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

The National Academies

What You Need To Know About Infectious Disease


HIV, or human immunodeficiency virus, is the virus that can lead to acquired immune deficiency syndrome, or AIDS. HIV damages the immune system by destroying specific blood cells, called CD4+ T cells, which are crucial to helping the body fight diseases. HIV is primarily transmitted by unprotected sex with an infected person. It can also be spread by sharing needles, syringes, and rinse water when preparing illicit drugs for injection and from mother to child during pregnancy, birth, or breast-feeding. Because HIV cannot reproduce outside the human body, it cannot be spread through air, water, insects, saliva, tears, or sweat, nor can it be transmitted through casual contact, such as shaking hands, sharing dishes, or closed mouth (“social”) kissing.

AIDS is the late stage of HIV infection. The onset of AIDS means that the immune system has become severely damaged and has difficulty fighting diseases and certain cancers.

Within a few weeks of being infected with HIV, some people develop flu-like symptoms that last for a week or two but others have no symptoms at all. Although people living with HIV may appear and feel healthy for several years, HIV is still affecting their bodies. Untreated HIV infection is associated with many diseases, including cardiovascular disease, kidney disease, liver disease, and cancer.

There is no cure for HIV/AIDS. Many people with HIV, including those who feel healthy, can benefit greatly from medications used to treat HIV infection. These medications can limit or slow the destruction of the immune system, improve the health of people living with HIV, and possibly reduce the likelihood of transmitting HIV. In some cases, HIV medications taken immediately after exposure can prevent infection, a phenomenon called post-exposure prophylaxis. Individuals already infected and on a treatment regimen must be monitored carefully, and the medications must be taken daily, for life. The medications have potential side effects, such as nausea, vomiting, or diarrhea; abnormal heartbeats; shortness of breath; and skin rash.

Knowing one’s HIV status can help prevent the spread of the disease in the population through sexual transmission. Limiting the number of sexual partners, abstaining from sex, or being in a long-term mutually monogamous relationship with an uninfected partner are all effective ways to prevent the spread of HIV. Correct and consistent condom use can also reduce the risk of transmission. Drug users should ideally receive counseling and treatment to stop or reduce drug use but at a minimum they should use clean needles when injecting.


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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


An external skeleton that protects and supports an organism, in contrast to an internal endoskeleton.

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