Viruses Generalities and DNA Viruses Flashcards
What do the naked an enveloped virus use to attach to the host cells?
- naked virus ▶️ proteins
- enveloped virus ▶️ glycoproteins
EBV receptor, cell infected
CD21 = CR2 ▶️ B lymphocytes
Rabies virus receptor, cell infected
Acetylcholine receptor ▶️ neurons
Rhinovirus receptor, cell infected
ICAM-1 ▶️ respiratory epithelial cells
What type of virus can be inactivated by heat, detergents, acid and organic solvents like ethers and alcohol? Why?
Enveloped viruses ▶️ dissolve the envelope ▶️ glycoproteins in it ⏩ inhibits attachment
*naked viruses are not affected by those agents
What is the exception of the DNA viruses that need an intermediate to REPLICATION? What does it need?
Hepatitis B virus
DNA polymerase for hepatitis B (RNA-dependent DNA polymerase)
How are released the naked viruses from the host cells? What type of infections do they produce?
Lyse the host cells (blow up).
Cytolytic productive or latent infections produce. NO persistent productive infections.
How are the enveloped viruses released from the host cells? What type of infections do they produce?
Budding the host cell membrane.
Aging of host cells, produce low level of virus for years (ex; chronic hepatitis B).
How does the IFN inhibit the viral protein synthesis?
- (+) RNA endonuclease ▶️ digest viral RNA
- (+) protein kinase ▶️ (-) eIF2
Overall effect of all IFN
⬆️ MHC I, II, and NK cells activity ▶️ ⬆️ efficiency of presentation of Ags to Th, CTL
Most common transmission pathway of naked virus? Why?
Feca-oral
Resist aggressive environments
Most common transmission pathway of enveloped virus. Why?
Close contact ▶️ sexual, parenteral
Are more sensitive to aggressive environments (acids, detergents, heat, organic solvents
Chronicity of hepatitis C and B, which more frequently give rise to chronic hepatitis?
Hepatitis B ▶️ 5-10% adults, 90% infants (immature immune system)
Hepatitis C ▶️ 80% become chronic
Markers that yo can find in thy window period of hepatitis B?
HBcAb IgG, HBeAb, HBcAb IgM (+ or -)
First antibody that you can find in acute infection of hepatitis B, when?
HBcAb IgM at 2-3 months
What means chronic active hepatitis B?
Presence of chronicity markers (HBcAb IgG,HBsAg) plus HBeAb negative
Fetus compromised with severe anemia, congestive heart failure, hydrops fetalis, spontaneous abortion, if mother is up to date with vaccine, what agents you should think about? And if is not up to date with vaccines, what is the most common cause of the presentation?
Parvovirus B19 or CMV ▶️ vaccines up to date
Rubella syndrome congenital ▶️ not up to date
Malignancy pathogenesis of HPV
E6 ▶️ (-) P53
E7 ▶️ (-) Rb
*tumor suppressor genes
Common etiology agent of dendritic ulcer at the eyes
HSV-1
Diagnose of encephalitis by HSV-1
PCR on CSF
Large numbers of RBC in CSF
Diagnose of genital infections by HSV-1
Tzank smear ▶️ multinucleated giant cells + cowdry type A intranuclear inclusions
*don’t allow differentiate from HSV-2 ▶️ use immunofluorescent staining
Uses of acyclovir. Which viruses can you treat? How does it work?
VZV, HSV-1, HSV-2
Requires activation by viral thymidine kinase
Disease that is caused by HHV-6. Clinical presentation.
Roseola (examthema subitum)
3-5 days high fever ▶️▶️ lacy body rash
Diagnose of CMV
Organ biopsy or urine ▶️ owl-eye intranuclear inclusion bodies.
Basophilic intranuclear inclusions.
Serology, DNA, virus culture
Heterophile antibodies mononucleosis (-)
