Micro. Chapter 19, Nervous System Diseases

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Micro. Chapter 19, Nervous System Diseases
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Micro. Chapter 19, Nervous System Diseases
1. Meningitis Neisseria meningitidis Gram (-)
diplococci (related to GC species) pg 580 A.
Virulence factors i. Capsule and pili ii.
Iga proteases enzymes that break down
antibody, Iga antibodies are secretory
antibodies on mucus membranes iii. Iron
binding enzyme can get to and use bodies
iron iv. Endotoxin producing strains are
really virulent, strain b and c are the
virulent ones, strain c is the one at UT
recently
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Micro. Chapter 19, Nervous System Diseases
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Micro. Chapter 19, Nervous System Diseases

• B. Mode of transmission respiratory droplets,
  type b and c are highly infectious
• C. Symptoms fever, stiff neck and headache,
  sometimes a rash not too alarming at first,
  but can rapidly progress to convulsions and coma
  
• D. Rapid diagnosis is essential, so antibiotic
  can be given before CNS damage is too severe
  penicillin and penicillin family antibiotics,
  rifampin given in prophylaxis (when there is
  exposure as in a dormitory or barracks)
• E. Vaccine is available, not that effective
  especially with children
• F. Meningitis can be caused by viruses (echovirus
  tends to be mild), other bacteria (such as
  Strep, Haemophilus, Listeria), fungi, even
  protozoans)

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Micro. Chapter 19, Nervous System Diseases
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Micro. Chapter 19, Nervous System Diseases

• G. Listeria monocytogenes see page 582,
  Checkpoint 19.1 resistant organism to normal
  environmental properties, in elderly, very
  young, and immunocompromised serious to fatal
  disease, in LA county in the 70s serious
  outbreak in pregnant women and transfer to fetus
  is possible
• (ingesting contaminated dairy products Mexican
  goat cheese)

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Micro. Chapter 19, Nervous System Diseases

• 2. Botulism (pg 603) Clostridum botulinum -
  Gram anaerobic spore forming bacillus, soil
  microbe
• A. A form of food poisoning intoxication,
  produces the most potent of natural toxins
• B. Exotoxin that is produced by the bacteria in
  an anaerobic condition like in canned goods
• C. Toxin effects the CNS, interferes with nerve
  transmission at neuron junctions
• D. Toxin is heat labile (destroyed by heat)

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Micro. Chapter 19, Nervous System Diseases

• E. 3 types of disease
• 1. Preformed toxin in food can goods
• A. Type a C. bot toxin can kill with just a
  taste
• B. Other types are bad too
• 2. Infant botulism
• A. Floppy baby syndrome neck is real flaccid-
  ?? Spores ingested and they grow in the
  digestive tract and slow absorption of toxin
  causes symptoms (raw honey)
• B. C bot grows in gut but in adults it is
  normal flora and not harmful
• 3. Wound botulism rare infections of wound
  (like C. perfringens)
• F. Treatment adults antitoxin, babies,
  supportive therapy and antibiotics (?)
• G. Prevention properly handling canned goods,
  never taste from a dented swollen can

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Micro. Chapter 19, Nervous System Diseases
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Micro. Chapter 19, Nervous System Diseases

• 3. Bacterial tetanus Clostridum tetani bacteria
  is also Gram, anaerobe, endospore forming soil
  organism
• (Pg 596 -597)
• A. Powerful exotoxin that is a neurotoxin
  interferes with signals for muscular
  contraction and relaxation
• B. Muscles stay contracted (tetanus)
• C. Soil contamination of deep wounds
• D. Treated with Immunoglobulin (antitoxin)
• E. Good vaccine toxoid (dpt)

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Micro. Chapter 19, Nervous System Diseases
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Micro. Chapter 19, Nervous System Diseases

• Viral diseases of the nervous system
• 1. Rabies rabies virus is a rhabdovirus rna
  virus, bullet shaped and has an envelope see
  page 596
• A. Fatal encephalitis
• B. Acquired by an animal bite or handling an
  infected animal
• C. Coyotes ,skunks, raccoons, bats (and others)
  different strains
• D. Type of infection with rabies virus has an
  affinity for nervous tissue, spreads from
  site of bite to nervous tissue. Very slow
  progression toward the CNS.
• 2. Rationale for post exposure rabies treatment
  active and passive immunity
• a. Injection of immunoglobulin at site of bite
  and then in the muscle
• b. Injection of rabies vaccine develop strong
  immunity before the virus can travel to the
  CNS and cause disastrous nervous tissue
  damage.
• c. Human diploid cell vaccine or chick embryo
  grown virus vaccine.
• d. 5 to 6 injections over 4 weeks (Im shot)
  (average cost was about 1200 for a post
  exposure treatment here in Austin)

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Micro. Chapter 19, Nervous System Diseases

• 3. Animal workers are now offered pre-exposure
  rabies vaccination- inter dermal or im
• 4. Prevention vaccination of domestic pets,
  newer wild animal vaccine programs (coyotes and
  foxes in Texas), avoid any sick or injured
  animals skunks active in daytime, downed bats,
  etc.

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Micro. Chapter 19, Nervous System Diseases
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• 2. Polio viral infection caused by small
  non-enveloped virus (naked) called a Picorna
  virus
• A. Enterovirus acquired by contaminated food
  or water, fomites, and mechanical vectors too
• B. Disease is usually limited to the throat,
  tonsils, and lymph nodes, but it can infect the
  nerve tissues, especially motor neurons of the
  spinal chord, leading to paralysis or even
  death
• C. Treatment is usually supportive therapy
• D. Prevention vaccine
• a. Salk vaccine inactivated viral vaccine,
  trivalent (3 strains)
• b. Sabin is live attenuated virus
• c. Salk for infants and Sabin for later, infant
  immune system not as developed and there is
  some potential for the attenuated virus to
  become infective
• d. WHO is till working on polio and measels to
  eradicate them

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Micro. Chapter 19, Nervous System Diseases
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Micro. Chapter 19, Nervous System Diseases Polio
iron lung Jonas Salk
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Micro. Chapter 19, Nervous System Diseases

• Fungal infections Cryptococcus neofrormans,
  causes meningitis, it is yeast with a very large
  capsule (we will save C. immitis to resp.
  diseases)
• 1. Mode of transmission, airborne from soil or
  bird droppings (pigeons)
• 2. Slow developing meningitis, travels from
  lungs to blood stream to nervous system
• 3. Diagnosis presence of yeast and capsule in
  csf
• 4. Treatment amphoteracin b
• Infection is uncommon but is very difficult to
  treat
• 5. now have a good Ag test used on CSF

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• Arboviruses
• 1. Arthropod borne viruses general term for
  many unrelated viruses transmitted by arthropods
  
• 2. There are at least 5 major encephalitis
  viruses in the us
• 3. Wee, EEE, SLE, VEE, CEE, and now here in Texas
  WNV
• 4. Transmitted by mosquito bite, and horses and
  birds are the reservoir
• 5. High fever and horrible headache, sometimes
  paralysis
• 6. Eliminate vector mosquito (spray and eliminate
  standing water)

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Micro. Chapter 19, Nervous System Diseases

• ARBOVIRUSES

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Micro. Chapter 19, Nervous System Diseases

• Protozoans Trypanosomes, will cover in lab,
  reservoir is in wild game animals, and the vector
  is the Tsetse fly African sleeping sickness
• PAM recently seen in the Hill country, stagnant
  water with bird fecal matter

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Micro. Chapter 19, Nervous System DiseasesPAM
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Micro. Chapter 19, Nervous System Diseases

• Prions infectious proteins
• Kuru- cannibalistic rituals in new guinea
• CJ Creutzfeldt-Jakob of humans
• Mad cow disease in cattle bovine spongiform
  encephalopathy
• 1. Very slow progressive disease that may attack
  proteins in CNS
• 2. Damage to brain gives brain tissue a spongy
  appearance encephalopathy very scary
• Video The Brain Eaters

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Micro. Chapter 19, Nervous System Diseases