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

What You Need To Know About Infectious Disease


Meningitis is an inflammation of the meninges, the coverings of the brain and spinal cord. Meningitis is usually caused by either a virus or bacteria, and treatment differs depending on the cause. Viral meningitis is usually less severe and can heal on its own. Bacterial meningitis, however, can be quite serious, potentially resulting in brain damage, hearing loss, or learning disabilities.

Meningococcal disease is caused by Neisseria meningitidis bacteria, of which there are five serogroups, or strains: A, B, C, W, and Y. These five strains cause most of the meningitis worldwide. Three strains—B, C, and Y—cause most of the illness seen in the United States. Vaccines are now available for all three of these strains. Meningitis caused by Neisseria meningitidis is called meningococcal meningitis.

The early symptoms of viral and bacterial meningitis are quite similar. In adults, they include nausea, vomiting, high fever, severe headache, and sensitivity to light. In infants, usual symptoms are fever, irritability, poor eating, and difficulty waking up. For people with viral meningitis, these symptoms usually disappear within 7 to 10 days. But bacterial meningitis progresses and becomes more serious, causing seizures and coma. When the infection enters the bloodstream, it is called meningococcemia. This disease is quite serious and causes additional symptoms—fever, fatigue, vomiting, cold hands and feet, cold chills, muscle and joint pain, rapid breathing, and diarrhea. In its later stages, a red or purplish rash may appear. Severe cases of meningococcemia can result in death in a matter of hours.

Bacterial meningitis is treated with a number of different antibiotics. For the best outcomes, it is important to start treatment early in the course of the disease. For viral meningitis, there is no specific treatment. Most people recover on their own from this form of the illness.

Vaccines are the best defense against meningitis. Those that are currently available protect against all three most common bacterial strains. All 11 to 12 year olds should be vaccinated against strains A, C, W, and Y. Teens and young adults between the ages of 16 and 23 should also be vaccinated against the B strain of the bacteria. Younger people should receive this vaccine if they are identified as being at risk for meningitis. Following healthy habits, such as eating properly and getting plenty of rest, helps give the immune system further protection against meningitis.


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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


The relative occurrence of a disease or a condition that causes illness.

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