HIV: Human Immunodeficiency Virus, infects human immune cells, particularly CD4+ T cells.
AIDS: Acquired Immunodeficiency Syndrome, the final stage of HIV infection. Characterized by a group of symptoms (syndrome) common to those with a deteriorated immune system. Defined by the U.S. Centers for Disease Control as a CD4 cell count below 200 or by the presence of particular opportunistic infections in individuals who have tested positive for HIV.
- More than 22 million people have already died from AIDS and more than 35 million (1 in every 100) are currently infected
- Half of those infected are women and children, half of the infected live in Africa
- According to the World Heath Organization (WHO), 5 million new infections occurred in 2005, more than 3 million of those occurring in Africa
- The WHO predicts that 45 million new infections will occur worldwide between 2002 and 2010
- Most new infections occur in those between the ages of 15 and 24
- AIDS is the 5th largest cause of death in adults between the ages of 25 and 44
- The largest growing group of infected individuals are the heterosexual female partners of infected men
How does infection occur?
The virus is transmitted from body fluid to body fluid and cannot live outside of the human body for any significant length of time. Disinfectants and barriers (such as bleach, condoms, and surgical gloves) are effective preventative measures to the spread of the virus.
- Sharing needles: 25% of reported cases are intravenous drug users, infected blood contaminates syringes and needles and is then injected into the bloodstream with the drugs
- Body fluid and blood exchange: Prior to testing blood bank donations for HIV (1986) some individuals were infected when undergoing transfusions for bleeding disorders. Also sexual contact transmits the virus when it is absorbed by the inflamed reproductive tissue during intercourse or infected fluids into the bloodstream through cuts or sores on the body or mouth. Healthcare workers are also at risk if pricked by contaminated needles/utensils used on HIV+ patients or if they come into direct contact with infected blood and it enters their bloodstream through a cut or sore.
- Pregnancy: Infection from mother to child can occur in utero from transplacental spread (meaning it crosses the placenta from the mothers bloodstream to the fetus'), during birth trauma if there is blood exchanged, and from the ingestion of infected breast milk. Breast milk infects approximately 2000 infants a day worldwide.
Opportunistic infections
These are infections that are sometimes seen in non-AIDS patients, but for the most part define AIDS because healthy individuals tend to clear the infectious agents without incident
- Pneumonia caused by Pneumocystis carnii
- Fungal infections including mucosal candidiasis
- Sever herpes ulcerations
- Meningitis and toxoplasmosis infections of the central nervous system
- Kaposi's Sarcoma: a secondary vascular neoplasm, or growth
AIDS dementia: Brain damage due to infection spreading to the brain; manifests as headaches, swelling of the brain, and cognitive difficulties. This is still being characterized and little is known as to why this occurs.
Treatment
Anti-retroviral therapy (ARVs): attacks the enzyme (reverse transcriptase) necessary for virus replication.
Protease inhibitors: prevents the full formation of viral proteins thus preventing virus replication
Most drugs are given as cocktails to attack the virus on many levels and prevent drug resistance by the virus. Depending on the strain of infection and the stage at which treatment is started, different drugs will work differently for different people in different combinations. This is why it is so difficult to treat HIV infection. HIV is persistent and will remain in the lymph nodes even with treatment, so it is a lifelong obligation.
As of now there is no vaccine. The virus mutates too rapidly to use a dead strain and the use of a weakened strain is not possible due to how it infects. It is predicted that a comprehensive approach to prevention will avert 63% of projected new infections by 2010!
