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

What You Need To Know About Infectious Disease


Measles is a highly contagious respiratory disease caused by a virus. The virus lives in mucus in the nose and throat of an infected person. The infected person can spread the virus through the air by breathing, coughing, or sneezing. 

While measles is very rare in many countries, and was considered eliminated in the United States in 2000, more cases have been reported in recent years, in part because some parents are choosing to forgo the vaccine for their children. According to the Centers for Disease Control and Prevention and the World Health Organization, 188 cases of measles in 24 states and 5 outbreaks were reported in 2015, compared to an average of 70 cases per year in the 2000s. Worldwide, however, measles continues to be one of the leading causes of deaths, but that is changing, largely because of more robust vaccination efforts. While globally there were 134,200 measles-related deaths in 2015, vaccination resulted in a 79 percent decline in mortality between 2000 and 2015.

A typical case of measles begins with mild to moderate fever, cough, runny nose, and red eyes. Tiny white spots may appear inside the mouth 2 to 3 days after symptoms begin, followed by a red or reddish-brown rash that appears 3 to 5 days after the start of symptoms. The rash usually begins on a person’s face at the hairline and spreads downward to the neck, trunk, arms, legs, and feet. When the rash appears, a person’s fever may spike to more than 104°F. After a few days, the fever subsides and the rash fades.

There is no specific treatment for measles. However, acetaminophen, general bed rest, and humidified air can all help relieve symptoms. In some developing countries, where children may not get enough vitamin A in their diet, supplements can help prevent eye damage and blindness and have been shown to reduce the risk of death and complications. It is not clear whether children in more developed countries would benefit from supplements.

Measles can be prevented by the combination MMR (measles, mumps, and rubella) vaccine. In the decade before the measles vaccination program began, an estimated 3 to 4 million people in the United States were infected each year, of whom 400 to 500 died and 48,000 were hospitalized. Another 4,000 suffered from encephalitis, or the swelling of the brain. Widespread use of the measles vaccine has led to a significant reduction in measles cases in the United States compared with the pre-vaccine era. 


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What do you know about infectious disease?

Which are larger?

  • Correct!

    Bacteria are 10 to 100 times larger than viruses.

  • Sorry, that’s incorrect.

    Bacteria are 10 to 100 times larger than viruses.

Infectious Disease Defined


An organism in which a parasite that is pathogenic for some other organism lives and reproduces without harming its host.

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