Neuro03-02 Flashcards
(24 cards)
(1)

(2)
(Routes and mechanisms of damage to CNS viral infection)
(Hematogenous infection - BBB)
- virus is carried by what acrros the BBB?
- virus infects endothelial cells, followed by direct extension into what?
(Extension along nerve processes - rabies, herpes)
- Retrograde axoplasmic transport from peripheral sites to paraspinal ganglia and ultimately the brainstem or spinal cord.
- leukcytes
- the neuropil
(3)


(4)
(Mechanisms by which virus infection damages the CNS: Direct and Indirect)
(Direct Virus-Induced damage to the CNS)
1-3. The relationship between a virus and its host cell can induce what three things?
- then the pic

- lytic infection (fulminat viral gene expression results in death of the host cell)
- persistent infection: low level viral gene expression
3 latent infection: no gene expression
(5)

(6)
(Indirect viruses-induced damages the CNS)
(Induction of an immunomediated response)
- look at virus list in pic
- immunopathogenic mechanisms
like infection of what by lentiviruses?
- highly inflammatory lesion that results in what?
- key factors in pathogeneis include what trhee things?
- microglia
- extensive demyelination with relative sparing of neurons
- look at pic

(7)
(Indirect virus-induced damage to the CNS)
fuck it… just read this…

(8)
read this too

(9)


(10)
(Canine Distemper Virus)
- Paramyxoviral multisystemic disease of what?
- Clinical signs may be referable to primary viral or secondary bacterial infection of the respiratory or gastrointestinal tract.
- replication in CNS very much related to what?
- canines, mustelids (eg skunk, mink, ferret), procyonids (raccoon)
- age
(11)
(CDV-Pathogenesis)
- intial virus replication where?
particularly where?
- Viremia with seeding of what tissues of the body?
virus replication results in what?
- Virus replication within other tissues for which CDV exhibits a tropism - like what?
1 lymphoid tissue of the upper respiratory tract
tonsils
- lymphoid
a second viremia (unless checked by a humoral immune response)
- in pic

(12)
(CDV-Pathogenesis)
(Acute encephalopathy/acute encephalitis)


(13)
(Rabies)

(14)
(Rabies - Pathogenesis)
- virus introduced into host - initial replication where?
aersol –> where?
bite wound –? where?
- enters peripheral sensoary nerve ending and ascends to associated ganglion by retrograde axonplasmic transport
associated ganglioneuritis
virus is shielded form what?
- spread to the spinal cord and ascension within the cord, also use what?
may be associated with what?
Intoduction via a cranial nerve places virus where? what is then expected?
- site of entry
neuroepithelial cells of nasal mucosa
muscle cells and cells of sensory apparatus
- immune surveiallance
- axoplasmic transporter
paralysis (tetraparesis or laryngeal paralysis)
directly into brainstem - more rapid and fatal course then expected
(15)
(Rabies: Pathogenesis)
- Axoplasmic transport of virus occurs as the virus ascends the spinal cord, doing what?
spread between neurons occurs through what?
infection of peripheral tissue follows and virus can be found within what?
- Fatality as virulent strains reach the brain - unhindered by significant host (inflammatory) response to virus
see virus inclusions where? where in carnivores? in herbivores?
maximal involvement of what three brain areas?
- infecting new populations of neurons.
synaptic complexes
all body fluids
- neurons (Negri bodies); hippocampus, purkinje cells
hippocampus, hypothalamus, pons

(16)
(Equine herpes myeloencephalitis)
- Equine herpesvirus 1 subtype 1 (abortogenic strain)
- encephalitogenic variants: propensity to cause CNS signs is a function of what?
- the insult
Viral lytic infection of endothelial cells and immune complex formation results in what?
lesions may occur anywhere in the CNS, though are most consistently present in what?
what may accumulate in or around affected vessels?
- The significance of this change lies in what?
what kind of degeneration?
since the lesions are random, what will accumulate the greatest number of hits?
- its tropism for endothelial cells of vessels of the spinal cord white matter.
- a necrotizing vasculitis with hemorrhage
the spinal cord and brainstem white matter
mononuclear cells
- the resultant white matter ischemia
Wallerian
- the longest fiber tracts (–> posterior paresis)
(17)
(Equine herpesvirus 1 subtype 1)
(histopath is generally characteristic)
- Involvement of what is also observed and facilitates a diagnosis?
- Are Intranuclear inclusions characteristic of herpesviruses observed?
3 Immunocytochemistry of affected tissues will demonstrate what?
- cerebrospinal ganglia
- no
- viral antigen.
(18)
(Feline Infectious Peritonitis Virus Infection)
- A coronavirus infection of cats resulting in a what kind of disease?
- CNS vasculature is affected in what % of the total number of cases?
CNS symptoms are evident in what %?
- CNS involvement:____?
- Affects vessels associated with what three parts?
- multisystemic necrotizing vascular disease.
- 2/3
1/3
- choroid
meninges (choriomeningoencephalitis, 1-3 mm vessel-associated nodular foci, ventrolateral aspect of the cerebrum, best visualized in the sulci)
ependyma (fibrinous exudation into the CSF = gel)
(19)
(Systemic Mycoses)
- hematogenous dissemination of fungal yeast forms results in what?
type of exudate may vary - what types?
(Opportunistic Fungi)
- debilitation or immunosuppression results in what?
- septic thromboemboli and mycelial forms which invade vessel walls result in what?
- agents include (4)
- seeding of the leptomeninges (Histoplasma, blastomyces, coccidioides, cryptococcus)
granulomatous, pyogranulomatous, negligible
- tissue invasion (hematogenous/direct extension)
- infarctive lesions
- aspergillus, mucor, rhizopus, candida (mycelia and yeast together)

(20)
(Cryptococcus Neoformans)
1-3. Cryptococcosis is unique amongst other systemic mycoses due to what three things?
(CNS lesion)
- solid masses of organisms occur - how much inflammation?
- grossly?
- entry by hematogenous or direct extension from nasal
- most frequent CNS mycosis - 50% exhibit CNS signs
- pathogenic variants have a thick mucopolysaccharide capsule (not chemotactic and resits phagocytosis) - inflammation is minimal
- little
- unapparent (or cloudly leptomeninges w or w/o hemorrhages)

(21)

(22)
(Equine Protozoal Myeloencephalitis (EPM))
- agent?
- DH?
- IH?
- accidental?
(Lesion)
- Perivascular cuffs of lymphocytes, macrophages, multinucleated giant cells, and eosinophils with edema, ischemic change (Wallerian degeneration → malacia)
- organisms may be found associated with lesions, free or encysted within macrophages and neurons
- Atrophy of peripheral nerves (from affected spinal cord/brainstem segments) and corresponding musculature may be present
- Sarcocystis neurona
- opposum
- raccoon
- horse
(23)
(Toxoplasmosis)
- agent?
- DH?
- IH?
- accidental?
- Although affecting multiple organ systems of dogs, what % of all Toxoplasmosis cases display CNS involvement
- Immune suppression predisposes to what?
- see what in more protracted infection?
- Toxoplasma gondii
- cat
- mice, moles, squirrels, and other prey
- dogs, humans, goats, and cats
- 1/3
(Replication of Toxoplasma gondii within CNS can result in disease or be asymptomatic)
- fulminate (acute) infection (associated with canine distemper)
lesions may include
malacic foci, large pseudocysts, histiocytic inflammatory response
- granuloma formation
pseudocysts may not be apparent
tachyzoites may be identified
(24)
(Metazoan parasites (parasitic or verminous encephalomyelitis))
- Aberrant migration through or encystment within the CNS by a parasite that normally is localized to other tissues of the affected host.
what three?
- Migration through the CNS by a parasite not normally encountered in the affected host (the animal is an aberrant host)
what two?
- strongylus vulgaris –> larval migrants in horses
Taenia solium –> tapeworm of humans, larval stages (cysticerus cellulosae) may encyst in brain of pigs or humans
cuterebra: diptera fly causing myiasis
2. Parelaphostrongylus tenuis (normal = white tailed deer, larval migrans in goats, sheep, and camelids)
Baylisascaris procyonis (normal = raccoon, larval migrans in dogs!!!)