Ch.22: Microbial Disease of The Nervous System Flashcards
What is Bacterial Meningitis
infection of the membrane surrounding the brain & spinal cord; cross the blood-brain barrier
What is Neisseria meningitides (meningococcal meningitis) caused by
caused by meningitides; gram-negative, aerobic diplococci with a capsule
What are the virulence factors of Neisseria meningitis?
-Opa protein (entry into cell)
-Endotoxin; capsule; pili
-phase variation
What is the diagnosis of meningococcal meningitis?
-begins as a throat infection, rash leads to bacteremia–> crosses the blood-brain barrier into the cerebrospinal fluid
What is listeriosis
foodborne illness, characterized by flu-like, and GI symptoms
What is listeria monocytogenes
-small, Gram-positive rods
-Widely distributed in soil/water
-in mammals, birds, fish, insects
-grow at low temps
What is Clostridium species?
-Anaerobe grows in canned food releasing toxins; spores survive unless autoclaved
-Toxins interferes with neural transmission by blocking release of acetylcholine
-causes flaccid paralysis
What is C. botulinum?
Botulism toxin (“Botox”)
What is Clostridium Tetani
- C. tetani: tetanus toxin (tetanospasmin
- Anaerobe, grows in picture wound; blood flow interrupted; tissue becomes anaerobic
What do tetanus toxin blocks
the release of GABA, inhibitory transmitter
What does tetanus toxin cause
nerve impulses to go unchecked; spastic paralysis via excessive nerve signaling
What are obligately anaerobic Gram-positive bacilli & endospore formers?
Clostridium tetani & clostridium botulinum
What are the modes of action of tetanospasmin, and botulism toxin?
-Have 30-40% identity, and similar modes of action. Each are a A-B type toxins.
What is rabies caused by
rabies virus (ss RNA); transmitted by animal bite; typically leads to fatal encephalitis.
Steps of rabies virus infection
1.) Virus enters tissue from saliva of biting animal
2.) Virus replicates in muscle near bite and enters neuron of peripheral nervous system
3.) Virus moves up peripheral nervous system CNS
4.) Virus ascends spinal cord
5.) Virus reaches brain and causes fatal encephalitis
6.) virus enters salivary glands and other organs of victim
What are the initial symptoms of rabies?
muscle spasms of the mouth and pharynx and hydrophobia
How does the rabies virus multiply?
In skeletal muscle and then brain cells, causing encephalitis
What is furious rabies?
animals are restless, then highly excitable
What is paralytic rabies?
animals seem unaware of surroundings
What are Negri bodies
viral inclusions present in affected nerve cells
What is a zoonotic disease?
infections that are spread between people and animals
