arthropod-borne virus Flashcards by Mikka Adynne Reyes

acronym for arthropod-borne virus.

Arbovirus

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___ known arboviruses, __pathogenic to human and___to animals

500
100
50

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arthropods

mosquito,ticks,ffly,mites

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aedes mosquito (near water) what disease?

dengue and yellow fever

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culex mosquito (forest) what disease?

st louis encephalitis

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primary infection in what cells

macrophage/monocytes

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secondary viremia affects

brain,liver,vasculature,skin

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3 families of arthropod

bunya
toga
flavi

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family:
flavivirus
genus:
flavivirus\

what diseases?

St. Louis encephalitis virus, Yellow fever virus,

dengue virus, West Nile virus

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fam:
Toga
genus:
alpha

Eastern equine encephalitis virus, Western

equine encephalitis virus, Chikungunya virus

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fam & genus:

bunya

California encephalitis virus

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Bunyaviridae

4 virus

California encephalitis virus
• Rift valley fever virus
• Sandfly fever virus
• Hantavirus – no arthropod vector

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Bunyaviridae

morphology

(-) ssRNA
3 segments
Helical symmetry
All are arthropod-borne except Hantavirus

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Bunyaviridae

clinical findings

Fever
• Encephalitis
• Hemorrhagic fever + renal syndrome (Europe and Asia)
• Hemorrhagic fevers
o Hantavirus
o Sandfly/Rift valley fever virus
o Crimean-Congo hemorrhagic fever
• Hantavirus pulmonary syndrome
- Fever, muscle aches, cough, N/V, pulmonary edema leading to
respiratory failure
-80% mortality

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bunya tx

ribavirin

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bunya target organs

cns 
liver
lungs
vasculature
endothelium

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California encephalitis virus

TRANSMISSION: 
• MORTALITY: 
• INCUBATION: 
• DIAGNOSIS:
• CLINICAL MANIFESTATION:

culex mosquito, forests of North America

< 1%

3-7 days

RT-PCR in lung tissue

o Prodrome: fever, chills, nausea, vomiting, headache, lethargy,
abdominal pain (1-4 days)
o Fever, drowsiness, lack of mental alertness/orientation, seizures (50%
of children), focal neurologic findings, coma (10%)

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hanta virus aka

Sin Nombre virus.

Korean hemorrhagic fever

Hantavirus pulmonary syndrome

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hantavirus transmission:

mortality:

inhalation of infected rodent urine/feces

up to 50%

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Togaviridae
alphavirus:
Western Equine encephalitis (WEE) from:

culex tarsalis mosquito

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Togaviridae
alphavirus:
Eastern Equine encephalitis (EEE) from

aedes, culex

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Togaviridae
alphavirus:
Venezuelan Equine encephalitis (VEE) from

Aedes, Psorophora, Culex

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Togaviridae

rubivirus

no insect vector

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Togaviridae
alphavirus:
morphology

(+) ssRNA
Non-segmented
Icosahedral symmetry
Replicates in the cytoplasm
Enveloped
Vector: insect for WEE, EEE, VEE
MOT: respiratory secretions, transplacental

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Togaviridae alphavirus: clin findings

* Headache and fever * Altered loss of consciousness * Focal neurologic deficits * rubella

Togaviridae alphavirus: lab dx

• Culture – can be grown in both vertebrate and mosquito cell lines but difficult to isolation • Cytopathologic studies • Immunofluorescence • Reverse transcriptase-PCR • Serology – hemagglutination inhibition, ELISA, latex agglutination o Presence of specific IgM or 4-fold rise in titer between acute and convalescent sera indicate a recent infection

Togaviridae alphavirus: prevention/tx

• MMR vaccine o Live attenuated o 3 doses

Togaviridae Alphavirus -Chikungunya virus morphology

* (+) ssRNA * Non-segmented * Icosahedral symmetry * Replicates in the cytoplasm * Enveloped

Togaviridae Alphavirus -Chikungunya virus vector

aedes aegypti, aedes albopictus, culex fatigans

Togaviridae Alphavirus -Chikungunya virus clin findings

* Benign dengue-like syndrome | * Fever, arthralgia, maculopapular rash, leukopenia

Togaviridae Alphavirus -Chikungunya virus prevention/tx

* Supportive * Antipyretics * Bed rest

chikungunya meaning

Swahili for “that which bends up”

Togaviridae Alphavirus -Chikungunya virus dx

sero,pcr,viral culture

Togaviridae Rubivirus -Rubella - aka - a _____ disease - transmission - peak incidence - IP

German measles, 3-day measles mild oral droplet and transplacental 5-14 years 14-21days

Togaviridae Rubivirus -Rubella clinical manifestation: • Rash occurs__ days after exposure • Prodrome: mild catarrhal symptoms (young children have prodromal symptoms) • 2/3: subclinical • In adolescents and adults: eye pain, sore throat, headache • Most characteristic sign: (4) • _____ evident 24 hours before the rash and remain for 1 week or more • _____: discrete rose spots on the soft palate (_____) à coalesce à red blush extend over the face • _____: erythematous, maculopapular and discrete • Starts centrally and spreads centrifugally • 2nd day: pinpoint appearance on the trunk • 3rd day: eruption clears • Rash is pruritic particularly in adults • Pharyngeal mucosa and conjunctiva slightly inflames • No photophobia • Temperature elevation not marked (low-grade fever x 1-3 days)

17 retro-auricular, post-cervical and postoccipital lymphadenopathy Lymphadenopathy Enanthem Forchheimer spots Exanthem

Togaviridae Rubivirus -Rubella Complications: • Joint involvement o ___ & ___ are the most common complications in adolescents and adults o Polyarthritis with arthralgia, swelling, tenderness with effusion x 2 weeks o Small joints of the hands o____ are affected 4-5 times more frequently than ____ • Thrombocytopenia o Rare complication o Occurring in 1 on 3000 cases • Neurologic o Encephalitis is a rare complication and occurs with greater frequency in children o Occurs in 1 per 6000 cases o Observed 2-4 days after the onset of the rash • Mild hepatitis o Rarely reported complication of rubella

Arthralgia and arthritis Females,males

Togaviridae Rubivirus -Rubella ``` tx:____ prevention: • MMR vaccine o ___months o 2nd dose: ____years o Females should be advised not to become pregnant 3 months after receiving rubella vaccine ```

Supportive 12-15 4-6 years

Togaviridae: Congenital rubella syndrome classic triad:

Sensorineural hearing loss Ocular abnormalities Sensorineural hearing loss

Togaviridae: Congenital rubella syndrome § Most common manifestation of congenital rubella syndrome § Occurs in approximately 58% of patients

Sensorineural hearing loss

Togaviridae: Congenital rubella syndrome § Cataract, infantile glaucoma, and pigmentary retinopathy § Occurs in approximately 43% of children

Ocular abnormalities

Togaviridae: Congenital rubella syndrome § Patent ductus arteriosus (PDA) and pulmonary artery stenosis § Present in 50% of infants infected in the first 2 months of gestation

Sensorineural hearing loss

Flaviviridae | 2 virus

``` • Hepatitis C virus • Arboviruses: o Dengue virus o St. Louis encephalitis virus o Yellow fever virus o West Nile virus o Zika virus ```

Flaviviridae | morphology

``` • (+) ssRNA • Non-segmented • Icosahedral symmetry • Replicates in the cytoplasm • Enveloped • Vector is mosquito o Aedes – Yellow fever, Dengue fever o Culex – St. Louis, Japanese, West Nile encephalitis ```

``` Flaviviridae clin findings: yellow fever (3) dengue/breakbone fever (2) st louis japanese, west nile encephalitis (2) ```

hepatitis, fever, backache painful fever, DHF encephalitis, fever

Flaviviridae | prevention/tx:__

mosquito control

Flaviviridae dx: ___ repeated infection,high risk of ___

viral culture/sero DHF

``` Flaviviridae Dengue Fever -how many serotypes? -acute febrile illness syndrome -caused by arbovirus ```

4- DEN-1 to DEN 4

Flaviviridae Dengue Fever Most common insect-borne viral disease in the world. t/f

Flaviviridae Dengue Fever transmission

Bite of female mosquito (aedes aegypti, aedes albopictus)

recognized by white markings on its legs and a | marking in the form of a lyre on the upper surface of its thorax

Aedes aegypti

Flaviviridae Dengue Fever clinical findings

• Fever • Maculopapular rash • Myalgia/Arthralgia – “breakbone fever” •Leukopenia/Thrombocytopenia/Inc hematocrit • Lymphadenopathy • Hemorrhagic shock is due to cross reacting antibody during the 2nd infection

Flaviviridae Dengue Fever diseases(2)

- Dengue fever (breakbone fever) | - Dengue hemorrhagic fever, under this is hemorrhagic shick syndrome

Influenza-like syndrome characterized by biphasic fever, | myalgia, arthralgia, rash, leukopenia and lymphadenopathy

Dengue fever (breakbone fever)

Severe, often fatal, febrile disease characterized by capillary permeability, abnormalities of hemostatic and protein-losing shock syndrome

Dengue hemorrhagic fever

_____is due to the production of large of cross-reacting antibody at the time of a second dengue infection (antibody-dependent enhancement)

Hemorrhagic shock syndrome

course of dengue illness: While the exact reason for the severity is still unknown, studies have linked the severity to _____. This theory was first described in 1964, when it was observed that serious dengue infection was linked to secondary infection.

antibody-dependent enhancement (ADE)

After a primary infection with one dengue virus serotype, the immune system produces antibodies that bind and neutralize secondary infection with the same serotype, however, a secondary heterotypic infection may lead to enhance severity. t/f

The antibodies produced from the primary infection have the ability to bind to the virus but lack the ability to neutralize.t/f

Flaviviridae Dengue Fever lab dx: ___: to detect gene product (NS1 glycoprotein) from day ___ until day __ from the onset of fever • ____: to detect dengue viral genes (RNA) in acute phase serum samples which coincide with the onset of viremia • ___: marker of recent infection • ___: marker of past infection; a fourfold increase confirms the diagnosis • ____: characteristic findings are thrombocytopenia with leukopenia. A hematocrit level increase >20% is a sign of hemoconcentration and precedes shock

``` NS1 antigen 1 6 RT-PCR Dengue IgM Dengue IgG CBC-PC ```

Flaviviridae Dengue Fever prevention

• Insecticides • Draining stagnant water • Mosquito repellent • Dengue vaccine o Dengvaxia (CYD-TDV) § First licensed in Mexico on December 2015 for use in individuals 9-45 y/o living in endemic areas § Live recombinant tetravalent dengue vaccine § Given as a 3-dose series on a 0/6/12-month schedule

Flaviviridae Japanese Encephalitis Virus - how many serotype? - vector - ___important source of viral amplification (some birds) - dead end host - prevalent among rural areas

1 culex mosquito pigs man

Flaviviridae Japanese Encephalitis Virus clin findings

* Fever * Rash * Myalgia/Arthralgia * Leukopenia/Thrombocytopenia * Lymphadenopathy

Flaviviridae Japanese Encephalitis Virus complications

* Aseptic meningitis or encephalitis * Fever, headache, nausea * Confusion, motor abnormalities * Seizures, respiratory failure

Flaviviridae Japanese Encephalitis Virus dx

• (+) Serum JE-specific IgM (ELISA) • (+) CSF IgM JE-specific (ELISA) • Four-fold increase in titer between acute and convalescent-phase serum by hemeagglutination inhibition (HAI)

Flaviviridae Japanese Encephalitis Virus prevention

Japanese encephalitis virus vaccines

Flaviviridae Japanese Encephalitis Virus tx

* Supportive, CFR 10-35% | * Remember: immunity is permanent after single infection

Togaviridae West Nile Virus transmission

* Bite of culex mosquito * Reservoir: wild birds * Humans are the dead-end hosts.

Most common cause of neuro-invasive arboviral disease

west nile virus

Togaviridae West Nile Virus most important clinical picture:

encephalitis with or without signs of | meningitis (typically in >60 years of age)

Togaviridae West Nile Virus Asymptomatic in 80%; fever and headache in 20%; encephalitis in 1% t/f

Togaviridae West Nile Virus lab dx

viral isol | pcr

Togaviridae West Nile Virus tx

no antiviral therapy

Togaviridae Yellow fever virus reservoir

monkey/human

Togaviridae Yellow fever virus diseases • Characterized by___&___ • Severe, life threatening disease that begins with sudden onset of fever, headache, myalgias, and photophobia • After this prodrome, the symptoms progress to involve the liver, kidneys, and heart • Prostration and shock occur, accompanied by ___ with ___

jaundice and fever UGIT hemorrhage with hematemesis (“black vomit”)

Togaviridae Yellow fever virus lab dx

May see councilman bodies or apoptotic bodies (eosinophilic | apoptotic globules) on liver biopsy

Togaviridae Yellow fever virus prevention

* Mosquito control | * Vaccine containing live, attenuated yellow fever virus

Togaviridae Hepa C virus transmission

parenteral, sexual, perinatal

Togaviridae Hepa C virus PHASES OF ACUTE HEPATITIS: o ____ – fever, malaise, anorexia o _____ – nausea, vomiting, abdominal pain, fever, chills o___ – jaundice, dark urine, increase in liver enzymes

Prodromal Preicteric Icteric

arthropod-borne virus Flashcards

(78 cards)