How much period of time for hiv to infect inblood?

HIV, the virus that causes AIDS, can infect a person within minutes or hours of exposure to infected blood. The virus enters the body through cuts or abrasions, or through the mucous membranes of the mouth, rectum, or vagina. Once in the body, the virus attacks the immune system and begins to make copies of itself. The first symptoms of HIV infection, such as fever, sore throat, and swollen glands, may not appear for 2 to 4 weeks after exposure. However, the virus is still contagious during this time, even if a person does not have symptoms.