ACQUIRED IMMUNODEFICIENCY SYNDROME
(AIDS)
INTRODUCTION:
✓ Worldwide – over 33 million individuals are seropositive for human
immunodeficiency virus (HIV).
✓ In India – about 2 million.
✓ AIDS is a clinical condition that is manifested due to severe HIV infection that
results in low CD4 count.
✓ It was first recognized in 1981 in USA.
✓ It is caused by a ss-RNA human retrovirus known as human immunodeficiency
virus.
AETIOLOGY:
✓ Human retrovirus → 2 distinct groups: Human T lymphotropic viruses (HTLV-I
& HTLV-11) & human immunodeficiency viruses (HIV-1 & HIV-2).
✓ Structure of HIV – icosahedral structure containing external spikes formed by
two major envelope proteins – gp120 & gp41).
✓ HIV RNA has 3 structural genes: gag, pal & env.
✓ Reverse transcriptase – converts viral RNA into DNA.
✓ Integrase – incorporates the viral DNA into the host chromosomal DNA.
DEFINITION:
✓ An individual infected with HIV is known as HIV-infected individual.
✓ AIDS is defined as a clinical diagnosis (presumptive or definite) of any stage 4
condition with confirmed infection.
WHO clinical staging of HIV:
✓ CLINICAL STAGE 1:
Asymptomatic
Persistent generalized lymphadenopathy.
✓ CLINICAL STAGE 2:
Moderate unexplained weight loss.
Recurrent RTI (sinusitis, tonsillitis, otitis media, pharyngitis).
Herpes zoster
Recurrent oral ulceration.
✓ CLINICAL STAGE 3:
Fungal nail infections.
Unexplained severe weight loss.
Unexplained chronic diarrhoea for longer than one month.
Unexplained persistent fever.
, Pulmonary tuberculosis.
Severe bacterial infections.
Unexplained anaemia, neutropenia or chronic thrombocytopaenia.
Persistent oral candidiasis, oral hairy leucoplakia.
ANUG, stomatitis or periodontitis.
✓ CLINICAL STAGE 4:
HIV wasting syndrome
Chronic Herpes simplex infection.
Cytomegalovirus infection.
Oesophageal candidiasis.
HIV encephalopathy
Disseminated non-tuberculous mycobacterial infection.
Kaposi’s sarcoma.
Lymphoma.
Extrapulmonary tuberculosis.
Chronic cryptosporidiosis.
TRANSMISSION:
PARENTERAL:
i. Transfusion of blood & blood products.
ii. Needle sharing (including IV drug users).
iii. Needle stick injuries.
iv. Injections with unsterile needles.
v. Splash of body fluids on mucosa.
SEXUAL:
a. Homosexual
b. Heterosexual
PERINATAL:
a) Vertical transmission from mother to foetus.
b) Peripartum.
c) Breast feeding.
CLINICAL MANIFESTATIONS:
ACUTE SEROCONVERSION ILLNESS:
ACUTE SEROCONVERSION: An acute viral illness develops about 6 weeks
after exposure – 15% of cases acquiring HIV infection – self-limiting &
lasts for 2-3 weeks.
CLINICAL FEATURES: Fever, fatigue, pharyngitis, headache, myalgia,
urticaria, skin rash, lymphadenopathy.
LABORATORY FEATURES:
o Person is in the “window period” – seronegative.
o Recovery period: HIV antibody test often turns positive.
o Diagnosis – Nucleic acid amplification tests that detect viral
genetic material from patient specimens.
ASYMPTOMATIC CARRIER STAGE:
(AIDS)
INTRODUCTION:
✓ Worldwide – over 33 million individuals are seropositive for human
immunodeficiency virus (HIV).
✓ In India – about 2 million.
✓ AIDS is a clinical condition that is manifested due to severe HIV infection that
results in low CD4 count.
✓ It was first recognized in 1981 in USA.
✓ It is caused by a ss-RNA human retrovirus known as human immunodeficiency
virus.
AETIOLOGY:
✓ Human retrovirus → 2 distinct groups: Human T lymphotropic viruses (HTLV-I
& HTLV-11) & human immunodeficiency viruses (HIV-1 & HIV-2).
✓ Structure of HIV – icosahedral structure containing external spikes formed by
two major envelope proteins – gp120 & gp41).
✓ HIV RNA has 3 structural genes: gag, pal & env.
✓ Reverse transcriptase – converts viral RNA into DNA.
✓ Integrase – incorporates the viral DNA into the host chromosomal DNA.
DEFINITION:
✓ An individual infected with HIV is known as HIV-infected individual.
✓ AIDS is defined as a clinical diagnosis (presumptive or definite) of any stage 4
condition with confirmed infection.
WHO clinical staging of HIV:
✓ CLINICAL STAGE 1:
Asymptomatic
Persistent generalized lymphadenopathy.
✓ CLINICAL STAGE 2:
Moderate unexplained weight loss.
Recurrent RTI (sinusitis, tonsillitis, otitis media, pharyngitis).
Herpes zoster
Recurrent oral ulceration.
✓ CLINICAL STAGE 3:
Fungal nail infections.
Unexplained severe weight loss.
Unexplained chronic diarrhoea for longer than one month.
Unexplained persistent fever.
, Pulmonary tuberculosis.
Severe bacterial infections.
Unexplained anaemia, neutropenia or chronic thrombocytopaenia.
Persistent oral candidiasis, oral hairy leucoplakia.
ANUG, stomatitis or periodontitis.
✓ CLINICAL STAGE 4:
HIV wasting syndrome
Chronic Herpes simplex infection.
Cytomegalovirus infection.
Oesophageal candidiasis.
HIV encephalopathy
Disseminated non-tuberculous mycobacterial infection.
Kaposi’s sarcoma.
Lymphoma.
Extrapulmonary tuberculosis.
Chronic cryptosporidiosis.
TRANSMISSION:
PARENTERAL:
i. Transfusion of blood & blood products.
ii. Needle sharing (including IV drug users).
iii. Needle stick injuries.
iv. Injections with unsterile needles.
v. Splash of body fluids on mucosa.
SEXUAL:
a. Homosexual
b. Heterosexual
PERINATAL:
a) Vertical transmission from mother to foetus.
b) Peripartum.
c) Breast feeding.
CLINICAL MANIFESTATIONS:
ACUTE SEROCONVERSION ILLNESS:
ACUTE SEROCONVERSION: An acute viral illness develops about 6 weeks
after exposure – 15% of cases acquiring HIV infection – self-limiting &
lasts for 2-3 weeks.
CLINICAL FEATURES: Fever, fatigue, pharyngitis, headache, myalgia,
urticaria, skin rash, lymphadenopathy.
LABORATORY FEATURES:
o Person is in the “window period” – seronegative.
o Recovery period: HIV antibody test often turns positive.
o Diagnosis – Nucleic acid amplification tests that detect viral
genetic material from patient specimens.
ASYMPTOMATIC CARRIER STAGE:
