Introduction
human immunodeficiency virus (HIV)
HIV belongs to Retroviridae family and is the causative agent
of acquired immunodeficiency syndrome (AIDS). It primarily spreads through
sexual contact, blood exposure, and mother-to-child transmission. HIV attacks
the immune system, specifically CD4+T cells, leading to immunodeficiency and
increasing the risk of opportunistic infections and certain cancers.
What is human immunodeficiency virus (HIV)?
Is a virus that attacks the immune system, especially CD4+ T
cells (the white blood cells that help protect the body from infections).Over
time, if HIV is not treated, it destroys so many of these cells that the body
can’t fight off infections and diseases. This stage of infection is known as
AIDS (Acquired Immunodeficiency Syndrome).
Structure of human immunodeficiency virus (HIV)
HIV is an
enveloped virus, meaning it is surrounded by an outer envelope derived from the
host cell membrane. The viral envelope contains viral glycoprotein, including:
Gp120 and gp41, which play a
crucial role in viral entry and immune evasion.
Inside the
envelope, HIV has a protein capsid that encloses the viral RNA and viral
enzymes.
Enzymes of HIV:
Reverse transcriptase: this enzyme is responsible for converting RNA genome into DNA during viral replication. This process is known as
reverse transcription.
Integrase: After reverse transcription, the
viral DNA integrates into the host cell’s DNA with the help of enzyme
integrase. This integration allows the virus to persist in infected cells and
replicate during cell division.
Protease: this enzyme plays a crucial role in viral maturation
by cleaving the viral polyproteins into individual functional proteins,
enabling the assembly of infectious viral particles.
Classification of human immunodeficiency virus (HIV)
HIV is classified into two main types: HIV-1 and HIV-2.
HIV-1: this is the most common and globally prevalent type of HIV. It is
responsible for the majority of HIV infections worldwide.
HIV-1
is transmitted mainly
through unprotected sexual contact, contaminated blood transfusions, sharing of
needles, and from mother to child during pregnancy, delivery,
or breastfeeding.
HIV-2: This type is primarily found in
West Africa, although it has been reported in other parts of the world as well.
HIV-2 generally progresses more slowly than HIV-1 and is less transmissible. It spreads through the same routes as HIV-1
(sexual contact, blood transfusion, needle sharing, and mother-to-child), but
with lower efficiency.
Genetic variability: HIV exhibits high genetic variability due to its error-prone
replication process and high replication rate. Genetic variability gives rise
to different strains and subtypes of HIV, making treatment and vaccine
development challenging. The genetic diversity of HIV is a result of both point
mutations, where individual nucleotides change, and recombination events
between different strains.
Clinical significance of human immunodeficiency virus (HIV)
1. Acute HIV infection:
During the acute stage of HIV infection, individuals may experience
flu-like symptoms, including fever, fatigue, sore throat, rash, and swollen
lymph nodes. Early diagnosis and
intervention during this stage are crucial as prompt initiation of
antiretroviral therapy (ART) can help control viral replication and preserve
immune function.
2. Chronic HIV infection:
Without treatment, HIV infection progresses to the chronic
stage, characterized by persistent viral replication and gradual depletion of
CD4+ T lymphocytes. Chronic HIV infection may be asymptomatic, but individuals
can still transmit the virus to others. As CD4+ cell counts decline, the immune
system becomes compromised, leading to increased susceptibility to
opportunistic infections and certain cancers.
3.Acquired
Immunodeficiency Syndrome (AIDS):
AIDS is the most advanced stage of HIV infection, characterized by severe immunodeficiency. In individuals with AIDS, the immune system is significantly compromised, leading to a wide range of opportunistic infections, such as pneumonia, tuberculosis, candidiasis, and cytomegalovirus (CMV) infection. AIDS is also associated with the development of certain cancers, including Kaposi's sarcoma, non-Hodgkin lymphoma, and cervical cancer. Wasting syndrome (unintentional weight loss) and neurological complications, such as HIV-associated neurocognitive disorders (HAND), can also occur.
Haw is HIV/AIDS transmitted?
Sexual contact - HIV is
spread most commonly by sexual contact with an infected partner. The virus
enters the body through the lining of the vagina, vulva, penis, rectum, or
mouth during sexual activity.
Blood contamination - HIV
may also be spread through contact with infected blood. However, due to the
screening of blood for evidence of HIV infection, the risk of acquiring HIV
from blood transfusions is extremely low. HIV is not transmitted
through casual ways such as living same room, using same crockery or through
coughing or bites.
What causes of human immunodeficiency virus (HIV)?
HIV (Human Immunodeficiency
Virus) is not caused by another disease.it is an infection that is acquired
when the virus enters the body. The cause of HIV infection is direct exposure
to the virus itself. HIV is not caused by casual contact such as
hugging, shaking hands, sharing food, or mosquito bites.
Clinical Manifestations of HIV
1. Acute Retroviral Syndrome:
Symptoms can resemble a flu-like
illness and may include fever, fatigue, headache, sore throat, swollen lymph nodes,
rash, and muscle aches. These symptoms typically occur within 2 to 4 weeks
after infection and may last for a few weeks.
2. 2. Asymptomatic Stage:
After the acute retroviral syndrome,
HIV infection enters a chronic asymptomatic stage, which can last for several
years. During this stage, individuals may not experience any noticeable
symptoms, but the virus continues to replicate and cause damage to the immune
system.
3 3. Persistent or Recurrent Infections:
As HIV
progresses and the immune system becomes compromised, individuals become more
susceptible to various infections. Common infections seen in people with
advanced HIV infection include: Respiratory infections, such as pneumonia and
tuberculosis. Fungal infections, including oral and esophageal candidiasis
(thrush) and cryptococcal meningitis.
4 4. Opportunistic
Infections:
Opportunistic
infections are infections caused by organisms that usually do not cause severe
illness in individuals with a healthy immune system
5 5. AIDS-Defining Conditions:
Acquired Immunodeficiency Syndrome (AIDS) is diagnosed when a person with HIV infection develops one or more specific opportunistic infections or certain cancers
Haw to diagnoses HIV
HIV Antibody Testing: The most common method for diagnosing HIV infection is through HIV antibody testing. Antibody tests detect the presence of antibodies produced by the immune system in response to HIV infection.
HIV
Antigen Testing: HIV antigen testing detects the presence of viral antigens,
specifically the p24 antigen, in the blood. Antigen tests can detect HIV
infection earlier than antibody tests, as the p24 antigen appears in the blood
before antibodies are produced.
Haw to treatment HIV
Antiretroviral Therapy (ART):
Antiretroviral therapy (ART) is the standard treatment for HIV infection. ART involves the use of a combination of antiretroviral drugs to suppress viral replication, preserve immune function, and prevent the progression to AIDS.
Haw to prevention HIV
HIV prevention is a Safe sex, sterile
needles, screened blood, ART for prevention, and education. Comprehensive
HIV education and awareness campaigns play a vital role in promoting prevention
behaviors, reducing stigma, and encouraging testing and treatment uptake.
Conclusion
HIV (Human Immunodeficiency Virus) is
a virus that attacks the immune system, mainly CD4 cells, weakening the body’s
defense against infections.
It is primarily transmitted through
unprotected sex, contaminated blood, sharing needles, and from mother to child.
Early detection through screening and
confirmatory tests is crucial for managing the disease.
Antiretroviral therapy (ART) is the
main treatment, which controls the virus, improves immunity, and prevents
complications.
Prevention through safe sex, sterile
injections, blood screening, and preventive medicines like PrEP is essential to
stop the spread.
With proper treatment and care,
people living with HIV can live long, healthy lives and reduce the risk of
transmitting the virus to others.
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