1/30 Nguyen Microbiology and Immunology Concepts II Flashcards
Herpesviruses are part of what family?
Herpesviridae
What viruses are part of herpesviridae?
- HSV 1 and 2
- Varicella-zoster virus
- Epstein-Barr virus
- Cytomegalovirus
- Human herpesviruses 6, 7, 8
Herpesviridae: three subfamilies
- alpha herpesviruses
- beta herpesviruses
- gamma herpesviruses
Alpha herpes viruses
- HSV 1 and 2
- Varicella zoster virus
Varicella zoster virus is also known as:
Human herpesvirus 3
Gamma herpes viruses
- Epstein-Barr virus
- Kaposi’s sarcoma-related virus
Epstein-Barr virus is also known as:
human herpesvirus 4
Kaposi’s sarcoma-related virus is also known as:
Human herpesvirus 8
Beta herpes viruses
- Cytomegalovirus
- Human herpes virus 6 and 7
Cytomegalovirus is also known as:
Human herpesvirus 5
Herpesviruses structure
- Enveloped
- icosahedral (equilateral triangles)
- large dsDNA
Herpesviruses encode:
Viral DNA polymerase
as opposed to host dna polymerase
All herpesviruses are _____ following initial primary infection
Latent
Herpesviruses are mostly ____, but problematic for ____ patients
Benign; immunocompromised (HIV/AIDS)
HSV-1 and HSV-2 spread by _____
Contact
HSV-1 and HSV-2 shed in:
Secretions (saliva, tears, genitals)
How long are HSV-1 and 2 shed in secretions?
For years after primary infection
HSV-1 and HSV-2 can be spread by ____ but are most contagious during ____
Asymptomatic transmission; outbreak
True or false: antibodies towards HSV-1 and HSV-2 are generally protective
False - can get infected over and over
Majority of HSV-1 infections are _____; a proportion are ____
Oral-facial herpes; genital-anal
HSV-2 is almost exclusively _____ transmitted
Sexually
True or false: HSV-2 infection is lifelong and incurable
True
____ is the most common infection in people living with HIV
HSV-2
Those with HIV and HSV-2 coinfection have:
- more severe clinical presentation
- more frequent recurrences
Some herpesviruses may recombine within genome, such as:
- Varicella zoster
- Herpes simplex (HSV)
- CMV (Cytomegalovirus)
Number of isomeric forms of VZV
2
Number of isomeric forms of HSV-1 and HSV-2
4
Number of isomeric forms of CMV
4
HSV vaccine: ____ approved yet
None
HSV RNA-based vaccines are being tested to:
Prevent viral attachment to host cells
HSV-1 site of viral latency
Trigeminal ganglia
HSV-1 and HSV-2 establish latency in:
Innervating sensory neuron
HSV-2 site of viral latency
Sacral ganglia
HSV infection - triggers for recurrence
- stress
- fever
- infection
- menstruation
- sunlight (UVB)
HSV can spread during:
Recurrence
viral replication in neuron, recurrent lesions in same location
HSV-1 recurrence %
45%
HSV-2 recurrence
60%
HSV clinical manifestations
- acute gingivostomatitis
- herpes labialis (cold sore)
- herpes genitalis
HSV-1 and 2 can both cause _____ infections
Oral and genital
What is acute gingivostomatitis?
- Inflamed oral mucosa and gingiva
- causes gingival pain and bleeding
Most common manifestation of primary herpetic infection (age 1-3 years)
acute gingivostomatitis
HSV-1 can have a co-infection with:
Candidiasis
Primary herpetic gingivitis may cause a risk of ____ because it is painful to drink
Dehydration
_____ can occur as a form of oral-facial herpes and can be very severe in children
Peri-oral herpes simplex
After the primary infection, oral-facial herpes is mostly:
Asymptomatic
Most common recurrent form of HSV-1 disease
Herpes labialis (cold sore, blisters, or ulcers)
Herpes labialis can be found on:
- vermillion border/edge of lips
- gingiva
- hard and soft palate
Herpes gladiatorum is also known as:
Mat herpes
Herpes gladiatorum is nearly always:
HSV-1
Cutaneous herpes can be caused by:
HSV-1 and HSV-2
Cutaneous herpes can occur:
Anywhere on the skin
What is herpetic whitlow?
Herpes lesions on fingernail; common from bare-handed dentistry
Cutaneous herpes recurrence tracks back to:
Nerve
True or false: you can autoinnoculate yourself in other parts of your body with cutaneous herpes
True
Patients with eczema or atopic dermatitis can develop:
Eczema herpeticum
HSV vesicles superimposed upon dermatitis
_____ most common cause of corneal blindness in the US
Ocular HSV-1
___ is associated with ocular herpes
Dendritic ulcer (scars when healing)
Herpes keratitis
HSV-1 infection of the eye due to autoinnoculation
Herpes keratitis is commonly limited to:
One eye
Genital herpes symptoms
Painful, burning, vestibular ulcers (1-8mm)
Herpes can spread to other areas and cause other infections such as:
- meningitis
- encephalitis
- neonatal (perinatal infection)
True or false: Herpes meningitis is usually benign and mostly self-limiting
True
Herpes encephalitis has a ____ mortality
High
Herpes encephalitis is usually caused by:
HSV-1
Herpes meningitis is usually caused by:
HSV-2 (more than HSV-1)
Herpes encephalitis treatment
Acyclovir IV
Perinatal infection, caused by HSV ____, can cause:
HSV-2; dissemination, encephalitis, and high mortality in the newborn
HSV laboratory diagnosis methods
- immunofluorescence microscopy (IFM)
- Tzanck preparation (herpes skin test/smear)
- PCR
Gold standard for herpes lab diagnosis
PCR
HSV treatment
- Multiple forms of acyclovir (topical, oral, IV, ointment)
- Valacyclovir (HSV-2)
Valacyclovir is used to treat _____. It is a derivative of ____. Its function is to ____
Genital herpes; Acyclovir; shorten infection severity, length, and shedding
Guanosine components
Guanine with ribose
Acyclovir is _____ nucleoside analog
Guanosine
Acyclovir treatment: mechanism of action
- ACV inert unless HSV is present
- HSV produces thymidine kinase to add a phosphate to ACV
- host completes phosphorylation to make active form of acyclovir (ACV-triphosphate)
- viral DNA incorporates ACV-TP
- ACV-TP competes, inhibits, inactivated HSV-specified DNA polymerase
- terminates viral DNA synthesis
HSV can also be treated with laser treatment in order to:
Stimulate ATP synthesis to increase cellular energy levels and promote tissue repair
True or false: HSV laser treatment can be done in a dental office
True
Varicella Zoster virus can establish:
Latent infection
Varicella causes:
Chicken pox
VZV spreads via:
Respiratory routes
VZV stages of infection
- primary infection in mucosa of respiratory tract
- secondary viremia (lesions may cover entire body)
- latency in neurons, recurrence
VZV chickenpox is spread through ____ and _____ contagious
Respiratory; highly
VZV causes a maculopapular rash which show up as:
Successive crops (varying stages)
Varying stages of chickenpox
- papule
- blister
- ulcer
- scabbing
True or false: chickenpox can be intraoral
True
VZV establishes latency in:
Cerebral or posterior root ganglia
VZV is ____ severe in older adults
More
VZV diagnosis - cytopathology
- Syncytia (giant, multinucleated cells)
- intranuclear inclusions
VZV clinical diagnosis
Several stages of rash at one time (papule, vesicle, pustule, scab)
Chickenpox is usually located on:
Torso
What are Shingles?
Recurrence of latent varicella
Symptom of latent varicella
- post herpetic neuralgia
- intense lasting pain
- pain worse in older patients
Latent varicella usually affects:
Single dermatome, does not cross midline
DOC for latent varicella
- Acyclovir
- Valacyclovir
Varicella vaccine is _____. It is administered in the ____ vaccine for _____
- live & attenuated
- part pf MMRV vaccine
- children 4-6 years old
Epstein Barr virus site of latency
B cell
Kaposi’s sarcoma-related virus site of latency
B cell
Cytomegalovirus site of latency
Monocyte, lymphocyte
Myeloid cells
Human herpesvirus 6/7 site of latency
T cells
EBV structure
- enveloped
- icosahedral
- dsDNA
EBV is transmitted mainly by:
Saliva (toothbrush, eating utensils, blood, semen)
EBV latency occurs in _____ and are reactivated by ____ to become active again
B cells; Th2 cells (Th2 response)
EBV associated diseases
- Infectious mononucleosis (mono)
- nasopharyngeal carcinoma
- lymphoma (Burkitt’s lymphoma)
- Hodgkin’s lymphoma
- gastric adenocarcinoma
EBV sheds in saliva, so it is termed the:
“Kissing disease” or “mono”
Infectious mononucleosis can lead to:
- lymphadenopathy (swollen glands)
- exudative pharyngitis (tonsillar membrane)
- palatal petechiae (soft palate)
HIV/AIDS patients who acquire EBV can get:
Hairy leukoplakia
True or false: hairy leukoplakia can rub off like candidiasis
False - cannot be rubbed off (differs from candidiasis)
____ can cause Burkitt’s lymphoma
EBV
What is Burkitt’s lymphoma?
Monoclonal B-cell tumor
Burkitt’s lymphoma is endemic in:
Malarial regions of Africa
Burkitt’s lymphoma involves chromosomal ____ which has sporadic occurrence in ____ patients
Translocations; HIV/AIDS
_____ can be a co-factor in Burkitt’s lymphoma
Malaria (co-infection with EBV)
What is Hodgkin’s lymphoma?
Cancer of lymphocytes; lymph node cancer
Hodgkin’s lymphoma is mostly attributed to ____ infection
EBV
EBV causes 2 types of lymphatic cancer:
- non-Hodgkin’s lymphoma
- Hodgkin’s lymphoma
Diagnosis of Hodgkin’s lymphoma involves identifying presence of:
Reed-Sternberg cells
What are Reed-Sternberg cells?
Multi-nucleated, bilobular malignant B-cell
Hodgkin’s lymphoma can affect _____ patients
Transplant and HIV/AIDS
Why are transplant patients more prone to developing Hodgkin’s lymphoma with EBV infection?
They are on immunosuppression therapy; infection of B cells
EBV can infect _____ to cause nasopharyngeal carcinoma
oropharyngeal and nasopharyngeal epithelia
Nasopharyngeal carcinoma is endemic in:
Southern China
EBV may activate genes that can affect risks for developing:
Autoimmune diseases
more research needed for links between other conditions
EBV clinical diagnosis
- Self-limiting
- splenomegaly (enlarged spleen)
EBV treatment
Supportive therapy
EBV laboratory diagnosis
- lab tests usually unnecessary
- can look for atypical lymphocytes (Downey cell)
- serology
What is Kaposi’s sarcoma?
- lymph or blood vessels cancer
- cancer then causes skin or mucosal tumors usually on mouth/palate
Kaposi’s sarcoma can be found in what locations?
Usually mouth and palate, also trachea
Kaposi’s sarcoma tumors can be:
Flat or raised
Kaposi’s sarcoma is caused by ____ which infects and establishes latency in _____
Kaposi’s sarcoma-associated herpesvirus (KSHV); B-cells
Phases of infection by Kaposi’s sarcoma-associated herpesvirus
Latent and lytic/productive phases
What happens during the lytic/productive phase of KSHV infection?
MHC Class I downregulation on the surface of infected cells
_____ immortalizes cells
KSHV (latent and lytic phase promotes cell cycle and growth, prevents apoptosis)
Kaposi’s sarcoma has characteristic ____ disease in HIV/AIDS patients
Opportunistic
True or false: CMV is a common human pathogen, infection 70-90% of people
True
CMV infection is usually:
Asymptomatic
CMV is transmitted via:
Secretions
CMV is an important opportunistic pathogens in:
Immunocompromised patients (HIV/AIDS, transplants, Pneumonia)
CMV forms nuclear and cytoplasmic inclusion bodies, such as:
- CMV Owl’s eye
- Marginated chromatin
- enlarged cell (cytomegaly)
CMV diagnosis
PCR
____ is the most common viral cause of congenital defects
CMV
Congenital defects associated with CMV
Loss of hearing, microencephaly
CMV DOC
Ganciclovir
HHV-6 and HHV-7 are:
genetically related
HHV-6-and HHV-7 are part of the ____ subfamily
Roseolovirus
“Roseola infantum”
“Exanthem subitum”
Symptoms of HHV-6 and 7
Fever and rash in infants for 1-5 days