Viruses: DNA Viruses Flashcards
List the DNA viruses
- Herpes simplex virus 1
- Herpes simplex virus 2
- Epstein-Barr Virus
- Cytomegalovirus
- Varicella-zoster virus
- HHV-6
- Roseola
- HHV-8
- Kaposi’s Sarcoma
- JC polyomavirus
- BK polyomavirus
- Human papillomavirus
- Parvovirus
- Adenovirus
- Smallpox virus
- Cowpox virus
- Molluscum
- contagisum virus
- Hepatitis B virus
herpes simplex virus type 1 & 2
- DNA viruses
- Herpesviridae family
- enveloped
- double stranded DNA
- Linear DNA
Cowdry bodies
Cowdry bodies are eosinophilic intranuclear inclusions that can be found in cells infected with HSV (as well as CMV and VZV)
HSV-1 and HSV-2 can be transmitted
vertically
HSV-1 and HSV-2 are
TORCHeS infection
the initial outbreak of HSV-1 often presents as
gingivostomatitis (vesicular lesions and ulcerations of the oral cavity and perioral area)
herpes labialis (or cold sores) presents
on the lips and is typically caused by HSV-1
keratoconjunctivitis caused by HSV (typically type 1) presents with
serpiginous corneal ulcers seen on fluorescein slit lamp exam
HSV (typically type 1) can cause
hemorrhagic temporal lobe encephalitis
HSV-1 is the number one cause of
sporadic encephalitis in the US
HSV (typically type 1) lies dormant in
trigeminal ganglia
HSV lesions have
a “dew drop on a rose petal” appearance
herpetic whitlow
is caused by HSV and is characterized by painful lesions on one or more fingers (herpetic whitlow is more common in dentists)
erythema multiforme
erythema multiforme is a hypersensitivity reaction associated with certain infections (such as HSV) that presents with small target lesions on the back of the hands and feet and move centrally
painful inguinal lymphadenopathy is associated with
HSV (typically type 2)
HSV (typically type 2) lies dormant in the
sacral ganglia
HSV (typically type 2) can lead to
aseptic meningitis in both adolescents and adults
a Tzanck smear can be used to visualize
multinucleated giant cells infected with HSV, which aids in diagnosis
_____ can be used to prevent HSV breakouts
valacyclovir or acyclovir
Epstein-Barr virus
a DNA virus in the Herpesviridae family
Epstein-Barr virus is primarily transmitted through
saliva
_____ is one of the classic features of Epstein-Barr virus-induced mononucleosis
- fever
2. painful lymphadenopathy in the posterior cervical region
Epstein-Barr virus infection causes
peripheral lymphocytosis and the presence of atypical lymphocytes (abnormally large reactive CD8+ T-cells with abundant cytoplasm) and Downey cells (atypical lymphocytes with strongly basophilic cytoplasm pathognomonic of EBV infection)
T-cell proliferation in response to Epstein-Barr virus infection can result in
splenomegaly and enlarged lymph nodes (splenomegaly is one of the classic features of EBV-induced mononucleosis)
Epstein-Barr virus remains latent in
B-Cells
to initiate infection, the Epstein-Barr virus
envelope glycoprotein binds to the CD21 membrane protein of B-cells
pharyngitis with production of tonsillar exudate is a common feature of
Epstein-Barr virus-induced mononucleosis
patients with Epstein-Barr virus infections who are mistakenly treated with penicillin or amoxicillin (due to suspicion of streptococcal pharyngitis) can develop a
maculopapular rash
Epstein-Barr virus infection is associated with a higher risk for development of
- some cancers, including Hodgkin’s and non-Hodgkin’s lymphoma and Burkitt lymphoma (B-cell cancers)
- nasopharyngeal carcinoma, which is more commonly seen in patients with Asian ancestry
- oral hairy leukoplakia, which occurs most commonly in HIV patients
Epstein-Barr virus infection may be associated with the development of
Hodgkin’s lymphoma, which is characterized by Reed-Sternberg cells (classically described as having an “owl eye” appearance)
African (or endemic) Burkitt lymphoma (sometimes associated with Epstein-Barr virus infection) often presents with
a large jaw lesion and jaw swelling
the monospot test
can be useful to rapidly diagnose acute Epstein-Barr virus infection; the monospot test utilizes horse or sheep RBCs, which will agglutinate when mixed with patient serum due to production of anti-horse/sheep blood IgM antibodies induced by the presence of Epstein-Barr virus
patients with infectious mononucleosis should avoid
contact sports due to risk of splenic rupture
Cytomegalovirus
a DNA virus in the Herpesviridae family
Cytomegalovirus can remain latent in
- mononuclear white blood cells (i.e. lymphocytes, monocytes, and macrophages)
- B-Cells and T-Cells
Cytomegalovirus can reactivate and
cause disease, most commonly in immunosuppressed patients
Cytomegalovirus can be transmitted
vertically and is a TORCHeS infection (Cytomegalovirus is the “C” in “TORCHeS”)
congenital cytomegalovirus infection can present with
- a characteristic “blueberry muffin” rash
- jaundice
- Hepatosplenomgealy
congenital cytomegalovirus infection is a cause of
bilateral or unilateral sensorineural hearing loss
congenital cytomegalovirus infection can result in structural abnormalities in the brain, including
- ventriculomegaly
2. intracranial (predominantly periventricular) calcifications
the changes in brain structure caused by congenital cytomegalovirus infection can lead to
developmental delay and/or seizures
80-90% of newborns with congenital cytomegalovirus infection are
asymptomatic
intrauterine Cytomegalovirus infection can result in
hydrops fetalis, which is characterized by fluid accumulation in multiple compartments of the fetus
Cytomegalovirus is the number one cause of
sensorineural hearing loss in children and the number one congenital viral infection
Cytomegalovirus is associated with
organ transplantation
transplant patients are at risk for developing
Cytomegalovirus pneumonia (as well as other CMV infections, including hepatitis, gastritis and colitis, and encephalitis)
immunocompromised patients (i.e. HIV patients) are at a higher risk for
Cytomegalovirus infection
patients with a CD4+ count <50 are at an especially high risk for
Cytomegalovirus infection and should be given antivirals prophylactically
a common manifestation of Cytomegalovirus infection in AIDS patients is
CMV retinitis, which is sometimes described as “pizza pie” retinopathy
Cytomegalovirus is a common cause of
HIV-associated esophagitis and is likely to present with singular, deep, and linear esophageal ulcerations
Cytomegalovirus colitis is likely to present with
ulcerations on the walls of the colon
“owl’s eye” inclusions can be seen upon microscopic examination of
Cytomegalovirus infected cells
Cytomegalovirus lines with the UL97 gene mutation require treatment with
foscarnet (the UL97 gene mutation confers resistance to ganciclovir)
Cytomegalovirus infection often presents with
sore throat, lymphadenopathy, and fatigue (symptoms are similar to those seen in EBV infection)
a monospot test can be performed to
differentiate Cytomegalovirus from EBV infection; the monospot test in Cytomegalovirus infection will be negative
_______ is effective against Cytomegalovirus strains without the UL97 gene mutation
gangciclovir
varicella-zoster virus
- a DNA virus in the Herpesviridae family
2. enveloped
varicella-zoster virus causes
chickenpox (a pruritic rash with small, fluid-filled blisters)
chickenpox may present with
fever (often before development of lesions)
headache is a common symptom of
chickenpox
varicella-zoster virus is transmitted via
respiratory droplets
the vesicular lesions caused by varicella-zoster virus are classically described as
“dew drops on a rose petal”
the vesicular lesions of chickenpox are typically found in
various stages of development and healing
__________ can be used to visualize multinucleated giant cells infected with varicella-zoster virus, which aids in diagnosis
a Tzanck smear
patients who contract varicella-zoster virus in adulthood have a higher likelihood of developing
pnuemonia
a major complication of varicella-zoster virus infection is
encephalitis
immunocompromised patients are at a higher risk of developing
varicella pneumonia or encephalitis
the vaccine for varicella-zoster virus is a
live attenuated vaccine typically administered in childhood
________ is effective against varicella-zoster virus infection in children ages 12+, adults, and immunocompromised patients
acyclovir
varicella-zoster virus remains latent in
dorsal root ganglia
reactivation of varicella-zoster virus occurs with
stress, aging, or immunosuppression
the reactivated form of varicella-zoster virus is called
shingles (or herpes zoster); shingles more commonly affects the elderly or immunocompromised
shingles (or herpes zoster) presents with a
“dew drop on a rose petal” appearing rash within a dermatomal distribution
shingles (or herpes zoster) is typically
extremely painful
postherpetic neuralgia is a complication of
shingles, which presents as burning pain in the nerve fibers and skin long after the shingles rash has cleared
herpes zoster ophthalmicus develops when
varicella-zoster virus reactivates in V1 (the ophthalmic division of the trigeminal nerve), and can lead to vision loss
the live attenuated varicella-zoster vaccine is recommended for adults over
60
HIV patients with a CD4+ count of >200 may receive the
varicella-zoster vaccine
________ is effective against varicella-zoster shingles infection
- famciclovir
2. valacyclovir
varicella-zoster virus can be transmitted
vertically and is a TORCHeS infection (varicella-zoster virus falls in the “other” category of “TORCHeS”)
congenital varicella syndrome
can develop if varicella-zoster virus is contracted during the first two trimesters of pregnancy and can result in cutaneous dermatomal scarring, blindness, and limb hypoplasia
HHV-6
a DNA virus in the Herpesviridae family
roseola
roseola (also known as sixth disease or exanthem subitum) is caused by HHV-6
HHV-6 infects
CD4+ helper T-cells, which can lead to immunosuppression
HHV-6 is a
DNA virus in the Herpesviridae family
roseola is characterized by
a fever generally lasting 4 days
children with roseola can develop
febrile seizures
roseola can present with
a diffuse, lacy body rash that spares the face (the rash typically presents after fever has subsided)
roseola affects children ages
6 months to 2 years and is usually self-limiting
HHV-8
a DNA virus in the Herpesviridae family
HHV-8 is a DNA virus in the Herpesviridae family and causes
Kaposi sarcoma
Kaposi sarcoma
(caused by HHV-8) is an AIDS-defining illness
Kaposi sarcoma is characterized by
violaceous lesions on the nose, extremities, and mucous membranes
Kaposi sarcoma causes
vascular proliferation
HHV-8 dysregulates
vascular endothelial growth factor (VEGF), leading to aberrant angiogenesis
Kaposi sarcoma lesions can be found within
the GI tract
Kaposi sarcoma lesions most commonly occur on
the hard palate
HHV-8 can infect
B-cells, which may result in primary effusion lymphoma (a B-cell lymphoma)
HHV-8 is endemic to
areas of Africa
Kaposi sarcoma lesions
Kaposi sarcoma lesions have a similar appearance to bacillary angiomatosis (caused by Bartonella henselae) and differentiation requires microscopic examination of tissue (Kaposi sarcoma lesions have lymphocytic infiltrate)
Polyomaviruses include
- JC Virus
2. BK virus
Polyomaviruses are
- circular, double-stranded DNA viruses
2. naked viruses
JC virus
(or John Cunningham virus) (a DNA virus in the Polyomaviridae family)
the JC virus can cause
progressive multifocal leukoencephalopathy
JC virus more commonly affects
immunocompromised patients and is known to reactivate in HIV or immunosuppressed states
JC virus affects (or can reactivate in) HIV patients with a
CD4+ count <200
JC virus has a
higher incidence of infection in HIV patients
progressive multifocal leukoencephalopathy (caused by JC virus) is characterized by
non-enhancing multifocal brain lesions in white matter
progressive multifocal leukoencephalopathy (caused by JC virus) is a
demyelinating disease
BK virus
a DNA virus in the Polyomaviridae family
BK virus infection can lead to
nephropathy (typically following organ transplantation and immunosuppression, when a latent infection reactivates)
BK virus infection can cause
hemorrhagic cystitis in immunocompromised patients
BK virus nephropathy typically occurs following
organ transplantation (particularly kidney and bone marrow transplants)
human papillomavirus
- a DNA virus in the Papillomaviridae family
2. naked virus
HPV serotypes 1-4
DNA viruses in the Papillomaviridae family associated with verruca vulgaris
common cutaneous warts (caused by HPV serotypes 1-4) often appear on
the hands and feet of children
transmission of cutaneous common warts (caused by HPV serotypes 1-4) requires
physical contact
HPV serotypes 6 and 11
DNA viruses in the Papillomaviridae family associated with laryngeal papillomatosis and anogenital warts
HPV serotypes 6 and 11 can cause
- laryngeal papillomatosis
2. anogenital warts (condyloma acuminata), which are sexually transmitted
condyloma acuminata (anogenital warts) are most frequently caused by
HPV serotypes 6 and 11
HPV serotype 16
a DNA virus in the Papillomaviridae family associated with cancer
HPV serotype 18
a DNA virus in the Papillomaviridae family associated with cancer
HPV serotypes 16, 18, 31, and 33 are known to cause
many anogenital and squamous cell cancers (including cervical, vulvar, vaginal, penile, and anal carcinomas)
HPV is primarily transmitted via
sexual contact
HPV can cause
squamous cell carcinoma, which often manifests in the anogenital region
Gardasil
Gardasil (an inactivated subunit vaccine) provides protection against HPV serotypes 6, 11, 16, and 18
Gardasil covers
HPV serotypes 6, 11, 16, and 18 (but not 1-4)
the p53 tumor suppressor protein
(which can inhibit progression from the G1 to S phase during mitosis) is destroyed by HPV’s E6 protein, leading to unchecked cell replication
the p53 tumor suppressor protein is a
checkpoint protein that can inhibit progression from the G1 to S phase during mitosis
the Rb tumor suppressor protein
(which can inhibit progression from the G1 to S phase during mitosis) is destroyed by HPV’s E7 protein, leading to unchecked cell replication
Pap smears
detect early signs of cervical cancer caused by HPV
koilocytes
(HPV-infected cells from the transformation zone) undergo morphological changes that cause cells to appear large and dense with a wrinkled nucleus (often binucleated)
HIV infection may enhance the expression of
HPV proteins E6 and E7
immunosuppression is a risk factor for the development of
cervical cancer caused by HPV
parvovirus B19
- a DNA virus in the Parvoviridae family
- naked virus
- smallest DNA virus
- single stranded DNA virus
parvovirus B19 is transmitted via
respiratory droplets
parvovirus B19 can be transmitted
vertically and is a TORCHeS infection (parvovirus falls in the “other” category of “TORCHeS”)
parvovirus B19 causes
- slapped cheek syndrome (also called fifth disease or erythema infectiosum)
- arthralgias, arthritis, and generalized edema in adults
- transient aplastic crisis in sickle cell patients
the rash caused by parvovirus B19 starts on the
face and spreads inferiorly
hydrops fetalis can occur with
fetal parvovirus B19 infection
adenovirus
- a DNA virus in the Adenoviridae family
2. naked virus
adenovirus is the most common cause of infection in the
adenoids and tonsils
adenovirus infection can cause
- tonsillitis
- hemorrhagic cystitis
- viral conjunctivitis (pink eye)
adenovirus can be transmitted via
- respiratory droplets
2. fecal orally
_______ are commonly affected by adenovirus
children
adenovirus is often spread via
public swimming pools
outbreaks of adenovirus are known to occur in
military barracks
military recruits may be administered a live vaccine to prevent
adenovirus infection
the adenovirus vaccine is a
live vaccine
poxviruses include
- smallpox
- cowpox
- molluscum contagiosum
poxviruses
- DNA viruses
- make their own envelope
- encode their own DNA-dependent RNA polymerase, which allows them to replicate in the cytoplasm of host cells
- replicate outside of the nucleus
- have a dumbbell shaped core
- largest known DNA viruses
Guarnieri bodies (inclusion bodies) are the sites of poxvirus (i.e. smallpox virus, Cowpox virus, Molluscum contagiosum virus)
replication in the cytoplasm of host cells
smallpox virus
smallpox virus (or Variola virus, a DNA virus in the Poxviridae family)
smallpox virus lesions
smallpox virus lesions develop at the same rate, which helps distinguish them from varicella (or chickenpox) virus lesions
Cowpox virus
a DNA virus in the Poxviridae family
cowpox is contracted via
contact with infected cow udders
Molluscum contagiosum virus
a DNA virus in the Poxviridae family
the poxvirus family includes the Molluscum contagiosum virus, which causesincludes
flesh-colored, dome-shaped, umbilicated skin lesions
molluscum contagiosum presents with
umbilicated lesions on the trunk in children
adults with diffuse molloscum contagiousum lesions suggests
immunosuppression (i.e. HIV patients)
Hepatitis B virus
- a DNA virus in the Hepadnaviridae family
- enveloped virus
- partially double stranded DNA virus
Hepatitis B virus is a cause of
hepatitis
Hepatitis B virus undergoes
both intranuclear and cytoplasmic replication
the reverse transcriptase of Hepatitis B virus is
an RNA-dependent DNA polymerase, which converts RNA to DNA
Hepatitis B virus is transmitted via
- sexual contact and blood products (IV drug use, needlesticks, or transfusions)
- vertically during delivery from mixing of maternal and fetal blood
hepatitis B is considered a
TORCHeS infection (Hepatitis B virus falls in the “other” category of “TORCHeS”)
90% of neonatal Hepatitis B virus infections progress to
chronic infections
10% of Hepatitis B virus infections among adults progress to
chronic infections
Hepatitis B virus infection can lead to
- polyarteritis nodosa (PAN), a form of chronic vasculitis
- arthralgias
- chronic kidney disease
- cirrhosis
Hepatitis B virus infection can present with
rash
Hepatitis B virus infection is associated with
- membranous glomerulopathy
2. membranoproliferative glomerulonephritis
ALT and Hep B
ALT rises during an acute Hepatitis B virus infection and falls when the symptomatic phase is over; in viral hepatitis, ALT>AST
ALT levels are often ______ in neonatal hepatitis B
normal
HBsAg
HBsAg (hepatitis B surface antigen) is the first serological marker of an active Hepatitis B virus infection
HBeAg
(hepatitis B envelope antigen) is an indicator of active viral replication and is a sign of high infectivity
during the symptomatic phase of Hepatitis B virus infection, patients will be positive for
HBsAg and HBeAg (hepatitis B surface and envelope antigens)
anti-HBc IgM
anti-HBc IgM (hepatitis B core antibodies) is the first detectable antibody, which may be the only detectable serological marker during the window period (when hepatitis B viral antigens (HBsAG and HBeAg) are no longer present and subsequent antibodies have yet to develop)
the presence of anti-HBe (hepatitis B envelope antibodies) is indicative of
low transmissibility
the presence of anti-HBs (hepatitis B surface antibodies) is indicative of
recovery from infection or previous immunization
patients who have received the hepatitis B vaccine will test positive for
patients who have received the hepatitis B vaccine will test positive for anti-HBs (surface antibodies), and negative for anti-HBc and anti-HBe (hepatitis B core and envelope antibodies)
Hepatitis B virus infection is a risk factor for
hepatocellular carcinoma
hepatitis D virus
- a negative-sense RNA virus that propagates only in the presence of Hepatitis B virus
- enveloped
- circular single stranded RNA virus
hepatitis D virus requires
HBsAg (hepatitis B surface antigen) to be infectious
co-infection occurs when both hepatitis D virus and Hepatitis B virus are transmitted
simultaneously
superinfection occurs when
superinfection occurs when hepatitis D virus infection is contracted by a patient with preexisting chronic hepatitis B
Hepatitis B virus and hepatitis D virus superinfection is associated with
a worse prognosis
_______ is effective against Hepatitis B virus
- iamivudine
- NRTIs
- interferon alpha
NRTIs
NRTIs (nucleoside reverse transcriptase inhibitors) are effective against Hepatitis B virus
at risk infants should be given hepatitis B immune globulin (HBIG) along with
passive vaccination