Virology Flashcards
T/F: all helical viruses are enveloped
True
T/F: all naked viruses are icosahedral
True
Which viral protein is responsible for evasion of host defense?
Antigenic (serotypic) variants
Lipid membrane is acquired as the virus exits from the cell in the process called
Budding
All enveloped viruses acquire envelope from plasma membrane except
Herpesvirus - from nuclear membrane
T/F: enveloped viruses are more stable and harder to inactivate
False
Infectious/not infectious?: naked nucleic acids of (-) strand ssRNA and dsRNA viruses
Not infectious
Infectious/not infectious?: purified nucleic acids of most dsDNA (except poxviruses and HBV)
Infectious
Infectious/not infectious?: (+) strand genome ssRNA viruses
Infectious
Cause of transmissible spongiform encephalopathies
Prions
Nonpathogenic as alpha-helix
Pathogenic as beta-pleated sheet
T/F: all viruses are haploid
False - retroviruses are not haploid
Viruses with segmented genomes
BOAR Bunyaviruses Orthomyxoviruses (influenza) Arenaviruses Reoviruses (Rotavirus)
Negative-strand RNA viruses
Always Bring Polymerase Or Fail Replication Arenaviruses Bunyaviruses Paramyxoviruses Orhtomyxoviruses Filoviruses Rhabdoviruses
When one virus produces a protein that can be used by another virus
Complementation
Eg. Hepatitis D and B
2 different viruses infect the same cell
Phenotypic mixing
Responsible for causing epidemics
Genomic ressortment
Phase in viral growth curve: no virus is detectable
Phase 2 eclipse period
Phase in viral growth curve: amount of detectable viruses reached plateau
Phase 4 latent period
Phase in viral growth curve: derrangement if cell function –> lysis and cell death, remarkable amplification in number of viral particles
Phase 5 cytopathic effect
What are the phases of the viral growth curve?
Phase 0: entry Phase 1: decline Phase 2: eclipse period Phase 3: rise period Phase 4: latent period Phase 5: cytopathic effect
Phase in viral growth curve: viruses decrease in number but continues to function
Phase 1: decline
Visual or functional change in infected cells
Cytopathic effect
Oncogenic viruses induce transformation and unrestrained growth
Malignant transformation
Infected cells appear normal but are producing large numbers of progeny viruses
Commensal symbiosis
Bind cytokines and block their ability to nteract with receptors on their intended targets
Cytokine decoys
Reduce the expression of antigen presenting cells and inactivate complement
Virokines
Produce viruse for long periods of time and can serve as a source of infection for others
Carrier state
Not producing virus at the present but can be reactivated at a subsequent time
Latent infections
Long incubation period, often measured in years
Slow virus infections
Laboratory diagnosis: definitive
Complement fixation, hemagglutination inhibition, neutralization, fluorescent-antibody assay, radioimmunoassay, ELISA
Gold standard in viral diagnosis
Presence of viral DNA or RNA
Killed vaccines
RIP Always Rabies Influenza Polio (Salk's) hepatitis A
Recombinant vaccines
Hepa B
HPV (types 6, 11, 16, 18)
Live attenuated vaccines
MMR (only live-attenuated may be given to HIV+ pts)
Varicella
Sabin’s polio
Yellow fever
DNA viruses
DNA viruses are HHAPPPPy viruses
Hepadna, Herpes
Adeno
Pox, Parvo, Polyoma, Papilloma
The only DNA virus with a single-stranded DNA
Parvovirus (parvovirus B19)
All DNA viruses have a LINEAR DNA..EXCEPT:
Papilloma
Polyoma
Hepadna
The only DNA virus that do not have an icosahedral symmetry
Poxvirus - complex
The ONLY DNA virus that replicated outside the nucleus
Poxvirus - because it cannot penetrate the nuclear membrane
Parvovirus are transmitted via
Respiratory drolets
Transplacental
Chronic B19 infection in immuodeficient patients can cause
Pancytopenia
The only virus with pentofiber
Adenovirus
Adenovirus infection in the GUT
Hemorrhagic cystitis
Parvovirus B19 histopath finding
Cowdry type B intranuclear inclusions
Naked virus with ds circular DNA, icosahedral nucleocapsid, infects squamous cells and induce formation of cytoplasmic vacuoles (koilocytes)
Human papilloma virus
Papovaviridae
HPV: encode proteins that inactivate tumor suppresor genes
Gene E6 and E7
HPV of skin and plantar warts
HPV 1-4
HPV in condylomata accuminata, respiratory tract papillomas; most common viral STD
HPV 6 and 11
HPV in carcinomas of the cervix, penis and anus
HPV 16, 18, 31 and 33
HPV treatment for genital, skin and plantar warts
Genital warts: podiohyllin
Skin warts: liquid nitrogen
Plantar warts: salicylic acid
2 types of viral symmetry
Spherical/ icosahedral
Helical
This drug is an immune disease modifier approved to treat actinic keratosis, superficial basal cell carcinoma and condylomata accuminata
Imiquimod
HSV 1&2 site of latency
HSV 1: trigeminal ganglia
HSV 2: lumbosacral ganglia
Large, pink to purple intranuclear inclusions which can be found in adenoviruses and herpes sinolex viruses
Cowdry type A inclusions
Tzanck smear: multinucleated giant cells
HSV
Tx HSV that can shorten duration of lesions, reduce extent of shedding with no effect on the latent state
Acyclovir
Dewdrop on rose petal appearance incubation period
Varicella 14-21 days
Ramsay Hunt Syndrome involves which ganglion and cranial nerve
Geniculate ganglion
Facial nerve - paralysis
Culture medium of CMV
Shell tubes
Most common cause of congenital abnormalities especially in the 1st trimester
CMV
Congenital CMV infection
Microcephaly, seizures, deafness, jaundice, blue berry muffin baby
Congenital CMV infection
DOC for CMV
Ganciclovir
Patient presents with fever, sore throat, lymphadenopathy and splenomegaly. Athlete is made to stop sports due to a rare but possible complication of
Splenic rupture
Infectious mononucleosis/ kissing disease
CMV
African man with unilateral facial asymmetry
Burkitt’s lymphoma
CMV
Associated with Kaposi’s sarcoma manifesting with dark purple flat to nodular skin lesions appearing at multiple sites
Human Herpesvirus-8
Tx: surgery, radiation
What is the brick-shaped poxvirus with linear dsDNA showing what intracytoplasmic eosinophilic inclusions?
Variola virus
Smallpox
Guarnieri bodies
Intracytoplasmic eosinophilic inclusions in molluscum contagiosun
Henderson-peterson bodies
Tx of molluscum
Cidofivir
Interpret: HBsAg positive Anti-HBs negative Anti-HBc negative HBeAg positive
Incubation period
Interpret: HBsAg positive Anti-HBs negative Anti-HBc positive IgG HBeAg negative
Chronic carrier
Interpret: HBsAg negative Anti-HBs positive Anti-HBc negative HBeAg negative
Vaccinated
Interpret: HBsAg positive Anti-HBs negative Anti-HBc positive IgM HBeAg positive
Acute infection
Interpret: HBsAg negative Anti-HBs negative Anti-HBc positive IgM HBeAg negative
Window period
Interpret: HBsAg negative Anti-HBs negative Anti-HBc positive IgG HBeAg positive
Chronic active
Interpret: HBsAg negative Anti-HBs negative Anti-HBc positive IgM HBeAg negative
Complete recovery
HepB infection is associated with which autoimmune vasculitides
Polyarteritis nodosa
HepB treatment
Interferon- alpha
Lamivudin
All RNA viruses have single-stranded RNA except
Reovirus and Rotavirus
All RNA viruses replicate in the cytoplasm except
Influenza
Retrovirus
All Picornaviridae viruses are transmitted via oro-fecal except
Rhinovirus