Pox Virus Flashcards
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?
Cytoplasm
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?
- DNA-dependent RNA polymerase
- Capping and methylating enzymes
- 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?
Smallpox
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?
- Smallpox lesions are firm, well define, and develop a pit. Chickenpox lesions are superficial.
- Chickenpox lesions in a certain area will all be at different stages
