Viruses and Prions Flashcards
polio, enterovirus, rhinovirus, hep A, or cocksakie combined with positive sense RNA naked icosahedral virus indicates________
picornaviridae
single strand, naked icosahedral that causes hep E or norwalk virus (norovirus) indicates____
caliciviridae (calix cup)
rubella (German measles), or equine encephalitis matched with enveloped icosahedral +ssRNA
togaviridae
west nile virus, hep c virus, tick/mosquito borne matched with +ssRNA, enveloped virus
flaviviridae
+ssRNA, enveloped helical nucleocapsids surrounded by glycoproteins, SARS, MERS
coronaviridae
which kinds of viruses cause common cold?
rhino, adeno, corona, paramyxiviridae
helical nucleocapsid, enveloped, H and N glycoproteins surrounding envelope, contains RNA transcriptase, segmented genome (8)
orthomyxoviridae (influenzaviridae)
What does hemagglutinin do? What does neuraminidase do?
Both are spikes on the orthomyxoviridae envelope (-ssRNA helical and segmented). Hemaglutinin is used for attachment of the virus to the host cell (attaches to sialic acid). Neuraminidase are enzymes that free the newly synthesized virus from the cells (helps it bud off).
changes in RNA at single residues, causing little change
genetic drift/ point mutations
whole segments substituted in viruses with segmented genomes (ie influenza) and in cells infected with more than 1 strain of the virus. Causes Pandemics, big change.
genetic shift/ reassortment
Enveloped helical -ssRNA unsegmented genome, F protein causes syncytium formation, patient presents with mumps, respiratory tract infections, RSV, also common cold and measles
paramyxoviridae
Bullet-shaped enveloped helical -ssRNA, causes encephalitis and is fatal
rhabdoviridae
Describe pathogenesis of rabies
Person is bitten by rabid animal, virus multiplies in muscle tissue and travels through axons to CNS. Virus replicates in gray matter of neurons and forms inclusion bodies in hippocampus and cerebellum.
Describe the three stages of rabies
1-Prodromal- nonspecific; may have abnormal sensations at site of bite
2-Excitation phase- increasing anxiety, eye problems, hydrophobia
3-Paralytic phase- progressive general flaccid paralysis. Apathy to stupor to coma, peripheral vascular collapse and death
Long pleomorphic enveloped helical -ssRNA, looks like thread hanging off end, causes hemorrhagic fevers in men and moneys, ebola nad marburg virus
filoviridae
Enveloped helical -ssRNA with segmented genome, arboviruses and hantaviruses in this group
bunyaviridae
Negative ssRNA, causes lassa virus and lymphocytic choriomeningitis
arenaviridae (arenosus-sandy)
How do protease inhibitors work, and what virus are they used against?
Since HIV has an envelope, proteases are needed to cleave active proteins (GAG, POL and ENV-120 and 41), which is necessary for the viability of the virion (cleavage needed for budding). Protease inhibitors stop this process, and can halt the spread of the virus
Describe features of retroviridae and name the three types
- Enveloped virus particles with two +ssRNA
- Uses reverse transcriptase to make a dsDNA intermediate tha goes into host chromosome
- Types are HTLV1 and HTLV2 and Lentiviridae
What transforming virus is associated with adult t-cell leukemia/lymphoma, transmitted via blood, and is enveloped with two idential copies of +ssRNA?
HTLV1 and HTLV2
Human T-Cell Lymphotrophic Viruses
HIV specificity protein that forms the ‘stick of lollipop’ and attaches to viral membrane, includes fusion proteins
Glycoprotein 41 (gp41)
HIV specificity protein that binds to CD4 and contains cells and a coreceptor, is ‘head of lollipop’; undergoes much antigenic drift in chronic HIV infection
Glycoprotein 120 (gp120)
HIV specificity protein that is present on T cells
CXCR4
HIV specificity protein that is present on macrophages and some T cells
CCR5
What is the molecular disease process of prions?
- PrPsc, protease resistant prion protein causes molecular switch of cellular protein PrPc to the prion conformation.
- Altered protein cannot be degraded by cellular proteases and accumulates in cytoplasm and extracellular areas of cells in the brain.
What type of virus is characterized by long incubation periods and attack of immune cells?
lentivirus
Describe some differences between HIV1 and HIV2
HIV2 less prevalent, endemic to W Africa, less virulent with slower rate of disease progression. Both simian viruses are similar
Describe the structure of the HIV virus
enveloped virion with two +ssRNA, reverse transcriptase (RNA dependent DNA polymerase), integrase, and two tRNAs, also gp41 and gp120 on the envelope
What is the receptor for HIV-1? What kind of tropic cells are bound first (and what chemokine receptor is associated)? Which ones second?
CD4 is receptor for HIV-1.
First M-tropic cells are infected (CCR5)
Then T-tropic cells are infected (CXCR4)
CJD, vCJD, FFI, BSE are all _____ diseases
prion diseases
