Chapter 34-35-36 Paramyxo- Rabies and Influenza Flashcards
what do paramyxoviruses cause
- measles virus
- mumps virus
- respiratory syncytial virus
- parainfluenza virus
what do rhabdoviruses cause
rabies
what do orthomyxoviruses cause
influenza viruses A B and C
describe the structure of paramyxoviruses
- helical nucleocapsid
- pleomorphic envelope
- hemagglutinin binds sialic acid
- minus stranded RNA
describe paramyxovirus replication
- virus brings in RNA polymerase which transcribes minus RNA into plus RNAs
- replication is cytoplasmic
describe measles viruses features
- hemagglutinings
- F protein
what does F protein do
causes membranes to fuse together to allow viral entry into cells
how does measles enter body
through respiratory tract
what responses modulate the outcome of measles
humoral and cellular immune
what are the characterisitc lesions of the oral cavity in measles caleld
koplik spots
what are the 3 C’s of measles
cough , coryza, and conjunctivitis
what is coryza
describes symptoms of a head cold
what are the complications of measles
- pneumonia
- bacterial superinfections of middle ear and lung
- pneumococci, staphylococci, and meningococci
what is subacute sclerosing panencephalitis in measles
rare progressive degeneration of CNS caused by measles
what is the treatment, prevention and control of measles
- symptomatic therapy
- attenuated measles vaccine: MMR
describe mumps virus
- paramyxovirus, pleomorphic, enveloped virus
- helical nucelocapsid
- negative strand RNA
what are the clincial manifestations of mumps and when do they develop
- develop 16-18 days after infection
- fever and swelling and tenderness of salivary glands
- complications include meningitis and orchitis
describe respiratory syncytial virus
- minus stranded RNA
- enveloped
- G protein binds host cells
- F protein causes membrane fusion
how does respiratory syncytial virus infect
- enters respiraotry epithelial cells then spreads downward along mucosa
- no clinically significatn spread to other sites
how is RSV spread
hand contact and respiratory secretions
what are the clinical manifestations of RSV
- acute onset of fever, cough, rhinitis, and nasal congestion
- often progresses quickly to severe bronchiolitis and pneumonia
what is bronchiolitis
bronchiole obstruction that can lead to respiratory failure
what is the treatment for RSV
rapid immunologic tests
describe rabies viruses
- negative strand RNA virus
- highly neurotropic
-enveloped
how is rabies transmitted
- bites of infected animals
- aerosols in caves where bats roost
- contamination of scratches, abrasions, open wounds or mucous membranes with saliva of infected animals
how long can incubation of rabies be
up to 12 months depending on size of inoculum and located of bite
what are negri bodies
masses of nucleocapsids in cytoplasm in brain tissue of 70-90% of rabies infected humans
what are the clinical manifestations of rabies and when does it begin
- 2-16 weeks after exposure
- pain or parasthesia at wound site, axiety, or irritablitie, depression , fatigue, loss of appetite, fever, and sensitivity to light and sound
- hydrophobia: contractions of muscles involved in swallwoing
- quickly progresses to paralysis
- death from destruction of regions of brain that regulate breathing
what is the treatment, prevention and control of rabies
- passive administration of antibody
- postexposure vaccine
- preexposure vaccine of individuals with high risk of exposure
describe orthomyxoviruses
- minus stranded RNA
- enveloped
what does neuraminidase do
release of virus from envelope
- cleaves sialic acid
what are typical flu symptoms due to
interferons
what is the treamtent for flu
- amantidine
- rimantidine (A strain only)
- ribavirin (A and B strain)
what is the flu vaccine
inactivated virus vaccine
what is antigenic shift
- caused by reassortment of viral genomic fragments during a mixed infection by two different flu viruses
what is antigenic drift
changes in influenze virus surface proteins due to point mutations that occur during viral replication
why was the spanish flu so deadly
killed from a cytokine storm from unchecked positive feedback loops
