RNA viruses Flashcards by Meghan May

Little boy, daycare, horrible diarrhea. Viral infection. What is the structure of the virus he is infected with?

Rotavirus: (Reovirus)

dsRNA linear

NO envelope

iscosahedral

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What is the strcture of the Picornaviruses?

What the Picornaviruses?

are they ds or ss?

+ssRNA: linear and Icosahedral, NO env

PERCH

Poliovirus—polio-Salk/Sabin vaccines—IPV/OPV

Echovirus—aseptic meningitis in the summer

Rhinovirus—“common cold”

Coxsackievirus—aseptic meningitis;

Herpangina (mouth blisters, fever); hand, foot, and mouth disease; myocarditis; pericarditis HAV—acute viral hepatitis

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Common cause of aseptic meningits in the summer?

What is this viral structure?

Echovirus: +ssRNA; linear and icosahedral; no envelope

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This nasty virus causes aseptic meinigit, herpangina (mouth blisters, fever); hand foot adn mouth disease and myocarditis; pericardits

Strcture of virus?

Coxsackievirus

(type of Picornovirus = ssRNA linear with icosahedral and no envelope)

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GI upset on a cruise ship

Bug?

genetics?

Norovirus (Calicivirus)

+ssRNA; linear with NO envelope

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What do the following viruses all have in common?

HCV
Yellow fevera
Denguea
St. Louis encephalitisa

West Nile virus

All Flavivirus:

+ssRNA, Linear and Icosahedral,

ENVELOPED

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Friend was in Thailand and comes back very ill. She is experienceing severe bone pain. What is the virus responsible?

ss or ds?

env or not?

Dengue fever

Flavivirus

ssRNA Linear Icosahedral

ENVELOPED

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Little boy with fever, swollen lymph nodes then developes rash starsts on face and then on body

As rash disappeares, skin flakes off.

Dx?

Structure of virus?

Rubella or German Measels

Togavirus:

+ssRNA Linear virus

Icosahedral

ENVELOPED

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Virus that causes common cold and is responsible for SARS?

Structure?

Coronavirus

+ssRNA linear and Helical

Enveloped

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What is the structure of the Influenza virus?

What family is it in?

Enveloped?

-ssRNA linear with 8 segments

Helical and ENVELOPED

from orthomyxofamily

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What all diseases belong in the Paramyxoviruses?

What is their strcture?

PaRaMyxovirus:

*P**arainfluenza—croup
*R**SV—bronchiolitis in babies;(ribavirin )

Measles, Mumps

-ssRNA linear with Envelope

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Baby with seal bark cough. What virus do they have? what’s it’s structure?

Croup = paramyxovirus

-ssRNA linear with capsid

ENVELOPED

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MMR vaccine covers what viruses?

What are their strctures?

Measels and Mumps = Paramyoviruses ; -ssRNA linear with helical caspid and ENVELOPED

Rubella = German measels= Toga virus and +ssRNA linear Icosehedral with ENVELOPE

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What is the most common cause of viral pneumonaie in children around two ages?

What can you tx it with?

RSV; paramyxovirus = +ssRNA linear with helical capsid and Envelope

tx RSV with Ribavirin

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Virus that causes fear of water and death!

family?

strcture?

Rabies = Rhabdoviruse

-ssRNA linear with ENVELOPE adn helical capsid

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California encephalitisa
Sandfly/Rift Valley feversa
Crimean-Congo hemorrhagic fever

Hantavirus—hemorrhagic fever, pneumonia

Bunyavirus: -ssRNA

enveleoped with 3 segments

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-ssRNA circurlar virus, Enveloped and is known as a ‘defective’ virus

Hepatitis D

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Pneumonic for (-) virus

What do they need to bring with them to infect cells?

Always Bring Polymerase Or Fail Replication.

must transcribe ⊝ strand to ⊕.

Virion brings its own RNA-dependent RNA polymerase.

They include Arenaviruses, Bunyaviruses, Paramyxoviruses, Orthomyxoviruses, Filoviruses, and Rhabdoviruses.

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What viruses are segmented viruses?

BOAR

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All are RNA viruses. They include

Bunyaviruses,

Orthomyxoviruses (influenza viruses),

Arenaviruses

Reoviruses

Picornavirus: Poliovirus, Echovirus, Rhinovirus, Coxsackievirus, and HAV.

RNA is translated into 1 large polypeptide that is

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cleaved by proteases into functional viral proteins.

What diseases are caused by the Picornaviruses?

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PERCH: Picornavirus, Echovirus, Rhinovirus, Coxsackievirus, HAV

Can cause aseptic (viral) meningitis (except rhinovirus and HAV).

All are enteroviruses (fecal-oral spread) except rhinovirus.

Rhinovirus causes shit tons of colds. What is route of transmission? What type of virus is it? Why does it cause enteral illness like all the other Picornoviruses?

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Rhinovirus = picornovirus

+ssRNA linear; non-enveloped

Acid labile! = destroyed by stomach acid

Pt with expansive travel hx comes to office with high fever and is jaundice. She is freaking out because she puked up stuff that look like ground coffee!

dx?

What is the vector?

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Yellow fever: Flavivirus = +ssRNA linear and is Enveloped

transmitted by Aedes mosquitos

Rotavirus A , the most important global cause of infantile gastroenteritis, is a segmented _____ virus (a reovirus). Major cause of acute diarrhea in the United States during winter, especially in day care centers, kindergartens. Villous destruction with atrophy leads to ?

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dsRNA

absorption of Na+ and loss of K+.

*CDC recommends routine vaccination of all infants.

What are two structures unique to influeza virus? What is their function? What severe complications do we worry about with influenza virus infection?

**Orthomyxoviruses**. Enveloped, **⊝ ssRNA viruses with 8-segment** genome. **Hemagglutinin** (promotes _viral entry)_ **Neuraminidase** (promotes _progeny virion release_) Contain antigens. Patients at risk for fatal bacterial superinfection, most commonly S. aureus, S. pneumoniae, and H. influenzae.

What structure promotes H.flu e_ntry into the cell_? What promotes _virion release_?

**hemagglutinin** (promotes _viral entry)_ **neuraminidase** (promotes progeny _virion release_) antigens

Reformulated vaccine (“the flu shot”) contains viral strains most likely to appear during the flu season. Which vaccine is most commonly used? Which one is administered intra-nasaly?

Killed viral vaccine is most frequently used. Live attenuated vaccine contains temperature- sensitive mutant that replicates in the nose but not in the lung; administered intranasally.

Compare and contrast genetic **drift** and **shift**

**Shift** = pandemics. Reassortment of viral genome segments, such as when segments of human flu A virus reassort with swine flu A virus. **Drift**=epidemics. _Mino_r (antigenic drift) changes based on random mutation in hemagglutinin or neuraminidase genes.

A little boy coes in with mother. He spiked a high fever and had a rash on his face but now it has spread to the rest of the body. You note lymphademopathy as well. Dx? What if the mother contracts this while she is pregnant?

German (3-day) measles: Togavirus--rubella Congenital rubella findings include **“blueberry muffin**” appearance, indicative of extramedullary hematopoiesis

MOther delivers her baby and you are concerned she may have gotten ill with something while pregnant. Below is a picture of the infant. What was the cause of the rash? What would this look like in a young child?

Congenital Rubella = Togavirus (+ssRNA linear and enveloped) Blueberry muffin rash = extramedullary hematopoeisis causes German measels or Rubella = fever with rash starting on face and spreading to body

Paramyxoviruses :They include those that cause **parainfluenza** (croup: seal-like barking cough), **mumps**, and **measles** as well as **RSV**, which causes respiratory tract infection (bronchiolitis, pneumonia) in infants. All \_\_\_\_\_\_\_\_\_\_, which causes respiratory epithelial cells to fuse and form multinucleated cells. What drug can we give to premies with RSV to prevent this?

contain surface F (fusion) protein **Palivizumab** (monoclonal antibody a_gainst F protein)_ prevents pneumonia caused by RSV infection in premature infants.

3 yo comes in and you dx him with viral pneumonia? Wha the most likely agent? What is the way in which this bug cauases disease?

viral pneumonia in young children = **RSV** (paramyxovirus -ssRNA and Enveloped) All contain **surface F (fusion) protein**, which causes respiratory epithelial cells to fuse and form _multinucleated cells._

All Paramyxoviruses (parainfluenza, measels, mumps, RSV) contain **surface F (fusion) protein,** what is it's mechanism in the respiratory system that causes damage?

respiratory epithelial cells to fuse and form multinucleated cells

During peds rotation you notice young child with a maculopapular rash on her arms and stomach. You check on her the next day and it is now on the tops of her legs. She has a cough and conjunctivitis. What would you expect to find on oral examination? What is responsible? What can you give to prevent excoriation of rash in malnourished child?

Measels Virus: Paramyxovirus See Koplick spots: bright red with blue-white centers prescede the rash Vitamin A to prevent sever exfoiliatve dermatitis

What are teh three C's of measels? What virus is this? What can occur later d/t measels

Cough, Coryza, Conjunctivitis Measels = **Paramyxovirus**: -ssRNA; linear and ENVELOPED SSPE (subacute sclerosing panencephalitis, occurring years later), encephalitis (1:2000), and giant cell pneumonia (rarely, in immunosuppressed) are possible sequelae.

Mom brings her son in to docotr. He's been very sick lately and she says his lymph nodes seem pretty swollen. You are looking through his history and see there have been NO vacccines. You notice swollen testicals and swollen parotid glands. What are immediate concerns with this virus? Late concerns?

Immediate: can cause Aseptic meningits Future: sterility in men From Mumps: paramyxovirus: -ssRNA linear and enveloped

A 25 yo male is brougt in to urgent care by his girlfriend. He has generalized maliase and a fever. In hx you discover he likes to catch game in the wood with his brothers and has some bite marks on his arm. You culture the bite and notice a **Bullet-shaped virus**. He says he got bit by a racoon a few days ago while hunging. How do you tx this pt? What characteristics are seen if this progresses withouth tx?

RABIES! Postexposure prophylaxis is wound cleaning plus i**mmunization with killed vaccine a**nd **rabies immunoglobulin.** Example of _passive-active immunity._ Progression of disease: fever, malaise ?agitation, photophobia, hydrophobia, hypersalivation?paralysis, coma?death.

Pt comes into clinic delirious, aggitated and states light 'KILLS' his eyes. You offer water to the pt to get a urine sample but he refuses. Shortly after he lapses into a coma and dies. What is the mechanims by which this virus causes diseas? What do you expect to see on autopsy?

Rabies virus = bullet shaped (Rhabdovirus = -**ssRNA linear enveloped)** Travels to the CNS by migrating in **retrograde** fashion up nerve axons after **binding to ACh receptors** Negri bodies B commonly found in _Purkinje cells_ of cerebellum and in _hippocampal neurons_.

Pt presents with abrupt onset of flu-like symptoms, diarrhea/vomiting, high fever, myalgia. You notice schistocytes in blood work and shortly after they go into shock and die. Eveyone is put into isolation. What is the virus that caused this and what parts of body does it affect? How is it transmited?

**Ebola**: filovirus that targets endothelial cells, phagocytes, hepatocytes. Transmission requires direct **contact with bodily fluids or fomites** (including dead bodies); high incidence of nosocomial infection.

Often an asymptomatic virus and is acquired thorugh the fecal oral route Not associated with HCC risk What is the virus

Hep A virus ssRNA pircornavirus

What is the genome of Hep B? HOw is it transmitted? What is it's risk for HCC?

Hep B = dsDNA virus it's a hepadnavirus transmission is parenteral or sexual adn maternal-fetal Increased HCC risk and integrates into the host genome; acts as an oncogene

What type of virus is Hep C? What is it's transmission? What increased risks are seen with it?

How does the Hep B virus replicate in the host?

In HBV, the DNA polymerase has _both DNA- and RNA-dependent activities._ Upon entry into the nucleus, the **polymerase** functions to _complete the partial dsDNA._ The host **RNA polymerase** t_ranscribes mRNA from viral DNA_ to **make viral proteins.** The _DNA polymerase then reverse transcribes_ viral RNA to DNA, which is the genome of the progeny virus.

HAV and HEV are fecal-oral: The vowels hit your bowels. What is special about these two?

Naked viruses do not rely on an envelope, so they are not destroyed by the gut.

RNA delta virus from sexual transmission. Seen along with Hep B

Superinfection (HDV after HBV)—short Coinfection (HDV with HBV)—long Defective virus Dependent on HBV; superinfection ??prognosis

What is present during a Hep B infection during the window period? During Recovery? If you are immunized

Window: Absent HBsAg Anti-HBs but **_PRESENT is HBeAg and the IgM or Anti-HBc_** Recovery: Present is Anti-HBs, Anti-HBe and Anti-HBc (IgM) Immunized: Anti-HBs

RNA viruses Flashcards

(47 cards)