Arbo 2 Flashcards by Chris Rodarte

4 hallmarks of WNV

Menigitis

Encephalitis

Mengingoencephalitis

PolioMyelitis

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Three conditions of WN encephalitis?

Asymptomatic infection

West Nile Fever

Neuroinvasive disease

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About __% of West Nile infections are asymptomatic

80%

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About __% of patients develop West Nile Fever, from which most people ____

20%, Recover

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West Nile Fever lasts about ______ days

3-6

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Hallmark for CNS disease from West Nile VIrus? How many patients progress to this stage?

Erythematous maculopapular or morbilliform rash

Less than 1%

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WNV infects ____ cells

Langerhans Dendritic

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WNV vauses primary viremia after migrating to ______

lymph nodes

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Does WNV cause 2’ viremia?

Yes

After dissemination to RE system

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_____ limits WNV dissemination to the CNS

Patients that progess past this point may have less robust ___ response

Antibodies

IgM

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_____ results in WNV clearance from infected neurons

CD8 T cell response

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WNV major vector and intermediate host

Mosquito Vector

Bird intermediate host

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Other than mosquito to man, what are other ways we can and can NOT get WNV?

No: Man to man or animal to man

Yes: Live or dead bird, consumption of infected bird

Other: Blood transfusions, organ transplants, lab exposure, or from Mom > Baby

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WNV vaccines are approved for ___

Equine use

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Dengue Serotypes

1-4

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Increased _______ helps in spreading Dengue

air travel

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Explain the Dengue infection in terms of serotypes and immunity

If infected with one, it does not provide protection against the other three

It actually increases the severity of subsequent Dengue infections

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Dengue presents ___ days after bite

3-15

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Does Dengue cause a fever?

Yes - saddleback fever up to 106 degrees

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Most people recover from Dengue within _____

one week

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Two Dengue Clinical presentations (syndromes)

Dengue Hemorrhagic Fever (DHF)
Dengue Shock Syndrome (DSS)

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Most DHF patients are how old?

under 15 years

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Characteristic manifestations of DHF

Plasma leakage
bleeding from trauma sites
GI bleed
Hematuria
Seizures and CNS symptoms

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What is DSS?

Dengue shock syndrome - it is untreated DHF that has progressed to circulatory failure

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Dengue targets what cells?

Langerhans (dendritic) cells

Dengue pathogenesis (6 steps)

1. **infects** langerhans 2. **APC** to T cells 3. **Enter** Monocyte/endothelial cells, **attacked** by CD4/CD8 and cytokines 4. **activates **immune system 5. increases vascular permeability (plasma **leaks**) 6. _Hemoconcentration_ and _hypovolemic_ shock occur

Dengue is enhanced in an __________ fashion

antibody-dependent \*they aid virus in getting into cells

sEach DENV (Dengue) serotype has the ability to cause _______ infections

ALL TYPES ## Footnote *(asymptomatic, DF, DHF, DSS)*

\_\_\_\_\_\_ are most affected by Dengue

Children

Dengue in US occurs primarily in \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

travelers from endemic areas

Dengue mainly spread by \_\_\_\_\_\_

**Aedes aegypti** mosquito

Can dengue be transmitted from human to human?

YES

Primate cycle of transmission is called \_\_\_\_\_\_\_\_

Sylvatic / Enzoonotic

Dengue control and treatment

No treatment (supportive therapy only) Immunization is hard because of SEROTYPES

Yellow Fever stages

Initial symptoms Toxic Stage Late Stages

YF initial symptoms

abrupt flu like symtoms (with fever)

YF toxic phase develops after...

initial remission of symptoms and fever

YF toxic phase hemorragic manifestations are caused by...

hepatic induced coagulopathy. causes **hematemesis**, **epistaxis**, **gingival** bleeding and **petechial** hemorrhages

YF toxic phase - systemic manifestations?

jaundice and albuminuria

Late stage YF manifestations

* Hypotension, shock * Metabolic Acidosis * Acute Tubular Necrosis * Heart dysfunction and arrhythmia

What distinguishes the CNS symptoms of the late stages of YF?

Confusion seizure Coma

\_\_\_\_\_\_\_\_ are complications in patients who survive late-stage YF

Secondary bacterial infections

YF replicates initially at \_\_\_\_\_\_\_\_\_\_\_

local lymph nodes

Where does YF spread to once initial infection occurs?

First to other lymph tissue, spleen and bone marrow Then to liver, lungs, and adrenals

Most important organ affected by YF?

Liver

\_\_\_\_\_\_ form in the liver during YF

Councilman bodies (apoptotic hepatocytes)

2nd most affected organ by YF? What systemic changes result from this?

Kidney Albuminuria and renal insufficiency

YF hemorrhage is from reduced _________ and can result in \_\_\_\_\_\_\_\_\_

reduced clotting factor production by liver Results in: **Hematemesis**, **thrombocytopenia**, and **platelet dysfunction**

The terminal event of YF is \_\_\_\_\_. What two things can this be attributed to?

shock from _direct parenchymal damage_ and _systemic inflammatory response_

Almost everyone that enters the toxic stage of YF...

progresses to the late (third) stage

Yellow Fever Vaccine properties/dosage

Vaccine = **Live attenuated** (Stamaril) Single dose gives 100% immunity for 10 years _single_ SubQ injection

The arboviral togaviridae are...

**Alphaviruses** EEEV, WEEV, VEEV

Alphavirus genome structure

ss+RNA Enveloped Icosahedral capsid

Alphavirus has ______ for attachment

glycoprotein spikes but NO receptor is known!!

Alphavirus replication occurs in \_\_\_\_\_

cytoplasm

Alphavirus parental ___ RNA strand encodes \_\_\_\_\_\_. The resulting molecule is re-coded into \_\_\_\_\_\_\_. This RNA is made into ___ and \_\_\_\_\_. This results in production of \_\_\_\_\_\_.

parental **+RNA** makes **Nonstructural proteins** in 5' end Molecule recoded into **(-) RNA** Made into **progeny +RNA** is made into **+mRNA** This results in production of **progeny virus**

EEE has a ____ period first

Prodromal

EEE progresses more rapidly to _____ and \_\_\_\_\_\_

CNS and death

CNS symptoms of EEE

_General_ (headavhe, nausea, confusion) _Focal defecits_ (sensory/motor loss, seizures, stiff neck, cranial nerve palsies, photophobia)

Pathogenesis of EEE

mosquito **injects** virus **subQ** Non-CNS **replication** during **prodrome** **2'** viremia = CNS **invasion** immune cells **enter** brain and damage Gross inspection = *edema*, vascular *congestion*, *hemorrhage*, *ENCEPHALOMALACIA*

Equine Encephalitis' resevoirs

**Mosquitos,** **Birds** (WEE and EEE) **Rodents** (VEE) \*also amphibians and reptiles

Incidence of EEE

only 5% of EEEV results in EEE

What happens immunologically after EEEV infection?

lifelong immunity

EEEV most common in ____ United States

Southeastern

WEE incubation time

Short (1-4 days)

Initial WEE symptoms are...

**flu-like** subclinical in many people

WEE Neuro symptoms indicate

poorer prognosis Symptoms similar to EEE (Focal defecits, seizures, neck stiffness and photophobia)

\_\_\_\_\_\_\_\_ is rarer in WEE than EEE

cranial nerve palsy

WEE is most common during

Summer months (April - September)

VEE presentation can be \_\_\_, \_\_\_, or \_\_\_ (with symptoms)

MILD (flulike) MODERATE (+ photophobia back pain, fever) SEVERE (acute high fever, severe myalgia and back pain, photophobia, prostration, confusion)

In Alphavirus, ____ and ____ are dead end hosts

humans and horses

Alphavirus can be transferred to mosquitos from \_\_\_\_

Birds

Alphavirus control is based on \_\_\_\_\_\_\_

disease surveillance

Vaccine for Alphavirus? Who is it used for?

Inactivated vaccine used for lab workers

What vaccine has been used for Alphavirus in horses?

**live-attenuated VEE** vaccine \*similar one used for lab workers

Arbo 2 Flashcards

(75 cards)