about hiv

1. HIV
Human Immunodeficiency virus

2. • HIV (human immunodeficiency virus) is a retrovirus. Its genetic material consists of
RNA.
• However, when it enters the host cell, the viral RNA converts back into DNA to be
incorporated into human chromosomes.
• HIV destroys T-helper lymphocytes, which control the immune system’s response to
infections.
• Loss of many of these cells can allow a range of pathogens to cause “Opportunistic
infections” due to the weakened immune system.
thus, the person develops “AIDS”, acquired immunodeficiency syndrome. It is not a
disease, but rather a collection of opportunistic diseases caused by the HIV infection.
Pathogen Information

3. Pathogen Structure
• the outer lipid membrane forms and
envelope which also has two
glycoproteins, Gp 120 and Gp 41
• The protein core contains genetic
material ( RNA) and two enzymes: a
protease and a reverse transcriptase.
• The reverse transcriptase uses the RNA
as a template to produce DNA once the
virus is inside a host cell.

4. Life
Cycle of
HIV
AIDS
AIDS is the last stage of HIV and severely impairs
your immune system. It’s characterized by a CD4
count under 200 cells per cubic millimeter of blood.
Chronic HIV
After the acute symptoms subside, you enter the
chronic stage where HIV replicates at low levels.
You’re still contagious in this stage, but you may not
have symptoms.
Acute HIV
A large amount of HIV is present in your blood. Some
people develop flu-like symptoms like chills, fever, and
a sore throat. It occurs about 2 to 4 weeks after
exposure
• The replication cycle, or life cycle, of HIV can be divided into seven stages. Medications that treat HIV
interrupt one of the seven stages of the HIV lifecycle.
• In an actively infected cell, the entire life cycle only lasts 1 or 2 days. But some cells can become latently
infected, meaning that HIV can potentially be present in them for years without producing new virus
particles. At any time, these cells may activate and begin making viruses.

5. Spread by intimate human contact; there is no vector
and the virus is unable to survive outside human body.
Initial epidemic in north America and Europe was by
male homosexuals having anal intercourse and many
sex partners. The mucus lining of rectum is not as
thick as that of vagina and there is less natural
lubrication. The rectal lining is easily damaged during
intercourse and virus pass from semen to blood.
• High risk infection were hemophiliacs who were
treated with a clotting substance[factor VIII]
isolated from blood pooled from many donors.
• Much transmission of HIV is by heterosexual
intercourse. Particularly rapid in some states, where
equal numbers of males and females are HIV+.
Transmission
• -in semen and vaginal
fluids during sexual
intercourse
• -infected blood or blood
products
• -contaminated
hypodermic syringes
• - mother to fetus across
placenta during birth
• - mother to infant in
breast milk

6. HIV is a slow virus, there may not be any symptoms until years later.
“incubation period” is the time between HIV infection and the onset of
acute HIV infection. ranges from 1 week to 10 months, but usually 2-4 weeks.
Up to 10 years or more before symptoms of AIDS may develop.
Fungi cause infections that can opportunistically develop to create aids;
• -oral thrush by candida albicans
• -pneumonia by pneumocystis jiroveci.
In the early years of the AIDS epidemic, people died within 12 hours of
contracting this unusual pneumonia. Now it is better managed by the usage of
drugs to prevent the disease from developing.
• As the immune system collapses further, it becomes less effective in finding
and destroying cancers. Kaposi’s sarcoma, a rare form of skin cancer caused
by herpes-like virus and cancers of internal organs are now the most likely
causes of deaths of people with AIDS.
Incubation
period

7. • AIDS was first reported in the West coast of the USA and Europe, doctors in
central Africa reported people with similar symptoms. HIV/AIDS is now
widespread throughout sub-Saharan Africa[Uganda to South Africa] and South
East Asia. It is a serious health problem there as HIV makes people more
vulnerable to existing diseases such as malnutrition, TB, and malaria.
• The World Bank estimated that AIDS had reversed 10-15 years of economic
growth for some African states by the end of the 20th century[affects sexually
active people in their 20s and 30s who are most economically productive,
expensive drugs drain economic funds].

8. Sites of action of pathogen
1. The t-helper lymphocytes – The
commanders
• HIV binds into these T- helper
lymphocytes receptors, enters the
cell and integrates into its DNA.
• The infected cells produce new
viruses instead of functioning
normally.
• Over times, the immune system
becomes too weak to fight infections
2. Macrophages- the messenger
• Acts as HIV reservoirs,
helping the virus persist in
the body.
• Contributes to the spread of
HIV to other immune cells.

9. 3. Brain cells
• HIV hides inside the infected
macrophages and monocytes
which can pass through the
blood-brain barrier (BBB)
• Once inside, these cells
release HIV
, allowing it to
spread in the brain.
• HIV doesn’t infect neurons
directly but it targets
support cells.
Example:
microglial cells (brain’s immune system)
Astrocytes (supports neurons)
• HIV infected cells trigger
inflammation, damaging neurons.
• Over times, this leads to HIV –
associated Neurocognitive
disorders

10. Clinical features of HIV/AIDS
1. Acute HIV infection(initial
stage)
• Develops 2-4 weeks after
infection
• Flu- like symptoms : fever,
sore throat, rash, muscle
aches, swollen lymph nodes.
2. Chronic HIV infection (asymptomatic
stage)
• Can last for several years without
symptoms
• The virus remains in the body,
progressively weakening the immune
system.
Final stage: AIDS(acquired, immunodeficiency syndrome):
• The immune system us too weak tot fight off infections. The person experiences
Opportunistic infections like: pneumonia: severe tung infection and tuberculosis (TB)
• Other symptoms such as weight loss, chronic disorder, fever. And if untreated, can cause
death.

11. Diagnosing HIV
1. Antibody tests – the first clue
• These tests check for HIV antibodies in blood, saliva or urine
2. Western biota test – the confirmation
• This test detects specific HIV proteins, confirming infection.
3. Viral load test – tracking HIV levels
• Measures how much HIV is present in blood.
• Helps monitor disease progression and treatment effectiveness
CD4( t-helper) count
If the CD4 count is low it means the immune system is
weakened.
If its drops below 200 cells/mm3, AIDS has developed
ELSA (enzyme- linked
immunosorbent assay)

12. Estimated total number of people
living with HIV present day
Current Statistics show approximately 39.9 million [36.1–44.6 million] people
globally were living with HIV, including 1.4 million [1.1–1.7 million] children aged
0–14 years and 38.6 million [34.9–43.1 million] adults aged 15 years and older
HIV Infection Rate: In 2023, there were about 1.3 million [1.0–1.7 million] new
HIV infections globally.
HIV-Related Mortality Rate: In 2023, approximately 630,000 [500,000–820,000]
people died from HIV-related diseases causes worldwide.

13. •Kaposi’s sarcoma – A rare cancer causing skin lesions, linked to human herpesvirus 8 (HHV-8).
•Non-Hodgkin’s lymphoma (NHL) – A cancer of the immune system, common in people with advanced HIV
.
•Cervical cancer – Strongly linked to human papillomavirus (HPV), more aggressive in HIV-positive women.
Anal cancer – Also linked to HPV and more common in HIV-positive individuals.
: Neurological Disorders
•HIV-associated neurocognitive disorder (HAND) – Memory loss, confusion, and coordination problems.
•Progressive multifocal leukoencephalopathy (PML) – A rare but severe brain infection caused by the JC
virus.
•Peripheral neuropathy – Nerve damage causing pain, tingling, or numbness in the hands and feet.
:Gastrointestinal and Wasting Syndromes
•HIV-associated diarrhea – Caused by infections like Cryptosporidium or Microsporidia.
•Wasting syndrome – Severe weight loss due to chronic infections and malnutrition.
•Hepatitis B & C – Liver diseases that progress faster in HIV-positive individuals.
HIV-Related Diseases: Cancers
Linked to HIV

14. Distribution:
o Sub-Saharan Africa: The most affected region, with a
significant proportion of global cases.
o Asia and the Pacific: Approximately 6.7 million people living
with HIV.
 Gender Distribution: In 2023, women and girls accounted
for 44% of all new HIV infections globally.
 Distribution of HIV positive cases by gender
shows women having higher risks than men
Age Groups: Every week, approximately 4,000
adolescent girls and young women aged 15–24 years
became infected with HIV globally in 2023.
Trends: While overall prevalence remains high, increased access
to antiretroviral therapy has improved life expectancy for those
living with HIV.

15. Estimated Number of New Cases of
HIV Infection Worldwide Present Day
 Global Figures: In 2023, there were approximately 1.3 million new HIV
infections worldwide.
 Comparison Over Time: This represents a significant decline from 2010,
when new infections were estimated at 2.1 million.

16.  Prevention Efforts: Increased use of preventive
measures such as pre-exposure prophylaxis
(PrEP) and education campaigns.
 Challenges:
o Stigma and Discrimination: Hindering
access to testing and treatment in certain
communities.
o Resource Limitations: Inadequate healthcare
infrastructure in low-income regions.
 Biological Aspect: The high mutation rate of
HIV contributes to challenges in vaccine
development
Factors Influencing New Infections

17. Estimated Number of Deaths from AIDS-
Related Diseases Worldwide Present Day
Current Data: In 2023, approximately 630,000 people died from
AIDS-related illnesses globally.
Decline Over Time: This marks a 69% reduction since the peak in
2004.
Tuberculosis among people living with HIV
Tuberculosis (TB) is the leading HIV-associated
opportunistic infection in low- and middle-income
countries, and it is a leading cause of death globally
among people living with HIV
. Death due to
tuberculosis remains high among people living with
HIV
. However, the number of deaths is decreasing.
Most of the global mortality due to TB among those
with HIV is from cases in Sub-Saharan Africa

18. Factors to Mortality Rates
• Access to Treatment: 77% of people living with HIV were receiving
antiretroviral therapy in 2023, improving survival rates.
• Barriers:
• Economic Constraints: Limited funding for healthcare in certain regions.
• Social Barriers: Cultural stigma preventing individuals from seeking care.
• Biological Insight: Without treatment, HIV progressively weakens the
immune system, leading to opportunistic infections and increased mortality.