36 - Virology Non-Eneveloped DNA Virus Flashcards
Nonenveloped, dsDNA viruses 36 Kb in length.
52 serotypes associated with human disease.
adenovirus
what does adenovirus infect? hwo does it spread
Infect lymphoid tissue, respiratory and intestinal
epithelia and conjunctiva.
Spread by respiratory and ocular secretions; fecal-
oral.
tx of adenovrus
Severe cases treated with interferon or Cidofovir,
a non-specific DNA polymerase inhibitor.
what virus associated with:
Inactivated polyvalent vaccine available for
military.
Live attenuated Types 4 & 7. Taken orally.
adenoviruses
disease manifestation of adenovirus
- respiratory
- eye
- UTI/acute hemorrhagic cystitis
- GI disease
Small (50-55 nm), non-enveloped, icosahedral
particles formed with 2 viral proteins.
Stable in the environment.
paillomavirus
genome of papilomavirus
Genome is circular dsDNA.
~8000 base pairs.
*
7-8 early (E) genes.
2 late (L) structural genes.
what is squamous epit growth, wart, or verruca
HPV
what causes HPv
100 diferent strains
how is HPV transmitted
Transmissible through direct contact or
contaminated fomites; incubation - 2 weeks to
more than a year.
what are most common warts that regress over time
HPV
wart treatment
- Chemical applications: Podophyllin (genital), salicylic acid, other topicals.
- Physical removal by cauterization, freezing, or laser surgery.
how does HPV infect tissue
HPVs only replicate in epithelial tissue.
Virus enters at wound and attaches to cells at the
basement membrane.
Presumably enter receptor mediated endocytosis.
Binding to genome transcription can take 1-3 days!
HPV replication deends on what
stage of epi cell differentiation
disease manigestations of warts
- common/seed
- flat
- plantar
- anogenital
incubation period of warts
3 month
what is painless elevated rough growth on skin
common/seed
what is deep, possible painful wart on soles of feet
plantar
what is warts of squamous epi of external genitalia and perianal areas (problematic can be malignant)
anogenitcal
disease manigestations of oral/laryngeal papillomas
- Benign epithelial tumors of the oral cavity. (Commonly HPV-6 and HPV-11)
- Typically pedunculated with a fibrovascular stalk with a rough surface.
- Laryngeal can be life-threatening in children if airway is obstructed.
- Occasionally found in trachea or bronchi.
disease manifestations of genital warts
certical papillomas and cancer
- HPV 16 and 18
carcinoma formation associated with HPV 16 and 18 results from what
partial integration of HPV genome resulting in high expression of the E6 and E7 genes
(why we do early detection)
HPV vaccines
- ceravarix (16 and 18)
- gardasil
- gardasil 9
orthomyxovirus is also called what
influenza
structure of infulenza
Enveloped, ssRNA, segmented
viruses.
types of flue
3 distinct influenza virus types: A, B, C
- Based on Ab. to core antigen.
- Type A causes most infections.
what does influenza traget
respiratory tract
where does virus replication occur in influenza
nucleus (transcribed/translated)
key influenza envelope proteins
- hemaglutinin (H)
- neuraminidase (N)
- M2
what does hemagglutinin do
faciliates binding to host cells and fusion
influenza nomenclature
how does influenza evolution occur
- antigenic DRIFT
- antigenic SHIFT
what is antigenic shift
Constant mutation is called antigenic drift - this
produces a gradual change in amino acid
composition.
0.5% - 1% per year in both HA and NA
what is antigenic chisft
Antigenic shift
occurs when one of the
genes or
RNA strands is substituted with a gene or strand
from another influenza virus from a different strain of
virus.
Produces PANDEMIC STRAINS.
what antigenic evolution produces PANDEMIC STRAINS
antigenic shift
Most important cause of medically attended acute respiratory illness.
- Seasonal flu morbidity is highest in young children and the elderly.
- High mortality pandemics are usually associated with increase incidence of lower respiratory complications, cardiovascular disease,
and pneumonia.
influenza A
tranmission of influenza A
airborne - mechanical self-inoculation is uncertain
Binds and replicates in ciliated cells of respiratory mucosa.
Causes massive apoptosis, rapid shedding of cells, stripping the respiratory epithelium; severe inflammation.
Pulmonary abnormalities can persist for weeks.
uncomplicated illness of influenza A
Fever, malaise, headache, chills, sore throat, shortness of breath,
coughing.
Pulmonary abnormalities can persist for 2-4 weeks.
complications of influenza A
what produce similar clinical signs/symptoms of A
B and C
primary reservoir for influenza B and C
humans
influenza B only undergoes antigenic ___
only DRIFT not know to do SHIFT
how many RNA segments in influenza C
7 RNA
whch influenza has the milder repiratory disease and probably not involved in epidemics
C
diagnosis of influenza
- Rapid immunofluorescence tests to detect antigens in a pharyngeal specimen;
- Serological testing can be done to screen for antibody titer
treatment of flu
- amantadine and rimantadine - M2 inhibitor
- zanamivir and tamiflu - NA inhibitor
- xofluza
mechanism of flu treatment
- M2 inhibitors (previously used)
- NA inhibitors (currently used e.g., zanamivir and tamiflu)
standard formulation of flu vaccine
quadrivalent comprised of 2 influenza A subtyeps and 2 influenza B strains
what are traditional vaccine type for flu
Traditional vaccine types were trivalent and comprised of 2
influenza A subtypes and only influenza B virus.
3 types of flu vaccines
- inactivated vaccine (traditional grown in eggs)
- flu mist (live attenuated)
- flucelvax (tissue culture derived no eggs)
paramyxovirus structure
paramyxo virus is associated with what
respiratory transmission and syncitia formation
3 genera of paramyxovirus
- Morbillivirus - Measles virus
- Paramyxovirus - Parainfluenza 1-4; Mumps virus
- Pneumovirus - Respiratory syncytial virus (RSV).
what is this:
Also known as red measles and rubeola.
Different from German measles.
Very contagious; transmitted by respiratory aerosols
(estimated at > 90%).
Humans are the only reservoir.
Used to be less than 100 cases/yr in U.S.; frequent cause of
death worldwide (mostly in developing countries).
Virus invades respiratory tract (primary replication).
Spread into lymphatic system via monocytes and
lymphocytes (secondary infection).
measles
symptoms of measles
Symptoms: Sore throat, dry cough, headache, conjunctivitis,
lymphadenitis, fever, Koplik spots diagnostic oral lesions.
what virus is characteristic maculopapular rash results from T cells targeting measles-infected endothelial cells lining small blood vessels.
measles virus
even tho vacc has cut measles in US, how do periodic epidemics still occur
Herd immunity requires 90% vaccination rate.
Usually in unvaccinated populations.
May be initiated by foreign traveler.
Notable outbreaks:
* 2014- Amish community (OH)
* 2014/15- Disneyland
* 2019- Unvaccinated in NY (73%)
complications of measles
tx and prevention of measles
what is:
Respiratory viruses that usually cause mild cold-
like symptoms.
Widespread as influenza, but more benign.
HPIV
four serotypes of HPIV
- 1,2, & 3 are commonly associated with upper respiratory infections, but also lower respiratory infections and laryngotracheobronchitis (croup).
(3 is more often associated with bronchiolitis, bronchitis, and pneumonia.) - Type 4 is associated with mild upper respiratory tract infections in children and adults. (Two subtypes, 4a & 4b.)
epidemiology of parainfluenza
what:
Epidemic parotitis; self-limited, associated with painful
swelling of parotid salivary glands.
Humans are the only reservoir.
40% of infections are subclinical; long-term immunity.
Used to be ~300 cases in U.S./year.
mumps virus
incubation and treatment of mumps
what is respiratory syncytial virus (RSV) also called
pneumovirus
what is this:
Infection initiates in the upper respiratory tract.
Cell-to-cell spread produces giant multinucleate cells.
Most prevalent cause of respiratory infections in
children 6 months or younger; most susceptible to
serious disease.
Epithelia of nose and eye portal of entry; replicates in
nasopharynx.
Viral and immune-mediated cell injury leading to
cytopathology.
Fever, rhinitis, pharyngitis, otitis, and croup.
RSV
monoclonal tx of RSV
Synagis- recommended for high-risk infants.
Beyfortus (nirsevimab)
Two new vaccines approved in 2023 for 60+ adults.
Pfizer vaccine approved during late pregnancy to provide
passive immunity to newborns.
what is most common cause of lower repiratory tract infection in young children in US, infection occur primarily during fall, winter and spring.
RSV
does natural immunity provice protection in RSV? what is the vaccine?
- Natural immunity does not provide protection.
- No vaccine available.
- Previous trials exhibited enhanced disease in vaccinated individuals.
