Microbiology - Virology

bananas's version from 2015-07-16 00:03


Question Answer
Recombinationexchange of genes b/t 2 chromosomes via crossing over
Reassortmentvirsues with segmented genomes (e.g. flu) exchange segments
Complementation1 of 2 viruses that infect the cell has a mutation that reults in nonfn. protein - the non mutated virus "compliments" the mutated one by making a protein that works for both viruses
Phenotypic mixingSimultaneous infection of cell with 2 viruses.
- Virus A genes coated by virus B surface proteins.
- Type A can infect cells that usually are infected by Type B, but future generations can't b/c Type B surface proteins are in genetic code
Genetic ShiftReassortment of viral genome
- Segments undergo high-frequency recombination
Genetic Driftminor (antigentic drift) changes based on random mutations
Which is worse - Genetic Drift or Shift?Sudden Shift is worse than graDual Drift


Question Answer
Live (attenuated) VaccinesSmallpox, Yellow Fever, Chickenpox, Sabin's Polio, MMR (Small Yellow Chickens vaccinated by Sabian's MMR)
Killed VaccinesRabies, Influenza, Salk Polio, HAV (RIP Always)
Recombinant vaccinesHBV (HBsAg)
HPV (types 6, 11, 16, 18)
Naked ____ viruses are infectious on their own (2)+ssRNA (basically mRNA) and dsDNA (except poxviruses and HBV)
Naked ____ viruses are NOT infectious on their own (2)(-)ssRNA and dsRNA
Mneumonic for all DNA virusesHHAPPPPy viruses (Hepadna (HBV), Herpes, Adeno, Pox, Parvo, Papilloma, Polyoma)
Naked RNA virusesCPR Calici, Picorna, Reo
Naked DNA virusesPAPP Parvo, Adeno, Papilloma, Polyoma (Must be naked for a PAPP smear)
Hemagglutinin fn.promotes viral entry
Neuraminidase fn.promotes progeny virion release
Negri BodiesIntracytoplasmic eosinophilic inclusions in axons (cerebellum) in Rabies
Cowdry A BodiesIntranuclear eosinophilic inclusion in HSV
the only dsRNA virusReoviridae (the "Reo" Grande is double wide to prevent illegal immigration)
+ stranded RNA virusesI went to a retro toga party where I drank flavorded Corona and ate hippy California pickles
retrovirus, togavirus, flavivirus, coronavirus, hepevirus, calicivirus, picornavirus
DNA virus replication locationnucleus (except poxvirus - carries its own DNA-dependent RNA polymerase)
RNA virus replication locationcytoplasm (except influenza and retroviruses replicate in nucleus)
Only ssDNA virusparvovirus
Only non-linear DNA virusespapilloma, polyoma, hepadna (circular)
Only non-icosahedral DNA viruspox

DNA Viruses

Question Answer
Mnemonic for all DNA virusesHHAPPPPy viruses (Hepadna, Herpes, Adeno, Pox, Parvo, Papilloma, Polyoma)
latent in trigeminal gangliaHSV-1
latent in sacral gangliaHSV-2
latent in dorsal root or trigeminal gangliaVZV
HepadnavirusHepatitis B Virus (HBV)
has reverse transcriptase but it's not a retrovirus
AdenovirusFebrile pharyngitis - sore throat
Acute hemorrhagic cystitis
Conjunctivits - "pink eye"
ParvovirusThink ssRBC disease
B19 virus:
- "slapped cheeks" rash
- hydrops fetalis & death
- aplastic crisis in sickle cell
- RBC aplasia and rheumatoid arthritis in adults
largest DNA viruspoxvirus
single stranded DNA virusparvovirus
Vaccinia - cowpox ("milkmaid's blisters")
Molluscum contagiosum: flesh-colored dome lesions with central dimple (common sexually transmitted)
PolyomavirusJC Virus - PML (progressive multifocal encephalopathy) in HIV (Junky Cerebrum)
BK Virus - kidney disease in transplant pts (Bad Kidney)
Naked DNA VirusesPapilloma, Polyoma, Adeno, Parvo (Must be naked for a PAPP smear)
HSV TestingPCR - test of choice
Tzank Smear (for HSV-1,-2, and VZV) have intranuclear Cowdry Bodies
temporal lobe encephalitisHSV-1

RNA Positive-Sense Viruses - Watch this first:

Question Answer
All ssRNA except (1)reoviridae
(+)ssRNA virsuesRetro-, toga-, flavi-, corona-, hepe- (HEV), calici-, picorna (RETRO TOGA party drinking FLAVored CORONA and ate HIPPY CALIfornia PICkles)
All replicate in ___ (except 2)cytoplasm (except influenza and retrovirus)
Which (+) RNA are non-envelopedReo, Pico, Hepe, Calici
Shape of all (+) RNA virusesIcosahedral (except Corona makes you spin - helical)
What are the picornaviruses(PERCH) Polio, Echo, Rhino, Coxsackie, HAV
Mode of transmission of picornaviruses(all fecal-oral minus rhino)
clinical symptoms of picornaviruses(all cause aseptic meningitis (except rhino and HAV)
FlavivirusesHepatitis Cheese Virus
The Dengue cheese is rotten and Yellow (fever)
West Nile mosquitos from St. Louis ate holes in it
All are arbo viruses except for Hep C
Yellow Fever - high fever, black vomit, jaundice - Aedes mosquito - monkey/human reservoir
ParamyxovirusesParainfluenza, RSV, Rubeola (Measles), mumps
ReovirusesRotavirus (rotating soccer ball)
- #1 cause of fatal diarrhea in children during winter
- segmented
- the only dsRNA virus
- Villous destruction with atrophy leads to ↓ absorption of Na and loss of K

Coltivirus (he should've rode a colt up the mountain)
- Colorado tick fever
HepevirusHepatitis E virus
CalicivirusesNorovirus (while in California, he hopped on a cruise shipp that was made in Norway)
viral gastroenteritis
TogavirusesA blonde chick (Rubella) riding a horse (Western/Eastern equine encephalitis) at the Toga party.
Rubella - German (3-day) measles
- fever
- Postauricular adenopathy
- lymphadenopathy
- arthralgial
- fine truncal rash that starts on head and moves down
- Infxn is serious if it's congenital
RetrovirusesHIV, HTLV (T-cell leukemia)
Has reverse transcriptase
Coronavirus"Common cold" and SARS
helical even though it's a (+) RNA virus - Corona makes you spin

RNA Negative-Sense Viruses - Watch this first:

Question Answer
Negative-stranded RNA viruses mnemonicAlways Bring Polymerase Or Fail Replication
(Arenaviruses, Bunyaviruses, Paramyxoviruses, Orthomyxoviruses, Filoviruses and Rhabdoviruses)
Segmented RNA virusesBOAR (Bunyaviruses, Orthomyxoviruses, Arena viruses, and Reoviruses)
BunyavirusesArbovirus: Crimean-Congo hemorrhagic fever, California encephalitis, Sandfly/Rift Valley fevers
Hantavirus - hemorrhagic fever, pneumonia
ArenavirusesLassa fever encephalitis - spread by mice
LCMV - lymphocytic choriomeningitis virus
both = 2 segments
FilovirusEbola/Marburg hemorrhagic fever - often fatal.
Orthomixoviruses- Hemagglutinin: viral entry and Neuraminidase: virion release
- Pts at risk for fatal bacterial superinfection
- Rapid genetic changes
- Killed vaccine given each fall (IM)
- Live vaccine: replicates in the nose, not the lungs - given to children intranasally
ParamyxovirusesPaRaMyxovirus-Parainfluenza, RSV, Measles, Mumps. Treat RSV in premature infants with palizumab
Delta virusHDV - "defective" virus that requires HBV co-infection.
Shape of negative-sense RNA viruses Helical capsid symetry
RNA structure of negative-sense RNA virusesLinear, except for the BAD circular (Bunya, Arena, Delta)
What does negative-sense actually mean?Must transcribe negative strand to positive.
Virion brings its own RNA-dependent RNA polymerase
MeaslesC's: Conjunctivitis, Cough, Coryza, Koplik spots (red spots with blue/white center on buccal mucosa)
Descending maculopapular rash
Subacute sclerosing panencephalitis - later years
Rare encephalitis and giant cell pneumonia (immunosuppressed)
Rash presents last and includes hands/feet (vs. truncal rubella rash)
DON'T confuse with roseola (high fevers - seizures)
Mumps virusCheeks and balls like POM-poms
Meningitis (aspetic)
(Can cause sterility if caught after puberty)
Rabies virusNegri bodies - found in Purkinje cells of cerebellum and hippocampus
Incubation period of weeks to months (retrograde travel up nerves)
Get the wound - clean it and vaccinate with/without rabies immune globulin
Disease: fever, malaise → agitation, photophobia, hydrophobia → paralysis, coma &rarr: death
steeple sign on X-raycroup
Pathway of rabies virusBind to Nicotinic Ach Post-synaptic receptors
Retrograde up axons
CNS: purkinje and hippocampus

Hepatitis Viruses

Question Answer
RNA picornavirusHAV
DNA hepadnavirusHBV
HCVRNA flavivirus
HDVRNA delta virus
HEVRNA hepevirus

HAV Serology

Question Answer
Anti HAVAb (IgM)best to detect active HAV
Anti-HAVAb (IgG)indicates (1) prior HAV infection or (2) prior HAV vaccination, protects against reinfection

HBV Serology

Question Answer
HBsAgHBV surface antigen, indicates hepatitis B infection
Anti-HBsAgAb to HBsAg (surface antigen), indicates immunity to HBV
HBcAgHBV core antigen
Anti-HBcAg (IgM)Ab to HBcAg (core antigen), positive during window period with anti-HBe
Anti-HBcAG (IgM)acute/recent HBV infection
Anti-HBcAG (IgG)chronic HBV disease or prior exposure
HBeAgHBV core antigen, indicates active replication, extremely high transmissibility
Anti-HBeAgAb to HBeAg (core replication antigen), indicates low transmissibility
Window Period Serologyonly see Anti-HBcAb
HBeAgextremely high transmissibility
Immunized Serologyonly see Anti-HBsAg
Acute HBV Serology(1) HBsAg (2) HBeAg (3) Anti-HBcAb IgM
Immune due to HBV Vaccine1) HBsAg-negative 2)Anti-HBcAg-negative 3) Anti-HBsAg-positive
Immune due to previous HBV Infection1) HBsAg-negative 2)Anti-HBcAg-positive 3) Anti-HBsAg-positive



Question Answer
3 structural genesenv (envelope gp41,gp120), gag (capsid), pol (RT polymerase)
envgp41 (fusion and entry)
gp120 (attachment to host T Cell)
gagp24 (capsid protein) (24 yos hate gagging)
polreverse transcriptase
gp120attachment to host CD4 t cell (antibodies to this can cross placenta)
gp41fusion and entry
p24capsid (gag)
p17matrix (shell) (i was 17 when i saw the matrix)
HIV binds what 2 coreceptorsCD4 as well as CXCR4 or CCR5
HIV binds what target cellCD4+ T cells
Mutation resulting in slower courseheterzygous CCR5 mutation
Mutation resulting in immunityhomozygous CCR5 mutation


Question Answer
AIDS diagnosis (3)(1) ≤200 CD4+ (2) CD4 percentage less than 14 percent
Screening TestELISA (high sensitivity)
Confirmation TestWestern Blot (high specificity)
Ring enhancing lesions in brainToxoplasma gondii
HIV pneumoniaPneumocystis jiroveci (formerly carinii (PCP))

HIV-positive - Diseases

Question Answer
oral hairy leukoplakialess than 500
EBVless than 500
Bartonellaless than 500
HHV-8less than 500
cryptosporidiumless than 500
HPVless than 500
toxoless than 200
HIV dementialess than 200
JCless than 200
PCPless than 200
aspergillusless than 100
cryptococcusless than 100
CMVless than 100
B cell lymphoma EBVless than 100
histoless than 100
MAIless than 100