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9.30 DNA viruses
at 10:00 by Dr. Foster
134
Microbiology
Professional
10/02/2011

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Term
What's the range of DNA genome sizes?
Definition
some of the smallest (5kb) to largest (over 200 kb) of all viruses
Term
Describe the herpesvirus genome.
Definition
DS, linear
Term
Describe the hepadnavirus genome.
Definition
DS, circular
Term
Describe the adenovirus genome.
Definition
DS, linear
Term
Describe the papovavirus genome.
Definition
DS circular
Term
Describe the poxvirus genome.
Definition
DS, linear
Term
Describe the parvovirus genome.
Definition
SS, linear
Term
What are the two types of papavavirus?
Definition
papillomavirus and polyomavirus
Term
T/F Many DNA viruses have evolved for milennia with their hosts.
Definition
true
Term
As a consequence of co-evolution most DNA viruses can...
Definition
persistently infect its host (integrative and transforming potential)
Term
What's the morphology/structure of parvoviruses?
Definition
naked icosahedral
Term
What's the morphology/structure of adenovirus?
Definition
naked icosahedral
Term
What's the morphology/structure of papovavirus (papilloma and polyoma)?
Definition
naked icosahedral
Term
What's the morphology/structure of hepadnavirus?
Definition
enveloped icosahedral, pleomorphic/filamentous
Term
What's the morphology/structure of herpesvirus?
Definition
enveloped icosahedral
Term
What's the morphology/structure of pox virus?
Definition
multi-enveloped, ovoid brick
Term
What DNA viruses are very capable of environmental persistence and are resistant to chemical inactivation?
Definition
non-enveloped ones
Term
Name three examples of broad spectrum drugs that can target multiple viruses by targeting general entry pathways?
Definition
amantidine, rimantadine and tromantadine
Term
Where do DNA viruses replicate?
Definition
in the cell's nucleus causing intranuclear inclusions (except for the poxvirus, which causes cytoplasmic inclusions)
Term
What types of proteins are made by the immediate early genes?
Definition
regulatory/evasion (IFNs)
Term
What types of proteins are made by the early genes?
Definition
regulatory/replication
Term
What types of proteins are made by the late genes?
Definition
structural
Term
What drugs inhibit DNA polymerase?
Definition
foscarnet, cidofivir
Term
What drug inhibits thymidine kinase?
Definition
acyclovir (nucleoside analogs)
Term
How do naked viruses exit the cell?
Definition
lysis
Term
What types of viruses produce polykaryon or syncytia?
Definition
enveloped viruses
Term
Syncytia are caused by ______ on membranes of cell or virus.
Definition
glycoproteins
Term
In 2003, a highly deadly respiratory disease caused by a virus with the absence of nuclear inclusions and multinucleated syncytia formation was diagnosed as what type of virus?
Definition
coronavirus (causing SARS)
Term
Why is it called an "adeno"virus?
Definition
first isolated from adenoids
Term
What's the genome size of an adenovirus?
Definition
moderately sized (36-40 kb)
Term
Adenovirus tropism:
Definition
epithelial, lymphoid, mesenchymal
Term
What is adenovirus transmission?
Definition
respiratory and oral-fecal
Term
What is the incubation time of an adenovirus?
Definition
5-9 days
Term
What is the pathogenesis of an adenovirus?
Definition
direct cell damage caused by replication although the cellularimmune response against infected cells has also been implicated in damage of infected tissue
Term
How do you diagnose an adenovirus infection?
Definition
cell-culture, viral antigen detection (IFA; immunoassay)
Term
Is there an adenovirus vaccine?
Definition
yes, live vaccine that was used in the military but was discontinued in 1999
Term
What's the therapy for adenovirus?
Definition
no antiviral drugs; cidofivir or I.V. ribavirin if rampant
Term
Are adenoviruses stable outside of the body?
Definition
yes, they are unusually stable to chemical or physical agents and adverse pH conditions, allowing for prolonged survival outside of the body and water
Term
What viruses used receptor CAR1?
Definition
adenovirus and coxsackievirus
Term
What types of diseases are caused by adenoviruses?
Definition
most commonly: respiratory
common: ocular infections
other: gastroenteritis and meningoencephalitis
Term
WWhat respiratory diseases are caused by adenoviruses?
Definition
adenoviral pneumonia, acute respiratory disease (ARD), endemic respiratory diases
Term
How are respiratory disease adenoviruses spread?
Definition
coughed-out droplets
Term
What ocular diseases are caused by adenoviruses?
Definition
epidemic conjunctivitis, sporadic-acute follicular conjunctivitis
Term
How are ocular disease caused by adenoviruses commonly spread?
Definition
in water of swimming pools that don't have enough chlorine in them
Term
T/F some people with adenovirus gastroenteritis may shed the virus in their stools for months after getting over the symptoms.
Definition
true
Term
Adenovirus URIs manifest as...
Definition
tonsilitis (that may look exactly like strep- need culture to distinguish), ear infection, or croup
Term
T/F Adenovirus can cause a UTI.
Definition
yes, rarely it causes hemorrhagic cystitis
Term
Which population is susceptible to bronchiolitis or pneumonia caused by an adenovirus?
Definition
children (esp. small ones)
Term
What virus can look exactly like whooping cough in babies?
Definition
adneovirus
Term
Who is at risk for acute respiratory illness caused by an adenovirus?
Definition
military recruits, boarding schools, etc. (1-5, 7, 10, 11, 13, 14, 21)
Term
What population is at risk for a pharyngitis caused by an adenovirus?
Definition
infants (1-5, 7)
Term
What population is at risk for a gastroenteritis caused by an adenovirus?
Definition
infants (40,41)
Term
What population is at risk for a conjunctivitis caused by an adenovirus?
Definition
all (3,4)
Term
What population is at risk for a pneumonia caused by an adenovirus?
Definition
infants, military recruits (4,7)
Term
What population is at risk for an acute hemorrhagic cystitis caused by an adenovirus?
Definition
infants (11)
Term
What population is at risk for a hepatitis caused by an adenovirus?
Definition
infants, liver transplant patients (4,5,7,10)
Term
What serotypes of adenovirus are commonly seen with respiratory disease?
Definition
mainly species HAdV-B and C
Term
What serotype of adenovirus are commonly seen with conjunctivits?
Definition
HAdV-B and D
Term
What type of adenovirus are commonly seen with gastroenteritis?
Definition
HAdV-F serotypes 40 and 41
Term
What are the symptoms of endemic respiratory disease (adenovirus)?
Definition
pharyngitis, tonsillitis, and nasopharyngitis (symptoms: cough, sore throat, tonsillar exudates, myalgia and headache)
Term
What are the symptoms of ARD?
Definition
flulike, seen in military recruits. Fever, pharyngitis, cervical adenopathy, cough, myalgia, and diarrhea
Term
What are the symptoms of adenoviral pneumonia?
Definition
fever, cough, dyspnea and wheezing. common in infants and the immunocompromised
Term
What are the symptoms of sporadic acute follicular conjunctivitis caused by adenovirus?
Definition
benign conjunctivitis; is the most common eye infection
Term
Which age group is most affected by epidemic keratoconjunctivitis caused by adenovirus?
Definition
common affliction across all ages
Term
What re the signs of meningoencephalitis caused by adenovirus?
Definition
aseptic meningitis, meningoencephalitis, and encephalitis. Common amongst children and immunocompromised patients
Term
Which adenovirus types caused gastroenteritis?
Definition
40 and 41
Term
What is the second most common cause of infantile viral diarrhea?
Definition
adenovirus (after rotavirus)
Term
What are the symptoms and typical patient of acute hemorrhagic cystitis caused by adenovirus?
Definition
almost exclusively in male children: urinary frequency, bladder pain and gross hematuria
Term
What is Ad14?
Definition
rare, emerging virus that can cause severe respiratory infection, which can sometimes be fatal, even in healthy young adults. Ad14 isolates from four states where outbreaks occurred were identical, based on DNA sequencing
Term
How was the adenovirus vaccine administered?
Definition
live, nonattenuated via an enteric-coated tablet that would replicate once when they reach the intestine causeing an asymptomatic infection of the GI tract
Term
What virus is linked to obesity?
Definition
adenovirus
Term
Why do adenvirusese in particular have immense potential as vectors for vaccination, gene, and cancer therapy?
Definition
adenoviruses can be genetically altered in vitro
Term
What are possible complications of using adenoviruses for gene therapy?
Definition
you have to limit hepatotoxicity and prevent multiple organ failure
Term
How are adenoviruses used to treat cancer?
Definition
specific modifications on fiber proteins are used to target adenovirus to certain cell types such as tumors and then utilize the lytic properties of adenoviruses to kill tumors
Term
Which viruses have been used in clinical trials for gene therapy/replacement studies?
Definition
adeno, retro and parvo
Term
Phase ____ clinical trials are ongoing for adeno and vaccinia virus based vectors for use in immunization against a plethora of diseases.
Definition
II and III
Term
Which viruses are used as oncolytic viral therapies?
Definition
herpes and adeno
Term
Name the erythrovirus parvoviruses.
Definition
human parvovirus B 19, human bocavirus, human parvovirus 4
Term
What is the tropism of parvovirus?
Definition
epithelial cells in S (synthesis) phase or needs helper virus. Erythroid progenitor cells-replicates in and destroys
Term
What is the transmission of parvoviruses?
Definition
respiratory
Term
What is the pathogenesis of parvoviruses?
Definition
direct cell damage caused by viremia, and the humoral immune response against infected cells has also been implicated in damage of infected tissue
Term
What are associated diseases of parvovirus infection?
Definition
fifth disease (enrythema infetiosum-common), hydrops fetalis (very rare, due to fetal anemia and not associated with fetal abnormalitis); persistent infection in immunocompromised: relapsing anemia
Term
How do you diagnose parvoviruses?
Definition
serology, PCR or DNA probe (differntial: rubella virus)
Term
What is the vaccine/therapy for parvoviruses?
Definition
none/human normal immunoglobulin (HNIG); red blood cell transfusion to control acute anemia
Term
How big is the parvovirus genome? What are the different genes on it?
Definition
5 kb flanked with inverted terminal repeats (ITR), Rep gene required for DNA replication and Cap gene encodes capsid proteins
Term
Why must thc cell be in S phase for viral replicationo of parvovirus?
Definition
because of limited number of genes and small size of parvovirus
Term
Parvovirus integrates its DNA where in the host genome?
Definition
chromosome 19
Term
Besides when the host cell is in S phase, parvovirus can also replicate when...
Definition
the cell is coinfected with a helper virus
Term
T/F Parvovirus is highly transmissible.
Definition
true, approx 60% of adults are seropositive
Term
What causes erythema infectiosum?
Definition
aka fifth disease. Caused by parvivirus following respiratory transmission and viremia.
Term
What are the symptoms of fifth disease?
Definition
malaise, fever, headache, chills, myalgia, maculopapular rash
Term
What is the three stage rash of fifth disease?
Definition
1)both cheecks "slapped face" 2) maculopapular on trunk and limbs 1-4 days post cheecks 3) periodic evanescence and recrudescence lasts 1-3 weeks
Term
What are examples of patients with RBC d/o's that often have complications with parvovirus infections?
Definition
d/o's with shoreter lifespan of RBCs: sickle cell, thalesemia, spherocytosis, disorders of hemoglobin expression
Term
What are the complications of immunocompromised individuals with parvovirus infections?
Definition
persistence in bone marrow, persistent anemia because of failure to clear virus, MIs, neurologic disorders
Term
What are complications of parvovirus infection of fetuses?
Definition
persistent anemia, hypoxic damage to heart and liver; edema; hydrops fetalis. Still birth if infection in first 20 weeks due to severe anemia
Term
How big is the poxvirus genome?
Definition
>200 kb
Term
What is the tropism of poxvirus?
Definition
respiratory epithelium to lymph nodes to skin
Term
What is the transmission of DNA viruses and disease?
Definition
respiratory/aerogenic transmission; skin contact with lesions
Term
What is the pathogenesis of pox viruses?
Definition
eruptions at skin (different than herpes varicella, all erupt at the same stage) due to route to reach skin; affects respiatory and intestinal tract mucosae
Term
What are the associated diseases of poxvirus?
Definition
small pox, molluscum contagiosum; monkey pox; accidental exposure generalized vaccinia
Term
How do you diagnose a pox virus?
Definition
histology, morphology
Term
What was the first virus to be visualized under a light microscope?
Definition
pox virus
Term
How big is the pox virus? is it ds or ss?
Definition
ds; 135 to 289 kpg in length
Term
How many ORFs are encoded by poxvirus?
Definition
136-260
Term
How many genes are conserved among poxviruses?
Definition
49 among all; 41 among orthopoxviruses
Term
Describe the genomic organizationo f poxvirus?
Definition
centrally located genes are most commonly conserved and encode genes essential for poxvirus replication and virion assembly. Terminally located genes are more variable and encode genes iwht regulating biological activity (e.g. host range restriction or immune evasion)
Term
What are the two infectious forms of poxvirus?
Definition
internal mature virus (exit via lysis) and external enveloped virus (acquire envelopes in the post-golgi machinery and exit via the cell membrane
Term
What two histological findings are indicative of poxvirus?
Definition
guarnieri bodies (b-type/basophilic inclusions), molluscum bodies (A type/acidophilic inclusions)
Term
What are guarnieri bodies?
Definition
B-type/basophilic inclusions formed by viral DNA and DNA replication machinery. In the cytoplasm. Associated with poxvirus
Term
What are molluscum bodies?
Definition
A type/acidophilic inclusions seen in the epidermis. A-type inclusions are accumulation of progeny virions and proteinaceous material
Term
What are the two antigenically indistinguishable strains of poxviruses?
Definition
variola major (CFR 5-40%0 and variola minor (CFR < 1%)
Term
What characteristics of smallpox allowed us to successfully eradicate it with a vaccine?
Definition
no subclinical infections. life-long immunity and virus clearance with resolution of disease (no carrier state). very narrow host range; no animal reservoir; availability of an effective vaccine
Term
What's the incubation of smallpox?
Definition
12 weeks
Term
What's the progressiono f the small pox rash?
Definition
mild rash, maculopapules, vesicles, pustules, scabs, scar
Term
How do you tell smallpox from varicella?
Definition
chickenpox is more concentrated on trunk and face and erupt at different times. Small pox is more concentrated on extremeties and face and all erupt at the same time.
Term
When was the first successful vaccination?
Definition
14 May 1796 cowpox virus by Edward Jenner
Term
What was the vaccine used to eradicate smallpox?
Definition
vaccinia virus; determined that vaccine strain was not or no longer CPV but a distinct poxvirus. (volved from variola by continual passage in skin of cows or humans, derived from CPV by continued repeated pasage in skin of animals, hybridization of CPV and variola virus; natural host is extinct)
Term
What is used as a gene delivery vector for smallpox innoculation? why?
Definition
fowlpox virus, an avipoxvirus, and modified vaccinia ankara strain. (b/c large capacity for insertion of exogenous DNA and no pre-existing immunity in mammalian hosts)
Term
What are the side effects of the small pox vaccine?
Definition
inadvertent innoculationof self (1:1700), gneralized vaccinia (1:5000), eczema vaccinatum, progressive vaccinia/vaccinia necrosum (only in immunosuppressed, can be fatal), encephalitis (1:200,000, fatal in 20%, neurologic problems in 25%), cardiovascular (increase in MIs)
Term
What is the treatment for vaccinia virus side effects?
Definition
vaccinia immune globulin from the CDC
Term
T/F many new vaccines are being created from a modified vaccinia.
Definition
true
Term
What is musculloscum contangiosum virus?
Definition
poxvirus that is a natural pathogen of humans
Term
Which population is susceptible to MCV?
Definition
children and HIV infected individuals
Term
How many strains of MCV are there?
Definition
4; MCV-1 is most prevalent; MCV-2 is seen mostly in adults and often transmitted by sexual contact
Term
How is MCV transmitted?
Definition
skin-to-skin contact or by contact with fomites, except on the palms of the hands and soles of the feet
Term
Which virus has the narrowest range of all poxviruses?
Definition
MCV only infects and replicates in the human epidermis
Term
What is the incubation of molluscum contagiosum?
Definition
2 weeks to 6 months (mean of 6 weeks)
Term
How long is the disease course of MC?
Definition
6-8 weeks but may last up to 2-3 months
Term
What reht the MCV lesions like?
Definition
flesh colored, dome-shaped, pearly, nonpainful but pruritic. Only cosmetic usually but scratching can lead to bleeding, secondary infections, scarring or autoinoculation of the skin or eyes
Term
How do you treat MCV?
Definition
ablation (cut, freeze, etc.)
Term
MCV is particularly prevalent in what patient population?
Definition
HIV patients
Term
What is the histology of MCV?
Definition
epithelium has a craterform indentation with inverted lobules of kartinocytes-cytoplasmic eosinophilic inclusions (molluscum bodies) are diagnostic
Term
T/F Removal of molluscum contagiosum virus can be accomplished by careful removal of the central core by expression with forceps.
Definition
true
Term
What is monkeypox virus?
Definition
zoonotic poxvirus causing disease similar to, but milder than, smallpox that also causes lymphadenopathy. generally presents as fever, rahs, respiratory symptoms and lymphadenopathy. First identified in monkeys but much more common in rodents
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