms include fever, headache, or a stomach ache. Throughout the course of the illness, it is not unusual for a person to have between 250 and 500 blisters. The blisters first appear on the face, chest, and scalp. After a couple of days, they become cloudy and then scab over. New blisters often appear in clusters and can be found in the mouth, on the eyelids, and in the genital area.

The most important part of treatment is keeping the individual comfortable and helping him/her not to scratch the blisters. Effective ways to accomplish this are keeping the fingernails short; having the individual wear loose, soft clothing; giving lukewarm baths with cornstarch and oatmeal; avoiding prolonged exposure to heat and humidity; and applying over-the-counter hydrocortisone cream to the blisters.

Otherwise healthy children should not be given antiviral medications, but teens or adults at risk for severe symptoms may benefit from these medications if given early. It is very important not to give children aspirin or ibuprofen; use of these products has been linked to a condition called Reyes syndrome, a potentially fatal ailment that can affect many organs, including the liver and the brain. Acetaminophen (Tylenol), however, is safe to use. Finally, children should not go back to school and adults should not go back to work until the blisters have crusted over or dried out.

Because chickenpox is so contagious, virtually the only way to avoid it is by getting the vaccine. It is given in two doses. Children should receive the first dose at 12 to 15 months, and the second dose between the ages of 4 and 5. If desired, the second dose can be given sooner, as long as 3 months have passed. For people 13 and older who have not had the chickenpox, they should also receive two doses 3 months apart.


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What do you know about infectious disease?

The human papillomavirus (HPV) causes about what percentage of cervical cancer cases?

  • Sorry, that’s incorrect.

    The human papillomavirus (HPV) causes more than 90% of cervical cancer cases.

  • Sorry, that’s incorrect.

    The human papillomavirus (HPV) causes more than 90% of cervical cancer cases.

  • Correct!

    The human papillomavirus (HPV) causes more than 90% of cervical cancer cases.

Infectious Disease Defined

Rheumatic Fever

An inflammatory disease that may be caused by an untreated or improperly treated case of strep throat.

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