Lecture 58 Rabies Flashcards
What type of virus is rabies?
Rhabdovirus
Enveloped Bullet shaped virion with ssRNA
Rabies clinical manifestations
Fatal once overt disease is present Incubation can be highly variable, days to years Two types: 1) Excitatory 2) Paralytic
Why do people with rabies “foam at the mouth”?
Virus replication in salivary glands => salivation, but pharyngitis makes it painful to swallow so the saliva comes out the mouth
Rabies course
Prodrome: fever, pharyngitis, abnormal sensations at bite
Excitatory phase: anxiety, aprehension, hydrophobia
Coma, hypertension, death
Rabies pathogenesis
Local replication at bite site, retrograde spread to the CNS and limbic region of the brain
Negri Bodies in the neurons are diagnostic (cytoplasmic inclusion bodies)
Administer therapy before virus gets to the CNS
Primary reservoirs for rabies
Skunk, fox, coyote, raccoon, bat
Rabies transmission
Usually involves contact with saliva of infected animal
Can be aerosolized in bat caves and lead to infection
Corneal transplants–rare
Rabies control
Nothing can be done once disease is overt
Control most important in companion and herd animals which are vaccinated
Post-exposure vaccination
Rabies diagnosis
Viral antigen in tissues
Negri body
Look at what happened and establish likelihood of infection
RT-PCR
Post exposure prophylaxis
Administer both human rabies immunoglobulin and vaccine
HSV encephalitis generally infects what part of the CNS?
Temporal lobes
Frontal lobes
Difference between HSV-1 and -2
HSV-1: labial, often infected as a kid, reactivation => encephalitis
HSV-2: sexual, causative agent in neonatal HSV encephalitis
HSV epidemiology
HSV infection is common, but encephalitis is rare
Infects most often infants, young adults, and adults over 50
Reactivation is common
HSV encephalitis pathogenesis and outcomes
Frontal and temporal lobes
High mortality rate
Sever sequelae common
HSV diagnosis and treatment
EEG, brain biopsy
MRI
Specimen sent for culture
Treat with acyclovir
