L13: Viral Skin Rashes Flashcards Preview

Medical Virology (UoG) Midterm 2 > L13: Viral Skin Rashes > Flashcards

Flashcards in L13: Viral Skin Rashes Deck (12):

Name some of the symptoms of Measles virus.

- Runny nose
- Red/watery eyes
- Cough
- Koplik's spots (white spots on the inside of the cheeks)
- Maculopapular rash (raised, red spots) usually on face and upper neck which tracks downward over a few days


What kind of IR is initiated upon MV infection?

Strong MV-specific humoural and cell-mediated immune response --> induces life-long immunity


Descirbe MV pathogenesis.

- MV enters host via infection of alveolar macrophages and/or DCs
- replicates in lungs/lymph nodes
- spreads to other tissues (viraemia here too)
- Come back to epithelial cells and do a bunch of damage to facilitate transmission via coughing/sneezing


What causes the characteristic rash of a MV infection?

Cell-mediated hypersensitivty


Is MV a good candidate for eradication? Why/why not?

- no non-human reservoirs
- sensitive AND specific diagnostic tests available
- effective vaccine is available


What are some limitations to MV eradication?

- Attenuated vaccines inactivated by light and heat
- Needs to be stored within a very specific and narrow temperature range
- Must be administered intramuscularly or subcutaneously (requires training and proper sharps disposal)
- Maternal Abs hinder protective efficacy of vaccines if given too early
- Can still lead to complications in severely immunocompromised individuals


Describe the pathogenesis of poxviruses.

- Incubation period of 7-10 days --> individual is asymptomatic
- Prodrome phase --> fever, malaise, head/body aches (**sometimes contagious)
- Early rash --> Emerges in nose/mouth/throat, sores break open too for inc transmission, moves to extremeties not as much on torso like in MV infections (MOST CONTAGIOUS)
- Pustular rash --> bumps become pustules, feel a bit like BB pellets (contagious)
- Pustules & scabs --> pustules start to scab (still contagious)
- Resolving scabs --> Scabs fall off, leave sexy pitted scars (contagious)
- Resolved scabs --> All your scabs are gone and you are no longer contagious


What are some general characteristics of viral skin rashes?

- Infection occurs in the upper respiratory tract and moves to the skin via the blood
- Usually accompanied by fever/malaise/headache
- Rash is usually due to the IR rather than the virus itself


What is the importance of vaccinia virus?

It is the vaccine virus for smallpox --> contributed significantly to eradication


Why was smallpox able to be eradicated? (3)

- No animal reservoir
- Vaccinia virus was an effective immunogen
- Patients either died or recovered with lifelong immunity


Describe the pathogenesis of VZV.

- Gains entry to the body via the repiratory epithelial cells
- Virus gains access to permissive T cells and replicateds in lymphoid tissues
- Also moves through the body (primary viraemia) and replicates in the skin, liver and spleen
- Replication in epidermal cells causes rash
- During secondary viraemia, virus can reach neurons in sensory ganglia where it can establish latency


Immunity to chicken pox does not mean immunity to latent VZV infection. True or False?

True! :)