Rabies Flashcards
rabies: what does it cause/in which organ inflammation?
encephalitis
what kind of pathogen is rabies?
virus
how is it transmitted?
infected animals: saliva from bite, or also air droplets from bats
if symptoms develop, is rabies fatal?
usually, yes
what kind of virus is rabies virus?
single/double strand? RNA/DNA? surrounded by capsule?
single strand RNA, surrouned by capsule shaped like a bullet
(they put genetic material into host DNA, carry their own DNA-polymerase to make mRNA)
how does rabies enter cells in the neuromuscular junction?
- binds to nicotin receptors on muscle cells -> nicotin channels open and virus enters
- can also cross the motor neuron membranes and replicates inside the neuron
does rabies prefer to enter neurons or muscle cells?
neurons
how does rabies move inside the motor neuron?
it binds to dynein, moves a few millimeters each day retrograde towards CNS
at which structure does rabies enter cells?
neuromuscular junction
where does rabies enter cells: the CNS or PNS?
PNS, at the neuromuscular junction
once rabies has reached the brain, to which other organ can is spread?
salivary glands
what do you see under the microscope in rabies infected cells? what color is this?
negri bodies: sacs filled with virus
=> eosinophilic (dark purple)
in which brain cells can you typically find negri bodies?
purkinje cells (cerebellum) and pyramidal cells (hippocampus)
via which animals is rabies usually transmitted in developing countries?
dogs
via which animals is rabeis transmitterd in developed countries?
wildlife: bats, foxes, raccoons, skunks
how long is the incubation period of rabies? where does it depend on?
1-3 months.
depend on how far from the CNS it enters the body
early phase symptoms?
fever, malaise, headache, paresthesia
encephatic rabies symptoms?
- fever
- hydrophobia (fear of water = unique symptom)
- foaming at the mouth -> because of uncontrollable spams in the pharynx whenever the person tries to drink
overactive autonomic nervous system:
- increased saliva production
- sweating
- dilated pupils
- agitated and aggressive
- coma
paralytic rabies symptoms?
paralysis that moves up the body
what leads to death in rabies?
respiratory failure from spasms or paralysis
diagnosis of rabies ante mortem: how?
multiple lab test
- saliva: RT-PCR of viral RNA
- skin biopsy: staining for viral antigen
- serology/CF sample: rabies virus
diagnosis of rabies postmortem?
negri bodies & viral antigens in brain cells
post-exposure treatment of rabies? (3)
- wound cleaning
- passive immunization (human rabies immunoglobins)
- killed vaccine (development of active immunization)
until when is treatment of rabies effective?
until symptoms develop
