UNIT 3 PART 2 Flashcards by FRANCHESCA MAUREEN CUISON

POSITIVE SENSE ENVELOPED RNA VIRUSES

Flaviviridae
Togaviridae
Matonavirisae
Retroviridae

CLASS 4

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single stranded RNA viruses of the positive sense
● transmitted by ticks and mosquitoes

Flaviviridae

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Only the female arthropod bites and does
the blood meal and transmits it.

True

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arthropod-borne viruses

Arbovirus

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name came from the Latin word “flavus” meaning
yellow because of its propensity to cause jaundice in
patients

Flaviviridae

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positive sense that can be DIRECTLY detected in
serum in CSF.

Flaviviridae

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Most sensitive - virus specific IgM via ELISA.

Flaviviridae

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Genus: Flavivirus

Vector: Aedes aegypti (breeds in stagnant water)

YFV

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causes Yellow fever characterized by jaundice, fever
● Target organ: liver

YFV

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pagkagat, the virus will replicate in the ____
then it will spread in the liver via hematogenous route

lymph node,

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in what day can it cause hemorrhage(15%)
○ It can cause severe illness and death in
elderly and children

severe days 7-10

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Genus: Orthoflavivirus
● Vector: Aedes aegypti
● causes Dengue Hemorrhagic Fever(DHF)

DENV

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Once bitten, it will cause symptoms for

4-7 days

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Fever, chills, joint pain, headache,
rash (usually in adults)

Without warning signs for Day 1-5

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Fever, chills, joint pain, headache,
rash (usually in adults)

Without warning signs for Day 1-5

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reddish skin
with white spots = Patient is
pagaling na

hermann’s rash

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With abdominal pain, severe
headache, vomiting, gum bleed
■ low platelet

with warning signs

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Dengue hemorrhagic fever
■ High Hemoglobin and Hematocrit
causing lasma leakage (mashado
malapot)
■ Narrow pulse pressure
● systolic-diastolic: 80/60
blood pressure

severe dengue

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Antigen of Dengue, Day 1 to 7

NS1

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first antibody in any virus na
lalabas.(Day 4 comes out; peaks
at Day 5). After the infection, a few
days before siya bumaba.

IgM

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would come up after Day 7
(Lifelong Immunity); but you are
only protected from 1 serotype.

IgG

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Basis for dengue vaccines like
dengvaxia. Only effective
to people who had
dengue before.

serotype 2

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The dominant serotype in 2010 and 2018 in
the Philippines is

DENV-3

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rapid detection on the 1st day
of fever, before antibodies appear some 5 or
more days later

NS1 antigen

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antibodies to dengue

IgG/IgM

combination of antigen and antibody test

combo

became available in 2016; only recommended to prevent re-infection in individuals who have been previously infected

dengvaxia

became available in 2022; suitable for adults, adolescents and children from 4 years of age

qdenga

Genus: Orthoflavivirus ● Vector: Culex pipiens (and other Culex sp.)

SLEV

Most important cause of epidemic encephalitis in North Amerixca.

SLEV

Genus: Orthoflavivirus ● Vector: Culex ● causes inflammation of the brain (encephalitis) 80% of infection have few or no symptoms ○ now, roughly 20% have symptoms

WNV

Most cases occur in old people.

WNV

Genus: Orthoflavivirus ● Vector: Psorophora ferox (and other mosquitoes) ● causes Rocio viral encephalitis ● Caused epidemic in Brazil in 1975-1976

ROCV

Genus: Orthoflavivirus ● Vector: A. aegypti and A. albopictus ● name came from Zika forest of Uganda ● Transmitted also through sexual contact or blood ● Caused an epidemic in 2015–2016

ZIKA VIRUS

Infection during pregnancy causes Microcephaly ○ affects skull formation of fetus

ZIKV

s/s: Rash, joint paints, conjunctivitis, and fever ● Virus seen in semen na vector-borne. ● Seen in Blood, Urine, Semen.

ZIKV

Genus: Orthoflavivirus ● causes zoonotic infection

TBE

Central European encephalitis virus, CEEV) – Vector: Ixodes ricinus

western european subtype of TBE

formerly West Siberian virus – Vector: Ixodes persulcatus

siberian subtype

formerly Russian Spring Summer encephalitis virus, RSSEV) – Vector: Ixodes persulcatus ■ most virulent subtype ■ Found in Russia and Northern part of China

far eastern subtype

Genus: Orthoflavivirus ● Vector: Ticks(Haemaphysalis spinigera) causes Kyasanur Forest Disease ● First reported in Karnataka, India

KFD

At risk: Forest Workers ● Most recover within 2 weeks ● Wood cutters are at high risk

KFD

Genus: Orthoflavivirus ● Vector: Sand Tampan(Ornithodoros savignyi) ○ Desert only. ● causes Alkhurma hemorrhagic fever(AHF) ● Based in Saudi Arabia

ALKV

Genus: Orthoflavivirus Vector: Ixodid ticks(Dermacentor sp.) ● causes Alkhurma hemorrhagic fever(AHF) ● Omsk, Western Siberia in Russia ● Rectal bleeding

OHFV

Genus: Orthoflavivirus ● Vector: Ixodid ticks(Ixodes and Dermacentor sp.) ● causes Powassan encephalitis ● Powassan, Ontario, Canada

POWV

causes both encephalitis and meningitis ● Low mortality and fatality

POWV

Genus: Orthoflaviviridae ● Culex spp. ● Asia ● Up to 50% of survivors had neurologic or pyschiatric sequelae (behavior changes)

JAPANESE B ENCEPHALITIS

Infections in pregnant patients in 1st and 2nd trimester could lead to fetal death ● most are pediatric patients ● with vaccine

JAPANESE B ENCEPHALITIS

Sand tampan (Ornithodoros savignyi)

ALKHURMA VIRUS

Ixodid ticks (Haemaphysalis spinigera)

KFDV

Ixodid ticks (Dermacentor sp.)

OHFV

Vector: Ixodid ticks(Ixodes and Dermacentor sp.

POWV

1. Fevers of an undifferentiated type with or without a maculopapular rash and usually benign 2. Encephalitis, often with a high case fatality rate 3. Hemorrhagic fevers, also frequently severe and fatal

human arboviral infections

Genus: Hepacivirus not transmitted by arthropod vector

HCV

Transmission : blood transfusion, sexual contact, needle stick injuries

HCV

screening test

ANTI- HCV

Anti-HCV (+) in and HCV RNA (-) =

occult hepa c

Additional testing: ______ for confirmatory

biopsy

viral load

HCV RNA

70-90% cases go to chronic hepatitis ● 1-5% will have HCC or Liver Cancer

HCV

Genus: Pegivirus ● a new genus under Flaviviridae a new genus under Flaviviridae name is derived from “Pe” for persistent and “g” to refer to its former name (Hepatitis G virus or “G” B virus) ● causes Hepatitis G

GB VIRUS C

Mode of Transmission: Blood Transfusion; Sexual Contact ● can cause Portal Hepatitis

GB VIRUS C

Small non-segmented positive sense single stranded RNA viruses ● Dubbed as such because of the “loose envelope” displayed in EM ● Also an Arbovirus

TOGAVIRIDAE

The only Genus in Togaviridae

GENUS ALPHAVIRUS/GROUP A

Popular: Chikungunya ● There are 32 alphavirus species

GENUS ALPHAVIRUS/GROUP A

Tropical Africa, India, SEA, Philippines SFI, arthropathy

Chikungunya virus

Sobrang sakit joints “Debilitating” Joint Pains that can last 2-3 years ○ Duration of infection: 7-10 days

chikungunya

distinguished rubella from measles and scarlet fever.

george de maton

Positive sense Single stranded RNA virus ● Cytoplasm site of replication

matonaviridae

Genus: Rubivirus ● causes German measles

RUBELLA VIRUS

milder and shorter form of measles

congenital rubella syndrome

may cause fetal disease ● the first member of Matonaviridae ● Rashes start in the face, with fever, sore throat. ● MMR Vaccine

RUBELLA VIRUS

cataract, congenital heart disease, low birth rate, microcephaly

congenital rubella syndrome

joined Rubella virus as second and third members of the genus Rubivirus ● Neither of them are known to infect people

2. ruhugu virus 3. rustrela virus

reverse transcribing viruses

retroviridae

normal genetic elements in the chromosomal DNA ■ Remnants of ancient retroviral infections ■ Became part of the normal human genome

endogenous

horizontally-transmitted infectious RNA-containing viruses

exogenous

Genus: Deltaretrovirus

HTLV

cause adult T-cell leukemia and other lymphoma ■ can also cause tropical spastic paraparesis

HTLV 1

cause Hairy cell leukemia ■ When there’s an increase in lymphocyte production by the bone marrow.

HTLV 2

Genus: Lentivirus ● causes AIDS

HIV

most common and most pathogenic strain

HIV 1

closely related to simian immunodeficiency virus ■ Mainly found in africa

HIV 2