Lecture 28 Flashcards
Reovirus
REO-respiratory enteric orphan
orthoreo virus is also called mammalian reovirus
rotovirus is a member
reovirus causes URI
rotovirus is a cause of viral gastroenteritis
rotovirus and reovirus
share several characteristics:
- icosahedral morphology
- double layered capside
- double stranded RNA in segments
- non enveloped
Reovirus and rotovirus disease
general do not cause significant disease in humans
infects ppl of all ages
usually mild or asymptomatic
common cold like URI
treatment usually not necessary; self-limiting
rotovirus patho
transmission by fecal oral route, fomites
infection can result from 10 particles
major cause of epidemic diarrhea in infants and young children
highly infectious 90% of children are positive by age 3
48 hour incubation
fever N/V/D
long-term immunity
supportive therapy
rotovirus prevention
ROTAteq - vaccine has been in use in US since 2006
infants should receive oral vaccine in three doses 2, 4, 6 months
Rhabdovirus
rabies virus is the most significant virus of rhabdoviruses
rabies invades CNS and causes encephalitis in domestic and wild animals and humans
human cases are sporadic, rabies is major health problem because of the millions of ppl bitten by wild animals
rabies virus structure
- bullet-shaped virons with two major components
- nucleocapside
- envelope composed of lipid protein bilayer - infectious component is the RNP core
- single stranded negative sense RNA
- carries own RNA polymerase
- envelope membrane is 50% lipid and 50% protein
- two viral membrane proteins externally G and internally M
rabies transmission
virus is world wide except for Australia
incubation time is less than one year but up to 5 years
symptoms during incubation are wound related
virus remains localized near bite wound
spreads via nerves to CNS
with onset of symptoms the virus has traveled from nerves to nearly all organs
Rabies disease
initial symptoms are nonspecific
acute neurologic period
- after 2-10 days the neurologic symptoms appear
- bizarre behavior including hydrophobia
if pt survives respiratory or cardiac arrest, paralysis develops
rabies treatment
almost always fatal
wash wound with soap
inject human anti-rabies IgG into wound
vaccinate on days 0, 3, 7, 28, and 90 post exposure
determine if animal is rabid
vesiculovirus
vesicular stomatitis virus
infections in livestock and humans
human infection due to direct contact with oral secretions of infected animals
human disease is flu like
onset is 24-48 hours and lasts 4-7 days
filoviruses
marburg and ebola viruses
severe or fatal hemorrhagic fevers
endemic in Africa
flu like symptoms
hemorrhage develops from multiple sites especially GI
90% mortality
Bunyavirus
most are arboviruses
negative stranded RNA in three segments
- large
- medium
- small
helical nucleocapside
enveloped
- two glycoproteins - G1 and G2 for cell entry
no matrix protein
hantavirus
transmission by aerosol rodent urine, feces and saliva
- deer mouse, cotton rat, white-footed mouse, striped field mouse, bank vole, rat
hantavirus disease
hemorrhagic fever with renal syndrome
liver and vascular endothelium targeted
hemorrhage, ARF, fever
15% mortality
