Lecture 25 - Herpes viruses Flashcards
(29 cards)
what are the three herpes virus infections?
chicken pox (90% of people)
glandular fever (90% of people)
cold sores (60% of people)
virally, what happens at each ‘pox’ of chicken pox?
each spot is a region where viruses are intracellularly replicating and living
raised red bump on skin, where fluid accumulates and turns a milky white, scab forms and falls off
what are three types of herpes viruses we learnt?
varicella zoster
epstein barr virus
herpes simplex virus
describe pharyngitis due to glandular fever
inflammation of tissues with swollen/infected lymph nodes in the mouth, but also occurs body-wide
describe cold sores from herpes simplex virus
similar to chicken pox, but can come in clusters of approx 1cm
can also appear on genetalia
describe common features of herpes virus infections
- common, cause minor illnesses
- cause persistent latent infection with intermittent shedding
describe herpes virus structure
outer envelope derived from host nuclear membrane around nucleocapsid containing a DNA genome
how do we diagnose herpes viruses?
immunofluorescence (AB binding, view in microscope), culture, serology (testing blood AB), PCR
how do we treat herpes viruses?
Acyclovir and related antiviral drugs
- only make mild difference, immune system is good enough
how does a herpes virus replicate
spike protein attaches to receptor on particular cells (skin, nerve cells etc)
same mechanism as others but instead its envelope is created with the nuclear envelope of the host cell, which is sometimes damaging
what are the three things that can happen after infection of a cell by a herpes virus
- prompt replication of virus and cell death
- latent infection, without viral replication for months/years
- reactivation of latent infection with replication and cell death
what type of virus is cytomegalovirus
herpes virus
transmission, replication location, latency location and reactivation of herpes simplex type 1 and 2?
infection via contact with contaminated saliva
replication in skin cells and oral membranes
latent infection in trigeminal ganglion
reactivation causing cold sores
how is the primary infection of herpes different?
can be more severe and last longer, involves lesions on the mouth as well as lips
describe the process of primary infection of herpes simplex virus
attachment to epithelial cells, travel up axons and reside in trigeminal ganglion (if type 1)
what severe diseases can stem from herpes simplex virus?
neonatal herpes obtained during birth when mother is infected with genetal herpes, and results in systemic infection
- systemic infection in immunocompromised patients such as AIDS
transmission, replication location, latency location and reactivation of varicella zoster?
infection via contact with contaminated saliva or skin
replication in skin or mucous membranes
Latent infection of dorsal root ganglion
reactivation causes shingles
what are the distinctive features of shingles?
infects a single dermatome, such as a line, because that is the distribution of the nerve fibres radiating from the midline
- only ever on one side of the body
what does shingles feel like?
hyperasthesia, an increased sensation of pain, just blowing on the skin can cause pain
is there a shingles virus
yes
transmission, replication location, latency location and reactivation of epstein barr virus?
infection via contact with infected saliva (kissing disease)
replication in B lymphocytes in lymph nodes in tonsils
latent infection in B lymphocytes within body, no longer causing disease
describe the infection process of epstein barr virus and glandular fever
- contact with infected saliva
- infection of B lymphocytes in tonsils
- spread of infection to B lymphocytes in other lymph organs
- cytotoxic T cells attack infected B lymphocytes, causing swollen lymph nodes and fever
describe the onset, disease and recovery of glandular fever
slow, 30 day onset
sore throat, swollen lymph nodes
lethargy, anorexia
recovery over weeks to months
how can EBV become more severe?
EBV infection results in B lymphocytes remaining in growth cycle, and don’t die when supposed to.
inadequate killing by cytotoxic T cells can result in B cell lymphomas (cancer) such as in AIDS, but otherwise very rare
