Viral Infections of the Eye Flashcards
(24 cards)
What is a viral infection of the cornea?
Keratitis
What is keratoconjunctivitis?
Viral infection of conjunctiva and cornea
Which viruses are dsDNA, icosahedral, and have enveloped?
HSV and VZ and CMV (Herpetoviridae)
Which virus is dsDNA, icosahedral but does not have an envelope?
Adenovirus (Adenoviridae)
Which viruses are ss(+)RNA, icosahedral, but do not have an envelope?
Enterovirus 70 and Coxasackie A24 (Picornaviridae)
Which virus is ss(-)RNA, helical and has an envelope?
Newcastle Disease (Paramyxoviridae)
Which virus is ss(+)RNA, icosahedral, and has an envelope?
West Nile Virus (Flaviviridae) and Rubella (Togaviridae)
Which viruses cause infections in the fetus?
Rubella and CMV
How does HSV lead to infections of the eye?
HSV can induce a latent infection in the trigeminal ganglia, and once reactivated may travel down the ophthalmic branch to cause secondary infections of the eye
Where does replication occur for primary HSV infections of the eye?
Corneal Epithelial Cells
The dendritic keratitis lesion caused by some strains of HSV can best be visualized how?
- Fluorescent Dye + Blue Light
2. Rose Bengal Dye
In addition to the dendritic lesions, HSV strains may also produce broader lesions called what?
Geographic Ulcers
How can some strains of HSV cause significant loss of vision?
Strains that infect keratocytes of the Stroma, upon resolution, result in the keratocytes laying down disordered collagen –> scarring –> loss of visual acuity
What is Corneal Melting?
A severe manifestation of a HSV infection that infected the stroma. Following the infection, left over antigens in the stroma attract PMNs which –> complement to damage the stroma; Macrophages and T cells follow and worsen the damage.
Which area of the cornea is often destroyed in corneal melting, and what is the consequence?
In addition to the stroma, the Endothelial cell layer is destroyed, resulting in the hydration of the cornea
What would be the problem with a corneal transplant in a patient who had corneal melting?
The HSV virus is still in the trigeminal ganglion, so the infectious process could start all over again
VZ usually causes infections where?
The conjunctiva (rare in the cornea but may occur)
What is Herpes Zoster Ophthalmicus?
Occurs when VZ becomes latent in the Trigeminal Ganglion and causes recurrent keratoconjunctivitis, uveitis and optical nerve palsies
CMV can cause what conditions in fetuses (and AIDS patients)?
Chorioretinitis, Cataract formation and Microphthalmia
What is the effect of Rubella on the fetus?
It stunts growth of tissues and leads to cataracts
Which virus can remain viable for weeks in water (pools, shipyards)?
Adenoviruses
What condition does Adenovirus cause in the eye?
Keratoconjunctivitis
Which tropical viruses can cause hemorrhagic conjunctivitis?
Enterovirus 70 and Coxackie A24
Farmers are susceptible to getting what viral infection from chickens?
Newcastle Disease
