Rhabdoviruses (Virus) Flashcards
What is the most significant virus of the rhabdoviruses? How do they look?
Rabies. They are bullet shaped, enveloped viruses, covered by G proteins that forms “spikes.” Has a helical nucleocaspid that is coiled into a cylinder, making it look like striations.
What is the role of the G proteins in rabies?
It generates proteins that neutralizes antibodies. It is also an attachment protein.
What is the genetic coding of rabies?
Single strand negative sense RNA.
What is the major structural protein of rabies?
N protein, which offers the virus protection from ribonucleases and offers structure to be in the proper transcription position.
What 2 proteins constitute the RNA dependent RNA polymerase?
L and NS proteins.
What two receptors can rabies bind to?
AChR and NCAM.
How does rabies replicate?
G protein attaches to either AChR or NCAM, gets endocytosed, fuses with the endosome and upon acidification the nuclear envelop uncoats releasing the virus into the cytoplasm and ready to replicate.
What is the primary reservoir for rabies world wide, and in the US? Transmission of the virus?
Dogs are primary reservoir worldwide, not in the U.S. Raccoons (primary reservoir), bats, skunks and foxes are the primary reservoirs in the U.S. Bite or contact with the rabid animal transfers the virus.
How does the virus travel from animal bite into the brain?
It replicates locally in the muscles after the bite via binding to the AChR, then travels backwards via retrograde axoplasmic transport to the dorsal root ganglion and the spinal cord. Once in the SC the brain becomes rapidly infected.
Does location of the bite matter?
Yes, the closer the bite is to the brain the faster a person develops clinical rabies.
How does the rabies disease present clinically?
Once in the CNS, 100% fatality. Initially non-specific flu like symptoms followed by seizures, disorientation, hallucination, hydrophobia (because it hurts to swallow), followed by coma and death.
How can rabies be diagnosed?
Usually done at autopsies (patient usually dies), look for Negri bodies, intracytoplasmic inclusion bodies. Can also do PCR and Fluorescent antibodies.
How can rabies be treated assuming it didnt hit the CNS yet?
Post bite prophalaxis in the form of a vaccine, which is a human rabies immunoglobulin (x1 dose). Follow up with 5 more doses of rabies vaccine, in the day of, 3 days later, 7, 14 and 28 days later. It is a killed virus vaccine.
