HIV Flashcards
Prevalence rate of HIV in adults aged 15-49?
1.3[ 0.9-1.7]
Virology
Genus: _______
Genome:
_____-stranded RNA
(linear or circular?)
_______ -sense, 9–10 kb, ___ploid; genome
four genes required for a replicating retrovirus— _____,_____,____ and _____
Lentivirus
Single; linear
Positive ; di
gag, pro, pol, and env
Virology
Proteins: ________________ undergoes antigenic variation; reverse transcriptase enzyme contained inside virions; ______ required for production of infectious virus
Envelope:(present or absent?)
Envelope glycoprotein
protease
Present
Virology
Replication:_________ makes DNA copy from genomic RNA; _______ is template for viral RNA.
Genetic variability is (common or rare?) .
Reverse transcriptase
provirus DNA
Common
Virology
Maturation: Particles _______ from ______
bud
plasma membrane
Virology
Outstanding features:
Infect cells of the _____ system
______ remain permanently associated with cells
_______________ is restricted in some cells in vivo
It Cause (slowly or rapidly ?) progressive, (acute or chronic ?) diseases
Replication is usually _____-specific
immune
Proviruses
Viral expression
Slowly ; chronic
species
Lentivirus
Viruses are transmitted by _______
Virus persists _______ in infected hosts, although it may be present at very ____ levels.
exchange of body fluids.
indefinitely; low
Lentivirus
Viruses have (low or high?) mutation rates, and __________ will be selected under different conditions (host factors, immune responses, tissue types).
Infected hosts contain “ ______ ” of ______ related viral genomes, known as _______.
High
different mutants
swarms; closely
quasispecies
Lentivirus
Cells in the macrophage lineage play ______ roles
It may take ______ for disease to develop.
Infected hosts and usually make _____, but they do not ___________
central; years
antibodies
clear the infection, so virus persists lifelong.
Modes of HIV Transmission
Mention 4
Sexual Contact
Parenteral
Blood transfusion
Perinatal
Modes of HIV Transmission
Sexual Contact: _________ with infected partner(s)
Parenteral: Contact with HIV-infected _________
Unprotected sexual contact
blood products
Modes of HIV Transmission
•Blood transfusion; __________ through needle sharing; needle-stick accidents; unsterilized sharp objects
Perinatal:_________ transmission
In utero; during ______ and ____; through ________
Mother-to-child
labour and delivery
breastfeeding
Transmission through Sexual Contact
• ___________ and ———— transmission of HIV most common
• (Receptive or insertive?) sexual partner at higher risk than ( Receptive or insertive?) partner
Heterosexual and male-to-male
Receptive
insertive
HIV CAN be transmitted by casual contact, surface contact, or insect bites
T/F
F
HIV CANNOT be transmitted by casual contact, surface contact, or insect bites
Molecular Epidemiology of HIV
HIV virus has two types: _____ and ______
Type 1 (HIV-1) and Type 2 (HIV-2)
Molecular Epidemiology of HIV
•
HIV-1 has a _______ distribution
HIV-2 is ____________
global
limited to West Africa
Molecular Epidemiology of HIV
HIV-___ is still the predominant type in West Africa
HIV-____ has been further divided into groups and subtypes
1
1
Primary subtypes of HIV-1
in Nigeria are _____________
A, G, and A/G
Virus receptors
Primary receptor is the _____ molecule, which is expressed on ________ and _____
A ________ in addition to ____ is necessary for HIV-1 to gain entry to cells.
CD4
macrophages and T lymphocytes.
second coreceptor
CD4
Virus receptors
The virus first binds to _____ and then to the ______.
_______ receptors serve as HIV-1 second receptors.
CD4
coreceptor
Chemokine
Chemokines are (soluble or insoluble ?) factors with ___________________ properties.
Soluble
chemoattractant and cytokine
Virus receptors
_____ is the predominant coreceptor for macrophage-tropic strains ofHIV-1
_____ ,the coreceptor for lymphocyte-tropic strains of HIV-1.
CCR5
CXCR4
Virus receptors
Individuals who possess _____zygous _____ in CCR5 and produce mutant forms of the protein may be protected from infection by HIV-1
Mutations in the CCR5 _______ appear to _____________ .
homo; deletions
gene promoter
delay disease progression
Major Steps in HIV Lifecycle
•HIV attaches to ____ cell
•Releases ___ and enzymes
•Enzyme _______ makes a ____ copy of viral ____
And this is integrated into CD4 cell ____ using enzyme ____
New viral components produced, using cell’s “machinery” . These are assembled together using enzyme ______ and are released as new viruses
CD4; RNA
Reverse Transcriptase ; DNA
RNA; nucleus; integrase
protease
Overview of HIV
The duration between primary infection and progression to clinical disease averages about ____ years.
In untreated cases, death usually occurs within ___ years after the onset of clinical symptoms.
10
2
Overview of HIV
Stages include
the ______________,
dissemination of virus to ______
clinical _______
_______ HIV expression
clinical _________
_______
Primary infection
lymphoid organs
latency; elevated
disease
Death
Overview of HIV
Following primary infection, there is a ________ period between _____ and ________
the viremia is detectable for about _______. Virus is widely disseminated throughout the body during this time, and the ________ become seeded.
____________ syndrome develops in many patients (50–75%) ____ weeks after primary infection.
There is a significant (drop or rise?) in numbers of circulating _____ cells at this early time.
An immune response to HIV occurs ____-_____ after infection, plasma viremia (drops or rises?) , and levels of CD4 cells rebound.
However, the immune response is _____________________________________________________
4- to 11-day
mucosal infection and initial viremia
8–12 weeks.; lymphoid organs
An acute mononucleosis- like
3–6 ; drop; CD4 T
1 week to 3 months ; drops
unable to clear the infection completely, and HIV-infected cells persist in the lymph nodes.
Natural History of HIV Infection in Adults
HIV-1 infection has the following phases:
Viral _______
_________ infection
____________
Clinical __________
(Early or late?) symptomatic HIV infection
_____ and severe HIV infection
transmission
Primary HIV; Sero-conversion
latent period; early
AIDS
AIDS and severe HIV infection
Characterized by Clinical Stage ____ or a CD4 cell count below ____/mm3
4
200
Primary Infection
During this phase, a person may experience (specific or non-specific?) ‘___-like’ symptoms.
These symptoms do not lead directly to the diagnosis of HIV infection and may not be present in all patients, but commonly include:
Fever
Fatigue
__________
_________
___________
flu
Non-specific
Pharyngitis
Lymphadenopathy
Rash
Primary Infection (2)
• Pathogenesis of Primary Infection:
Initial infection of _________ and _______ with receptors at site of exposure
Dissemination of infection to _______
Burst of viral replication results in __________
Development of ______ immunity (HIV-specific ______)
Response by ______ immunity (HIV-specific ___________ cells)
CD4 T-lymphocytes and macrophages
lymph nodes; intense viraemia
humoral; antibodies
cellular
CD4 and CD8
Symptomatic Phase (1)
Presentation depends on CD4 count
At CD4 cell counts over _____ cells/μl, PLHIV may develop complications found in the general population:
_________
Bacterial _______
___________
Minor __________
500
Malaria
pneumonia
Tuberculosis
skin conditions
Symptomatic Phase (1)
Presentation depends on CD4 count
At CD4 counts between _____ and ______ cells/μl, other conditions, or opportunistic infections, begin to appear:
• Pulmonary ________________
• ____________ candidiasis
•____________
200 and 500
Tuberculosis (current)
Oral or vaginal
Symptomatic Phase (1)
Presentation depends on CD4 count
The late symptomatic phase is characterized by patients having a CD4 cell count less than ______ cells/μl and conditions such as:
______ syndrome
________ candidiasis
____________-pulmonary TB
___________ pneumonia
Recurrent, invasive herpes simplex virus infections
200
Wasting
Esophageal
Atypical and extra
Pneumocystis
Severe HIV Infection and AIDS
This phase is characterized by patients having a CD4 cell count less than __ cells/μl and conditions such as:
________ meningitis
_________________
_____________ of the brain
HIV _________ (PML/dementia) CMV retinitis
50
Cryptococcal
Cryptosporidiosis
Toxoplasmosis
encephalopathy
CD4 Count is an indicator of _________ status (distance to the cliff)
Viral Load is an indicator of the ___________ (speed of the train)
immune system
amount of virus in the blood
HIV associated Cancers
List 2
Kaposi carcinoma
Cervical cancer
Key Points (1)
The HIV lifecycle involves the following steps:
Virus _______ and ______
Transcription of ________ into _______
_________ into human genome
New viral components ______ using ______ enzyme.
________ and _________ of virus particles
entry into cell and fusion
viral RNA into DNA
Integration; assembled; protease
Assembly and budding off
Viral replication persists throughout infection
T/F
T
HIV manifests the same way in adults and children
T/F
F
HIV manifests differently in adults and children
HIV disease progression is determined by ________ and _______
CD4 count and viral load
ARV = _________
ART =________
HAART = _______________
Antiretroviral
Antiretroviral Therapy
Highly Active Antiretroviral Therapy
Antiretroviral Drugs
Antiretroviral drugs act on different points in the life cycle of the virus to prevent _________
viral replication
Goals of ART
Virological: ____________ to ___________ (<_______ HIV RNA copies/mL for as long as possible).
Immunologic: Quantitative and qualitative _______ with improved immune function
Clinical: Prolongation and improved quality of life by reducing ___________ and ____________
Reduction in viral load to undetectable levels; 400
immune reconstitution
HIV- associated morbidity and mortality
Goals of ART
Therapeutic: Appropriate choice of _________ to achieve the goals of therapy while preserving __________, minimising ______________ and promoting excellent ___________
Epidemiologic: ______________________
ARV regimen
future therapeutic options
ARV toxicities; adherence
Reduce transmission of HIV
Classes of Antiretroviral Drugs
_________________________________ (NRTI)
_____________________________(NNRTI).
____________________ (PIs)
________________
_______ inhibitors (or ______ inhibitors)
_________ inhibitors
Nucleoside and nucleotide reverse transcriptase inhibitors
Non-nucleoside reverse transcriptase inhibitors
Protease inhibitors
Integrase inhibitors
Entry ; fusion
Maturation
Antiretroviral drugs are broadly classified by the ___________________________________
phase of retrovirus lifecycle that the drug inhibits
Laboratory Testing for HIV Diagnosis
Antibody Assays:
_________
_________
Confirmatory Assays
—————
_____________
Nucleic Acid-based Test (Virologic tests)
Assays to detect HIV DNA or RNA (PCR)
Other tests:
1. Antigen detection test (_____ antigen)
2. Viral _______
Rapid tests
ELISA
p24; isolation
Antibody Tests
suitable for use in infants under 18 months
T/F
F
Not suitable for use in infants under 18 months (use PCR instead)
