Final Exam Study Guide Flashcards
What are the different types of transmission for contact diseases?
- direct: skin-to-skin, mucous membranes, bodily fluids
- indirect: contaminated surfaces, instruments, clothing
What are the different ways contact diseases spread in healthcare and daily life?
- frequent skin contact
- use of shared medical equipment
- high-contact areas (gyms, bus, schools)
Who are the most at risk for contact diseases?
immunocompromised individuals
What are STIs?
previously known as STDs
- sexually transmitted infections
What are the different ways of spreading STIs in sexual and everyday settings?
sexual contact
- direct transmission
- exchange of bodily fluids
- skin-to-skin contact
everyday settings
- shared personal items
- non-sexual blood contact
What are the different ways to test for STIs?
at home test kits
- OraQuick
- uritest dipstick test
What are the pros and cons of at-home STIs home testing kits?
pros
- more cases are diagnosed
- better access with patients
- quicker treatment
cons
- cost
- privacy concerns
- concerns about accuracy
What are the different stages of syphilis?
- primary stage: chancre at the site of infection about 3 weeks after exposure
- secondary stage: skin and mucosal rashes, especially on the palms and soles
- latent stage: no symptoms
- tertiary stage: years after latency
What is the difference between vaginitis and vaginosis?
vaginitis: inflammation of vagina
vaginosis: no in inflammation
What environment does Trichomoniasis grow in?
vagina and urethra
- when normal acidity of the vagina is disturbed
What does HIV stand for?
human immunodeficiency virus
What does HIV attack?
immune system, specifically CD4+ cells
What is CD4+?
t-helper cells
What is the role of the T helper cell?
produces cytokines and differentiates into Th1, Th2, Th17, and memory cells
What are the different T helper cells and what is their relation to HIV?
- TH1 cells: HIV leads to depletion of CD4+ TH1 cells (weakens immune system’s ability to combat intracellular pathogens)
- TH2 cells: balance between TH1 and TH2 is ruined in HIV (TH2 more dominant = reduced cell-mediated immunity)
- TH17 cells: HIV infection impairs TH17 cells, contributing to the weakening of mucosal defenses and gut barrier integrity (leads to systemic inflammation and microbial translocation
- Memory cells: HIV establishes reservoirs in memory CD4+ T cells = hard to eradicate virus entirely
What type of virus is HIV?
retrovirus
What is the structure of HIV?
- 2 identical + stranded RNA genome molecules
- reverse transcriptase enzyme
- phospholipid envelope
- gp 120 glycoprotein spikes
capsid
How does the HIV attach and enter susceptible CD4+ host cells?
1) Attachment: gp120 spike attaches to a receptor and CCR5/CXCR4 receptor (gp41 helps with fusion of HIV with the cell)
2) virus envelope merges with the cell membrane
3) entry pore is created, so viral envelope remains behind and HIV uncoats, releasing RNA core for directing synthesis of new viruses
What is the mechanism of RNA and DNA for using reverse transcriptase in the pathogenicity of HIV?
1) viral RNA is transcribed into DNA using reverse transcriptase
2) DNA is integrated into the host’s chromosomal DNA
3) Virus undergoes rapid antigenic changes and a high rate of mutation
What is the difference between active and latent infections?
active: new viruses bud from the host cell
latent: DNA is hidden in the chromosome as a provirus (some become memory cells that serve as reservoir for HIV)
What are the different subtypes of HIV?
HIV1: related to viruses that infect chimpanzees and gorillas
HIV2: longer asymptomatic period with lower viral load and mortality rate than HIV-1
How is HIV transmitted?
- sexual contact
- breast milk
- transplacental infection of a fetus
- blood-contaminated needles
- organ transplants
- artificial insemination
- blood transfusion
What are the different phases of infection for HIV?
Phase 1: asymptomatic or lymphadenopathy
Phase 2: CD4+ T cells decline steadily
Phase 3: AIDS develops, CD4+ is count below 200 cells/microliter
Who is more impacted in response in HIV exposure?
older adults and young children
- those without fully developed immune system