AIDS (Acquired Immuno
Deficiency Syndrome)-HIV (Human Immunodeficiency Virus)
Ø Retrovirus RNA virus ®
DNA during replication
Ø Virulence:
Invades TH lymphocytes,
macrophages
Ø Transmission:
Sexual intercourse, blood transfusions, shared needles (intravenous drug abusers),
mother ® fetus (trans placentally) &
nursing infants
Ø Disease:
Virus infects TH lymphocytes ®
provirus permanently incorporated into host cell DNA ®
infectious virions synthesized and released ®
TH lymphocyte dies, or is destroyed by cells & antibodies of
immune system ® eventual failure of immune
system. Virus may also spread to
macrophages ® virus carried to brain, bone
marrow, intestinal mucosa
Ø Onset
of Disease: Occurs in 3 stages: 1). Incubation period. 6 days - 6 weeks. ®
Initial infection flu-like illness or asymptomatic. May be followed by long
asymptomatic period.2). Frequent opportunistic infections: frequent URT
infections, nausea, diarrhea, fever, night sweats, enlarged lymph nodes, fungal
skin infections, yeast infections of gums, mouth, hepatitis, etc.3). Severe
opportunistic infections: Pneumocystis pneumonia, TB, Toxoplasmosis, CMV, Herpes
virus, Kaposi’s sarcoma, systemic fungal infections, brain lesions &
dementia, chronic weight loss, muscle wasting syndrome.
Ø Identification:
ELISA most widely used test. Infected individuals seroconvert to positive in 1
to 3 months; some in 6 months to a year.
Ø Prevention:
safe sex, voluntary blood donation
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