RNA Virus 2 Flashcards
1
Q
Rotavirus
A
- reovirus
- dsRNA
- segmented
- naked icosahedron (round)
2
Q
Influenza Virus
A
- orthomyxovirus
- neg ss RNA
- segmented
- enveloped
3
Q
HIV
A
- retrovirus
- ssRNA, 2 copies
- enveloped
4
Q
rotavirus disease
A
- causes severe gastroenteritis
- profuse watery diarrhea
- dehydration
- maladsorption
- affects infants and children (adults are usually asymptomatic)
- > 60,000 deaths annually, mostly in developing world
- peak incidence during winter
5
Q
Rotavirus life cycle
A
- genome is segmented, one gene each (dsRNA)
- enters by endocytosis
- escapes from early endosome by acidification
- RDRP in the virion first transcribes mRNA
- after viral proteins are translated, new virions and genome segments are synthesized in the cytoplasm
- virions assemble and then bud into the rough ER (displace membrane they get there)
- egress via exocytosis (membrane vesicles carry virions out) or by cell lysis
- virions mature in gut lumen, then infect more enterocytes or are shed in profuse diarrhea
6
Q
rotavirus diagnosis, treatment, prevention
A
- diagnosis not required in most cases
- trt-oral rehydration solutions
- prevention- live attenuated vaccine-rotarix (1) and rotareq (5)
7
Q
influenza virus disease
A
- acute respiratory illness, mainly during the winter
- uncomplicated-upper/lower resp tract involvement, fever, headache, myalgia, weakness
- complicated-primary pneumonia caused by flus
- secondary bacteria pneumonia
- mixed viral and bacteria pneumonia
- muscle involvement, myositis, rhabdomyelitis (breakdown)
8
Q
symptoms of flu
A
- central-headache
- nasopharynx-runny or stuffy nose, sore throat, aches
- resp-coughing
- gastric-vomiting
- joints-aches
- muscular-extreme tiredness
- systemic-fever
9
Q
Influenza life cycle
A
- genome is segmented, neg ss RNA
- binds via hemagglutin and fuses to endosome, pH change releases genes
- genome segments traffic to the nucleus for transcription and replication by RDRP
- viral proteins and genome segments accumulate at the PM
- virions assemble and egress by budding
- neuraminidase releases virions from sialic acid on cell surface
- shed in resp droplets
10
Q
flu treatment and prevention
A
- antiviral drugs-tamiflu (A and B)- stops release from PM, Relenza (A and B), Amantadine and Rimantadine-A
- vaccines-fluzone and trivalent inactivated, flu mist
- giving H1N1, H3N2 and B this year
11
Q
antigenic shift
A
-genetic shuffling makes new versions of A subtype from other subtypes
12
Q
antigentic drift
A
random mutation- makes new strains from the new A subtype
-can stay for about 10 years
13
Q
acute HIV infection
A
- systemic-fever, WEIGHTLOSS
- central-MALAISE, NEUROPATHY, headache
- lymph-LYMPHADENOPATHY
- skin-RASH
- gastric-vomiting, nausea
- liver and spleen-ENLARGEMENT
- muscles-myalgia
- esophagus-sores
- pharyngitis-SORES, THRUSH
14
Q
stages of HIV disease
A
- exposure to virus
- primary HIV infection (acute phase)
- seroconversion
- latent period
- early symptomatic HIV infection
- AIDS- CD4 < 200
- Advanced HIV infection- CD4 < 50
15
Q
HIV cell tropism
A
- only humans can be infected
- virus binds to CD4 and chemokine receptors (CCR5) on T cells and macrophages
- depletion of these cells and chronic immune activation cause immunodeficiency
16
Q
HIV R5
A
-CCR5
17
Q
HIV R5X4
A
-CCR5 and CXCR4
18
Q
HIV load and CD4 T cells
A
- initial-most HIV and least T cells
- then T cells recover slightly, HIV drops a little
- then HIV gradually increases while T cells gradually decrease
- as T cells decrease, opportunistic infections increase
19
Q
AIDS and loss of T cells
A
- bacterial skin infections, shingles, thrush, athletes foot, oral hairy leukoplakia, TB
- then AIDS defining
20
Q
top 10 AIDS defining infections
A
- pneumocytis cariniii pneumonia
- esophageal candidiasis
- wasting
- Kaposi’s sarcoma
- disseminated M avium infection
- TB
- Cytomegalovirus disease
- HIV associated dementia
- recurrent bacterial pneumonia
- toxoplasmosis
21
Q
main symptoms of AIDS
A
- neuro-encephalitis/meningitis
- eyes-retinitis
- lungs-pneumocystis pneumonia, TB, tumors
- skin-tumors
- GI-esophagitis, chronic diarrhea, tumors
22
Q
HIV life cycle
A
- virion fuses with CD4 and CCR5
- fuses with PM- brings in protease, integrase and RT-can hang out there until T cell divides and many nts around
- the RT converts the + ss RNA into dsDNA (hypermutation here)
- the dsDNA genomes integrate into the host chromosome for life
- host RNA pol II transcribes mRNA from the integrated genome, which also serves as the genome that is packaged into the new virions (because its + ss)
- viral proteins and 2 genomes bud from PM
- virion maturation occurs outside the cell when the viral protease cleaves the capsid proteins, forming the final trapezoidal step
23
Q
HIV diagnosis and prevention
A
- diagnosis-serologic assays for antibodies
- nucleic acid assays for viral load
- CD4 cell count
- prevention- risk avoidance
- community awareness
- public health measures
- antiviral drugs-chemoprophylaxis
24
Q
HIV treatment
A
- ART
- must be combined to avoid resistance
- new formulations reduce pills and doses increase compliance
25
Q
types of HIV drugsq
A
- nucleoside reverse transcriptase inhibitors (NRTIs)
- non-nucleoside RT inhibitors (NNRTIs)
- Protease inhibitors (PI)
- integrase strand transfer inhibitors (INSTIs)
- CCR5 agaonists
26
Q
goals of HIV treatment
A
- durable suppression of HIV viral load
- restoration of immune function
- prevention of transmission
- prevention of drug resistance
- improvement of QOL
27
Q
vaccine?
A
- more is known about HIV than any other virus, but vaccine remains elusive
- what should it accomplish-sterilizing immunity? no progression to AIDS? no transmission?
