Viruses of skin Flashcards
localised infection of skin is where?
basal cells and fibroblasts
skin inf becomes systemic when?
if it enters the bs
describe the pathogenesis of a skin inf from inside?
- inf of conjuctivae/mucosa of URT
- viral replication in regional lymph nodes
PRIMARY VIRAEMIA - viral replication in liver, spleen etc
SECONDARY VIRAEMIA - inf of skin, appearance of vesicular rash
give 3 examples of viruses that cuase localised inf in the skin
1) HPV- warts
2) Molluscum contagiosum-water warts
3) Herpes simplex virus- cold sores
Molluscum contagiosum is from which family?
describe the size of ts genome?
poxvirus (only poxvirus that specifically infects humans)
large DNA genome
where does replication of Molluscum contagiosum occur?
human epidermis
HPV is from what family?
how big is its genome?
Papillomaviridae
small DNA genome
where does HPV replicate?
ONLY in differentiated keratinocytes
how many HPV types are there?
> 130 cutaneous and mucosal
cutaneous HPV causes what?
skin and genital warts, verrucas
what does high risk mucosal HPV cause?
cervical cancer
Herpes is from what family?
describe the genome
alphaherpesvirus
large DNA genome
Herpes presents on skin mainly as?
cold sore or
herpes keratitis - infection of eye
herpes whitlow - infection on hands or wrists
herpes gladiatorum and scrum pox - skin lesions in wrestlers and rugby players
eczema herpeticum - children with eczema become infected with HSV
HSV1 infection comes from where?
outside and inside
what are the 2 ways that HSV is transmitted?
direct contact w/ infected blisters (cold sore)
contact w/ saliva( also cont infectious virus)
Varicella zoster virus (VZV) causes what?
secondary disease of the skin, chickenpox
Varicella zoster virus (VZV)
is from what family?
alphaherpesvirus
describe the latency of VZV?
latency establishes in sensory ganglia of PNS
- reactivation results in shingles POSTHERPETIC neuralgia
areHSV and VZV part of our lifelong virome?
yes
what family is smallpox from?
describe the genetic info of smallpox
Variola virus- orthopoxviruses
large DNA genome
describe the pathogenesis of smallpox
- inhalation or transmission by scabs
- multiplication in URT
- multiply in lymphatics and lymph nodes
- hemorrhage of small vessels of dermis, leading to rash and pox SECONDARY VIRAEMIA
- movement to spleen, liver, bone marrow
what virus was used to vaccinate against smallpox?
Vaccinia
hand foot and mouth disease is caused by what virus?
Cocksackie
Cocksackie comes from what family? what kind of genome?
Picornavirus
RNA genome
how is Cocksackie transmitted?
from nose and throat secretions
blisteer fluid
faeces
which disease causes maculopapular rashes on the skin?
what do they infect via?
measles, Rubella (german measles), Parovirus B12 (slapped cheek disease)
infect via resp route and are transported systemically to skin where they infect DERMAL endothelial cells
how is HPV and Molluscum (growth formers) transmitted
dead cells slough off skin
how are viruses that cause rashes transmitted?
via resp route (aerosols, droplets)
how are viruses that enter through insect bite transmitted?
via another insect feed
how does HPV and molluscum evade immune system?
make new virus particles in upper layers where there are no immune cells
don’t make antigens in lower layers, so aren’t recognised as foreign
how do HSV, VZV and smallpox gain access to epidermis?
from blood/neurons
