Poxviridae

Question 1

Largest of all animal viruses
• 300-400 nm in length x 230 nm in diameter

Answer 1

Poxviridae

Question 2

• Complex structure, oval or brick shaped
• Proteolipid envelope, with ridges on the external surfaces

Answer 2

Poxviridae

Question 3

• Contain linear dsDNA genomes that replicate in the cytoplasm
• Have a core with many enzymes (including transcriptional system) & two lateral bodies

Answer 3

Poxviridae

Question 4

• Synthesize its own “uncoating protein,” form their own
“factories” (inclusion bodies) in the cytoplasm

• Some genes resemble mammalian genes for proteins that inhibit host defense mechanisms, i.e. TNF, interferon-y receptor, interleukin-1 receptor, & a complement-binding protein

Answer 4

Poxviridae

Question 5

Localized lesion; used for smallpox vaccination

Answer 5

Vaccinia

Question 6

Smallpox (now eliminated)

Answer 6

Variola

Question 7

Human infections rare; localized lesion

Human infections rare; generalized disease

Human infections rare; localized ulcerating lesion

Answer 7

Buffalopox

Monkeypox

Cowpox

Question 8

Humans
Many benign skin nodules

Answer 8

Molluscum contagiosum

Question 9

SMALLPOX (VARIOLA)
*Latin:_____ (spotted) or____ (pimple)

•________(a bag or pouch) - describes an exanthematous disease (accompanied by skin eruption); highly contagious - airborne droplet secretions, direct contact with lesions or contaminated fomites

Answer 9

varius; varus

poc or pocca

Question 10

•’small’ to distinguish from the great pox, syphilis
• In the 20th century, global death toll was over 300 million.

Answer 10

Smallpox (variola)

Question 11

SMALLPOX (VARIOLA)

•Vaccinia virus, the “vaccine virus,” a relative of variola virus, which is the prototype of poxviruses

Answer 11

Smallpox( virus)

Question 12

SMALLPOX (VARIOLA)

• *Two strains:
1. _____ - more common, severe disease, more extensive rash, higher fever, 30% fatality
2. _____ - milder disease, 1%-2% fatality rate in unvaccinated persons

Answer 12

Variola major

Variola minor

Question 13

• Incubation period: 10-14 days

Answer 13

SMALLPOX (VARIOLA)

Question 14

Symptoms:_____ of fever & malaise, exanthems (7-10 mm dm) appear as macules then papules, then vesicles, finally pustules, crusts that fell off after about 2 weeks, leaving pink scars that faded slowly. Lesions (centrifugal rash) abundant on face and less so on the trunk. Severe cases - hemorrhagic rashes.

Answer 14

1-5 days

SMALLPOX (VARIOLA)

Question 15

Lesions (centrifugal rash) abundant on face and less so on the trunk. Severe cases – hemorrhagic rashes.

Answer 15

Variola

Question 16

Reported: 99% in men aged 0-65 years (self-identified as
men who have sex with other men)

Answer 16

Monkeypox

Question 17

Clinical picture: fever, swollen lymph nodes, centrifugal
evolving rash.

Atypical features: presentation of only a few or even just a single lesion.

Answer 17

Monkeypox

Question 18

o Used to be a rare zoonotic disease first detected in Congo & West Africa

First outbreak in the US in 2003, source traced to an exotic pet store where an imported African rat spread the virus to pet prairie dogs and transmitted it to humans

Answer 18

Monkeypox

Question 19

– a benign epidermal tumor that occurs only in humans.

Agent: a sole member of the Molluscipoxvirus.
Four subtypes – genotype 1most common cause in the U.S.

Occurs worldwide both sporadic and epidemic forms, frequent in children (daycare centers & kindergartens), adolescents than in adults

Transmission: physical contact, autoinoculation, fomites (barbers, towels, swimming pools)

Answer 19

Molluscum contagiosum

Question 20

Virus has not yet been transmitted to animals and has not been grown in tissue culture.

Studied by electron microscopy.
The purified virus resembles vaccinia.

Answer 20

Molluscum contagiosum

Question 21

Antibodies to the virus do not cross-react with any other poxviruses

Answer 21

MOLLUSCUM CONTAGIOSUM VIRUS

Question 22

MCV

Skin penetration → stratum spinosum → replication within basal
keratinocytes → epidermal hypertrophy → papules

Incubation period:_____?

Answer 22

2-6 weeks may extend up to 6 months

Question 23

Lesions: small, pink, pearl-like lesions (______) or wart- like tumors on the face, arms, back, and buttocks

rarely on palms, soles, or mucous membranes, 1-5 mm in diameter, has a dimple center or umbilicated;

in the genitals – may be confused
with herpes simplex virus; may itch – leading to autoinoculation;
persist up to 2 years but regress spontaneously (self-limiting
infection)

Answer 23

molluscum

Question 24

The virus – a poor immunogen

1/3 of patients never produce
antibodies against it.

Second attacks are common.

Answer 24

MCV

Question 25

Directly responsible for the successful eradication of the smallpox Infection provides adequate cross-protective immunity against smallpox and monkeypox Cause exanthematous lesions in the teats of dairy cows and hands of milkers

Answer 25

VACCINIA VIRUS

Question 26

Produce localized skin infection and fever when inoculated; contraindicated in people with eczema or are immunosuppressed May disseminate, cause severe disease (ex. Myopericarditis) in immunocompromised host (approx. 1-2 people out of every 1 million people vaccinated could die of life-threatening reactions to the vaccination)

Answer 26

VACCINIA VIRUS