Herpesviridae Flashcards
How is HSV-1 transmitted?
- Direct contact of mucous membranes.
2. Sexually
What is the morphology of HSV-1?
- Double stranded linear DNA
- Enveloped
- Icosahedral symmetry
What is the travel course of HSV?
Travels up sensory nerve fibers to the sensory nerve ganglia, where it replicates, then returns along the sensory nerve fibers to produce skin lesions.
What is the morphology of HSV-2?
Same as HSV-1.
How is HSV-2 transmitted?
Same way as HSV-1.
What can the HSV cause?
- Gingivostomatitis (cold sores)
- Reactivation of gingivostomatitis
- Herpetic keratitis of the eye
- Encephalitis
- Genital herpes
- Reactivation of genital herpes
- Neonatal herpes
- Herpetic whitlow
- Disseminated herpes infection of organs
What happens in gingivostomatitis?
Painful group of vesicles on the lips and mouth, which ulcerate, and heal usually without leaving a scar.
Often accompanied by fever and “viral” symptoms.
What happens in herpetic keratitis of the eye?
Recurrence is common. MCC of corneal blindness in USA.
What happens in encephalitis?
- MCC of viral encephalitis in USA.
- Most cases are reactivation of latent HSV-1.
- Cell death and brain tissue swelling
- Fever, headache + neurologic abnormalities.
What happens in genital herpes?
- Painful group of local vesicles on the cervix, or on the external genitalia of men and women.
- Often associated with fever and viral symptoms.
- These vesicles usually do not scar.
What happens in neonatal herpes?
- Acquired through the passage of fetus through an infected birth canal.
- The risk of transmission is highest when a primary genital infection is present during delivery.
- Disseminated - CNS - skin - eye.
How do we diagnose HSV infection?
- Tzanck prep: reveals multinucleated giant cells and intranuclear inclusion bodies.
- Viral culture.
- PCR
- Serology
- Direct fluorescent antibodies (DFA)
What is the morphology of Varicella-zoster virus?
- Double-stranded linear DNA.
- Enveloped
- Icosahedral symmetry
How is Varicella-zoster virus transmitted?
- HIGHLY CONTAGIOUS
- Aerosolized respiratory secretions
- Contact with ruptured vesicles
- Zoster - reactivation from dorsal root ganglion
What can Varicella-zoster virus cause?
- Varicella (chicken pox)
2. Zoster (shingles)