VIROLOGY Flashcards
HIV + pt comes to clinic with compliant of vision loss. He has been noncompliant with his antivirals. During a fundoscopy exam you see the following:
What is the cause of this finding?
What would you expect the pts viral load to be at?
What will you tx the disease with?
CMV retinopathy most common cause of HIV retinitis: you can see inflammatoyr vascular sheathing and associated hemorrhage
CD4+ counts are likely <50
Tx: Ganciclovir
- Exchange of genes between 2 chromosomes by crossing over within regions of significant base sequence homology.
- When viruses with segmented genomes (e.g., influenza virus) exchange genetic material. For example, the 2009 novel H1N1 influenza A pandemic emerged via complex viral reassortment of genes from human, swine, and avian viruses.
- Recombination
- Reassortment
When 1 of 2 viruses that infect the cell has a mutation that results in a nonfunctional protein. The nonmutated virus “complements” the mutated one by making a functional protein that serves both viruses. For example, hepatitis D virus requires the presence of replicating hepatitis B virus to supply HBsAg, the envelope protein for HDV.
Complementation
Occurs with simultaneous infection of a cell with 2 viruses. Genome of virus A can be partially or completely coated (forming pseudovirion) with the surface proteins of virus B. Type B protein coat determines the tropism (infectivity) of the hybrid virus.
****However, the _progeny from this infection have a type A coa_t that is encoded by its type A genetic material.
Phenotypic mixing
Induce humoral and cell-mediated immunity but have reverted to virulence on rare occasions.
What are examples of this?
Live attenuated vaccines
Live attenuated: smallpox, yellow fever, rotavirus, chickenpox (VZV), Sabin polio virus, MMR, Influenza (intranasal).
“Live! One night only! See small yellow rotating chickens get vaccinated with Sabin
and MMR! It’s incredible!”
Do we use boosters for live vaccine?
Who should not get live vaccines?
When is it okay to give HIV + people MMR live vaccine?
No booster needed for live attenuated vaccines.
Dangerous to give live vaccines to immunocompromised patients or their close
contacts.
Can be given to HIV- positive patients who do not show signs of immunodeficiency.
What 4 viruses have killed vaccines?
Rabies, Influenza (injected), Salk Polio, and HAV vaccines.
SalK = Killed.
RIP Always.
All DNA viruses except the _____ are dsDNA.
All DNA viruses are linear except
Parvoviridae (ssDNA)
papilloma-, polyoma-, and hepadnaviruses (circular).
All RNA viruses except _____ are ssRNA.
Reoviridae
All are ssRNA (like our mRNA), except “repeato-virus” (reovirus) is dsRNA.
Positive-stranded RNA viruses: I went to a retro toga party, where I drank flavored Corona and ate hippy California pickels
retro (retrovirus) toga (togavirus) party, where I drank flavored (flavivirus) Corona (coronavirus) and ate hippy (hepevirus) California (calicivirus) pickles (picornavirus).
What DNA and RNA viruses are infectious?
Which are not? How do they become infectious
Purified nucleic acids of most dsDNA (except poxviruses and HBV) and ⊕ strand ssRNA
(≈ mRNA) viruses are infectious.
Naked nucleic acids of ⊝ strand ssRNA and dsRNA viruses are not infectious. They require polymerases contained in the complete virion.
IG where do DNA and RNA viruses replicate?
DNA: in the nucleus (except poxvirus)
RNA: in the cytoplasm (except influenza)
PNeumonic to remember enveloped viruses:
Pappi and Addy took a Pair of Pollys to Pick Real California Hippys
Naked (nonenveloped) viruses include Papillomavirus, Adenovirus, Parvovirus, Polyomavirus, Calicivirus, Picornavirus, Reovirus, and Hepevirus
Generally, enveloped viruses acquire their envelopes from _____when they exit from cell.
Exceptions include herpesviruses, which acquire envelopes from ______
plasma membrane
nuclear membrane.
General rules on DNA viruses
Are HHAPPPPy viruses
Are double stranded except
Are linear except
Are icosahedral expept
Replicate in nucleus expept
Hepadna, Herpes, Adeno, Pox, Parvo, Papilloma, Polyoma.
Except parvo (single stranded).
Except papilloma and polyoma (circular, supercoiled) and hepadna (circular, incomplete).
Except pox (complex).
Except pox (carries own DNA-dependent RNA polymerase).
HIV pt comes to clinic very disoriented. You are looking over his list of medications and notice a rheumatology doctor prescribed him Rituximab. You are very concerened that his current status will progress rapidly and be fatal. You get imaging of his brain and see below.
What diseaes does this pt have?
Why?
What pathogen was responsible?
progressive multifocal leukoencephalopathy
Demyleninating disease from destruction of olidendrogliomas (myelinate CNS)
Caused by Reactivation of JC virus in HIV pts often from Rituximab
dsDNA cirucular , no
Teenager comes to clinic with a sore throat, fever and fatigue. Her exam is significant for posterior cervical lymphadenopathy. You suspect it’s viral and have seen several of her classmates with the same illness. You inform her mother she needs to be out of contact sports for 6 weeks and to get plenty of rest and stay hydrated.
What test would you order to confirm her illness?
What would you see on peripheral smear?
What cancers is this implicated in?
Detect by ⊕ Monospot test—heterophile antibodies detected by agglutination of sheep or horse RBCs
Atypical lymphocytes seen on peripheral blood smear are not infected B cells but rather reactive cytotoxic T cells.
Associated with lymphomas (e.g., endemic Burkitt lymphoma), nasopharyngeal carcinoma.
Young woman comes in worried about several small vesciles on her genitals. You take a scraping and prep them on a slide (see below)
Whats the Dx?
Tzanck test— multinucleated giant cells commonly
seen in HSV-1, HSV-2, and VZV infection A .
Intranuclear inclusions (below)also seen with HSV-1, HSV-2, VZV.
