Alternate Names : Human Immunodeficiency Virus, AIDS, Acquired Immune Deficiency Syndrome
Human immunodeficiency virus, or HIV, infection damages the body's immune system. Over time, it leads to acquired immune deficiency syndrome, or AIDS.
What is going on in the body?
HIV affects the immune system in broad and devastating ways. Its main target is a special immune system cell called the CD4+ T lymphocyte. These cells help the body fight infections of all kinds. When HIV infects these cells, it decreases their numbers and affects how the cells that are left function.
After an adult is infected with HIV, he or she usually has no obvious symptoms for 5 to 10 years. During this time, however, the virus is slowly attacking the immune system. When the immune system is weakened enough, it becomes susceptible to other organisms that the body can usually fight off or keep under control. These other organisms include bacteria, other viruses, fungi, and parasites.
Many serious health problems occur as a result of the immune system damage caused by HIV. The most serious is AIDS.
What are the causes and risks of the disease?
HIV infection is caused by a type of virus known as a lentivirus. Seventy percent of HIV infections worldwide are sexually transmitted, or spread by sexual contact. The remaining 30% of the infections are spread in one of the following ways:
by contact with HIV-infected blood or other secretions at the site of a cut or wound
by skin punctures from needles or other sharp devices contaminated with HIV-infected blood or other body secretions
from contaminated blood products received before March 1985, when a screening test for HIV in blood products was first used
from mother to infant around the time of birth
Following are some of the risk factors for HIV infections:
having received blood transfusions or blood products, especially from 1975 to March 1985
having received pooled plasma for treatment of hemophilia, a blood clotting disorder
intravenous drug use
sexual activity with an infected individual, particularly male homosexual contact