Viral Diseases II Flashcards
What are the key facts surrounding smallpox?
- One of the most devastating human diseases
- Extremely contagious
- Estimated 300 million deaths in the 20th century alone
- 30% mortality rate
What is the structure of the pox virus?
- A double-Stranded DNA virus
- it has a large linear genome that can encode many proteins
- It replicates in the cytoplasm
What are the two forms of PoxVirus?
- Intracellular mature virus
- Extracellular enveloped virus
What do pox viruses create when they are in the cytoplasm of the cell?
They create vacuoles or inclusion bodies
What is the first poxvirus pathogenesis?
The virus produces non-structural proteins which inhibit host innate immune responses
* Blocks internal cell signalling
* switches off the host complement cascade
What is the benefit of the poxvirus ‘stealing’ some of the cell membrane?
Uses it as a cloak to hide itself and stops the cell from commiting suicide
What is the second poxvirus pathogenesis?
Transmission is most commonly via contact of infectious material with broken skin
You cannot infect in-tact skin
What is the meaning of poxviruses being epitheliotropic?
they infect keratinocytes
What is the current monkey pox strain travelling around the UK?
B.1
What does cowpox in cats look like?
- It is usually acquired from rodents
- Pox skin lesions on the head
- in cats it can also effect the liver and the lungs
- can be fatal
What are the key features of vaccinia?
- closely related to smallpox and cowpox
- the natural reservoir host species remains unknown
- it is used as a vaccine during the smallpox campaign
What are the key features of orf?
- occurs worldwide
- affects sheep and goats
- also known as contagious pustular dermatitis
- usually just a cutaneous disease, not systemic
- pox lesions on the mouth and lip
- can infect humans via skin abrasions
What is sheep pox/ Goat pox?
systemic disease with nodules in the lungs, liver, GIT and the kidney
severe in young with a high mortality
What is lumpy skin disease?
Not systemic
Causes nodules all over the body
Low mortality
has a high economic impact as you cannot sell hides
How may you diagnose pox virus?
- sample fluid from vesicles, this provides large quantities of the virus
- Diagnostic assays such as PCR + Sequencing