HIV (short for "Human Immunodeficiency Virus") is a virus that attacks the body’s immune system. If HIV is not treated, it can lead to AIDS (Acquired Immunodeficiency Syndrome). There is currently no effective cure. Once people get HIV, they have it for life but with proper medical care, HIV can be controlled. People with HIV who get effective HIV treatment can live long, healthy lives and protect their partners.


HIV infection in humans came from a type of chimpanzee in Central Africa. Studies show that HIV may have jumped from chimpanzees to humans as far back as the late 1800s. The chimpanzee version of the virus is called Simian Immunodeficiency Virus. It was probably passed to humans when humans hunted these chimpanzees for meat and came in contact with their infected blood. Over decades, HIV slowly spread across Africa and later into other parts of the world. The virus has existed in the United States since at least the mid to late 1970s.


The virus is spread (transmitted) person-to-person through certain body fluids:

  • Blood
  • Semen and preseminal fluid
  • Rectal fluids
  • Vaginal fluids
  • Breast milk

HIV can be spread if these fluids come in contact with:

  • Mucous membranes (inside of the mouth, penis, vagina, rectum)
  • Damaged tissue (tissue that has been cut or scraped)
  • The blood stream by injection
  • HIV cannot be spread through sweat, saliva, or urine.

In the United States, HIV is mainly spread:

Through vaginal or anal sex without using a condom with someone who has HIV who is not taking medicines to prevent or treat HIV
Through needle sharing or other equipment used to inject drugs with someone who has HIV

Less often, HIV is spread:

  • From mother to child. A pregnant woman can spread the virus to her fetus through their shared blood circulation, or a nursing mother can pass it to her baby through her breast milk. Testing and treatment of HIV-positive mothers has helped lower the number of babies getting HIV.
  • Through needle sticks or other sharp objects that are contaminated with HIV (mainly health care workers).

The virus is NOT spread by:

  • Casual contact, such as hugging or closed-mouth kissing
  • Mosquitoes or pets
  • Participating in sports
  • Touching items that were touched by a person infected with the virus
  • Eating food handled by a person with HIV
  • Intimate contact with an HIV-positive person with a stably undetectable viral load

Risk factors for getting HIV include:

  • Having unprotected anal or vaginal sex. Receptive anal sex is the riskiest.
  • Having multiple partners also increases the risk. Using a new condom correctly every time you have sex greatly helps lower this risk.
  • Using drugs and sharing needles or syringes.
  • Having a sexual partner with HIV who is not taking HIV medicines or who has a detectable viral load.
  • Having a sexually-transmitted disease (STD).


Symptoms related to acute HIV infection (when a person is first infected) can be similar to the flu or other viral illnesses. They include:

  • Fever and muscle pains
  • Headache
  • Sore throat
  • Night sweats
  • Mouth sores, including yeast infection (thrush)
  • Swollen lymph glands
  • Diarrhea

For additional information and vaccine referral services, please email at or call (509) 431-4958.

DISCLOSURE: Content displayed on this page is collected from:

Centers for Disease Control and Prevention

Unversity of Pennsylvania School of Medicine, PennMed

Disclaimer: This project is supported by the Centers for Disease Control and Prevention (CDC) of the U.S. Department of Health and Human Services (HHS) as part of a financial assistance award totaling $9 million for HIV; $5 million for Mpox with 100 percent funded by CDC/HHS. The contents are those of the author(s) and do not necessarily represent the official views of, nor an endorsement by, CDC/HHS or the U.S. Government.