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