AIDS Flashcards
HIV primarily targets
CD4+ lymphocytes, which are critical to proper immune system function.
diagnosis: depletion of CD4+ cells to** ≤200 cells/mL** or because of the development of new opportunistic infections
modes of transmission
Sexual: if unprotected
Parenteral:
Injectable drug use OR Receiving contaminated blood products
Perinatal: Mother-to-infant transmission during gestation, delivery, or breast-feeding
Occupational exposure via needle stick or exposure to eyes, nose, or open wound
Organ donation from an HIV infected donor
hiv is not transmissited by:
- Working or playing with an HIV positive person
- Closed mouth kissing
- Shaking hands
- Public pools
- Hugging
- Public toilet
Risk factors for HIV/AIDS infection
- Men who have sex with men (MSM)
- Unprotected sex with high-risk individuals
- History of or current IV drug use (needle or equipment sharing)
- Presence of other sexually transmitted infections (e.g., Chlamydia trachomatis or Neisseria gonorrhoeae)
- Persons with coagulation / hemophilia disorders
Previous blood product recipients
Pathophysiology
HIV is RNA virus, its contents include single-stranded RNA, reverse transcriptase and other enzymes.
types of hiv
There are two molecularly and serologically distinct but related types of HIV: HIV-1 and HIV-2.
HIV-1 is a retrovirus and member of the genus Lentivirus.
HIV-2 is a less common cause of the epidemic and is found primarily in West Africa.
These viruses have a prolonged latency period.
HIV lifecycle
- Binding
- Fusion
- Reverse transcriptase
- Integration
- Replication
- Assembly
- Budding
Q: Why is it so hard to cure AIDS completely?
A: The viral RT enzyme is highly error-prone, and many mutations occur in the conversion of RNA to DNA. This inefficient RT activity is responsible for HIV’s ability to rapidly mutate and develop drug resistance.
HIV infection stages
- The initial immune response against HIV is relatively effective, but it is unable to completely clear the infection
- Patient enters a latent, asymptomatic, or mildly symptomatic stage lasting 5 - 15 years (some references: 10 years).During this time, a high rate of viral replication can be seen in the lymph nodes.
- immune deficiency occurs when the body is no longer able to produce helper T cells at a rate equal to that at which HIV is destroying them.
acute HIV
rapid production of hiv
some poeple develope flu like symptoms
stage 2 chronic hiv
- asymtomatic
- slow reproduction of hiv
- gradual reduction of cd4 cells
- no symptoms
stage 3 aids
- symptomatic
- low levels of cd4 cells in the body
- appearance of oppurtunistic infection
Clinical presentation
Acute retroviral syndrome:
When the patient is present within (fever, myalgia, lymphadenopathy, pharyngitis, or rash)
Occur 2-6 weeks after initial infection and the symptoms last 2-4 weeks.
Diagnosis of HIV is made by either:
Positive HIV ELISA (enzyme linked immunosorbent assay)
Rapid test (e.g. OraQuick ADVANCE)
Diagnosis needs to be confirmed by a +ve HIV WB (Western Blotting) technique
A diagnosis of AIDS is made when an HIV positive patient has:
CD4 count ˂ 200 or 14% or the patient diagnosed with an AIDS indicating condition (pulmonary TB, recurrent pneumonia or cervical cancer)