Herpes Flashcards
Macule
Smooth area of colour change less than 1.5cm
Patch is a larger area
Papule
Solid RAISED spot on skin <1.5cm
Larger= plaque
Nodule
Circumscribed(within limits) elevated solid lesion <1cm
Larger is tumour
Postule
Circumscribed collection on leukocyte
Herpes labialis
HSV1
Orofacial disease - gingivostomatitis
Common manifestation recurrent
Postules/vesicles around lips
HSV1 common manifestations
Ocular keratoconjunctivitis
Gingivostomatitis
Type 4 herpes - Epstein Barr virus
Mononucleosis or kissing disease
Fever fatigue sore throats swollen lymph glands
Type 5 cytomegalovirus
Mainly in immuncompromised ppl ENCEPHALITIS Retinitis Pneumonia Gastroenteritis
Cytomegalic means enlargement of cell
Type 4 Roseola
Acute disease in infants and kids
High fever
Trunk rash limbs neck face
May play role in MS in adults
Type 7
Febrile illness similar to measles
Concussions due to ENCEPHALITIS
Type 8
Kaposis sarcoma (malignancy of blood vessels)
Primary lymphoma
Nasopharyngeal carcinoma
Type 3 varicella roster
Chicken pox n shingles
Type 2
Genital herpes
Transmitted to babies 25-50%
General herpes properties
Able to establish latent infection Induce cell mediated immunity Mode of replication Virus morphology Alpha beta gamma
Double stranded
Spherical virion
Alpha herpes
Cytolytic
Live in neurons
HSV1 hsv2 varcella zoster
Cytolytic means destruction of cell
Beta herpes
Cytomegalic (enlargement of cell)
Live in mononuclear cells /glands/ kidneys
Cytomegalovirus, type 6,7
Gamma herpes
Lymphoproliferative
Live in lymphoid tissue blood vessels
Epstein Barr virus
Kaposis sarcoma
HSV 4 basic structural elements
Electron opaque core contains DNA
Icosahedral capsid surrounding core
Tegument- unstructured proteinacous layer surrounding capsid
Outer lipid bilayer with spikes on surface (envelope has 11 glycoproteins)
Important tegument proteins
Surround the capsid
Involved in initiation of replication
VP16 virion transactivator (aka alpha-TIF)
Virion host shut off protein VHS
Steps for fusion (1’pathway)
Viral envelope fuses w cell membrane
Capsid transported to nucleus via microtubular network
Capsid fuses w nuclear pore
Viral DNA is released
Secondary pathway for entry
Endocytosis of enveloped capsid
Receptor dependent fusion of envelope w membrane of endocytic vesicle
Capsid has to be released from envelope and the membrane it got from the cell membrane durin endocytosis
How virus envelope interacts with cell surface - glycoproteins
Binding of gC and gB to cell GAGs
gD interacts with specific receptors to allow for fusion of envelope to plasma membrane
VHS
Turns off host protein synthesis
Degrades host mRNA
Released from tegument
Alpha TIF or VP16
Imitates transcription of immediate early genes
Released from tegument
Once at the nuclear pore viral replication step: TREE
Transcription of genes
Relocation of dna
Encapsidstion - pack DNA
Egress of virion out of nucleus
Immediate early protein alpha
Regulate viral replication
Early protein beta
Make and pack dna
Uses viral DNA polymerase
Late proteins gamma
Involved in capsid formation
How does latent infections happen
Some of the viral DNA is made to heterchromatin (inaccessible to DNA binding factorS)
Results in latency associated transcript lat RNA
= latent infection
VP16 activation will cause reactivation = acute infection
Epithelial lyric infection
VP16 and host cell factors go to nucleus
IE genes are expressed
VP16 n icp0 infected cell protein decrease heterochromatin infx
Genome associates w euchromatin
Active gene expression
Neuronal cell latent infx
VP16 goes to cytoplasm
lat promotes heterochromatin formation
Genomes associates w heterochromatin
Silence of gene expression
Syncytium
Formation of multi nucleate enlarged cells due to fusion of infected cell w neighbouring cells
Allows spread of viral proteins
Trigeminal ganglion
Primary site for latency of HSV1
Sacral ganglion
Primary site of latency for hsv2
Clinical manifestations of HSV1
Herpes labialis -cold sore
Eczema herpeticum - loss of large area of epithelium. Loss of body fluids. Causes secondary bacterial infections
Meningoencephalitis - can be fatal
Eye- blepharitis and keratoconjunctivitis