7_Herpes Virus Flashcards
HHV strain and common name
HHV-7: Orphan virus
herpesvirus:
structure and & of viruses
- double strand DNA genome, eveloped virus w/ viral proteins
- over 120 viruses in this family
how are herpes viruses transmitted?
why?
Must be transmitted by close contact (resp/ sexually transmitted)
BECAUSE IT HAS AN ENVELOPE –> Unstable in the environment
what is the hallmark of a herpesvirus infection?
- establishment of lifelong, latent infxn;
- viral gene products that promote productive replication are not made
- cells harboring latent genome are poorly recognized by the immune system
- viral genome remains in tact
name and describe the diff’t patterns of infection
- Acute
- Perisistent - Smoldering
- Persistent - Latent
- Persistent - Slow
does reactivation of the infxn always correspond to symptoms?
no, there can be recurrence of virulence w/o infection;
some pts are asymptomatic
virus,
and corresponding primary infxn, site of latency, recurrent infxn, and route of transmission
HSV-1 and HSV-2
prevalence and common sxs;
latency?
recurrence?
Herpes Simplex Virus
HSV-1: COLD SORES; carried by 54% of US population
- latent in trigeminal ganglion
- recurs on lower lips/face
HSV-2: GENITAL HERPES; carried by 16% of the US population
- latent in sacral ganglion
- recurs in genital area
How does HSV-1 and HSV-2 affect the following sites in the body?
how is Herpes simplex virus transmitted?
- respiratory droplets
- contact
what triggers can cause reactivation of HSV infection from latency?
- trauma/ stress
- fever
- sunlight
- hormonal changes
4 key diseases caused by HSV-1
-
herpes labialis (fever blister or cold sore)
- crops of vesicles, usually around lip; recurrence often appears at same site
-
keratoconjunctivitis (corneal ulcers/lesions of the conjunctival epithelium)
- recurrences –> scarring or blindness
-
herpes gladiatorum (rash w/ clusters of sometimes painful, fluid-filled blisters, often on neck, chest, face, stomach, legs)
- transmitted by skin-skin contact; *one of most infectious herpes-caused disease
-
encephalitis (necrotic lesion of 1 temporal lobe)
- sxs: fever, HA, vomiting, seizure –>severe neurologic sequelae in survivors OR high mortality rate
- can be primary infxn or recurrent
What is one of the most infectious herpes-caused disease? Why?
Herpes Gladiatorum;
transmitted by skin-skin contact; *one of most infectious herpes-caused disease
characterized by rash w/ clusters of sometimes painful fluid-filled blisters
how is HSV-2 transmitted?
What is the process of infxn?
- transmission: sexual contact
- very commonly reactivated and asymptomatic
Two main diseases caused by HSV-2,
what characterizes these?
-
Genital herpes (painful lesions of M/F genital and anal areas)
- Primary disease (assoc. w/ fever &inguinal adneopathy) is more severe than recurrences
- Most infxns are asymptomatic
-
Neonatal herpes (milder local lesions of skin/eye/mouth –> severe disseminated lesions/ encephalitis)
- transmitted by contact w/ vesicular lesions w/in birth canal
- prevented by C-section (if mom has active lesion or positive viral cultures)
Which strain can cause severe neonatal infection acquired after birth?
Both HSV-1 and HSV-2 can cause severe neonatal infxn that are acquired after birth from carriers handling the child
Herpesvirus:
diagnosis and treatment
- Dx: laboratory diagnosis required
- isolation of virus from lesions by growth in cell culture –>
- ELISA allows distinction b/w HSV-1 and HSV-2
- PCR assay to detect HSV DNA
- Tx:
- No vaccine
- Antiviral drugs: Acyclovir, Valacyclovir, Famciclovier
Acyclovir:
how does this work?
acts as a purine nucleoside analog –> to inhibit viral DNA synthesis
Herpesvirus - Varicella Zoster virus
nomenclature,
diseases that result
- alphaherpesvirus: HHV-3, VZV
- diseases caused:
- Chicken pox
- Shingles
Varicella-zoster virus:
- epidemiology,
- at risk,
- prevention
- epidemiology
- ubiquitous
- no seasonal incidence
- risk factors
- children (5-9 y/o)
- teenagers/adults (more severe disease, possibly pneumonia)
- immunocompromised & neonates (fatal pneumonia, encephalitis, disseminated varicella)
- elderly immunocompromised (recurrent zoster)
- Live vaccine (Oka strain)
Varicella-Zoster virus:
manifestations/sxs
-
Varicella (chickenpox)
- vesicles on an erythematous base, caused by varicella-zoster virus
-
Shingles:
- vesicles along dermatome of thoracic nerve caused by varicella-zoster virus
Varicella-zoster:
transmission
- respiratory droplet
- contact
during which stages does Chickenpox manifest from the VZV virus?
- Primary viremia
during which phases does Shingles affect a patient?
Occurs during reactivation by ONE DERMATOME;
usually would only infect a patient once bc it would increase the immune response
name the different vaccines for Varicella-Zoster virus for the different age groups
- Varivax (12 mo & older)
- ProQuad (combined live-attenuated MMR-V, for children 1-12 yrs)
- Zostavax (herpes zoster vaccine approves for 50 y/o and older)
Epstein-barr virus:
nomenclature
diseases caused
- gammaherpesviruses: HHV-4, EBV
- disease:
- infectious mononucleosis
- assoc. w/ variety of lymphomas
Epstein-barr virus:
epidemiology;
patients at risk
- epidemiology:
- ubiquitous, no seasonal influence
- 90-95% of population WW is infected w/ EBV
- pts at risk:
- children (asymptomatic or mild)
- teens (infectious mononucleosis)
- immunocompromised (neoplastic disease)
- malaria (Burkitt’s lymphoma)
Epstein-barr virus:
transmission,
symptoms
- transmission:
- saliva (shared items, e.g. cup/toothbrush)
- blood
- semen
- sxs: (if sxs from EBV, usually resolve in 2-4 weeks)
- fever
- fatigue
- inflamed throat, swollen lymph in neck
- enlarged spleen
- swollen liver
- rash
what kinds of cancers can result from EBV virus in immunocompromised patients?
- lymphomas in immunosupressed patients (lymphoma: cancer that begins in infection-fighting cells of the immune system)
- burkitt’s lymphoma
- nasopharyngeal carcinoma
Epstein barr virus:
diagnosis and tx
- challenging to dx due to similar sxs to other illnesses
-
Laboratory tests
- VCA - viral capsid antigen
- EA - early antigen
- EBNA - EBV nuclear antigen
- Monospot test
- No vaccines nor antiviral drugs
Cytomegalovirus:
nomenclature
diseases caused
- betaherpesviruses: HHV-5, CMV
- diseases
- congenital defects
- opportunistic in immunocompromised patients
Cytomegalovirus:
epidemiology,
at risk populations
- epidemiology:
- ubiquitous, no seasonal incidence
- 50-80% of adults in USA are infected w/ CMV by time they are 40 y/o –> once infected, stays in the system for the rest of the life and can hide from immune system
- at risk populations (most healthy children/adults are asymptomatic and may not know they’re infected)
- babies whose mothers became infected during pregnancy
- immunocompromised (recurrent disease)
- sexual activity
- blood/transplant recipients
- burn victims
Cytomegalovirus:
transmission and sxs
- transmission:
- blood
- tissue
- body secretions (incl. breast milk & tears)
- CMV can be transmitted from a pregnant woman to her fetus during pregnancy
- symptoms:
In which patients can CMV cause severe disease?
what sxs does it cause?
Immunocompromised patients, such as:
- organ and bone marrow transplant recipients
- cancer patients
- pts receiving immunosuppressive drugs
- HIV patients
Sxs:
- fever
- pneumonia
- diarrhea
- ulcers in digestive tract –> possibly causing bleeding
- hepatitis
- inflammation of the brain (encephalitis)
- visual impairment & blindness
congenital CMV infection:
- define
- sxs at birth
- sxs - permanent
- epidemiology
- serious disease in babies affected by CMV before birth –> congenital CMV infxn
- sxs present at birth:
- premature birth
- jaundice (yellow skin/eyes)
- liver, lung, spleen problems
- small size at birth,
- small head size at birth
- seizure
- permanent sxs due to congenital CMV
- hearing and vision loss
- mental disability
- lack of coordination
- seizure
- 30-50% of childbearing-aged women have CMV –> affects 1-150 infants at birth –> 20% of which have permanent disabilities
cytomegalovirus:
- diagnosis in adults
- diagnosis in infants
- CMV testing
- treatment
- dx:
- CMV primary infxn - usually asymptomatic
- Primary CMV can be suspected in pts:
- w/ sxs of mononucleosis but negative EBV test
- w/ signs of hepatitis but negative HepA, B, and C
- dx in infants:
- presence of CMV infection in infants in urine, saliva, blood, or other tissue
- w/in 2-3 wks of birth
- CMV testing:
- serological test (IgM and IgG for CMV) - ELISA
- PCR for CMV DNA from urine, saliva, throat swab specimens or other tissues
- viral culture of CMV from urine, saliva, throat swab speciments, or other body tissues
- tx: antiviral tx for pts w/ depressed immunity who have sight-related or life-threatening illnesses due to CMV infxn
HHV-6
- nomenclature,
- disease caused / sxs
- epidemiology
- betaherpesviruses: HHV-6,
- two variants: HHV-6A, HHV-6B
- Roseola
- 90% of children are infected by age 2 (mostly HHV-6B)
- ubiquitous, no seasonal incidence
- Infants, young children, & immunocompromised individuals are at risk
HHV-6
- transmission,
- sxs
- transmission: saliva
- sxs
- eye redness
- irritability
- runny nose
- sore throat
- high fever (3-7 days)
- rash (pink or rose)
HHV-6
diagnosis and tx
- dx: serological test (IgM and IgG for HHV-6)
- tx
- no vaccines
- no formal tx: some use antiviral drugs (acyclovir, ganciclovir)
Kaposi’s sarcoma related virus:
- nomenclature,
- diseases caused
- epidemiology and at risk populations
- gammaherpesviruses: HHV-8, KSHV
- disease:
- Kaposi’s sarcoma
- Rare B-cell lymphoma
- epidemiology: 2-4% north europe, south asia; most in sub-saharan african countries (40%)
- at risk: immuocompromised pts
