Paramyxoviruses and Rhabdovirus Part 1

• para: spherical , can be found as filaments
• R: bullet-shaped

Their envelope is derived from the plasma membrane

coiled helical nucleocapsid

Both P and R are highly related. They all have comparable genes and proteins to one another. 

Five to nine genes, transcribed in series from the 3' end of the genome

• single mRNA; single protein
• nucleocapsid, matrix, fusion, hemagglutinin/neuraminidase or envelope (H, HN, or G) and RNA pol (L)

There is not alot of room for genes as there is a linear, negative sense ssRNA

• four families
• mononegaviruses
• negative antigenome DNA
• non-segmented DNA

single, linear RNA molecule packaged in a helical nucleocapsid

nucleocapsids are packaged in an envelope derived from the plasma membrane of the cell

• virus-coded RNA polymerase
• synthesizes viral mRNAs by transcribing the RNA in the nucleocapsid after it enters the cell

• 3' end of the genome
• sequentially transcribes five to ten genes
• terminating and releasing

alternate mucus

the flue

measles, mumps, respiratory syncytial, parainfluenza viruses

Newcastle disease virus (chickens), viruses infecting pigs, cats, dogs, etc.

• humans: rabies virus
• cattle: vesicular stomatitis virus

It can be used as a model for rabies. It looks exactly the same and has similar genes. You don't have to worry about contracting it.

they evolved as an old family

a fatal human encephalitis caused by rhabdovirus

one of the most fatal viruses on the planet. Without tx, it will kill you 99.99% of the time

transmission: bite of infected animal whose saliva contains the virus

symptoms: encephalitis symptoms, nervous system effects

fatality: fatal once symptoms appear

everyone has had it as a kid. Alot of people get better, but there are potential and serious fatal complications of it. It is caused by paramyxovirus

• transmission: in aerosols from coughs and sneezes
• Symptoms: subacute sclerosing panencephalitis is a rare and fatal complication of measles

Mumps: respiratory complications

• Respiratory syncytial virus: run rampant in day cares and causes respiratory complications
• Human parainfluenza: respiratory infections

• Nipah 
• Hendra

• capsid: bullet-shaped and enveloped
• genome: negative sense ssRNA (this virus was the prototype for - RNA viruses
• requirement: they only need to get into the cytoplasm and use our cellular machinery there to replicate

it has an ascending phase and a descending phase

Bitten--> virus inoculated; transmitted in saliva; it is not very cytolytc and seems to remain cell-associated

virus replicates in muscle at teh site of the bite with minimal or no symptoms

After weeks to months, it gets into neurons that help control the muscles (PNS)--> prodrome phase

Because neurons are all connected, the virus transmits itself up via sensory fibers

It replicates in the dorsal ganglion

It ascends in the spinal cord, infecting the spinal cord and brain

During the neurologic phase, the virus descends via NS to the eye, salivary glands, skin, and other organs to allow transmittance of the virus

there is avariable incubation phase depending on where you're bitten and the dose. For example, is the infection site close to the CNS and brain? 

Can be weeks to months

Some people can be asymptomatic; it is possible to block progression of the virus with antibodies

infection of the brain causes classic symptoms, coma, and death--> neurologic phase

1) antibodies, which respond at the late stages; antibodies block progression of hte virus

2) one makes the antibodies

3) if you have a long immunization, you can be protected if you have all of the symptoms: active immunization as a postexposure treatment

it as one of the second viral vaccines made in 1885 from dead infected viruses

• Take the nervous tissue out
• naturally inactivated early vaccine
• the more shots= the more effective

Louis Pasteur; and a safer, more modern one is given to vets

Because rabies is slow to develop, people can successfully be vaccinated after exposure