Overview
HIV (Human Immunodeficiency Virus) is a virus that attacks the immune system, especially CD4 T-helper cells, which are essential for protecting the body against infections. When HIV destroys a large number of these cells, the immune system becomes weak and vulnerable to many infections and certain cancers.
There are two main types of HIV:
1. HIV-1
- Most common type worldwide
- Responsible for the majority of global HIV infections
- Spreads easily
- Progresses faster than HIV-2
2. HIV-2
- Mainly found in West Africa
- Spreads less easily
- Progression is slower
- Some treatments work differently for HIV-2
If HIV is not diagnosed and treated on time, it can progress to AIDS (Acquired Immunodeficiency Syndrome), a life-threatening stage where the immune system becomes extremely weak.
Where HIV Comes From and How It Replicates in the Body
HIV is not produced naturally by the body. It is an external virus that enters through:
- Blood
- Semen
- Vaginal fluids
- Rectal fluids
- Breast milk
Once HIV enters the bloodstream, it immediately seeks out CD4 T-cells. Inside these cells, the virus uses the cell machinery to make copies of itself. Over time, the number of CD4 cells decreases, weakening immunity.
HIV can remain hidden in some cells (viral reservoirs), making it a lifelong infection unless treated with antiretroviral therapy (ART).
Importance of Understanding HIV-1 and HIV-2
HIV does not have any useful function in the human body. Instead, its presence is harmful. Understanding the virus and its types helps in:
✔ 1. Diagnosing HIV Correctly
Identifying whether a person has HIV-1, HIV-2, or both helps doctors choose accurate and effective treatment.
✔ 2. Starting Proper Treatment (ART)
HIV-2 responds differently to some medicines.
Correct typing ensures the right drug regimen.
✔ 3. Preventing Opportunistic Infections
HIV weakens immunity, increasing the risk of:
- Tuberculosis
- Pneumonia
- Fungal infections
- Viral reactivation
Early testing prevents these complications.
✔ 4. Reducing Risk of Transmission
Knowing one’s HIV status helps prevent spreading the virus to partners or unborn babies.
Causes of Low or Negative HIV Test Values
A negative HIV result means no HIV antibodies or viral load detected. This can occur due to:
1. No HIV Infection
The person has not been exposed to HIV.
2. Very Early HIV Infection
During the early “window period” (first 10–20 days), tests may not detect the virus.
3. Effective Antiretroviral Therapy
ART can suppress HIV so strongly that viral load becomes undetectable.
Symptoms When HIV Test Results Are Negative
A negative result usually indicates:
- Healthy immune system
- No HIV-related symptoms
- No immunodeficiency
However, if someone has symptoms and still tests negative, repeat testing may be required after the window period.
Causes of High or Positive HIV Test Values
A positive HIV test means HIV antibodies or viral RNA have been detected. Causes include:
1. Active HIV-1 or HIV-2 Infection
The person is infected and has viral replication occurring.
2. Untreated or Poorly Managed Infection
Without treatment, viral load increases, leading to immune damage.
3. Advanced Infection (AIDS Stage)
CD4 count becomes extremely low, and viral load increases.
Symptoms When HIV Test Is Positive
Symptoms vary based on the stage of infection:
Early Stage: Acute HIV Infection
This happens 2–4 weeks after exposure.
- Fever
- Sore throat
- Body aches
- Rash
- Mouth ulcers
- Swollen lymph nodes
These symptoms resemble viral flu and often go unnoticed.
Chronic Stage: Progressive HIV Infection
If untreated, HIV slowly damages immunity.
- Persistent fatigue
- Weight loss
- Recurrent infections
- Night sweats
- Chronic diarrhea
- Skin problems
Advanced Stage: AIDS
At this stage, immunity becomes extremely weak.
Opportunistic Infections
- Tuberculosis (TB)
- Pneumonia
- Fungal infections (Candida, Cryptococcus)
- Viral infections (CMV, HSV)
Associated Cancers
- Kaposi’s sarcoma
- Lymphoma
Without treatment, AIDS is life-threatening.
Reference Ranges
Negative / Non-Reactive
- No HIV antibodies or HIV RNA detected
- May need repeat testing after 2–6 weeks if exposure is recent
Positive / Reactive
- HIV infection is present
- Requires confirmatory tests such as Western Blot, p24 antigen, or HIV RNA test
Sample Types Used for HIV Testing
HIV can be detected using:
1. Blood Sample (Serum or Plasma)
- Most accurate
- Used for antibody, antigen, and viral load testing
2. Oral Fluid Tests
- Used in some rapid HIV kits
- Less sensitive than blood tests but helpful for quick screening
How HIV Testing Helps Patients
- Confirms HIV infection early
- Helps start ART immediately
- Reduces viral load to undetectable levels
- Prevents AIDS
- Helps prevent mother-to-child transmission
- Improves life expectancy and quality of life
With modern treatment, people with HIV can live long, healthy lives.
Test Preparation
- No fasting required
- Inform the doctor about recent exposure risks
- Do not panic—testing is confidential and safe
- If pregnant, screening is strongly recommended
- Avoid taking home remedies before testing
When to Consult a Doctor
You should see a doctor if you have:
- History of unprotected sex
- Needle sharing
- Blood transfusion in the past
- Symptoms of acute HIV
- Sudden unexplained weight loss
- Repeated infections
- Night sweats
- Chronic diarrhea
Immediate care is needed if symptoms suggest AIDS or if exposure was recent.
Important Word Explanations
- HIV – Virus that damages the immune system
- HIV-1 & HIV-2 – Two types of HIV, with HIV-1 being more common
- CD4 Cells – Immune cells that fight infections
- AIDS – Final stage of HIV infection
- Antiretroviral Therapy (ART) – Lifelong treatment used to control HIV
- Viral Load – Amount of HIV in the blood
- Window Period – Early stage when HIV may not be detectable
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