Viral Infections of the Eye

Question 1

What is a viral infection of the cornea?

Answer 1

Keratitis

Question 2

What is keratoconjunctivitis?

Answer 2

Viral infection of conjunctiva and cornea

Question 3

Which viruses are dsDNA, icosahedral, and have enveloped?

Answer 3

HSV and VZ and CMV (Herpetoviridae)

Question 4

Which virus is dsDNA, icosahedral but does not have an envelope?

Answer 4

Adenovirus (Adenoviridae)

Question 5

Which viruses are ss(+)RNA, icosahedral, but do not have an envelope?

Answer 5

Enterovirus 70 and Coxasackie A24 (Picornaviridae)

Question 6

Which virus is ss(-)RNA, helical and has an envelope?

Answer 6

Newcastle Disease (Paramyxoviridae)

Question 7

Which virus is ss(+)RNA, icosahedral, and has an envelope?

Answer 7

West Nile Virus (Flaviviridae) and Rubella (Togaviridae)

Question 8

Which viruses cause infections in the fetus?

Answer 8

Rubella and CMV

Question 9

How does HSV lead to infections of the eye?

Answer 9

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

Question 10

Where does replication occur for primary HSV infections of the eye?

Answer 10

Corneal Epithelial Cells

Question 11

The dendritic keratitis lesion caused by some strains of HSV can best be visualized how?

Answer 11

1. Fluorescent Dye + Blue Light

2. Rose Bengal Dye

Question 12

In addition to the dendritic lesions, HSV strains may also produce broader lesions called what?

Answer 12

Geographic Ulcers

Question 13

How can some strains of HSV cause significant loss of vision?

Answer 13

Strains that infect keratocytes of the Stroma, upon resolution, result in the keratocytes laying down disordered collagen –> scarring –> loss of visual acuity

Question 14

What is Corneal Melting?

Answer 14

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.

Question 15

Which area of the cornea is often destroyed in corneal melting, and what is the consequence?

Answer 15

In addition to the stroma, the Endothelial cell layer is destroyed, resulting in the hydration of the cornea

Question 16

What would be the problem with a corneal transplant in a patient who had corneal melting?

Answer 16

The HSV virus is still in the trigeminal ganglion, so the infectious process could start all over again

Question 17

VZ usually causes infections where?

Answer 17

The conjunctiva (rare in the cornea but may occur)

Question 18

What is Herpes Zoster Ophthalmicus?

Answer 18

Occurs when VZ becomes latent in the Trigeminal Ganglion and causes recurrent keratoconjunctivitis, uveitis and optical nerve palsies

Question 19

CMV can cause what conditions in fetuses (and AIDS patients)?

Answer 19

Chorioretinitis, Cataract formation and Microphthalmia

Question 20

What is the effect of Rubella on the fetus?

Answer 20

It stunts growth of tissues and leads to cataracts

Question 21

Which virus can remain viable for weeks in water (pools, shipyards)?

Answer 21

Adenoviruses

Question 22

What condition does Adenovirus cause in the eye?

Answer 22

Keratoconjunctivitis

Question 23

Which tropical viruses can cause hemorrhagic conjunctivitis?

Answer 23

Enterovirus 70 and Coxackie A24

Question 24

Farmers are susceptible to getting what viral infection from chickens?

Answer 24

Newcastle Disease