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CA (630,000)
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HLTB21H3 (200)
Lecture 11

lecture 11


Department
Health Studies
Course Code
HLTB21H3
Professor
Caroline Barakat
Lecture
11

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L11
- Human Immunodeficiency Virus
Æ
attacks the immune system resulting in chronic,
progressive illness
- leaves people vulnerable to opportunistic infections and cancers
- results in AIDS (Acquired Immunodeficiency Syndrome)
Æ
when the body can no
longer fight infections
- on average - it takes more than 10 years for the disease to progress HIV
Æ
AIDS
Etiology
- retrovirus
- contains an enzyme 'reverse transcriptase'
- replicates to produce viral DNA from its RNA genome
- HIV-1, found throughout the world
- 1981 in United States --
- HIV-2, primarily found in West Africa - where virus may have been in circulation
since the 1960s and 1970s
- both types have several subtypes
Modes of Transmission
- must enter the bloodstream
- unprotected sex
- occupational exposure in health care settings
- the sharing of needles or equipment for injecting drugs, tattooing, skin
piercing or acupuncture
- pregnancy, delivery and breastfeeding (from an HIV-infected mother to her
infant)
- mainly depends on behavioural, occupational settings
- referred to as victims versus perpetrators
- HIV makes contact with T-Helper lymphocyte (T4 or CD4 cells)
- functions of T4: to "orchestrate" the immune system in the event of attack from
harmful foreign invaders
- results in the decline of immune system
Clinical manifestations
- healthy person has 800-1200 CD4 cells/mm3
- CD4 count below 200 cells/mm3 produces vulnerability to opportunistic infections
and cancers that typify AIDS
- % of CD4 are also used to diagnose AIDS -- count below 14%
- may be no symptoms with initial infection
- individuals may experience a flu-like illness within a month or two after exposure to
the virus
- asymptomatic -- several months to more than 10 years
- as the immune system weakens, a variety of complications begin:
- large lymph nodes (for more than 3 months)
- frequent fevers and sweats
- lack of energy
- may take a long time for someone to feel better upon infections
immunology with HIV/AIDS
- develop opportunistic infections -- weak immuned system
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