Semester 2 - Enveloped DNA Viruses

Question 1

What are characteristics of herpesvirueses?

Answer 1

Large dsDNA viruses, enveloped
Latency a hallmark feature
Replicate in the nucleus
No Non-human reservoirs for any human herpesvirues

Question 2

What is a tegument?

Answer 2

An amorphous layer between icosahedral capsid and lipid envelope of herpesvirueses

Question 3

What are the three stages of herpes infection?

Answer 3

Immediate-early: genes that regulate early and late gene expression
Early: Non-structural/regulatory genes (enzymes)
Late: Structural genes

Question 4

What is HHV1?

Answer 4

Herpes simplex type 1

Question 5

What is HHV2

Answer 5

Herpes simplex type 2

Question 6

What is HHV3?

Answer 6

Varicella Zoster Virus (VZV)

Question 7

What is HHV4?

Answer 7

Epstein Barr Virus (EBV)

Question 8

What is HHV5?

Answer 8

Cytomegalovirus (CMV/HCMV)

Question 9

What is HHV6/7?

Answer 9

Roseola Infantum

Question 10

What is HHV8?

Answer 10

Kaposi’s sarcoma Virus (KSV/KSHV)

Question 11

What are LATs?

Answer 11

Latency associated transcripts
Interfere with the function of viral proteins
Affect chromatin organization, preventing viral gene expression
miRNA against apoptosis-promoting genes

Question 12

What is reactivation from latency?

Answer 12

Typically occurs in the first few years following primary infection, but may occur anytime
Is associated with immune competency, stress

Question 13

What is shedding during latency?

Answer 13

Occurs at a higher level in the first few years following primary infection but may occur any time
Infection may be passed on in the absence of symptoms (WHY?)

Question 14

What are some characteristics of Herpes Simplex Type 1?

Answer 14

Oral cold sores (70%) accounts for 30% of genital herpes cases
Latent in trigeminal ganglion

Question 15

What does a herpes labialis infection look like?

Answer 15

Oral cold sores
Small fluid filled blisters, may occur in clumps
Broken blisters crust over, resolve in approx 2 weeks without treatment
Reccurent - reactivation from stress, immune compromise

Question 16

How is Herpes simplex 1 transmitted?

Answer 16

Contact, mucous, sexual

Question 17

What are the signs and symptoms of a herpes whitlow infection?

Answer 17

Occurs on tips of fingers/thumbs, more common in health care workers
Burning tingling of fingers
Fluid filled vesicles over erythematous base - fluid may be cloudy or bloody

Question 18

What is herpes keratitis/conjunctivits?

Answer 18

Inflammation of the cornea or conjunctiva of the eye
Redness, pain, swelling of the eye, itching and lesions
Typically infects one eye at a time

Question 19

What is Herpes encephalitis?

Answer 19

Most common cause of viral encephalitis. Follows an acute infection or reactivation
Headache, fever, fatigue, cognitive impairment, altered consciousness, confusion, disorientation, clumsiness
Complications - Seizure, memory loss, paralysis

Question 20

What are some characteristics of herpes simplex type 2?

Answer 20

Genital cold sores (70%) and accounts for 30% of oral herpes cases
Latent in sacral ganglion

Question 21

What is herpes genitalis?

Answer 21

Genital lesions - small fluid filled may crust over

Risk maternal transmission (congenital herpes)

Question 22

What are some characteristics of Varicella zoster virus?

Answer 22

Chicken pox (varicella)
Reactivation as shingles (zoster)
Latent in dorsal root ganglion

Question 23

What are signs and symptoms of chicken pox?

Answer 23

Small, itchy blisters/pustules, widespread rash
Fever
Complications: pneumonia, sepsis, joint/bone infections
Adults at greater risk for complications (Skin and soft tissue, septic arthritis, osteomyelitis, pneumonia)

Question 24

What are the signs and symptoms of shingles?

Answer 24

Asymmetric blisters/pustules
typically on the neck, trunk or leg
Radates from one dermatome (asymmetry)
Neuralgia, which may occur prior to blister appearance

Question 25

How is VZV transmitted?

Answer 25

Aerosol, contact

Question 26

What is the difference between chicken pox and shingles?

Answer 26

Chicken pox occurs after first exposure shingles is a reactivation of infection after latency Chicken pox may occur in children or adults, and is more severe in adults Shingles most often occurs in adults

Question 27

When is a VZV vaccine administered?

Answer 27

May be given prophylactically, or post-exposure to shorten the course of disease and reduce severity/complications

Question 28

What are some characteristics of the epstein barr virus?

Answer 28

Infectious mononucleosis Latent in B cells Occurs most commonly in teens/young adults

Question 29

What are the signs and symptoms of mono?

Answer 29

Fever, sore throat, extreme malaise, nausea Exudative pharyngitis, tonsillitis Lymphadenopathy, splenomegaly, hepatospenomegaly Arthritic symptoms sometimes present Mild, non-itchy rash may be present

Question 30

What are some complications of mono?

Answer 30

Risk of splenic rupture - patients should refrain from aggressive physical activity for several months following infection Risk of hemolytic anemia, infective cardiopathies (very rare)

Question 31

What are some long term complications of mono?

Answer 31

Burkitt's lymphoma | Nasopharyngeal carcinoma

Question 32

How is epstein barr virus transmitted?

Answer 32

Mucosal (saliva, sexual) | Shedding may occur in the absence of symptoms - easily transmissible

Question 33

Where is cytomegalovirus latent?

Answer 33

lymphocytes

Question 34

What are the signs and symptoms of a cytomegalovirus infection?

Answer 34

Most people seropostive with no symptoms Immunocompromised individuals - mono like illness Risk of passing to child during pregnancy: congenital CMV = developmental disabilities, hearing loss, low birth weight, jaundice, CNS abnormalities

Question 35

How is CMV transmitted?

Answer 35

Bodily fluids: saliva, urine, breastmilk, sexual contact

Question 36

What are the signs and symptoms of CMV mononucleosis?

Answer 36

Primary cause of seronegative mononucleosis cases | Fever/systemic symptoms predominate, while hepatosplenomegaly and lymphadeopathy less severe

Question 37

What are some CMV related diseases in immunocompromised individuals?

Answer 37

CMV colities - ulceration, pseudomembrane formation CNS infection - encephalitis CMV pneumonia CMV retinitis

Question 38

What are diseases that CMV is associated with?

Answer 38

Atherosclerosis, cardiopathies Guillan-Barre syndrome Autoimmune arthritis (SpA, ReA, PsA)

Question 39

What are some characteristics of HHV6 and HHV7

Answer 39

Roseola infantum (exanthema subitum): Three day fever, baby measles High seropositivity rate (60%) Latent in thymocytes

Question 40

What are the signs and symptoms of roseola infantum?

Answer 40

Sudden transient non-itchy rash in young children | Self-resolving lasts 3 days

Question 41

What are the signs and symptoms of roseola infantum in an immunocompromised individual?

Answer 41

Mono-like illness, fever, lymphadenopathy, encephalitis, post-transplantation complications (GVH) Associated with CNS diseases, autoimmune exacerbation, AIDS dementia, complex development

Question 42

What are some characteristics of Kaposi's Sarcoma Virus?

Answer 42

Latent in B cells Associated with HIV progression to AIDS Small tumors of the connective tissue lining blood vessels

Question 43

What are the signs and symptoms of Kaposi's Sarcoma virus?

Answer 43

Blue-red or purple macules/nodules localized to lower extremities, diffusing throughout the body Heterogeneity of dermatological morphologies Nodules may bleed easily Bloody sputum, SOB Progressive - ulceration of mucous membranes of the mouth, GIT, lymph nodes

Question 44

What are characteristics of Poxviruses?

Answer 44

Large dsDNA virus with a double membrane | Replicates in cytoplasm: encodes viral DNA-dependent RNA polymerase

Question 45

What are human pathogens of poxviruses?

Answer 45

Variola virus: smallpox Vaccinia virus: vaccination Zoonotic infections: cowpox, monkeypox

Question 46

How do poxviruses replicate?

Answer 46

Two uncoating steps Replication occurs in the cytoplasm: viruses encodes replication machinery Assembly/Maturation involves acquisition of two envelopes Golgi wrapping leads to IMV formation: can spread to neighboring cells Egress from cell membrane leads to EEV formation: can spread to any cell, can survive extracellularly.

Question 47

What are clinical features of smallpox?

Answer 47

High fever Deep set maculopapular rash with papules at the same stage of development Progress to fluid-filled blisters Leads to hemorrhagic disease, high mortality rate