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67 Cards in this Set
- Front
- Back
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how many adenoviruses are known?
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about 40 in humans
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how many adeno viruses cause diseases in humans?
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about 20 (half): pharyngitis, conjunctivitis, "colds", pneumonia, hemorrhagic cystitis, gastroenteritis
certain serotypes assoc. w/ specific Sx most infections asymptomatic but can still shed/spread virus |
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whats the structure of adenovirus?
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1. resists inactivation
2. non-enveloped, icosahedral 3. dsDNA 4. human strains grouped A-F by DNA homology and serotype (>50) |
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how do adenoviruses replicate their genome?
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has own viral polymerase
assembles in nucleus |
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how are early viral genes of adenovirus transcribed
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host cell RNA pol
splicing occurs |
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how are progeny adenoviruses released?
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lysis
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can adenovirus establish a latent infection?
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yes,in lymphoid cells
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what kinds of infections do adenoviruses cause?
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lytic, persistent, and latent
some strains can immortalize certain animal cells |
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what's the most common time of year for adenovirus infection and where are they found
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winter
ubiquitous worldwide |
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fun fact about adenovirus that I'll never remember if it wasn't for this flashcard
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causes 5-10% of respiratory dz
1/2 of kids before 5 yo will have 4 different adenovirus infections |
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how is adenovirus transmitted?
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1. aerosol droplets
2. fecal-oral, fomite 3. direct inoculation of conjunctiva (swimming pool, opthalmic instruments, meds) |
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where does primary replication of adenovirus occur?
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mucosal epithelium or respiratory tract, GI tract, conjunctiva
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where is adenovirus shed?
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upper respiratory tract
fecal shedding for months even w/o Sx |
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how is the immune response to adenovirus determined?
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serotype-specific:
1. IgG Ab--life long, type-specific immunity 2. CMI important to control latency 3. maternal Abs protect infant for 6 mo |
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what are 5 clinical manifestations of adenovirus?
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"Adenovirus Provokes Rapid Onset Disease"
Acute Respiratory Disease (ARD) Pharyngitis/pharygoconjuctival fever respiratory tract diseases ocular infections diarrhea/gastroenteritis |
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what kinds of disease does adenovirus provoke in the pharynx?
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1. acute febrile pharyngitis--presents in kids <3 yo as a cough, stuffy nose, inflammed pharynx (like strep)
2.pharyngoconjuntival fever - more common in older kids |
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what kinds of respiratory disease does adenovirus cause?
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ARD: military recruits, Sx=fever, cough, pharyngitis
"colds", laryngitis, croup, bronchiolitis, pneumonia |
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what causes "swimming pool" conjunctivitis?
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adenovirus
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can adenoviruses cause GI dz?
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yes, gastroenteritis and diarrhea by enteric adenoviruses (rarely cause fever or Resp tract dz)
commonly types 40 and 41 |
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how is adenovirus diagnosed in the lab?
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difficult to do
>50% infections asymptomatic |
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Tx of adenovirus?
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supportive
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prevention of adenovirus?
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disinfect eating utensils, sanitary disposal of nose/mouth discharge
personal hygiene |
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parvo viruses
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smallest viruses
high predilection for dividing cells: marrow, gut, embryo B19 most important for humans |
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structure of parvo virus?
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very hardy (survives pH3-9) and heat stable
non-enveloped, icosahedral ssDNA, negative sense |
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how delicate is a parvo virus?
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very hardy:
survives pH 3-9 and heat stable |
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where does parvovirus replicate?
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tsc, replication and assembly in the nuclei of dividing cells, esp. erythroid cells
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what does parvo virus require for replication?
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a cell in S phase and host cell DNA pol
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how is parvo released?
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lysis of host cell
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where is spread of parvovirus greatest?
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close contact with children: teachers, daycare, families
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what happens when you come into contact with parvo?
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most infections subclinical
or: erythema infectiosum, infection during pregnancy/hydrops fetalis, aplastic crises in sickle cell, polyarthritis |
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how is parvo transmitted?
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respiratory
B19 via transfusion/clotting factors or tattoo vertically |
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pathogenesis of parvovirus?
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primary replication site: respiratory or GI epithelium
viremia w/ 2ary targets: marrow, lymphs infect 2 cell types: RBC precursors, endothelial cells path: cell destruction, immune complexes |
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how is immunity to parvovirus obtained?
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after 1st infection
B19 only has one serotype |
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what are 4 clinical syndromes associated with parvovirus?
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1. erythema infectiosum (Fifth Dz)
2. infection during pregnancy (hydrops fetalis) 3. aplastic crisis in sickle cell 4. polyarthritis |
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what is Fifth Disease?
what does the rash look like? |
caused by parvo B19
acute, benign contagious exanthem of childhood (common) slapped cheek rash: begins as erythema on face and spreads to trunk/limbs 1-4 days later aggravated by sunlight, heat |
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what can B19 cause in pregnancy?
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1. fetal death during 1st trimester
2. hydrops fetalis during 2nd; causes anemia and CHF |
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what does B19 cause in sickle cell anemia?
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B19 replicates in human erythroid progenitor cells causes aplastic crises
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what does B19 cause in adults?
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usually asymptomatic;
can cause polyarthritis (immune-mediated) |
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how many types of Human papilloma virus are there? what do they cause (generally)?
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over 100 types cause warts, papillomas, carcinoma
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what's the structure of HPV?
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small, non-enveloped,icosahedral capsid
dsDNA |
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how are HPVs classified?
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based on DNA sequence homology (no in vitro infectivity assay)
over 100 types identified |
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how does HPV replicate?
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enters through breaks in skin
high tropism for epith cell in skin/mucous memb stages of replication based on differentiation of epithelial cell |
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why is HPV tropic for epithelial cells?
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based on host cell R's and tsc factors
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what do stages of HPV replication depend on?
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specific factors in the host which depend on sequential differentiation of epithelial cells:
early viral gene expression--stim cell division so virus can replicate w/ host DNA pol virus shed--in dead cells of upper keratinocytes |
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where and when does HPV occur?
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ubiquitous
no seasonal variation |
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how does HPV get around?
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resistant to inactivation
trans by direct contact w/ virus through skin break: fomite, sex, perinatal, chewing warts, asymptomatic shedding |
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what kinds of warts do HPV cause?
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1. benign common skin warts, plantar, flat in kids, yg adult
2. laryngeal papilloma in kids, middle aged 3. sexually transmitted |
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laryngeal papilloma in children
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by HPV6 and HPV-11
transmitted during passage through birth canal of a mother w/ genital warts |
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how common are anogenital warts?
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about 20 million in US infected w/ HPV
several types assoc w/ anogenital cancer (2nd most frequent cancer cause worldwide) |
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warts
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due to HPV replication in squamous epithelium, induce epith proliferation
infection local; typically regresses (months/yrs); frequent recurrence |
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genital, oral, conjunctival papillomas
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in mucous membranes
benign or malignant HPV-16,18 w/ oncogenes |
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what kind of immunity to resolve HPV?
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CMI--more frequent recurrence in immunosuppressed
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clinical syndromes of HPV
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HPV type tissue specific, variable presentation:
warts benign H/N tumors: single oral or layrngeal papillomas anogenital warts cervical neoplasia |
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how long do warts take to appear?
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very long incubation period (3-4 months)
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what kind of benign head and neck tumors can HPV cause?
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1. single oral papilloma: have stalk, rough surface, any age, usually solitary, rarely recur after removal
2. laryngeal papilloma: most common benign epith tumor of larynx, can be dangerous in kids |
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what's the most common benign epithelial tumor of the larynx?
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laryngeal papilloma caused by HPV
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what's condylomata acuminata?
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genital warts
occur on squam. epith. of external genitalia/perianal |
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warts are diagnosed by visual inspection and microscopically confirmed how?
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papanicolaou smear: to detect koilocytotic squamous epith cells (rounded in clumps), this is a presumptive test
definitive: cervical swab/specimen w/ DNA probe, PCR |
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why are warts removed?
what's the problem? |
relieve pain, cosmetic, prevent spread
frequent recurrence |
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how is spread of HPV prevented?
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avoid contact
condom vaccine for HPV types 6, 11, 16, 18 (composed of non-infectious virus-like particles) |
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what kind of vaccine is available for HPV?
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Quadrivalent vaccine for HPV types 6, 11, 16, 18 (composed of non-infectious virus-like particles)
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what's polyomavirus?
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JC and BK viruses
ubiquitous-don't usually cause dz in nl host immunocompromised: renal dz (BK) and PML (JC) |
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what's SV40?
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a simian polyomavirus that has been studied as a model for oncogenic viruses
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what can JC virus cause?
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demyelinating disease in immunocompromised
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what can BK virus cause?
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renal dz in immunocompromised
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who gets infected with JC and BK virus?
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most ppl by age 15
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how is polyomavirus spread?
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respiratory route
reactivated w/ immunosuppression |
