Description of HIV
Human immunodeficiency virus infection / acquired immunodeficiency syndrome (HIV/AIDS) is a disease of the human immune system
caused by infection with human immunodeficiency virus (HIV). During the initial infection, a person may experience a brief period of
influenza-like illness. This is typically followed by a prolonged period without symptoms. As the illness progresses, it interferes more and
more with the immune system, making the person much more likely to get infections, including opportunistic infections and tumors that
do not usually affect people who have working immune systems.
Description of AIDS
Acquired immunodeficiency syndrome (AIDS) is defined in terms of either a CD4+ T cell count below 200 cells per L or the occurrence of
specific diseases in association with an HIV infection. In the absence of specific treatment, around half the people infected with HIV
develop AIDS within ten years. The most common initial conditions that alert to the presence of AIDS are pneumocystis pneumonia
(40%), cachexia in the form of HIV wasting syndrome (20%) and esophageal candidiasis. Other common signs include recurring
respiratory tract infections.
Opportunistic infections may be caused by bacteria, viruses, fungi and parasites that are normally controlled by the immune system.
Which infections occur partly depends on what organisms are common in the person's environment. These infections may affect nearly
every organ system. People with AIDS have an increased risk of developing various viral induced cancers
Origination of HIV
Genetic research indicates that HIV originated in west-central Africa during the early twentieth century. AIDS
was first recognized by the Centers for Disease Control and Prevention (CDC) in 1981 and its cause HIV
infection was identified in the early part of the decade. Since its discovery, AIDS has caused nearly
30 million deaths (as of 2009). As of 2010, approximately 34 million people are living with HIV globally.
AIDS is considered a pandemic a disease outbreak which is present over a large area and is actively
Effect of HIV on the immunity system
After the virus enters the body there is a period of rapid viral replication, leading to an abundance of virus in
the peripheral blood. During primary infection, the level of HIV may reach several million virus particles per
milliliter of blood. This response is accompanied by a marked drop in the number of circulating CD4+ T cells.
The acute viremia is almost invariably associated with activation of CD8+ T cells, which kill HIV-infected
cells, and subsequently with antibody production, or seroconversion. The CD8+ T cell response is thought to
be important in controlling virus levels, which peak and then decline, as the CD4+ T cell counts recover. A
good CD8+ T cell response has been linked to slower disease progression and a better prognosis, though it
does not eliminate the virus.
Spreading of HIV
HIV is transmitted by three main routes: sexual contact, exposure to infected body fluids or tissues, and from
mother to child during pregnancy, delivery, or breastfeeding (known as vertical transmission). There is no risk
of acquiring HIV if exposed to feces, nasal secretions, saliva, sputum, sweat, tears, urine, or vomit unless these
are contaminated with blood. It is possible to be co-infected by more than one strain of HIV a condition
known as HIV superinfection
Symptoms of AIDS
Additionally, people with AIDS frequently have systemic symptoms such as prolonged fevers, sweats
(particularly at night), swollen lymph nodes, chills, weakness, and weight loss. Diarrhea is another common
symptom present in about 90% of people with AIDS.
Most people infected with HIV develop specific antibodies (i.e. seroconvert) within three to twelve weeks of
the initial infection. Diagnosis of primary HIV before seroconversion is done by measuring HIV-RNA or p24
antigen. Positive results obtained by antibody or PCR testing are confirmed either by a different antibody or by
Antibody tests in children younger than 18 months are typically inaccurate due to the continued presence of
maternal antibodies. Thus HIV infection can only be diagnosed by PCR testing for HIV RNA or DNA, or via
testing for the p24 antigen.
Need for Medication
If HIV is allowed to reproduce, or "replicate," inside the body, it will cause damage to the immune
system. Ultimately, the immune system becomes so weak that the body becomes vulnerable to other
diseases. This is the point at which a person is usually diagnosed with full-blown AIDS, which can
result in death due to other opportunistic infections like Tuberculosis, etc
Anti-HIV drugs can help HIV-infected people live longer. Treatment, therefore, is a very important
option, and people living with HIV should consider starting treatment before the virus has had a
chance to do serious damage to the immune system.
The management of HIV/AIDS normally includes the use of multiple antiretroviral drugs in an attempt to
control HIV infection. There are several classes of antiretroviral agents that act on different stages of the HIV
life-cycle. it can take 10-15 years for an HIV-infected person to develop AIDS; antiretroviral drugs can slow
down the process even further.
Antiretroviral (ARV) drugs are classified by the phase of the retrovirus life-cycle that the drug inhibits.
There are currently 5 major classes of antiretroviral drugs :
Binding and Fusion inhibitors
Nucleoside and Nucleotide Analogue Reverse Transcriptase Inhibitors (NRTI)
Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTI)