A. RNA virus
B. DNA virus
C. HSV-1, HSV-2 and VZV
D. Colorado tick fever
E. HTLV-1 and HIV
F. Polio, Coxsackie and Hepatitis A viruses
G. California encephalitis
H. WEE, EEE, and VEE
J. WNV, YFV and dengue
1. Picornaviruses - F. Polio, Coxsackie and Hepatitis A viruses
2. Flaviviruses - J. WNV, YFV and dengue
3. Togaviruses - H. WEE, EEE, and VEE
4. Reoviruses - D. Colorado tick fever
5. Rhabdoviruses - I. Rabies
6. Bunyaviruses - G. California encephalitis
7. Retroviruses - E. HTLV-1 and HIV
8. Herpes viruses - C. HSV-1, HSV-2 and VZV
What are the 5 genera of picornaviruses and what disease do they cause? (remember: R.E.A.C.H.!)
Rhinovirus - common cold
Enterovirus (polio, coxsackie A and B, echo virus) - diseases of the human alimentary tract
Aphthovirus - foot and mouth disease in cloven-footed
Cardiovirus - murine encephalomyocarditis
Hepatovirus - human hepatitis virus A
What are the characteristics of an ideal vaccine? (remember: L.E.A.S.E.S.!)
What are some properties of the entero-, hepato-, and cardioviruses (picornaviruses)?
resistant to low pH and grow at 37 degrees celsius
no envelope - resistant to detergents
affects GI tract
leads to CNS infections - paralysis and encephalitis
What are some properties of the rhino- and apthovirus (picornaviruses)?
labile at low pH and grow at 33 degrees celsius
acquired through aerosol inhalation
What is the organization/structure of picornaviruses?
Internal Ribosome Entry Site (IRES) - regulates genome replication and translation
5' linked to VPg protein
3' controls RNA synthesis
Describe the polyprotein of picornaviruses and its derivatives.
P2 and P3 - encodes proteins involved in protein processing and genome replication
Which 2 picornaviruses encode a leader (L) protein before the P1 region of the polyprotein?
What are some characteristics of picornavirus host cell receptors?
share cellular receptors (some use a single type receptor, i.e. polio and rhinoviruses)
few viruses require a co-receptor (i.e. coxsackievirus)
Describe the replication cycle of picornaviruses.
replicates in cytoplasm
virus binds to cell surface receptor (via VP1)
uncoating of genome
viral RNA translation
synthesis of RNA and copying of + stranded RNA to - stranded RNAs
copying to multiple +RNAs from -RNAs
additonal proteins from newly synthesized +RNAs
encapsidation of RNA and viral assembly
release of new viral particles by cell lysis
How do picornaviruses "shut off" host protein synthesis?
cleavage of host cell protein elF-4G (eukaryotic inition factor 4G) - mediated by viral 2A protease
Match the following.
1. viral protease
2. enhances the vesicle formation in host cells which serve as sites of RNA synthesis
3. RNA helicase
4. stimulates the 3D pol activity and proteolytic activity of 3CDpro
5. viral protease
6. RNA dependent RNA polymerase - RNA synthesis
7. provides poly(U) primer
1. viral protease - D. 2A
2. enhances the vesicle formation in host cells which serve as sites of RNA synthesis - B. 2B
3. RNA helicase - G. 2C
4. stimulates the 3D pol activity and proteolytic activity of 3CDpro - A. 3AB
5. RNA dependent RNA polymerase, RNA synthesis - F. 3D
6. provides poly(U) primer - C. VPg
What is the pathogenesis of picornaviruses?
GI ingestion (fecal-oral)
targets lymphoid tissue of oropharynx and gut > viral replication
virus can localize in various organs (viremia) > invasion of CNS
primarily infection occurs in gray matter > paralysis
virus is excreted in feces
What are the general characteristics of the poliovirus infection?
causes most severe disease "poliomyelitis" - results from type 1 poliovirus
destruction of motor neurons in the anterior horn of spinal cord > flaccid paralysis
vaccines available: IPV (Salk) and OPV (Sabin)
True or false. Humans are the only reservoir for poliovirus.
What are the general characteristics of the coxsackievirus infection?
children are at the most risk
Group A and B cause aseptic meningitis - headache, stiff neck and fever)
Group A causes Herpangina - sudden onset of fever with ulcers on tongue and palate
Group A16 causes hand-foot-mouth disease (HFM)
acute type 1 diabetes
What are the general characteristics of the rhinovirus infection?
entry via URT
causes common cold
pleconaril against enteroviruses and rhinoviruses
no vaccines are available
What are the general characteristics of the aphthoviruses infection?
causes foot-mouth disease (FMD) - NOT THE SAME AS HAND-FOOT-MOUTH DISEASE!
vaccine available - effective against symptoms but doesn't block transmission
What disease is usually associated with HIV and neurological disease?
What are the 2 subtypes of HIV?
1. T-cell trophic
2. macrophage tropic
What are the 4 target sites for HIV-1 antiviral agents? (remember: R.I.P.E.!)
Describe the mechanism of action for reverse transcriptase inhibitors?
inhibits reverse transcriptase enzyme
Name 5 common reverse transcriptase inhibitors.
What are the 2 common non-nucleoside reverse transcriptase inhibitor analogues used to treat HIV?
What is the mechanism of action for non-nucleotide reverse transcriptase inhibitors analoguesused to treat HIV?
directly interacts with reverse transcriptase and inhibits its function
What are the 4 common HIV protease inhibitors? (remember: R.I.N.S.!)
What is the mechanism of action for HIV protease inhibitors?
inhibit the function of the HIV protease
What are the 2 most common drugs that HIV patients build resistance to?
What is the "cocktail" of HIV antiviral treatment?
1 nucleoside RTI + 1 (or 2) PI
True or false. HAART helps to provide full protection against neurological damage in AIDS patients.
False, because blood-brain-barrier is only partially permeable to antiviral agents.
Which virus was the first identified human retrovirus?
Viral assembly in cytoplasm and maturation of virion> accumulates within membrane boud vesicles
transport of virus by secretory pathway
Match the following.
1. C protein
2. PrM protein
3. E protein
4. NS1 protein
5. NS2A and NS2B
7. NS4A and NS4B
A. Structural proteins
B. Non-structural proteins
C. Maturation of virion
D. Binds to cell surface receptors and facilitates viral entry
E. Encapsidates viral RNA
F. Viral protease
G. RNA replication
H. Soluble haemagglutinin - elicits humoral response
I. RNA dependent RNA polymerase
J. RNA synthesis
1. C protein - A. Structural proteins, E. Encapsidates viral RNA
2. PrM protein - A. Structural proteins, C. Maturation of virion
3. E protein - A. Structural proteins, D. Binds to cell surface receptors and facilitates viral entry
4. NS1 protein - B. Non-structural proteins, H. Soluble haemagglutinin - elicits humoral response
5. NS2A and NS2B - B. Non-structural proteins, J. RNA synthesis
6. NS3 - B. Non-structural proteins, F. Viral protease
7. NS4A and NS4B - B. Non-structural proteins, G. RNA replication
8. NS5 - B. Non-structural proteins, I. RNA dependent RNA polymerase
Match the following picornaviruses and flavivirus proteins with their functionally analogous proteins.