RNA viruses Flashcards by Emma <3 Meagher

Reoviruses

No ENV, DS linear, 10-12 segments,
Isocahedral(double)

Coltivirus-Colorado tick fever
Rotavirus-#1 cause of fatal diarrhea in children

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Picornavirus

No ENV, ss + linear, icosahedrral

Polio
Echovirus: aseptic meningitis
Rhinovirus: common 
Coxsackies: aspetic meningitis, herpangina (mouth blisters, fever), hand, food and mouth disease, myocarditis
HAV: acute viral hepatitis

PERCH

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Hepevirus

NO ENV, ss + linear, icosahedral

HEV

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Calcifivirus

NO EVN, ss + linear, icosahedral

Norovirus-viral gastritis

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Flavivirus

ENV, ss + linear, icosahedral
HCV,
Yellow fever
Dengue,
St. Louis encephalitis
West Nile virus

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Togavirus

ENV, ss + linear, icosahedral

Rubella
Eastern equine encephalitis
Western quine encephalitis

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Retrovirus

ENV, ss + linear, icosahedral (HTLV) vs complex and conical (HIV)

Have RT
HTLV- T cell leukemia
HIV-AIDS

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Coronavirus

ENV, ss + linear, helica

Common cold and SARS

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Orthomyxoviruses

ENV, ss - linear, helical, 8 segments

Influenza

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Paramyxoviruses

ENV, ss - linear, helical, nonsegmented

Parainfluenza = CROUP
RSV= bronchiolitis in babies, treat with ribavirin
Measles
Mumps

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Rhabdovirus

ENV, ss - linear, helical

Rabies

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Filovirus

ENV, ss - linear, helical

Ebola/Marburg hemorrhagic fever

often FATAL

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Arenaviruses

ENV, ss - linear, helical, 2 segments

LCMV-lymphocytic choriomeningitis virus
Lassa fever encephalitis: spread by mice

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Bunyaviruses

ENV, ss - linear, helical, 3 segments (vs. Arena with 2)

California encephalitis
Sandfly/Rift valley fevers
Crimean-Congo hemorrhagic fever
Hantavirus-hemorrhagic fever, pneumonia

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Delta virus

ENV, ss - linear, Uncertain

HDV is defective virus that requires HBV.

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Negative stranded viruses

Must transcribe negative to positive
Must bring its own RNA dependent RNA pol

Arenavirus, buynavirus, paramyxo, orthomyxo, filovirus, and rhabdovirus

“Always Bring Polymerase Or Fail Replication”

Segmented viruses

All are RNA viruses
Bunya, orthomyxo, arena, and reoviruses

“BOAR segments”

Picornavirus

PERCH

RNA translated into a large polypeptide leaved by proteases.

Can cause aseptic viral meningitis (except rhino and HAV)

All are entero (fecal oral) except rhinovirus

Rhinovirus

Picnoa
Non enveloped RNA
Common cause of cold, >100 serotypes
Acid labile, therfore does not infect the GI

Yellow fever

Flavivirus and arbovirus
Transmitted by Aedes mosquitos
Monkey and human reservoir

Symptoms: high fever, black vomitus, and jaundice

Flavi: means yellow and jaundice

Rotavirus

Most important global cause of infantile GI
Segmented RNA, reovirus

Major cause of acute diarrhea in the US during winter esp in dare care centers

Villous destruction with atrophy leads to decreased absorption of Na and loss of K+

Influenza

Enveloped, negative single stranded with 8 segments
HA: promotes viral entry
NA: promotes viral eggress

Patients at risk for fatal bacterial superinfection

Shift: assortment of genomes, causes PANDEMIC
Drift: minor changes, causes EPIDEMIC

“Sudden shifts are more deadly than graDual Drift”

Rubella virus

Togavirus
Cause rubella, one know as German measles (3day)

Fever, posauricular adenopathy, LAD, arthralgia, fine TRUNKAL rash that starts at HAND move moves DOWN
(Vs. Scarlett fever with face sparing)
“Rub-ear=postauricular, rubella”

Causes mild disease in children but serious congenital disease.

Paramyxoviruses

Paramyxovirus cause disease in children

Parainfluenza: croup: bark like cough
RSV: bronchiolitis, pneumonia
Mumps and measles

All contain surFace protein F (fusion) protein, which causes respiatory epithelial cells to fuse and form multinucleated cells

Palivizumab (antibody against F protein) prevents pneumonia caused by RSV in premature infants.

Measles virus

Paramyxo Koplit spot and descending maculopapular rash Possible sequelae: SSPE (subacute sclerosing panecephalitis, occuring years later), encephalitis (1:2000), and giant cell pneumonia (rarely, in immunosuppressed) Rash presents LAST and spreads from head to TOE Includes HANDS and FEET (vs. truncal rash in rubella) Do not confuse with roseola (caused by HHV 6) "Three C's of Measles: Cough, coryza, conjuctivitis"

Mumps virus

Also paramyxo Parotitis, Orchitis and aseptic Meningitis (POM) can cause sterility, especially after puberty.

Rabies

Bullet shaped, Negri bodies Commonly found in Purkinjee cells of cerebellum Rabies have LONG incubation period (wks to months) Postexposure treatment is wound cleansing and vaccination with rabies immune globulin Travel to the CNS by retrograde fashion. Progression of disease: fever, malaise => agitation, photophobia, hydrophobia => paralysis, coma => death More commonly from bat, raccoon, and skunk bites than from dog bites in the US.

HEV

``` RNA hepevirus (no env, ss+linear icosahedral) Fecal oral (like HA), esp with waterborne epidemics ``` No carriers, short incubation time No HCC risk High mortality in pregnant women "enteric, expectant mother, and epidemic"

Viral hepatitis

Episodes of fver, jaundice, elevated ALT and AST HAV/HEV are oral fecal HBV: use its own DNA dependent DNA pol to make full strand dsDNA. Then the host RNA polymerase transcribes them.

Hepatitis markers

Anti HBc: antibody to HBcAg = IgM=acute/recent infection, IgG=prior exposure or chronic infection. HBeAg: a second different antigenic determinants in the HBV core. HBeAg indicates active viral replicaiton and thus high transmissibility Anti HBe: antibody to E antigen, indicates low transmissiblity Window period: no antigen, but anti HBe and anti HBc (IgM) and no anti HBs Chronic with high infectivity: HBsAg, HBeAg and anti HBc (IgG), but no anti HBs Chronic with low infectivity: HBsAg, anti HBe and anti HBc (IgG), but no anti HBs

HIV

Diploid genome (RNA), three structural proteins. Env (gp120, gp41): fromed from cleavage of gp160 to form enveloped proteins - gp120: attachment CD4 cells - gp41: fusion protein Gag(p24): capsid protein Pol: RT, aspartate protease, integrase Virus binds CCR5 (early), or CXCR4 (late coreceptors and CD4 on T cells; it only binds to CCR5 and CD4 on macrophages.

HIV diagnosis

ELISA: high sensitive, to rule out Western: high specific, to rule in PCR: viral load, to monitor drug efficacy AID dx: <1.5 ELISA/Western: falsely negative in the first 2 months of HIV infectipn and falsely positive initially in babies born to infected mother (as anti gp120 crosses placental).

HIV time course

Four stages Flu like, feeling fine, falling count, final crisis CD4 < 200: AIDS. During the latent phase, the virus replicates in the LN