Learn: RNA Virus Genomes, Replication, and Influenza: Virology Review

Correct genome type of each virus: Polio

+ssRNA

Correct genome type of each virus: HCV

+ssRNA

Correct genome type of each virus: Measles

-ssRNA

Correct genome type of each virus: Influenza

-ssRNA

Correct genome type of each virus: Ebola

-ssRNA

Correct genome type of each virus: TMV

+ssRNA

Which virus package both RNA and protein in virion?

Ebola

RdRP is NOT required by

Smallpox

Which proteins responsible for antigenic variation in influenza? (select all that apply)

HA and NA

mRNA editing is used by (select all that apply)

Ebola and Measles

Leaky scanning is used by

Measles

Influenza virus uses

mRNA splicing

Which virus is segmented?

Influenza (8 segments)

Host receptor of Influenza

Sialic acid

Which virus can change shape during culture?

Influenza

How does influenza change shape during culture?

Immediately after isolation, particles are filamentous. After several passages in cell cultures, particles become spherical.

Geminiviridae is--- (select all that apply)

Plant virus; bipartite (some species are monopartite)

Choose the correct maturation site: Measles

Plasma membrane

Choose the correct maturation site: Ebola

Plasma membrane

Choose the correct maturation site: Polio

Cytoplasm

Choose the correct maturation site: TMV

Cytoplasm

Influenza has two different +ssRNA: mRNA and antigenome

False

What switch occurs when a viral genome is not an mRNA?

A switch from mRNA synthesis to genome RNA synthesis.

What causes the switch from mRNA synthesis to genome synthesis?

Nucleoprotein switch.

1918 influenza pandemics - (select all that's correct)

Killed young adults and elderly; higher transmission rate.

Tulip bulb infection was caused by

Virus

HCV

+ssRNA, enveloped

Choose correct statement about Viroids

Circular, naked, infectious ssRNA; do not code protein; replicate autonomously.

Do viroids encode capsid proteins?

No.

Satellite virus can replicate on its own

False

Why can't satellite viruses replicate on their own?

They are replication defective and depend on a helper virus for replication.

What do satellite viruses encode?

Their own coat protein, but they lack genes for replication.

How many segments does influenza virus have?

8 segments

Which flavivirus is not transmitted by vector?

Hepatitis C

Genome type of Hepatitis C virus?

Positive sense ssRNA (+ssRNA)

Which virus is non-enveloped?

Poliovirus

Hepatitis C virus has IRES at 5' end

True

Hepatitis C virus has IRES at 3' end

False

Hepatitis C virus can encode polyprotein

True

Which viruses follow cap-independent translation? (Select all that apply)

Polio and Hepatitis C

Which virus carry RNA-dependent RNA polymerase (RdRP) in virion?

Measles

There is no vaccine for

Hep C

Which virus can lead to liver cancer?

Hep C

Trans-golgi network is involved in hepatitis C virion release

True

Influenza virus is naked and resistant to environmental factors

False

Influenza virus is vector-borne

False

Which influenza type can cause pandemic?

Influenza A

Which animals were used for first isolation of influenza virus?

Ferrets

Previous exposure and recovery from Influenza A will provide protection against future infection with Influenza B

False

H1N1 led to

Swine flu

H5N1 subtype is associated with

Bird flu

Humans can be infected by Influenza D virus

False

Influenza virus has monopartite genome

False

Influenza virus has positive sense ssRNA

False

Influenza virus has 8 genome segments?

True

Which criteria are not used in influenza virus nomenclature?

Scientist name

H7N2 subtype of influenza virus, hemagglutinin subtype is ______ and neuraminidase subtype is ______

7, 2

Which influenza A subtype is mostly in circulation in humans?

H1N1

Influenza virus replication occurs in

Nucleus

Influenza virus uses its own 5' cap for mRNA synthesis

False (uses cap-snatching from host mRNA)

Influenza virus translation occurs in

Cytoplasm

In influenza virus, mRNAs are complete copies of the virion (-) strand RNAs (vRNAs)

False

Influenza virus mRNAs are missing sequences from both the 5′- and 3′-ends of virion (-) strand RNA

True

Influenza virus exit involves

Budding process

In influenza virus replication cycle, two types of mRNA are produced?

True (professor's feedback: viral mRNA and antigenome)

Which protein cleaves surface receptor, sialic acid, to allow exit of influenza virus progeny virion from host cell?

Neuraminidase (NA)

Influenza virus can destroy cilia

True

Infected individuals develop antibodies against which of the outer proteins of influenza A virions? (Select all that apply)

HA and NA

The severe respiratory symptoms of influenza virus infection can be due to

Cytokine storm

Antigenic shift caused by genetic reassortment and can create pandemic strain

True

Which one is NOT correct about Antigenic drift in influenza virus?

Can cause genetic reassortment

RdRP has efficient proofreading activity

False

Triple reassortment occurred in 2009 swine-origin influenza A strain. Which statement about 2009 pandemic is incorrect?

Result of antigenic drift

Influenza virus is prevalent in

Winter

Influenza virus is best transmitted at low humidity (20%) and colder temperatures

True

Which is False about 1918 Spanish flu?

Did not affect adult population

Antivirals are available for influenza treatment

True

What do NA inhibitors do?

Prevent neuraminidase from cleaving sialic acid during budding

Name three NA inhibitor drugs used for influenza treatment

Oseltamivir phosphate (Tamiflu), zanamivir (Relenza), and peramivir (Rapivab)

What is Xofluza and what does it target?

A drug that targets cap-snatching

Type of influenza vaccines available

Both inactivated and live attenuated

Is trivalent or quadrivalent vaccine available for influenza?

Yes. Trivalent = 3 strains; quadrivalent = 4 strains.

What is included in a trivalent influenza vaccine?

2 influenza A strains and 1 influenza B strain

What is included in a quadrivalent influenza vaccine?

2 influenza A strains and 2 influenza B strains

Influenza strain could be zoonotic

True

Which of the following are respiratory viruses? (Select all that apply)

Measles and Influenza

Which of the following is TRUE about measles?

3-5 days after symptoms, tiny white spots (Koplik's spots) may appear inside the mouth

Which is CORRECT about measles virus?

Enveloped, negative sense ssRNA

There are multiple antigenic types of measles virus

False (only one antigenic type)

Measles virus genome is multi-segmented

False (one segment, approximately 16 kb)

How many proteins are encoded by measles virus and how many of them are structural proteins?

8 proteins; 6 structural proteins

Which surface viral protein attaches to host receptor in the human respiratory tract?

Hemagglutinin (H)

Which host cellular receptors can measles hemagglutinin bind?

CD46 and CD150

Measles can replicate in lymphatic system and can spread to multiple organs

True

What is the primary replication site of measles?

Respiratory tract

What is the efficiency of herd immunity required to prevent measles?

95%

Can measles virus spread before rash appears?

True. 4 days before the rash through 4 days after it appears.

Which age group is at risk for measles complications? (Select all that apply)

Children under 5 years old and adults over 20 years old

Long-term complication of measles?

Subacute sclerosing panencephalitis (SSPE)

What is SSPE?

A progressive neurological disorder affecting the central nervous system, caused by persistent defective measles virus infection.