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

What You Need To Know About Infectious Disease


Chickenpox is a highly contagious disease characterized by itchy, blister-like sores all over the body. It is caused by the varicella-zoster virus, part of the herpesvirus family. The virus spreads 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. Most cases of chickenpox appear in children under the age of 15.

The rash appears 10 to 21 days after the individual comes in contact with the virus. Before then, typical symptoms include fever, headache, or a stomachache. Throughout the course of the illness, it is not unusual for a person to have between 200 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 preventing him or her from scratching 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, 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 highly 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 between 12 and 15 months, and the second dose between the ages of 4 and 5. For people ages 13 and older who have not had the chickenpox, they should also receive two doses 4 to 8 weeks 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


A type of virus that is responsible for causing upper respiratory tract infections in humans, otherwise known as the common cold.

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