Viruses Flashcards

Question

Hepatitis C Virus

Answer 1

``` Family: Flavivirus Structure: ss (+) linear RNA virus Envelope: Yes Caspid: Icosahedral Replication: Cytoplasm Transmission: blood, placenta, sex, IV drug users ``` Envelope has high antigenic variability makes vaccine difficult. *viral RNA polymerase lacks proofreading exonuclease activity in 3'->5' --> increased mutation rate Clinical features: Acute hepatitis: jaundice, RUQ pain, HSM -ALT rises and falls w/in 6mo -Anti HCV made after 2-3mo, seen in acute or chronic *60-80% become chronic -> cirrhosis, HCC Chronic hepatitis: viral RNA persists >6mo and lymphocytes in portal tract on biopsy *HCV associated w cryoglobulins, Igs that precipitate in cold temps Treatment: Ribavirin + IFNalpha OR Protease inhibitors( Simeprevir) + Ribavirin + IFNalpha OR Sofosbuvir (HCV RNA polymerase inhibitor) + Ribavirin + IFNalpha

Answer 2

``` Family: Togavirus Structure: ss (+) linear RNA virus Envelope: Yes Caspid: Icosahedral Replication: Cytoplasm ``` Arbovirus Transmission: arthropod borne virus Western equine encephalitis -> Western U.S. Eastern equine encephalitis -> Eastern U.S. Venezuelan equine encephalitis -> C. and S. America Clinical features: encephalitis -HA, fever, AMS, focal neurological deficits No treatment

Answer 3

``` Family: Togavirus Structure: ss (+) linear RNA virus Envelope: Yes Caspid: Icosahedral Replication: Cytoplasm ``` **Immigrant, Descending rash, LAD** Childhood infection: - Transmitted via respiratory drops - Tender postauricular and occipital LAD - Maculopapular rash starting on face and moving downward (moves faster than measles and doesn't darken or coalesce) lasts ~3days Congenital Rubella (TORCHES) - Transmitted across placenta * Deaf and blindness * Cataracts * PDA - 'blueberry muffin' rash (purpura) - Jaundice - Mental retardation - Microencephaly - Pulm. stenosis - radiolucent bone lesions Adult infection: LAD, fever, arthralgias and arthritis MMR vaccine- Live attenuated-> humoral and cell mediated immunity (do not give in pregnancy or immunocompromised until CD4>200)

Answer 4

``` Family: Coronavirus Structure: ss (+) linear RNA virus Envelope: Yes Caspid: *Helical* Replication: Cytoplasm Transmission: respiratory droplets ``` Common cold SARS and MERS - acute bronchitis that leads to ARDS - diagnose w PCR or antibodies to SARS Treatment: steroids, ribavirin

Answer 5

``` Family: Retrovirus Structure: ss (+) linear RNA virus Envelope: Yes Caspid: Complex and conical Replication: Cytoplasm Transmission: sex, blood, childbirth ``` Components: -diploid: 2 copies in each virus 3 genes for replication * gag= p24, capsule for RNA strands * env= make gp41 (TM protein for fusion and entry) and gp120 (outer glycoprotein, adheres to CD4+ T cell) * pol= reverse transcriptase polymerase Progression of disease: Pathogenesis: HIV infects macrophages by binding CCR5 initially and then helper CD4+ T cells by binding CXCR4. (if host has CCR5 mutation can be immune to HIV) 1. Initial symptoms: several weeks flu-like symptoms w/ cervical LAD, may have enlarged tonsils 2. Latent period (replicating in LNs): up to 10 years steep drop in CD4+ count do western blot [Vertical transmission: will be falsely + for ELISA and western blot-> do HIV RNA and DNA amplification to look for virus and not just abs] *measure viral load by PCR *CD4 count Treatment: Antiretroviral therapy (HAART) *2 NRTIs- nucleotide analogs get incorporated and halt elongation, Zidovudane for pregnancy +1 of below: *NNRTIs- do not incorporate but inhibit reverse transcriptase (Delavirdine, Efavirenz, Nevirapine) *Protease inhibitor (-navir) *CCR5 inhibitor- Maraviroc *Enfuviritide- inhibits viral entry, binds gp41 *Raltegravir- integrase inhibitor, prevents genome integration into host

Answer 6

Must transcribe (-) to (+). Virion brings its own RNA dependent RNA polymerase; All replicate in cytosol except Orthomyxovirus and all are single stranded except Rheovirus ``` Arenavirus Bunyavirus Paramyxovirus Orthomyxovirus Filovirus Rhabdovirus ``` 'Always Bring Polymerase Or Fail Replication'

Answer 7

Bunyaviruses Orthomyxovirus Arenaviruses Reoviruses BOAR

Answer 8

Family: Orthomyxovirus Structure: ss (-) linear RNA virus Envelope: Yes Caspid: Helical Replication: **Nucleus**is the exception for (-) RNA Transmission: Respiratory droplets, Dec-Feb ``` Segments: 8 ->antigenic variation antigenic drift (point mutation-> epidemic) antigenic shift (segments shared between different species-> pandemic) ``` Influenza A, B, C - A: epidemic/pandemic - B: endemic Virulence factors: *HA (hemagluttin) binds to cells of respiratory tract via sialic acid residues and enters, also causes RBCs to clump (H1, H2, H3..) -determines tropism * M2 protein (only influ. A) needed for viral uncoating (create proper pH) * NA (neuraminidase) needed to break sialic acid binding and release virions from host cell Drugs targeting virulence factors: * Amantadine - inhibits M2, prevents uncoating (now resistance) only influenza A * Oseltamivir/Anamivir (Tamiflu) - inhibits NA, must give uncoupling of ox phos in hepatic mitochondria

Answer 9

``` Family: Paramyxovirus Structure: ss (-) linear RNA virus Envelope: Yes Caspid: Helical Replication: Cytoplasm Transmission: Respiratory droplets ``` Virulence factors: HA, fusion proteins -> form multinucleated giant cells Warthin-Finkeldey cells (fused lymphocytes) Clinical features * 4'C's: - Cough - Coryza (runny nose) - Conjunctivits - Koplik spots (small bluish spots surrounded by red on buccal mucosa) * Lymphadenitis w/ giant cells * High fever x4 days * Maculopapular rash: pruritic, starts at face and moves down, begins as small dots then coalesce Complications - pneumonia - Subacute sclerosing panencephalitis (SSPE) years later: personality changes, ataxia, seizures, coma, death MMR Vaccine- live attenuated, contraindicated in pregnancy Vitamin A can reduce measles mortality and morbidity

Answer 10

``` Family: Paramyxovirus Structure: ss (-) linear RNA virus Envelope: Yes Caspid: Helical Replication: Cytoplasm Transmission: Respiratory droplets ``` Replicates in salivary glands -> parotitis Replicates in testes -> unilateral orchitis Can cause meningitis Virulence factors: HA, NA, Fusion protein MMR Vaccine- live attenuated, contraindicated in pregnancy

Answer 11

``` Family: Paramyxovirus Structure: ss (-) linear RNA virus Envelope: Yes Caspid: Helical Replication: Cytoplasm Transmission: Respiratory droplets ``` - Fusion protein virulence factor - Attaches to G protein to infect respiratory epithelial cells Most common cause of pneumonia and bronchiolitis in infants

Answer 12

``` Family: Paramyxovirus Structure: ss (-) linear RNA virus Envelope: Yes Caspid: Helical Replication: Cytoplasm Transmission: Respiratory droplets ``` Laryngeotracheobronchitis (Croup) - mainly children - inspiratory stridor - "steeple sign" on CXR Adults- cold Virulence factors: HA, NA, fusion protein

Answer 13

``` Family: Rhabdovirus Structure: ss (-) linear RNA virus Envelope: Yes Caspid: Helical, 'bullet shaped' Replication: Cytoplasm Transmission: zoonotic ``` Rabies - Bats #1 carrier in U.S, also rodents - glycoprotein binds to Nicotinic ACh receptors at NMJ post synaptic end plate and infects neurons Replication/Infection - incubates weeks-months - travels retrograde via peripheral nerves until reaches DRG - replicates in motor neurons - when reaches brain -> fever, encephalitis, drooling Negri bodies (eosinophilic inclusions) in hippocampus pyramidal cells and purkinje cell cytoplasm Antidote: passive immunization with rabies Ig and then active immunization with killed vaccine after exposure

Answer 14

``` Family: Filovirus Structure: ss (-) linear RNA virus Envelope: Yes Caspid: Helical Replication: Cytoplasm Transmission: contact with animal- monkeys or bats in endemic areas, via bodily fluids even after death ``` Ebola 1. fever, petechial rash (days-weeks after infection) 2. Hemorrhagic fever, end-organ failure 3. Death from hypovolemic shock

Answer 15

Family: Bunyavirus Structure: ss (-) linear RNA virus Envelope: Yes, obtains envelope from host golgi bodies Caspid: Helical Replication: Cytoplasm Transmission: Via arthopod host (Arborviruses) except Hantavirus Segmented: 3 circular segments Hantavirus reservoir: deer mice, transmitted via rodent urine/feces Symptoms: pulmonary edema, pre-renal azotemia and hemorrhagic fever Rift valley Fever & California encephalitis - both transmitted by Aedes mosquitos - cause seizures and encephalits - myalgias and fever

Answer 16

``` Family: Arenavirus; 'sandy' look on EM Structure: ss (-) CIRCULAR RNA virus Envelope: Yes Caspid: Helical Replication: Cytoplasm Transmission: rodents ``` Segmented: 2 segments -Can code (+) too -> ambisense* -grainy appearance on EM LCMV (Lymphocytic choriomengitis virus) -febrile aseptic meningioencephalitis Lassa fever encephalitis -spread by rodents Inactivated by heating, irradiation

Answer 17

``` Family: Reovirus Structure: **DS linear RNA virus Envelope: No Caspid: Icosahedral (double) Replication: Cytoplasm Transmission: Fecal-oral ``` Segmented: 10-12 #1 cause of diarrhea in young children NSP4 toxin (viral enterotoxin) -> increases Cl- permeability -> secretory diarrhea Seasonal : peaks in winter Live attenuated vaccine- oral, give 1st dose before 3mo *Side effect: increase risk of intussusception of bowel CO tick virus - also Reovirus - myalgia, fever, vomiting (no rash) - Treatment supportive

Answer 18

Family: Hepesvirus Structure: ss RNA virus Envelope: No Transmission: fecal-oral Primarily in young adults in Asia, sub-Saharan African and Mexico high mortality rate observed in infected pregnant women -no carrier state or chronic disease

Answer 19

single-stranded +sense, linear non-segmented RNA viruses Picornavirus - Polio, echovirus, rhinovirus, HAV, Coxsackie virus Hepesvirus - HEV Calicivirus - Norovirus Flavivirus- HCV, yellow fever, west nile virus, dengue Togavirus- Rubella, equine encephalitis Coronavirus- SARS, common cold

Viruses Flashcards

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