med micro microbial disease of the nervous system

what virus can cross the placental fetal barrier cause induce microcephaly during fetal development?

zika virus

meninges

protect brain and spinal cord

dura mater

outermost layer of the meninges

arachnoid mater

middle layer of the meninges

pia mater

innermost layer of the meninges

subarachnoid space

contains cerebrospinal fluid; between arachnoid mater and pia mater

what are defenses of the nervous system?

bony structures, blood-brain barrier, microglial cells, and macrophages

microglial cells =

phagocytic functions

Immune privileged

no normal microbiota; very low usage of complement system; very low usage of MHC display systems

meningitis

inflammation of the meninges

encephalitis

inflammation of the brain

meningoencephalitis

inflammation of both

Clostridium botulinum and Clostridium tetani

gram positives that form endospores

Clostridum botulinum

botulism (intoxication)

Clostridium tetani

tetanus (intoxication)

Streptococcus agalactiae, Streptococcus pneumoniae, Listeria monocytogenes

gram positives

Streptococcus agalactiae

neonatal meningitis

Streptococcus pneumoniae

pneumococcal meningitis

Listeria monocytogenes

listeriosis

Cronobacter sakazakii, Escherichia coli K1, Haemophilus influenza, Neisseria meningitidis

gram negatives

Cronobacter sakazakii

neonatal meningitis

Escherichia coli K1

neonatal meningitis

Haemophilus influenza

haemophilus meningitis

Neisseria meningitidis

meningococcal meningitis

PRPsc prion

spongiform encephalitis; kuru

herpes simplex virus 1 and 2

DNA viruses; encephalitis

arboviruses, measles virus, lyssavirus

RNA viruses

arboviruses

encephalitis

measles virus

subacute sclerosing panencephalitis

poliovirus

poliomyselitis

lyssavirus

rabies

Crytococcus neoformans, Coccidioides spp

fungi

Cryptococcus neoformans

Cryptococcosis

Coccidioides spp

meningitis

Acanthamoeba spp, Naegleria fowleri, Toxoplasma gondii, Trypanosoma brucei

protozoa

Acanthamoeba spp

meningoencephalitis

Naegleria fowleri

meningoencephalitis

Toxoplasma gondii

subacute encephalitis

Trypanosoma brucei

African sleeping sickness

symptoms of bacterial meningitis

fever, headache, stiff neck followed by nausea and vomiting; may progress to convulsions and coma

diagnosis of bacterial meningitis

gram stain of csf; serological latex agglutination of csf

Neisseria meningitis

also called meningococcal meningitis; caused by Neisseria meningitidis

Neisseria meningitidis

gram -, aerobic diplococcus with a capsule

what percent of pop are healthy nasopharyngeal carriers?

10%

Neisseria meningitis begins ________ infection, ______ signs

throat, rash

Neisseria meningitis capsular serotypes

A, B, C, Y, W-135

Neisseria meningitis POE

respiratory tract

tetravalent vaccine

recommended for college students; Neisseria meningitis

treatment for Neisseria meningitis

cephalosporin

Neisseria meningitis virulence factors

endotoxin, IgA protease, capsule

Neisseria meningitis endotoxin

induce anaphylaxis; WBC induction release cytokines; damage vessels

Neisseria meningitis IgA protease

digests secretory antibodies/ evade complement/ evade phagocytes

Neisseria meningitis capsule

evade phagocytosis

petechiae

red or purple lesions on trunk and appendages due to blood vessel damage

what obligate aerobe does Neisseria meningitides have?

cytochrome c oxidase

addition of oxidase test reagent to Neisseria meningitides renders colony what color?

bluish-black

Streptococcus pneumoiae meningitis

also called pneumococcal meningitis; caused by S. pneumoniae; prevented by vaccination

what percent of people are healthy nasopharyngeal carriers?

70%

what population is Streptococcus pneumoiae meningitis most common in?

children

mortality Streptococcus pneumoiae meningitis in children

30%

mortality Streptococcus pneumoiae meningitis elderly

80%

Hamophilus influenzae meningitis

occurs mostly in children; gram - aerobic bacteria, normal throat microbiota; prevented by Hib vaccine

Hamophilus influenzae meningitis capsule antigen

serotype b

listeriosis

caused by Listeria monocytogenes; gram +, facultative anaerobic rod

listeriosis transmission

usually foodborne; it can be transmitted to fetus; reproduce in phagocytes; spread phagocyte to phagocyte

Listeria monocytogenes

endospores

catalase

oxidase

hemolysis

no

positive

negative

beta

Cryptococcus neoformans meningitis

also called cryptococcosis; soil fungus associated with pigeon and chicken droppings;

Cryptococcus neoformans meningitis transmission

transmitted by the respiratory route; spreads through blood to the CNS

Cryptococcus neoformans meningitis mortality

up to 30%

Cryptococcus neoformans meningitis treatment

amphotericin B and flucytosine

Coccidiodes spp.

also called coccidioidomycosis of the meninges; soil fungus of the american southwest

Coccidiodes spp. transmission

transmitted initially by the respiratory route from inhaled spores

Coccidiodes spp. two major pathogenic species

C. immitis and C. posadasii

C. immitis

Cailfornia

C. posadasii

Mexico/Arizona; causes 60% of cases

Coccioiodes spp. treatment

fluconazole

what triggers the release of Coccidioides?

rain

viral meningitis

generally milder than bacterial or fungal meningitis

viral meningitis transmission

droplet contact

viral meningitis primarily caused by

herpes simplex viruses 1 and 2

if viral meningitis suspected, immediate treatment with what?

acyclovir to block viral specific DNAP

neonatal meningitis fetal risk

brain development abnormalities

neonatal meningitis: Streptococcus agalctiae, Escherichia coli K1, Listeria monocytogenes transmission

birth canal

neonatal meningitis: Cronobacter sakazakii transmission

soli/environment

Meningoencephalitis

extremely rare but almost 100% mortality rate; Naegleria fowleri (PAM), Acanthamoeba (GAM), Balamuthia (GAE)

Naegleria fowleri

thermophilic, free living amoeba flagellate; protozoan infects nasal mucosa from swimming water; flagellate-amoeba-cyst stages

Naegleria fowleri causes

primary amebic meningoencephalitis (PAM)

Naegleria fowleri flagellate stage

biflagellated, in warm waters

Naegleria fowleri trophozoite stage

non flagellated, amoeboid

Naegleria fowleri cyst stage

hibernation stage

Naegleria fowleri portal of entry

nasal passage

Naegleria fowleri cysts form at ____ C

10

diving or playing in warm or hot waters allows N. fowleri flagellate access to _______ ___________

nasal passage

N. fowleri amoeboid crosses _________ _________ and crawls along _______ _______ _______

cribriform plate; olfactory neuronal axons

N. fowleri phagocytose _________, ________, and _________

red blood cells, neurons, and astrocytes

N. fowleri release ________ _________ that damage host tissue

cytolytic compounds

N. fowleri only 4 of 148 infected survived, what case fatality rate? who does it mostly affect? rapid or slow disease progression?

97% mostly in children rapid disease progression

N. fowleri treatment

amphotericin B, fluconazole, micronazole, rifampicin, azithromycin, and miltefosine

miltefosine

blocks cytochrome c oxidase, affects mitochondria; amoeba dies via apoptosis

Acanthamoeba castellani

double walled cyst and non flagellated amoeba