HIV is a virus that attacks a type of white blood cells called CD4 cells in the body's immune system. HIV reduces the body's ability to fight infection and illness. While humans can fight off many other viruses, the body can never completely remove HIV once it is contracted.
AIDS is a condition that may develop after a person gets HIV. It is possible to have HIV without developing AIDS, but it is not possible to have AIDS without first having HIV.
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How does HIV lead to AIDS?
AIDS will always develop after HIV. It is possible to have HIV without developing AIDS.
Not everyone who gets HIV goes on to develop AIDS. However, a proper treatment program is necessary to slow or stop this progression in most cases.
If left untreated, HIV continues to damage the immune system and increases the risk of developing an opportunistic infection.
The Centers for Disease Control and Prevention (CDC) define opportunistic infections as "infections that occur more frequently and are more severe in individuals with weakened immune systems."
Examples of opportunistic infections that develop in those with HIV include:
- cancers, such as invasive cervical cancer, lung cancer, Kaposi's sarcoma, carcinomas, and lymphomas
- candidiasis, a fungal infection of the mouth, throat, or vagina
- cytomegalovirus, a viral infection that can cause blindness
- pneumocystis pneumonia, a fungal form of pneumonia that can be fatal
- toxoplasmosis, a parasitic infection of the brain
- tuberculosis, a bacterial infection of the lungs
AIDS: Stage 3 of HIV infection
AIDS is the final stage (stage 3) of HIV infection. It is diagnosed based on a CD4 cell count or the development of one or more opportunistic infections. Stage 1 is the acute stage of HIV and stage 2 is the clinical latency stage. More information on these two stages is included later in the article.
The CD4 cell count in healthy individuals ranges from 500 to 1,600 cells per cubic millimeter of blood (cells/mm3). According to AIDS.gov, those with HIV are considered to have developed AIDS when their CD4 cell count drops to under 200 cells/mm3.
If treatment is not sought, AIDS typically develops between 2 and 15 years after infection with HIV. The rate at which the virus develops depends on many factors, including the patient's age, general health, genetics, the presence of other infections, and standard of health care.
People who seek treatment before the condition advances, and maintain treatment throughout their lives, can usually expect to live almost as long as a person without HIV.
Causes of HIV and AIDS
HIV may be transmitted in a number of ways such as through unprotected sex and during childbirth.
AIDS was first recognized as a distinct condition in 1981 due to an increase in the incidence of rare opportunistic infections and cancers in homosexual men who presented as otherwise healthy.
It is believed to have originated in the late nineteenth or early twentieth century in Western and Central Africa. Scientists suggest that a primate version of the virus was transmitted to humans who killed and ate the infected creatures.
HIV is transmitted between humans through the exchange of bodily fluids. It can spread via:
- Sexual contact: AIDS is primarily considered to be a sexually transmitted disease. HIV is passed from one person to another through unprotected oral, anal, or vaginal intercourse.
- Pregnancy or childbirth: A mother who is infected with HIV, or who has developed AIDS, may pass the virus to her child during pregnancy, childbirth, or even through breastfeeding.
- Blood transfusion: While HIV can be passed along through blood transfusions, the risk is extremely low in developed countries due to comprehensive screening systems.
- Syringe and needle use: Drug users who share syringes with others are at increased risk of getting the virus. Those who give and receive tattoos and piercings may also be at risk if needles are not cleaned properly.
Symptoms of HIV and AIDS
The symptoms of HIV vary widely and depend on both the individual and the stage of the disease.
Acute stage symptoms
In the first stage of HIV, 2 to 4 weeks after getting the virus, people can experience flu-like symptoms including:
- aching muscles
- mouth ulcers
- night sweats
- sore throat
- swollen lymph nodes
It should be noted that not everyone with HIV will experience these symptoms. Some people with HIV do not experience symptoms for 10 years or more.
Clinical latency stage symptoms
During stage 2, the virus is active but reproduces at very low levels. People in this stage may experience only mild symptoms, or none at all.
Medication for HIV can help to halt progression and keep the virus in this stage for many decades.
AIDS is considered to be the third and final stage of the virus. Symptoms at this stage are related to the various infections that develop as a result of a compromised immune system.
For this reason, symptoms can vary greatly. Some of the more common ones include:
- blotches under the skin or in the mouth and nose
- blurred vision
- chronic diarrhea
- continuous swelling of the lymph glands
- extreme fatigue
- fever that keeps returning
- neurological issues including memory loss
- rapid weight loss
- sores in the mouth, anus, or genitals
Due to the variety of symptoms associated with the various stages of HIV and AIDS, it is not possible to diagnose either the virus or the syndrome based on symptoms alone. A healthcare provider will need to carry out tests to make a formal diagnosis.
Testing and diagnosis
HIV is diagnosed with a blood test and early testing is always recommended.
HIV is diagnosed by a simple blood test that looks for the presence of antibodies produced by the body in an attempt to fight the virus.
It can take anywhere from several weeks to several months for these antibodies to show up in tests. Repeat testing may be necessary depending on the initial time of exposure.
However, early testing is always advisable, as an appropriate treatment plan can then be implemented to help stop further progression of the virus. Those who get tested early after exposure are at a lower risk of transmitting the virus to others.
People with HIV who receive a CD4 cell count result of under 200 cells/mm3, or who are diagnosed with certain opportunistic infections, will then be considered to have a diagnosis of AIDS rather than HIV.
Treating HIV and AIDS
Proper treatment plans and early intervention mean those with HIV can enjoy a relatively good quality of life.
However, without treatment, those diagnosed with AIDS typically survive for 3 years. If an opportunistic illness develops and treatment is not sought, life expectancy drops to 12 months.
Treatment for HIV and AIDS consists primarily of medication, including:
Post-exposure prophylaxis (PEP)
This is an emergency treatment administered to reduce the likelihood of HIV infection after exposure to someone who has the virus. To be effective, it should be taken within 72 hours of exposure, and the full 28-day course of treatment completed.
If taken correctly, the World Health Organization estimate that PEP can reduce the risk of HIV infection by over 80 percent.
Antiretroviral therapy (ART)
People with HIV or AIDS are generally prescribed a combination of highly active antiretroviral therapy (HAART) drugs to help to slow down the progression of HIV.
This medication is adjusted to suit each individual and it needs to be taken for life.
Several steps can be taken to prevent contraction of HIV. These include:
- Using condoms: As HIV can be spread through unprotected sexual intercourse, using condoms can reduce the risk of transmission.
- Taking certain steps during pregnancy: The risk of HIV transmission from mother to child can be reduced with HIV medications. Additional steps to reduce transmission include delivery by Cesarean section, and bottle feeding rather than breast feeding.
- Avoiding sharing needles: Needle exchange programs exist to reduce the need to share syringes and needles.
- Reducing exposure to bodily fluids: Healthcare workers should use gloves, masks, and other forms of barrier protection to reduce their risk of contact with HIV-infected blood. Thoroughly and regularly washing the skin after contact with bodily fluids also reduces risk.
Those who have already been diagnosed with HIV can slow or halt its progression to AIDS by adhering to the treatment plan devised by their doctor, avoiding exposure to other infections, and maintaining a healthful lifestyle to support their immune systems.