L1 Herpes Viruses (I)
What does herpes viruses cause?
Latent infections in humans
Describe the structure of herpes viruses.
A viral envelop derived from host cell nuclear membrane. Between the envelop and capsid is a structure
called tegument.
List the recognized forms of human herpes viruses:
1. Herpes simplex virus 1 - HSV-1
2. Herpes simplex virus 2 - HSV-2
3. Varicella-Zoster virus - VZV
4. Epstein-Barr virus - EBV
5. Cyto-Megalo virus - CMV
6. Human herpes virus - HHV6
7. Human herpes virus - HHV7
8. Human herpes virus - HHV8
What are the three types of herpes viruses?
α-Herpes Viruses β-Herpes Viruses γ-Herpes Viruses
HSV & VZV CMV EBV
Short replication cycle (12-18h) Slow replication cycle (<24h) Grow in lymphoblastoid cells (B
& T - Cells)
Latent infection in sensory Latent infection in salivary
ganglia glands and other organs
Infected cells become enlarged
(cytomegaly)
Herpes Simple Virus
Provide some information on Herpes Simplex Virus (HSV)
HSV occurs only in humans.
HSV consists of two types:
- HSV-1
isolated from lesions found in and around the mouth
transmitted by direct contact
droplets spread: droplets linger in the air after people talk, cough or sneeze and they
contribute to the spread of viruses.
- HSV-2
accountable for genital herpes infection
transmitted through venereal sexual contact
, What is the morphology of HSV?
HSVs are large and spherical, with an icosahedral symmetry.
They possess a nucleocapsid, which is a capsid that encloses nucleic acid.
dsDNA surrounded by a capsid composed of 162 capsomeres.
HSV also has an envelop composed of several glycoproteins.
gB, gD, and gH are glycoproteins essential for infection.
gB and gD are involved in adsorption and penetration, while gH is involved in the release of
virus into host cells.
Explain the pathogenesis of HSV
A. Primary infection
Entry
Multiplication and Spread
Virus enters
through skin or Spread
mucous membrane Virus invades host
cells, multiplies, Centrifugal Migration
and locally spreads The virus will enter
from cell to cell. cutanuous nerve Latent Infection
fibers and spread Virus spreads from
intra axonally to ganglia to skin and
the ganglia. mucosa, which Virus remains in
The virus will causes cutaneous the ganglia -
replicate within the and mucosal Trigeminal Nerves
ganglia. lesions. (HSV-1) and Sacral
Nerves (HSV-2),
activated years
after the onset of
infection.
It is important to note that HSV-1 produces lesions above the waist, while HSV-2 produces lesions below
the waist.
What are the clinical manifestations for HSV?
- Cutaneous infections: most common infection site
lesions may appear on the buttocks in infants, similar to napkin rash.
What does herpes viruses cause?
Latent infections in humans
Describe the structure of herpes viruses.
A viral envelop derived from host cell nuclear membrane. Between the envelop and capsid is a structure
called tegument.
List the recognized forms of human herpes viruses:
1. Herpes simplex virus 1 - HSV-1
2. Herpes simplex virus 2 - HSV-2
3. Varicella-Zoster virus - VZV
4. Epstein-Barr virus - EBV
5. Cyto-Megalo virus - CMV
6. Human herpes virus - HHV6
7. Human herpes virus - HHV7
8. Human herpes virus - HHV8
What are the three types of herpes viruses?
α-Herpes Viruses β-Herpes Viruses γ-Herpes Viruses
HSV & VZV CMV EBV
Short replication cycle (12-18h) Slow replication cycle (<24h) Grow in lymphoblastoid cells (B
& T - Cells)
Latent infection in sensory Latent infection in salivary
ganglia glands and other organs
Infected cells become enlarged
(cytomegaly)
Herpes Simple Virus
Provide some information on Herpes Simplex Virus (HSV)
HSV occurs only in humans.
HSV consists of two types:
- HSV-1
isolated from lesions found in and around the mouth
transmitted by direct contact
droplets spread: droplets linger in the air after people talk, cough or sneeze and they
contribute to the spread of viruses.
- HSV-2
accountable for genital herpes infection
transmitted through venereal sexual contact
, What is the morphology of HSV?
HSVs are large and spherical, with an icosahedral symmetry.
They possess a nucleocapsid, which is a capsid that encloses nucleic acid.
dsDNA surrounded by a capsid composed of 162 capsomeres.
HSV also has an envelop composed of several glycoproteins.
gB, gD, and gH are glycoproteins essential for infection.
gB and gD are involved in adsorption and penetration, while gH is involved in the release of
virus into host cells.
Explain the pathogenesis of HSV
A. Primary infection
Entry
Multiplication and Spread
Virus enters
through skin or Spread
mucous membrane Virus invades host
cells, multiplies, Centrifugal Migration
and locally spreads The virus will enter
from cell to cell. cutanuous nerve Latent Infection
fibers and spread Virus spreads from
intra axonally to ganglia to skin and
the ganglia. mucosa, which Virus remains in
The virus will causes cutaneous the ganglia -
replicate within the and mucosal Trigeminal Nerves
ganglia. lesions. (HSV-1) and Sacral
Nerves (HSV-2),
activated years
after the onset of
infection.
It is important to note that HSV-1 produces lesions above the waist, while HSV-2 produces lesions below
the waist.
What are the clinical manifestations for HSV?
- Cutaneous infections: most common infection site
lesions may appear on the buttocks in infants, similar to napkin rash.
