Term
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Definition
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Listeria monocytogenes
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Gram-positive aerobic rod
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Usually causes mild flu-like disease in adults but can enter the CNS and cause meningitis, with a mortality rate as high as 50%
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Usually foodborne; it can be transmitted to fetus where it may cause abortion, stillbirth, or meningitis in the infant.
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An important factor in the virulence of Listeria is that it can reproduce in phagocytes.
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Term
|
Definition
Inflammation of meninges.
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Term
Neisseria or *Meningococcal Meningitis
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Definition
-
N. meningitidis, common name meningococcus
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Gram-negative aerobic cocci, capsule
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10% of people are healthy nasopharyngeal carriers
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Begins as throat infection, often accompanied by a petechial rash
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The only meningitis with a rash
-
Vaccination recommended for college students.
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Term
VIRAL DISEASES of the Nervous System
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Definition
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Poliomyelitis
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Salk Polio Vaccine
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Rabies
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Arboviral Encephalitis
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Term
VIRAL DISEASES of the Nervous System:
Poliomyelitis
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Definition
Poliovirus
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Transmitted by ingestion
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Initial symptoms: Sore throat and nausea
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Viremia may occur; if persistent, virus can enter the CNS; destruction of motor cells and paralysis occurs in <1% of cases.
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Prevention is by vaccination (enhancedinactivated polio vaccine).
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Term
|
Definition
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Term
|
Definition
-
Clostridium botulinum
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Gram-positive, endospore-forming, obligate anaerobe
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Intoxication comes from ingesting botulinal toxin.
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Botulinal toxin blocks release of neurotransmitter causing flaccid paralysis.
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Botox is a form of botulism toxin that is used cosmetically; it also has some applications in controlling neurological disorders such as cerebral palsy.
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Wound botulism results from growth of C. botulinum in wounds.
-
Infant botulism results from C. botulinum growing in intestines.
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Term
*Botulism Source of Infection
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|
Definition
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Term
|
Definition
-
Clostridium tetani
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Gram-positive, endospore-forming, obligate anaerobe
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Grows in deep wounds.
-
Tetanospasmin (a toxin) blocks relaxation pathway in muscles, causing constant muscle contraction.
-
Infants in developing countries often get tetanus through an infected umbilicus.
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Term
African Trypanosomiasis (“sleeping sickness”)
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|
Definition
-
Trypanosoma brucei gambiense infection is chronic (2 to 4 years).
-
T. b. rhodesiense infection is more acute (few months).
-
Transmitted from animals to humans by tsetse fly.
-
Prevention: Elimination of the vector.
-
Parasite evades the antibodies through antigenic variation (see next slide).
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Term
Amebic Meningoencephalitis
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|
Definition
-
Naegleria fowleri infects the nasal mucosa (typically during swimming) and then penetrates the brain.
-
The fatality rate is nearly 100%, death occurring soon after the appearance of symptoms.
-
Acanthameba causes a granulomatous encephalitis, which is chronic and slowly progressive.
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Term
|
Definition
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Term
|
Definition
- Fever, headache, and stiff neck
- Followed by nausea and vomiting
- May progress to convulsions and coma
- Diagnosis by Gram stain or agglutination test of CSF
- Meningitis is a medical emergency and can be highly contagious.
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Term
Bacterial Meningitis Treatment
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|
Definition
Treatment with antibiotics can be effective; which
drug depends on the organism involved.
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Term
|
Definition
-
Infant botulism is characterized by constipation and muscle weakness;
-
Occurs through ingestion of spores which germinate and produce toxin in the gut.
-
Honey has been implicated in infant botulism.
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Term
|
Definition
Inflammation of the brain.
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|
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Term
Haemophilus influenzae
Meningitis
|
|
Definition
-
Occurs mostly in children (6 months to 4 years).
-
Gram-negative aerobic bacteria, normal throat microbiota
-
Caused most often by one strain, identified as capsule antigen type b, Haemophilus influenzae type b or Hib
-
Prevented by Hib vaccine
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Term
|
Definition
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|
Term
Leprosy (Hansen’s Disease)
|
|
Definition
Mycobacterium leprae
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Acid-fast rod that grows best at 30°C.
-
Grows in peripheral nerves and skin cells.
-
Transmission requires prolonged contact with an infected person.
-
One of the first signs of leprosy is loss of pigment in the skin, along with numbness.
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Term
Leprosy (Hansen’s Disease)
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Definition
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Term
PRION DISEASES of the Nervous System
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Definition
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Term
PROTOZOAL DISEASES of the Nervous System
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Definition
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Term
|
Definition
Animals seem unaware of surroundings
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|
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Term
Petechial rash of meningococcal disease
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|
Definition
A petechial rash is caused by hemorrhages under the skin.
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Term
|
Definition
-
The Sabin vaccine (attenuated virus) is administered orally, which enhances its use in areas where trained medical personnel may not be available to give inoculations.
-
However, there is a small risk of paralytic polio resulting from the oral vaccine, so it is no longer recommended for routine use in the U.S.
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|
|
Term
Streptococcus pneumoniae
Meningitis
(Pneumococcal Meningitis)
|
|
Definition
-
Streptococcus pneumoniae (common name pneumococcus), a Gram-positive encapsulated diplococcus
-
70% of people are healthy nasopharyngeal carriers
-
Most common in children (1 month to 4 years)
-
Mortality: 30% in children, 80% in elderly
-
Prevented by vaccination, now recommended for infants as well as the elderly
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Term
|
Definition
|
|
Term
Transmissible Spongiform Encephalopathies
|
|
Definition
-
Caused by prions
-
Sheep scrapie
-
Bovine spongiform encephalopathy (BSE, “mad cow disease”)
-
Variant Creutzfeldt-Jakob disease (vCJD; transmissible)
-
Kuru
-
Transmitted by ingestion or transplant
-
All prion diseases are chronic and fatal
|
|
|
Term
|
Definition
-
Rabies is controlled largely through licensing (requiring vaccination) of domestic pets, both cats and dogs.
-
Distribution of oral vaccine in baits helps control rabies in wild animals.
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|
|
Term
Cryptococcus neoformans
Meningitis
(Cryptococcosis)
|
|
Definition
-
Soil fungus associated with pigeon and chicken droppings.
-
Transmitted by the respiratory route; spreads through blood to the CNS.
-
Mortality up to 30%.
-
Treatment: Amphotericin B and flucytosine.
-
Pigeon droppings provide ideal conditions for growth of Cryptococcus
-
Cryptococcus maydisseminate and cause skin lesions prior to invading the CNS.
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Term
FUNGAL DISEASES of the Nervous System
|
|
Definition
There is one fungal disease of the nervous
system, although it is possible for other fungal
pathogens to gain access to nervous tissue and
cause disease.
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|
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Term
|
Definition
Animals are restless then highly excitable.
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|
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Term
|
Definition
|
|
Term
|
Definition
Vaccine plus immune globulin.
|
|
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Term
|
Definition
Injection of human cell vaccine.
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|
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Term
|
Definition
-
Infectious proteins
-
Inherited and transmissible by ingestion, transplant, and surgical instruments
-
Extremely resistant to heat; even autoclaving cannot halt infectivity
|
|
|
Term
|
Definition
-
Transmitted by animal bite.
-
Virus multiplies in skeletal muscles, then in brain cells, causing encephalitis.
-
Initial symptoms may include muscle spasms of the mouth and pharynx, and hydrophobia.
-
Rabies is notifiable in both humans and animals.
|
|
|
Term
|
Definition
-
Prions normally occur on all cells of the body, and are especially abundant on nerve tissue (brain)
-
PrPC: Normal cellular prion protein, on cell surface
-
PrPSc: Scrapie protein; accumulates in brain cells forming plaques and vacuoles (holes in the brain tissue, giving it a spongy appearance.
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|
|
Term
Bacterial Diseases of the NS |
|
Definition
- The following group of diseases are all caused by bacteria.
- If treatable, antibiotics may be effective.
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|
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Term
How Microobes Enter the Nervous System |
|
Definition
|
|
Term
Microbial Diseases of the Nervous System |
|
Definition
|
|
Term
VIRAL DISEASES of the Nervous System:
Salk Polio Vaccine
|
|
Definition
-
In 1954, the Salk vaccine was tested nationwide, with mass inoculations of school children.
-
A million children participated in the tests, making it the largest clinical test of a drug or vaccine in medical history.
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