chapter22 Flashcards
1
Q
define meningitis
A
inflammation of meninges
2
Q
define encephalitis
A
inflammation of the brain
3
Q
define meningoencephalitis
A
inflammation of both meninges and the brain
4
Q
initial symptoms of meningitis include?
A
fever, headache and stiff neck
nausea and vomiting usually follow
5
Q
what are the types of pathogens that could cause meningitis
A
viruses, bacteria, protozoa and fungi
6
Q
most common cause of meningitis?
A
viruses
7
Q
the mild type of meningitis is?
A
viral meningitis
8
Q
haemophilus influenzae is gram…
A
negative
9
Q
does haemophilus influenzae require oxygen?
A
yes its aerobic
10
Q
name a bacteria of the normal throat microbiota
A
haemophilus influenzae
11
Q
pathogenicity of haemophilus influenzae is due to
A
capsule antigen type B
12
Q
H. influenzae meningitis is prevented by
A
the Hib vaccine
13
Q
whats the most prevalent type of bacterial meningitis ?
A
Haemophilus influenzae meningitis
14
Q
most people affected with H. influenzae meningitis are of age….
A
6 months to 4 years
15
Q
does Neisseria meningitidis require oxygen?
A
yes its aerobic
16
Q
Neisseria meningitidis is gram…
A
negative
17
Q
describe the shape of Neisseria meningitidis
A
diplococcus with a capsule
18
Q
how many serotypes associated with meningitis does Neisseria meningitidis have?
A
6 serotypes
19
Q
Neisseria meningitidis meningitis is also called?
A
meningococcal meningitis
20
Q
vaccination for Neisseria meningitidis meningitis protects from all serotypes except
A
Serotype X
21
Q
Neisseria meningitidis meningitis initial symptoms include
A
rash, bacteremia and throat infection
22
Q
Streptococcus pneumoniae Meningitis is also called
A
pneumococcal meningitis
23
Q
S. pneumoniae is gram…
A
positive
24
Q
describe the shape of S. pneumoniae
A
encapsulated diplocooccus
25
S. pneumoniae causes other diseases including
otits media
pneumonia
26
S. pneumoniae Meningitis is prevented by
conjugated vaccine
27
70% of people with S. pneumoniae are
healthy nasopharyngeal carriers
28
how do you diagnose a case of bacterial meningitis?
by taking a sample of CSF obtained by a spinal tap or lumbar puncture
29
how do you stain a sample of CSF
a single gram stain is often useful to identify the pathogen with considerable reliability
30
when is chemotherapy of suspected cases of bacterial meningitis usually initiated?
before identification of the pathogen is complete
31
whats the first choice of antibiotics for bacterial meningitis?
Broad-spectrum third-generation cephalosporins
32
Listeriosis is caused by the bacterium...
Listeria monocytogenes
33
Listeria monocytogenes is gram...
positive
34
describe the shape of L. monocytogenes
rod shaped (bacilli)
35
the method of transmission of L. monocytogenes is usually
foodborne
36
how is the effect of Listeria monocytogenes different in healthy humans than compromised ones?
**in healthy individuals**: mild and often symptomless
**compromised immunity individuals**: invades the CNS causing meningitis
37
presence of Listeria monocytogenes in the blood causes...
sepsis
38
Listeria monocytogenes is usually shed through...
feces
39
what are the important factors of virulence in Listeria monocytogenes?
1. it proliferates inside phagocytes in the liver instead of being destroyed
2. it has the ability to move from one phagocyte to another
40
whats the effect of Listeria monocytogenes on pregnant women and their fetus?
1. on the pregnant woman: no more than mild flulike symptoms
2. on the fetus: infected via the placenta, leads to abortion or stillborn infant
41
the bacterium that causes tetanus is called
Clostridium tetani
42
C. tetani is gram...
positive
43
Does C. tetani require oxygen?
no its an **obligate anaerobe** that grows in deep wounds with anaerobic conditions
44
the toxin released from dead cells in tetanus is known as
tetanospasmin neurotoxin
45
how does tetanospasmin neurotoxin cause tetanus?
it enters CNS and blocks the relaxation pathway of muscles causing spasms
46
death of tetanus is usually due to
spasms iof respiratory muscles
47
tetanus is prevented by
vaccination with a tetanus toxoid (DTaP)
48
how does DTaP work to prevent tetanus
stimulates production of antibodies that neutralize the tetanospasmin neurotoxin
49
treatment of tetanus
tetanus immune globulin TIG
50
the process of removal of tissue affected with tetanus is called
debridement
51
botulism is caused by the bacterium
Clostridium botulinum
52
Clostridium botulinum is gram...
positive
53
does Clostridium botulinum require oxygen
no its an obligate anaerobe
54
name two endospore forming bacteria
Clostridium botulinum
Clostridium tetani
55
intoxication in botulism comes from
**ingesting** the botulinal exotoxin
56
what part of the nerve does the botulinal exotoxin attack
the synaptic end
57
the botulinal exotoxin blocks release of...
the neurotransmitter acetylcholine
causing flaccid paralysis
58
death of botulism usually comes from
cardiac or respiratory failure
59
infant botulism can be caused by...
ingestion of soil or endospore contaminated materials
but mostly because of ingestion of honey
60
growth of C. botulinum in wounds is called
wound botulism
61
the treatment of botulism relies heavily on..
supportive care
62
antitoxins of A, B and E botulism toxins are aimed at...
**neutralizing** the different types of the toxin
63
the antitoxin derived from horses and used for adults can cause serious side effects, including:
serum sickness
anaphylaxis
64
immune complexes formed by reaction with antigens in the antitoxin, is the definition of?
serum sickness
65
how can we prevent botulism?
1. proper canning of foods
2. the use of nitrites to inhibit spore germination
nitrites also inhibit C. botulinum growth after endospore germination
66
Hansen's disease is another name for
leprosy (الجُذام)
67
leprosy is caused by
mycobacterium leprae
68
describe Mycobacterium leprae
acid fast rod (bacilli)
grows best at 30°C
69
mycobacterium leprae usually gorws in...
peripheral nerves
skin cells
70
mycobacterium leprae can cause leprosy by...
invading the myelin sheaths of peripheral nerves
71
one virulence factor of M. leprae is...
that it survives macrophages
72
what are the methods of transmission of leprosy?
1. prolonged contact with an infected person
2. inhalation of secretions
73
what are the two types of leprosy?
1. tuberculoid form (neural)
2. lepromatous form (progressive)
74
loss of sensation of the skin is a characteristic of .... leprosy
tuberculoid from
75
effect on mucos membranes and disfiguring nodules all over the body are characteristics of ..... leprosy
lepromatous form
76
how do you diagnose leprosy?
skin biopsy
skin smear and a blood test
77
.... are usually used for treatment of leprosy
antibiotics
78
poliomyelitis (شلل الاطفال) is caused by
poliovirus
79
initial symptoms of poliomyelitis include
sore throat and nausea
80
what effects does poliovirus leave if it enters the CNS?
destruction of motor nerve cells
81
death of poliomyelitis is due to
respiratory failure
82
rabies is caused by
rabies virus
83
rabies virus belongs to the genus...
lyssavirus (bullet shaped)
84
the genetic material of rabies virus contains ...
single stranded RNA
85
why do mutant strains of rabies virus develop easily?
because it has no proofreading capability
86
how is rabies transmitted
1. mostly by the saliva of an animal bite
2. rarely can cross mucos membranes
87
the most common cause of rabies is
silver haired bats
88
what are the initial symptoms of rabies?
muscle spasms of the mouth and pharynx
hydrophobia
89
rabies virus multiples in...
skeletal muscles
90
rabies virus travels through ... to the brain to cause encephalitis
the PNS
91
average incubation period for rabies virus?
30-50 days
92
viral inclusions into host cells are called
negri bodies
93
rabies virus usually forms negri bodies in the...
brain stem
94
diagnosis of rabies in laboratory is usually done by
direct fluorescent-antibody (DFA): detection of viral antigen
95
what's postexposure prophylaxis (PEP)?
vaccine: human diploid cell vaccine (HDCV)
passive immunization: human rabies immue globulin (RIG)
96
when are we supposed to use PEP?
right after the person gets bit by a rabid animal
before the end of incubation period of rabies virus
97
whats an arbovirus?
arthropod borne virus
98
arboviral encephalitis are caused by
mosquito borne viruses
99
name 3 examples of arboviral encephalitis?
1. Eastern equine encephalitis EEE
2. Western equine encephalitis WEE
3. Japanese encephalitis
100
symptoms of WEE and EEE include?
deafness
neurological damage
brain damage
101
give an example of arboviruses?
West Nile virus (WNV)
102
virus maintained in the bird-mosquito-bird cycle?
west nile virus
103
results of infection with WNV include:
poliolike paralysis
fatal encephalitis
104
japanese encephalitis is diagnosed by..l
ELISA test to identify igM antibodies
105
ZIka virus is primarily transmitted by
the bite of infected Aedes spp. mosquitoes
106
other ways of transmission of zika virus include
sexual transmission
mother to child
blood transfusions
107
zika virus infection during pregnancy increases the risk of...
microcephaly in infants
108
how can you possibly diagnose zika virus disease (ZVD)?
by reverse transcriptase PCR
109
name 4 viral infections of nervous system?
poliomyelitis
rabies
arboviral encephalitis
zika virus disease
110
name 5 bacterial diseases that affect the nervous system?
tetanus
botulism
meningitis (H. influenzae, N. meningitidis, S. pneumoniae)
listeriosis
leprosy
111
Cryptococcosis is another name for...
Cryptococcus neoformans meningitis (fungal disease)
112
what type ot fungus is C. neoformans?
soil fungus associated with chicken and pigeon droppings
113
C. neoformans is usually transmitted via...
respiratory route through dried contaminated droppings
114
whats the effect of C. neoformans in immunocompromised patients?
it spreads through blood to the CNS
115
African trypanosomiasis is a .... disease that affects the .... system
protozoan
nervous
116
sleeping sickness is another name for?
african trypanosomiasis
117
what are the two types of brucei that affect humans?
trypanosoma brucei gambiense
trypanosoma brucei rhodesiense
118
.... is a trypanosoma that the only reservoir of is human.
trypanosoma brucei gambiense
119
whats the reservoir of trypanosoma brucei rhodesiense?
wild animals and livestock
120
brucei rhodesiense is transmitted from animals to humans by...
tsetse fly
121
why is it difficult to develop a vaccine for african trypanosomiasis?
because the parasite evades antibodies through antigenic variations
122
what are the three parasites that cause amebic meningoencephalitis?
1. Naegleria fowleri
2. Acanthamoeba spp.
3. Balamuthia mandrillaris
123
the parasite that causes primary amebic meningoencephalitis is called...
Naegleria fowleri
124
name 2 parasites that could possibly cause granulomatous amebic encephalitis (GAE)?
Acanthamoeba spp.
Balamuthia mandrillaris
125
signs of primary amebic meningoencephalitis (PAM) include?
N. fowleri infects nasal mucosa from swimming water
penetrates the brain
feeds on brain tissue
126
multiple lesions around the brain, called granulomas are a sign of?
granulmatous amebic encephalitis
