There are a number of steps in the infection process:
Researchers have found HIV in virtually every body fluid, including tears, saliva, urine, blood, semen, mucus, and vaginal and anal secretions. Despite that, HIV is not easily transmitted from one individual to another.
Successful transmission of HIV is dependent upon a number of factors. These factors include:
Taking all of these factors into consideration, 3 conditions must be met for disease transmission of HIV:
1. HIV must pass beyond the body's barrier protection, either cutaneous or membraneous .
2. HIV must contact and gain access to a receptive host cell
3. HIV must replicate.
Infection takes place only when
the human immunodeficiency virus (HIV) enters the body and completes a specific set
of processes:
1. Binding and fusion: The virus binds with receptors (CD4 and one additional)
on the surface of a cell, then fuses with the host cell, inserting
its RNA into the host cell.
2. Reverse transcription: An HIV enzyme (reverse transcriptase) uses
the single-stranded HIV RNA to assemble a double-stranded HIV DNA molecule.
3. Integration: The HIV DNA enters the host cell's nucleus, where an HIV
enzyme (integrase) integrates the HIV DNA into the host cell's own
DNA. This now-integrated DNA is called a provirus and may remain inactive for
several years, producing few or no new copies of HIV.
4. Transcription: When the host cells receives a signal to activate,
the provirus uses a host enzyme called "RNA polymerase" to
create copies of the HIV RNA. The RNA is used as a template by host ribosomes to create HIV protein strands.
5. Assembly: An HIV enzyme, called protease, cuts the long chains of
HIV proteins at specific sites into smaller individual proteins. These small proteins come together
with copies of HIV's RNA genetic material, to create a new viral particle.
6. Budding: The new virus pushes out, or buds, from the host cell.
During budding, the new viruses take part of the cell's outer envelope, which
acts as a covering, and is studded with protein/sugar combinations, called HIV
glycoproteins. These HIV glycoproteins are necessary for the virus to bind CD4
and co-receptors on other host cells. The new copies of HIV can then move on
and infect other cells.
The replication process destroys the
CD4+ T-cells. HIV viral load increases rapidly until the CD4+ T-cell count begins to go down.
A person who is HIV positive does not automatically have AIDS. AIDS, by definition, is a syndrome with multiple specific symptoms. Approximately 50-90% of patients will have symptoms of acute retroviral syndrome within 1-4 weeks of infection. However, some individuals remain asymptomatic during this period.
|
Acute Signs |
| Flu-like symptoms: |
|
| Rash (Erythematous maculopapular with lesions on face, trunk, and sometimes extremities, including palms and soles; mucocutaneous ulceration of mouth, esophagus, or genitals) |
| Elevated liver enzymes |
| Thrombocytopenia, leukopenia |
| Thrush |
| Neurologic symptoms: |
|
A diagnosis of AIDS means that a patient's HIV disease has progressed to include .
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