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Herpesviridae - 1

Herpesviridae - Objectives. To review the members of the Herpesviridae familyTo understand the concepts of primary infection, latent infection and reactivation diseaseTo recognize the common clinical syndromes associated with each virus and the principles of management. . Herpesviridae Family. do

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Herpesviridae - 1

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    3. Herpesviridae Family double stranded DNA viruses with envelope ubiquitous, world-wide distribution 8 human herpesviruses recognized; species specific Latency - once infected, always infected - site varies with virus type: - HSV 1 & 2, VZV - sensory nerve ganglia - CMV, EBV, HHV6, HHV7 lymphocytes Replication occurs in the nucleus of infected cell Viral DNA remains episomal (i.e. not integrated into host cell DNA)

    5. Transmission & Seroepidemiology of Herpesviridae

    6. Herpesviridae Transmission: do not survive for prolonged periods in the environment requires inoculation of fresh virus-containing body fluid of infected person into susceptible tissue of uninfected person may be transmitted during primary or reactivation infections; often the person shedding virus is asymptomatic

    11. Epidemiology of HSV Infections Only 10-15% of HSV-2 primary infections are symptomatic 4 out of every 5 people with genital herpes have not been diagnosed; three out of five people have symptoms that are unrecognized as genital herpes Recurrent disease can be either symptomatic or asymptomatic

    12. Primary herpes, male

    13. Herpes, female

    14. Herpes cervicitis

    19. Recurrences of Genital HSV HSV-2 versus HSV-1 genital herpes rates Reactivates 49 days versus 310 days after primary 4.5 recurrences per year versus <1 HSV-2 recurrence rates vary widely across people: 26% women and 8% of men have none in first year 14% women and 26% men: >10 recurrences Recurrence rates trend down (frequency and severity) over the long term HSV-2 shedding: 5-32% of days (40% subclinical)

    20. HSV Complications CNS infections Perinatal/Congenital

    21. Herpes Simplex Virus: CNS Infections Encephalitis: temporal lobes are the principle target; hemorrhagic necrosis all ages, all seasons, both sexes sudden onset or after flu-like prodrome may be no signs of HSV elsewhere

    22. Herpes Simplex Encephalitis

    23. Herpes Simplex Virus: CNS Infections Encephalitis: MRI may detect earlier changes than CT untreated, rapid deterioration over few days with 60-80% mortality; 90% of survivors have significant neurological sequelae acyclovir treatment reduces mortality by 50%

    25. HSV Congenital/Perinatal Intrauterine infection: rare; follows 10 infection Perinatal infection: 75% are due to HSV 2; acquired during delivery many women unaware they are infected; 60 - 80% have no signs or symptoms of genital herpes at time of labour (asymptomatic shedders) HSV-1 acquired from maternal genital, oral or breast lesions, paternal or other family member, or nosocomial infection from other infected babies

    26. HSV Congenital/Perinatal Perinatal Infections: pregnancy is associated with state of immuno-suppression:?? shedding, ??reactivation, ?recurrences subclinical infection in neonates is uncommon not all infants of infected mothers will become infected; depends on 10 (30 50% risk) vs recurrent disease (1 3% risk)

    27. HSV Congenital/Perinatal Clinical manifestations of perinatal infection: disseminated CNS disease (49%) liver, lungs, eyes, CNS 80 - 85% mortality localized to CNS, skin, eyes, oral cavity (50%) 10 - 40% mortality asymptomatic infection (1%)

    28. HSV Congenital/Perinatal Treatment: Mother - acyclovir relatively contraindicated during pregnancy Neonate - acyclovir if mother has active lesions or prolonged membrane rupture Prevention: maternal history, surveillance if active lesions at time of delivery then C-section indicated

    29. Herpes Simplex Virus - Diagnosis History and physical examination Vesicle fluid: culture, EM, immunofluorescence, molecular (e.g. PCR) Serology difficult to distinguish HSV-1 and HSV-2; no reliable IgM test seroprevalence cannot distinguish 1 infection from recurrent disease ? Value of type-specific serology

    30. Immunoglobulin Response in HSV Infection

    31. HSV Serology Patients with Recurrent HSV Infection 65% only IgG 35% both IgG and IgM Patients with Primary Infection 18% -30% with both IgG and IgM antibodies

    32. HSV Type-specific Serology: Clinical Role?

    33. Why do we need to know who has HSV 2? A)To stop the epidemic spread of genital herpes. HSV is quickly and silently spreading at varying rates across Canada and not just in the high risk populations B)To permit high risk groups to be able to protect themselves better. HSV has been shown to increase the chance of acquiring HIV by two to three fold and accelerate the rate of HIV disease progression C)To identify women at risk of acquiring HSV in pregnancy endangering the baby. HSV is potentially fatal in infants if the mother is shedding virus at the time of delivery. D)To provide counseling HSV-2 infected patients can expect several outbreaks per year and are more likely to benefit from suppression therapy than HSV-1 patients E)To determine partner sero-status- 75% of source partners find out about their own infection only when their newly-infected partner is diagnosed

    34. When should we test for HSV 2? Symptomatic patients: Use to supplement virus detection tests when: Lesions are negative or not sampled for virus Recurring symptoms suggest atypical or undiagnosed herpes Lesions appear herpetic but may have other etiology High risk patients but not symptomatic: Patient has history of symptoms Patients partner has genital herpes Patient has a history of other STDs Patient is at risk of HIV infection Pregnancy: To screen for HSV-2 unrecognized infection To determine risk of acquiring infection To determine partners status for treatment and counseling

    37. HHV-6: Roseola Infantum

    38. Common Childhood Infections

    41. Cytomegalovirus (CMV) Transmission: 1) Sexual 2) Perinatal / Intrauterine 3) Blood / Blood product transfusion 4) Organ / tissue transplantation 5) Close contact most infections transmitted asymptomatically

    42. Cytomegalovirus (CMV) - Clinical Manifestations acute infection is usually asymptomatic or mild; may present as mono-like illness and / or hepatitis severe disease in: AIDS - 25% develop site or life - threatening disease - >90% infected at autopsy Transplants - 20 - 60% develop infection Neonates - CMV isolated in urine of 1:100 infants

    44. Cytomegalovirus (CMV) Diagnosis: Culture - slow growing, may take weeks for virus to grow Electron microscopy - morphology of herpes viruses Immunofluoresence techniques Serology - IgM for acute infection - IgG for past infection PCR, DNA hybridization

    45. Cytomegalovirus (CMV) Treatment: Immunocompetent patients: None Immunocompromised patients: Ganciclovir Foscarnet Prevention: No vaccine

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