Virology Flashcards
all known viruses with a helical structure have
RNA genomes
Most helical viruses possess
An outer envelope
Adenoviruses are what shape?
Icosahedral and non-enveloped
What’s an example of a enveloped cubic virus?
Herpesviridae
What’s an example of a enveloped tubular virus?
Influenza
Vast majority of viruses have what type of genome
RNA
What are the 6 DNA viruses?
1 - herpes 2- Hep B 3- Parvovirus b 4- Adeno 5- HPV 6- Polyoma
Most neutralizing Abs target what part of the virus?
Often attachment proteins- surface
Where does the DNA virus replicate its DNA?
In host cell nucleus - mediated by viral enzymes
The “+” strand of RNA virsues
Codes for proteins directly - like mRNA
The “-“ strand of RNA viruses
needs to make a “+” strand like influenza
Enveloped viruses enter cells via….
Non-enveloped viruses enter via
Fusion
Endocytosis
Outcome of a viral infection depends on 2 things
1- host’s defence mechanisms
2- Organism’s ability to evade destruction
An example of a slow virus infection
measles
example of chronic carriers (virus)
CMV, Rubella, Hep B HepC
What are 2 good disinfectants for viruses
Hypochlorite and gluteraldehyde
viruses resistant to phenols
What type of viruses have hours to 1-2 day incubation periods
GI viruses
Respiratory viruses
What type of viruses have week long incubations (1-3 weeks)
MMR VSV, HSV, Chlamydia Enteroviruses, Polio WNV
4 viruses that take weeks to months to incubat
HIV
EBV
Rabies
Hepatitis virsues - B
How long after infection is IgM formed?
1 week persists for 4-6 weeks - up to 6 mo
IgG persists for how long?
months to years
Delayed hypersensitivity T cells release
macrophage activating factor
Il-1 and IL-2 modulate
the immune response against a virus
Detect viruses in 3 ways
cytopathic effect
serology - detect antigen
EM
Which virus is a double stranded DNA virus with an envelope?
Herpesviridae
What 2 types of infections do the herpes viruses cause
Lytic and Latent infections
Which viruses commonly transmit via transfusion or transplant?
CMV
EBV
HHV6
HHV8
which virus is commonly transmitted via aerosols
VZV
Herpes viruses dont survive very well where?
Environment, low fomite transmission
What % of HSV-2 primary infections are symptomatic?
10-15%
What % of HSV-1 is urogenital
10-30%
Is there value in checking antibodies to HSV?
no - cant tell if it’s primary or recurrent
what 3 antivirals limit replication of HSV
Acyclovir, famciclovir, valacyclovir
Lifetime risk of reactivation of VZV is
30%
Most common site for shingles
Thoraxix and cranial
2 ways of preventing VZV
1 - VZIG given within 96 hours of exposure
2- vaccination - varicella
Both varicella and zoster vaccines are
live attenuated virus
HHV-6 is
roseola infantum
HHV-7 is
EBV
incubation period for EBV
Incubation period for VZV
4-7 weeks
10-21 days
Specific subtypes of EBV are associated with
Burkitt’s lymphoma and nasopharyngeal carcinoma
which patients get severe disease with CMV?
- HIV patients
- Transplants (20-60% of people develop an infection)
- Neonates -
CMV infection in neonates is associated with
cytomegalic inclusion disease
- hepatosplenomegaly
- microcephaly etc.
Acute infection of healthy persons with HHV-8 can result in
Febrile exanthem
mononucleosis ?
In immunocompromised individuals HHV-8 can lead to
kaposi’s sarcoma
casteleman’s disease
pEL
