Family Poxviridae I

Question 1

DNA or RNA family virus?

Answer 1

DNA

Question 2

-subfamily of poxviridae
-how many genus total
-infects who?
- 6 genus we have to know

Answer 2

chordopoxvirinae - vertebrates!
8 genera
infects humans, animals and birds
Orthopox, parapox, avipox, capripox, leporipox, suipox

Question 3

• size of viruses
  -shape of most vs. exception

Answer 3

largest virus in animals!
most are pleomorphic, brick shaped with irregular surface of projectinb tubules
-vs. parapoxvirus is exception which are ovoid, with surface tubules in crisscross

Question 4

2 forms regarding the envelope - and layers of membranes

Answer 4

intracellular mature virus (IMV) = lacks lipid envelope, only has inner membrane and exit by host cell disruption
extracellular enveloped virus (EEV)= has lipid envelope and inner membrane, exits by budding
BOTH FORMS ARE INFECTIOUS

Question 5

-type of symmetry?
-what does the outer layer enclose?
-what does the core contain
how many genes in genome

Answer 5

complex symmetry
outer layer encloses dumbbell shaped core and 2 lateral bodies (storage for enzymes)
core contains viral DNA and proteins
200 genes in genome

Question 6

what shape is genome?
majority of proteins encoded are ???

Answer 6

single molecule of linear double stranded DNA
-majority of proteins encoded are enzymes involved in nucleic acid synthesis and virion structural components, and proteins that counteract host adaptive and innate IR

Question 7

where does replication of poxviruses occur?
why does it occur there?

Answer 7

CYTOPLASM, because they encode enzymes for transcription and replication of viral genome

Question 8

after replication, how are virions released from the cell?
which is more common

Answer 8

budding (enveloped) vs. cell lysis (non enveloped)
most viruses are not enveloped and released by cell lysis

Question 9

regarding stability:
-enveloped viruses: stable in envi and why?
-what are they surviving in

Answer 9

high envi stability!! - infectious for months in environment, this is due to low lipid content in envelope and high resistance to drying
-survive in envi in dried scabs!!

Question 10

3 routes poxviruses are transmitted

Answer 10

1. skin - must be broken and in contact with infectious material
2. respiratory route - inhalation of aerosol
3. mechanically transmitted - by biting arthropod

Question 11

what do poxviruses infect, and cause what?
host specific?

Answer 11

infect skin and cause cutaneous skin lesions
yes host specific and cause systemic diseases sometimes

Question 12

how does poxvirus spread

Answer 12

introduction to body –> virus gains access to systemic ciruculation via lymphatics –> second viremia disseminates the virus back to skin and to other target organs

Question 13

skin lesions in poxvirus infection - types and definitions

Answer 13

1. Macule - flat, red
2. papule - rasied, red
3. vescile - small blister
4. pustule
5. scab/scar - scab that falls off is contagious

degenerative changes in epithelium, rupture of pustule = secondary bacT infection, ulceration can develop