HERPES VIRUS – HERPES SIMPLEX VIRUS

HERPES VIRUS – HERPES SIMPLEX VIRUS

Definition:

• Herpes simplex virus (HSV) is a double-stranded DNA virus.
• It causes infections in humans and animals.
• HSV is classified into two types: HSV-1 and HSV-2.

Causes:

• HSV is highly contagious and spreads through skin-to-skin contact.
• It can also be spread through touching contaminated objects or surfaces.

Types:

• HSV-1 typically causes oral herpes (cold sores).
• HSV-2 typically causes genital herpes.

Pathogenesis: → HSV enters the body through a cut or abrasion in the skin. → The virus multiplies in the epithelial cells. → The virus travels to the nerve cells and remains there in a dormant state. → The virus reactivates when the host is under stress or has a weakened immune system. → The virus multiplies again and travels back to the skin, causing symptoms.

Pathogenesis Step-by-Step:

1. Attachment: HSV attaches to the host cells through a protein called glycoprotein D.
2. Penetration: The virus penetrates the host cells through a process called fusion.
3. Uncoating: The virus releases its genetic material from the viral capsid.
4. Replication: The virus multiplies in the host cells.
5. Transcription: The virus transcribes its genetic material into messenger RNA.
6. Translation: The virus translates the messenger RNA into proteins.
7. Assembly: The virus assembles new viral particles.

Morphology:

• HSV has a double-stranded DNA genome.
• The virus has a viral capsid, which is composed of 162 capsomeres.
• The virus has a lipid envelope, which is derived from the host cell membrane.

Clinical Features:

• Oral herpes (HSV-1): causes cold sores, fever blisters, and sores in the mouth and on the lips.
• Genital herpes (HSV-2): causes sores, blisters, and ulcers in the genital area.
• HSV can also cause encephalitis, meningitis, and neonatal herpes.

Complications:

• HSV can cause encephalitis and meningitis.
• HSV can cause neonatal herpes, which is a serious condition that can be fatal.
• HSV can cause herpetic whitlow, which is a painful infection of the fingers or toes.

Laboratory Diagnosis:

• HSV can be diagnosed through a variety of tests, including:
  • PCR (polymerase chain reaction)
  • ELISA (enzyme-linked immunosorbent assay)
  • Culture
  • Serology

Memory Trick: "HSV Enters, Multiplies, Travels, Reactivates, Multiplies Again, Travels Back"

→ HSV enters the body through a cut or abrasion. → HSV multiplies in the epithelial cells. → HSV travels to the nerve cells and remains there in a dormant state. → HSV reactivates when the host is under stress or has a weakened immune system. → HSV multiplies again and travels back to the skin, causing symptoms.

Word Trick: "HSV = Hide, Multiply, Travel, Sleep, Multiply Again, Travel Back"

→ HSV hides in the nerve cells. → HSV multiplies in the epithelial cells. → HSV travels to the nerve cells and remains there in a dormant state. → HSV reactivates when the host is under stress or has a weakened immune system. → HSV multiplies again and travels back to the skin, causing symptoms.