Meningitis/Encephalitis

Question 0

Herpes simplex virus

Answer 0

• Herpesviridae
• large, envelope, dsDNA genome
• *replicates in DNA
• HSV-1, HSV-2, HSV-3

Question 1

Enteroviruses

Answer 1

-Picornaviridae (family)
-small, *non-enveloped, +sense ssRNA
-replicates in cytoplasm
-infects GI tract,
-transmitted fecal-orally; secretions; childbirth
Disease
-most common cause of meningitis
Treatment
-only supportive care
-no specific antivirals or vaccines available
Prevention
-hand washing
-formaldehyde, bleach, and >70% ethanol hand sanitizer

Question 2

Herpes simplex virus 1

HSV-1

Answer 2

-large, enveloped, dsDNA genome
-replicates in nucleus
-remains latent in trigeminal ganglia
Transmission
-oral secretions
At risk
-kids
Diseases
“above the waist”
-encephalitis
-meningitis (less than HSV-2)
Diagnosis
-Cowdry type A inclusions - eosinophilic bodies sorrounded by clear halo
-Tzanck smear - to see multinucleated giant cells
-PCR using CSF - best, most rapid diagnosis
Treatment
-Acyclovir - doesn’t cure, decreases duration
-foscarnet
Prevention
-avoid kissing/saliva contact (if blisters present)

Question 3

Human Simplex Virus 2

HSV-2

Answer 3

-large, enveloped, dsDNA genome
-replicates in nucleus
-remains latent in sacral ganglia
Transmission
-sex
At risk
-sexually active
Diseases
“below the waist”
-encephalitis
-meningitis
Diagnosis
-Cowdry type A inclusions - eosinophilic bodies sorrounded by clear halo
-Tzanck smear - to see multinucleated giant cells
-PCR using CSF - best, most rapid diagnosis
Treatment
-Acyclovir - doesn’t cure, decreases duration
-foscarnet
Prevention
-safe sex
-cesarean delivery

Question 4

Varicella-Zoster virus

VZV

Answer 4

-large enveloped, dsDNA
-*remains latent in sensory ganglia (DRG)
-transmitted through respiratory secretions & contact w/ lesions
Diseases
-chickenpox (varicella) in kids
-shingles (zoster) in elderly. reactivation of latent VZV
-rarely, can lead to pneumonia, hearing problems, blindness, encephalitis or death
Diagnostic
-Tzanck smear - for giant multinucleated cells
-PCR of CSF (best)
Treatment
-Acyclovir
Prevention
-VariZIG - (varicella ig) post exposure prophylaxis
-2 VZV vaccines

Question 5

Cytomegalovirus

CMV

Answer 5

-large, enveloped, dsDNA
-*remains latent in monocytes, activated in macrophages
-transmitted through body fluids, in utero
At risk
-immunocompromised
-congential, preemies
Diseases
-encephalitis in *neonates, HIV pt & transplant recipients
Diagnostic
-shell vial assay
-DNA by PCR (best)
-serology - a dense, central “owl’s eye” basophilic intranuclear inclusion body
Treatment
-Ganciclovir
-Cidofovir
-Foscarnet
-Valganiciclovir
Prevention
-safe sex
-blood screening
-hygienic precautions
-antivirals for transplant recipients

Question 6

West Nile Virus*

Answer 6

-Arbovirus, Flavivirus
-small, enveloped, +sense ssRNA
-*replicates in cytoplasm
-Vector: mosquitoes, Reservoir: birds
-also transmitted by blood transfusions & organ transplants
-most important arbovirus in N. America
Disease
-usually no symptoms
-causes fever in 20%
-encephalitis
-meningitis
-acute flaccid paralysis
Diagnosis
-RT-PCR
Treatment
-usually supportive
Prevention
-avoid contact w/ insects
-elimination of vectors and breeding sites
-vaccinations

Question 7

Dengue Virus*

Answer 7

-Arbovirus, Flavirviridae
-small, enveloped, +sense ssRNA
-replicates in cytoplasm
-Vector: mosquitoes, Reservoir: humans
Disease
-Dengue hemorrhagic fever and dengue shock syndrome, can be lethal
-there are 4 serotypes, each causing disease
-*antibody dependent enhancement
Diagnosis
-RT-PCR
Treatment
-usually supportive
Prevention
-avoid contact w/ insects
-elimination of vectors and breeding sites
-vaccinations