Flavivirus Flashcards by joseph dizon

Flavivirus are

Yellow fever virus
Dengue virus
St. Louis encephalitis virus
Japanese encephalitis virus
West Nile virus
Murray valley 
Tick bone

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Yellow fever

Vector

Aedes aegypti

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Yellow fever

Location

Latin America, Caribbean, Africa

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Yellow fever

Manifestation

Jaundice
Hemorrhage
Albumin urea

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Yellow fever

Microscopy

Hepatic necrosis
Councilman
Torres bodies

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Yellow fever

Diagnosis

Cell culture
Serology
PCR
Immunohistochemistry

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Yellow fever

Vaccine

Live attenuated 17D vaccine

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Dengue fever

Has 4 types

DEN 1-4

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Dengue fever

Vector

Aedes aegypti

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Dengue fever

Most common presentation

Undifferentiated fever

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Dengue fever

Inflate blood pressure cuff to a point midway between systolic and diastolic pressure for 5 minutes

Tourniquet test

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Dengue fever

Tourniquet test positive result

20 or more petechiae per 1 inch

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Dengue fever

4 necessary criteria

Fever
Hemorrhagic manifestations
Low platelet count
Leaky capillaries

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Dengue fever

Leak capillaries

Elevated hematocrit
Low albumin
Pleural or other effusions

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Dengue fever

Evidence of circulatory failure manifested indirectly by all of the ff

Rapid and weak pulse
Narrow pulse pressure
Cold, clammy skin
Altered mental status

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Dengue fever

Direct evidence of circulatory failure

Frank shock

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Dengue fever

Alarm signals

Severe abdominal pain
Prolonged vomiting
Abrupt change from fever to hypothermia
Change in level of consciousness

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Dengue fever

Four criteria

Fever
Hemorrhagic manifestations
Excessive capillary permeability

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Dengue fever

Initial warning

Disappearance of fever
Drop in platelets
Increase in Hct

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Dengue fever

When PT develops DSS

3-6 days after onset of symptoms

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Dengue fever

Clinical laboratory test

CBC, WBC, platelet, hematocrit
Albumin
Live function test
Urine

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Dengue fever

Specific test

Virus isolation

Serology

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Dengue fever

To determine serotype of the infecting virus

Virus isolation

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Dengue fever

Test for serologic diagnosis

IgM ELISA

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Dengue fever No hemorrhagic manifestations and patient is well hydrated

Home treatment

Dengue fever Hemorrhagic manifestations or hydration borderline

Consider hospitalization

Dengue fever Warning sign even without shock

Hospitalize

Dengue fever Management

``` Fluids Antypiretics (avoid aspirin and NSAIDS ) Monitor BP, hematocrit, platelet Blood product when needed Level of consciousness ```

Dengue fever Mosquito barriers

Only needed until fever subsides, to prevent Aedes aegypti mosquitoes from biting patients and acquiring virus Keep patient in screened sickroom or under a mosquito net

Dengue fever Prevention

Public education Vector control Vaccine in developmant

Single serotype, 5 genotype-based on E protein | Asia, including SEA

Japanese encephalitis virus

Japanese encephalitis virus Cycle

``` Birds Culex mosquitoes Swine Humans Horses ```

Japanese encephalitis virus Manifestations

Lethargy Behavioral changes Motor abnormalities

Japanese encephalitis virus Diagnosis

CSF analysis EEG IgM ELISA NT

Japanese encephalitis virus Treatment

Supportive

Japanese encephalitis virus Prevention

Inactivated vaccine (3yr protection)

Famous flavi virus

Vector borne transmitted by mosquitoes

Yellow fever | Pathology involvement

Hepatic cirrhosis | Renal involvement

Yellow fever Dx

Reverse transcriptase

Yellow fever Vaccine

Given 2 weeks before departure to Africa

Dengue fever Most common serotype

Type 2

Dengue 1st infection

Mild dengue fever

Dengue fever 2nd infection

More serious, DHF, plasma loss and plasma leakage

Aedes aegypti

Male bites plants Flies house to house Can't fly long distance

Dengue most common site of bleeding

GIT

Tourniquet test

+ not always dengue | - not always absence of dengue

Dengue manifestation of leaky capillary or plasma loss

2-7 days usually 4-5 days | Fever gone - platelet fall

Dengue Narrow PP

Push fluid fast drip PNSS/PLR

Dengue Weak PP that sign of shock

Dengue Lab test WBC

High then low

Dengue Virus isolation

Cell lines T lymphocytes | Monkey kidney cell

St. Louis encephalitis, Murray valley encephalitis, West Nile fever Structure

40-60 nm in diameter Positive sense Single stranded RNA Envelope

St. Louis encephalitis, Murray valley encephalitis, West Nile fever Other description

3 structural polypeptides | Two glycosylated

St. Louis encephalitis, Murray valley encephalitis, West Nile fever Replication

Cytoplasm

St. Louis encephalitis, Murray valley encephalitis, West Nile fever Assembly

Within endoplasmic reticulum

Japanese encephalitis fever Location

Central luzon and bicol region

Japanese encephalitis fever Animal reservoir

Swine and horses

Japanese encephalitis fever Mostly seen in

Rice fields

Japanese encephalitis fever Dx

ELISA blood ans CSF

Structure

``` Small Spherical Enveloped SS RNA Cross related ```