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Flashcards in Pox Virus Deck (37)
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What is the structure of pox viruses?

Non-icosahedral with complex structure known as "brick-shaped." Virus can actually be seen under LM.


What does the intracellular pox virus contain?

Core and lateral bodies surrounded by an envelope.


What does the extracellular pox virus contain?

Everything that the intracellular virus has with the addition of an extra envelope.


What is the genome of pox viruses?

Large, double stranded linear DNA genomes that are complexed with proteins.


Replication occurs where for pox viruses?



What happens during uncoating 1 for pox viruses?

Virus enters cells and releases core particle into the cytoplasm


For pox viruses, what does the core particle contain?

1. DNA-dependent RNA polymerase
2. Capping and methylating enzymes
3. PolyA polymerase


For pox viruses, what happens with the core particle upon release into the cytoplasm?

A round of early mRNA synthesis proceeds inside the core. mRNAs then travel to the cytoplasm and are translated.


What happens during uncoating 2 of pox viruses?

The early proteins that have been synthesized lead to complete uncoating. DNA is released into the cytoplasm and DNA replication begins.


For pox viruses, how and where does virus assembly take place?

Late transcripts and proteins (structural proteins and virion enzymes) are produced in the cytoplasm leading to virus assembly there. Known as "virus factories."


How do pox virus virions attain an envelope?

Most virions remain intracellularly and the membrane appears to develop de novo. "Crescents" with no detectable contacts with existing membranes begin to envelope core structures. 1% derive a second envelope from the Golgi membrane and eventually are released from the cell.


What are the pertinent infectious agents of pox virus in the real world?

Extracellular enveloped viruses (EEVs)


What is variola virus?



What is vaccinia virus?

Used for smallpox vaccination. Essentially a lab strain. Reservoir is unknown.


For pox viruses, what do agents of molluscum contagiosum cause?

Nodular skin lesions


What are the 2 basic forms of smallpox?

Variola major and variola minor


What does smallpox cause?

A systemic dz with a generalized rash


How is smallpox spread?

Inhalation of virus released from ruptured mouth lesions


What are the early symptoms of smallpox?

High fever, malaise, body aches, and viremia followed by small red spots in mouth and on tongue


When is a smallpox pt most contagious?

When a red spot in mouth or on tongue ruptures


What is the toxemic phase of smallpox?

After second viremia, infected macrophages migrate to epidermis leading to skin lesions.


What are the skin lesions like of the toxemic phase of smallpox?

Initial skin lesion is a raised bump with a depression in the middle. Then become pustules that feel as if there's a BB pellet inside. Pustules then scab over leading to pitted scars.


How long is a smallpox pt contagious?

Until the last scab falls off


How do you distinguish smallpox from chickenpox?

1. Smallpox lesions are firm, well define, and develop a pit. Chickenpox lesions are superficial.
2. Chickenpox lesions in a certain area will all be at different stages


What are the 2 forms of molluscum contagiosum?

1. Childhood
2. Young adulthood


What are the characteristics of the childhood form of molluscum contagiosum?

Lesions appear on face, trunk, and limbs. Spread via direct contact from skin to skin. Mostly tropical.


What are the characteristics of the young adulthood form of molluscum contagiosum?

Most lesions are on the lower abdomen. Spread via sexual transmission.


What happens to the lesions of molluscum contagiosum?

Spontaneously disappear in 2-12 months


How is molluscum contagiosum diagnosed?

Appearance of lesions. Confirmed by demonstration of large cytoplasmic inclusions in eosinophils of the affected area.


Describe the vaccinia vaccine for smallpox.

1. live vaccine
2. inoculate epidermis: produces localized lesion that heals w/in 2 weeks
3. vaccination 3 days postexposure can protect (7 days post can lessen severity)
4. effectiveness declines after 3 years: completely gone after 20 years