HIV/AIDS: Etiology and Oral Manifestations

HIV is a relatively fragile virus. It is not spread by casual contact. It is not easy to "catch"; it must be acquired. HIV is considered to be a fragile virus when exposed to air and room temperatures. Hepatitis B (HBV) and hepatitis C (HCV) are both considered "stronger" viruses that can remain infectious for a longer period of time. When these viruses are outside the human body, much depends on environmental factors such as heat, cold, exposure to oxygen, etc.). HBV and HCV will be discussed later in this course.

The Chain of Infection provides a model for understanding how any infection is spread. All of the components below must be present for an infection to occur.

The pathogenic microorganism is the micro-organism that causes infection such as bacteria, viruses, fungi and parasites.

The reservoir is the place where micro-organisms live, such as in humans and animals, in soils, food, plants, air or water. The reservoir must meet the needs of the pathogen in order for the pathogen to survive and multiply.

The means of escape are how the micro-organism leaves the reservoir.

The method of transmission is how the micro-organism moves from place to place.

The means of entry is how the micro-organism enters the host. There must be an adequate number of organisms to cause infection.

The host susceptibility is the person who may become infected.

All of these components together are considered to be the "chain of infection". In the dental care setting, all of these factors come into play in the spread or the control of infection. There are effective strategies of infection control that will prevent infection transmission by interrupting one or more links in the chain of infection (CDC, 2003).

As this chain of infection relates to HIV/AIDS:

The pathogenic microorganism is the human immune deficiency virus, or HIV.
The reservoir is blood or body fluids of the "source" patient; anyone with the virus can be an HIV source.
The means of escape are how the blood or body fluids of the source patient exit the source patient. This includes infected blood, semen, vaginal secretions or breast milk.
Mode of transmission is through direct contact with infected blood or body fluids noted above.
The means of entry is through the non-intact skin that can occur through unprotected sex, injecting drug use, and rarely splashing onto mucous membranes.
Host susceptibility is the person who may now become infected with HIV.

Anyone who is infected with HIV can be the HIV source. As above, transmission occurs primarily through infected blood, semen, vaginal secretions or breast milk. Sweat, tears, saliva, urine and feces are not capable of transmitting HIV unless visibly contaminated with blood. In settings such as hospital operating rooms, other fluids, like cerebrospinal fluid, synovial fluid, pleural fluid, pericardial fluid and amniotic fluid may be considered infectious if the source is HIV positive. These fluids are generally not found outside the hospital setting, so we consider the most common fluids -- blood, semen, vaginal secretions and breast milk -- as infectious in the "real world." Again, outside of the laboratory or medical and dental operation situations, ONLY blood, semen, vaginal fluids and breast milk are considered to be infectious for HIV.