Rabies

Question 1

rabies: what does it cause/in which organ inflammation?

Answer 1

encephalitis

Question 2

what kind of pathogen is rabies?

Answer 2

virus

Question 3

how is it transmitted?

Answer 3

infected animals: saliva from bite, or also air droplets from bats

Question 4

if symptoms develop, is rabies fatal?

Answer 4

usually, yes

Question 5

what kind of virus is rabies virus?

single/double strand? RNA/DNA? surrounded by capsule?

Answer 5

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)

Question 6

how does rabies enter cells in the neuromuscular junction?

Answer 6

• 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

Question 7

does rabies prefer to enter neurons or muscle cells?

Answer 7

neurons

Question 8

how does rabies move inside the motor neuron?

Answer 8

it binds to dynein, moves a few millimeters each day retrograde towards CNS

Question 9

at which structure does rabies enter cells?

Answer 9

neuromuscular junction

Question 10

where does rabies enter cells: the CNS or PNS?

Answer 10

PNS, at the neuromuscular junction

Question 11

once rabies has reached the brain, to which other organ can is spread?

Answer 11

salivary glands

Question 12

what do you see under the microscope in rabies infected cells? what color is this?

Answer 12

negri bodies: sacs filled with virus

=> eosinophilic (dark purple)

Question 13

in which brain cells can you typically find negri bodies?

Answer 13

purkinje cells (cerebellum) and pyramidal cells (hippocampus)

Question 14

via which animals is rabies usually transmitted in developing countries?

Answer 14

dogs

Question 15

via which animals is rabeis transmitterd in developed countries?

Answer 15

wildlife: bats, foxes, raccoons, skunks

Question 16

how long is the incubation period of rabies? where does it depend on?

Answer 16

1-3 months.
depend on how far from the CNS it enters the body

Question 17

early phase symptoms?

Answer 17

fever, malaise, headache, paresthesia

Question 18

encephatic rabies symptoms?

Answer 18

• 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

Question 19

paralytic rabies symptoms?

Answer 19

paralysis that moves up the body

Question 20

what leads to death in rabies?

Answer 20

respiratory failure from spasms or paralysis

Question 21

diagnosis of rabies ante mortem: how?

Answer 21

multiple lab test
- saliva: RT-PCR of viral RNA
- skin biopsy: staining for viral antigen
- serology/CF sample: rabies virus

Question 22

diagnosis of rabies postmortem?

Answer 22

negri bodies & viral antigens in brain cells

Question 23

post-exposure treatment of rabies? (3)

Answer 23

• wound cleaning
• passive immunization (human rabies immunoglobins)
• killed vaccine (development of active immunization)

Question 24

until when is treatment of rabies effective?

Answer 24

until symptoms develop

Question 25

is it still possible to cure rabies after symptoms develop?

Answer 25

no

Question 26

what kind of treatment after rabies symptoms develop?

Answer 26

palliative

Question 27

rabies is part of which family of viruses?

Answer 27

rhabdovirae