Poxviridae

Question 1

Pocks

Answer 1

Caused by small pox (variola) virus

- has now been eradicated

Question 2

Poxvirus diseases occur in _______

Answer 2

Most animal species

Question 3

Vaccinia virus

Answer 3

Used as a vector for delivering a wide range of viral antigens
- originally derived from cowpox

Question 4

Is smallpox completely eradicated?

Answer 4

No, can be used as a biological weapon

Question 5

What is the largest and most complex family of all viruses?

Answer 5

Poxviruses

Question 6

What are 2 subfamilies of poxvirus?

Answer 6

• chordopoxvirinae: poxviruses of vertebrates (8 genera)

- entomopoxvirinae: poxviruses of insects

Question 7

Properties of chordopoxvirinae

Answer 7

Brick-shaped virion, irregular arrangement of tubules on outer membrane
- parapoxvirus: ovoid, regular spiral arrangement of tubules on outer membrane

Question 8

Components of chordopoxvirinae structure

Answer 8

• core
• lateral bodies
• outer membrane
• sometimes an envelope

Question 9

Chordopoxvirinae genomic properties

Answer 9

Linear dsDNA genome

• resistant to ambient temperatures, may survive years in dried scabs
• approx 200 genes in the genome
• cytoplasmic replication!!

Question 10

Orthopoxvirus

Answer 10

Vaccinia virus

Question 11

Parapoxvirus

Answer 11

Pseudocowpox virus

Question 12

Capripoxvirus

Answer 12

Sheeppox virus

Question 13

Suipoxvirus

Answer 13

Swinepox virus

Question 14

Leporipoxvirus

Answer 14

Infects rabbits, myxoma virus

Question 15

Avipoxvirus

Answer 15

Fowlpox virus

Question 16

Molluscipoxvirus

Answer 16

Specific for humans

- molluscum contagiosum virus

Question 17

Yatapoxvirus

Answer 17

Yaba monkey tumor poxvirus

Question 18

When does cross-neutralization and cross-protection occur?

Answer 18

Occurs between viruses belonging to the same genus, but not between viruses of different genera

Question 19

When does genetic recombination occur?

Answer 19

Between viruses of the same genus, but rarely between those of different genera

Question 20

Poxviruses have ______ immunity

Answer 20

Long term

Question 21

Do all pox viruses have an envelope?

Answer 21

No

- non enveloped enter via endocytosis –> replication does not overwhelm the host

Question 22

What facilitates DNA replication?

Answer 22

Early mRNA

Question 23

What facilitates early transcription factor and structural proteins?

Answer 23

Late mRNA

Question 24

Entry of poxviruses

Answer 24

Via fusion or endocytosis

- cytoplasmic replication, enveloped particles released by exocytosis, nonenveloped particles released by cell lysis

Question 25

Are enveloped or noneveloped particles infectious?

Answer 25

Both

Question 26

All poxvirus infections are associated with ________

Answer 26

Lesions of the skin

Question 27

Several poxviruses, such as sheeppox, cause _______

Answer 27

Generalized disease throughout the viscera and cause significant mortality

Question 28

Cell-associated viremia

Answer 28

Leads to localization in the skin and to a lesser extent in internal organs - found in generalized poxvirus - can carry the virus without detection by host immune system

Question 29

Immunity induced by poxviruses

Answer 29

Long immunity | - induced by parapoxviruses is short and reinfection is common

Question 30

Laboratory diagnosis

Answer 30

- electron microscopic examination - inoculation of chorioallantoic membrane of chicken embryonated eggs = pocks lesions - cell cultures - ELISA - histology-intracytoplasmatic inclusion bodies

Question 31

Which methods can not be used for parapoxviruses and molluscum contagiosum virus?

Answer 31

Inoculation of chorioallantoic membrane of chicken-embryonated eggs, and cell cultures

Question 32

Poxvirus transmission

Answer 32

Direct contact from skin lesions - contaminated environment (orf) - droplet infection of the respiratory tract (sheeppox) - mechanical transmission by insects (swinepox, fowlpox, and myxomatosis)

Question 33

Vaccinia virus

Answer 33

Numerous, man, cow, buffalo, pig, rabbit

Question 34

Cowpox virus

Answer 34

Numerous, cow, man, rats, cats, large felines

Question 35

Monkeypox virus

Answer 35

Numerous, squirrels, prairie dog, monkey, great apes, man

Question 36

Raccoon poxvirus

Answer 36

Raccoon

Question 37

35 confirmed human cases of monkeypox have been associated with ________

Answer 37

Prairie dogs - infected thru contact with Gambian giant rats and dormice - humans get a vesicular rash - prairie dogs get bronchopneumonia, conjunctivits, tongue ulceration

Question 38

What are the 3 parapoxvirus zoonotic diseases?

Answer 38

- pseudocowpox virus: cattle, man - bovine papular stomatitis virus: cattle, man - orf virus: sheep, goat, man

Question 39

Pseudocowpox

Answer 39

Common endemic infection in cattle in most countries - small papule on the teat, develops into a small, dark red scab - ring or horseshoe scab - similar lesions can develop on muzzles

Question 40

Transmission of pseudocowpox virus

Answer 40

- cross suckling of calves - contaminated milking machines - mechanical transmission by flies

Question 41

Orf

Answer 41

Contagious pustular dermatitis, scabby mouth - affects muzzle and lips, eyelids, feet, and teats of ewes - sheep are susceptible to reinfection and chronic infection can occur - difficult to eradicate - ewes can be vaccinated with live-virus vaccines before lambing - short-lived immunity

Question 42

All parapoxviruses have ________ immunity

Answer 42

Short lived!!

Question 43

Capripoxvirus genus

Answer 43

- sheeppox virus: sheep, goat - goatpox virus: goat, sheep - lumpyskin disease virus: cattle, buffalo

Question 44

Does capripoxvirus cross protect with orf?

Answer 44

No, do not share common antigens

Question 45

Suipoxvirus

Answer 45

Swinepox virus | - swine

Question 46

Leporipoxvirus

Answer 46

Myxoma virus | - rabbits

Question 47

Avipoxvirus

Answer 47

Fowlpox virus | - chickens, turkey, other birds

Question 48

Yatapoxvirus

Answer 48

Yaba monkey tumor poxvirus | - monkeys

Question 49

Fowlpox

Answer 49

Occurred worldwide - characterized by small papules on the comb, wattles, around beak/feet - wet pox (diphtheritic) involves infection of mucous membranes of mouth, pharyns, larynx and sometimes trachea

Question 50

Results of fowlpox

Answer 50

- declines in egg production - little mortality - recovered birds are immune - poultry can be protected by vaccination with pigeonpox

Question 51

Which genus of poxvirus only induces short term immunity?

Answer 51

Paramyxovirus

Question 52

How does a poxvirus replicate?

Answer 52

Cytoplasm

Question 53

What is Variola virus? What is Vaccinia virus?

Answer 53

Smallpox; cowpox derived

Question 54

Is chicken pox a poxvirus?

Answer 54

No, it is a herpes virus