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Herpesviridae By: Dr.Malak El-Hazmi Assistant Professor & Consultant Virologist College of Medicine & KKUH
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Herpesviridae 1-Herpes simplex type -1 HSV-1 1-Herpes simplex virus type -1 HSV-1 2-Herpes simplex virus type -2 HSV-2 3-Varicella –Zoster virus VZV 4-Epstein- Barr virus EBV 5-Cytomegalovirus CMV 6-Human herpes virus type-6 HHV-6 7-Human herpes virus type-7 HHV-7 8-Human herpes virus type-8 HHV-8
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HERPESVIRVS dsDNA, Enveloped, Icosahedral Virus
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Features of herpesviruses All herpesviruses are structurally identical Replicate in nucleus Intranuclear inclusions Envelope from nuclear mb Latent infection Cause high morbidity and mortality in immuno ed patients Some herpesviruses Associated with cancers e.g. EBV & HHV8 Herpesviridae
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Short, cytolytic Muco- Neurons Simplex 1 Herpes simplex virus-1 Short, cytolytic Muco- Neurons Simplex 1 Herpes simplex virus-1 Alpha epithelial Alpha epithelial 2 Herpes simplex virus-2 2 Herpes simplex virus-2 Varicello 3 Varicella-zoster virus Varicello 3 Varicella-zoster virus Long, cytomegalic Epithelial cells ? Cytomegalo 5 Cytomegalovirus Long, cytomegalic Epithelial cells ? Cytomegalo 5 Cytomegalovirus Beta M,L cells Beta M,L cells Long, lympho- lympho- Lymphoid Roseolo 6 Human herpesvirus-6 Long, lympho- lympho- Lymphoid Roseolo 6 Human herpesvirus-6 proliferative cytes tissue proliferative cytes tissue 7 Human herpesvirus-7 7 Human herpesvirus-7 Variable, lympho Epithelial Lymphoid Lymphocrypto 4 Epstein-Barr virus Variable, lympho Epithelial Lymphoid Lymphocrypto 4 Epstein-Barr virus Gamma proliferative lympho- tissue Gamma proliferative lympho- tissue cytes Rhadino 8 Kaposi’s sarcoma- cytes Rhadino 8 Kaposi’s sarcoma- associated herpesvirus associated herpesvirus ? = monocytes,leucocytes,kidney& gland ? = monocytes,leucocytes,kidney& gland Subfamily Growth Cycle & Target Latency Genus Official Name (“-virinae”) Cytopathology cell (‘virus”) (“Human Common herpesvirus”) Name Biologic Properties Examples Classification of Human Herpesviruses
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HERPES SIMPLEX VIRUS HSV Location of lesions
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Pathogenesis HSV-1 becomes latent in trigeminal g HSV-1 becomes latent in trigeminal g HSV-2 becomes latent in lumber & sacral g Typical Lesion Immunity Not Completed
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Transmission Direct contact with lesions & Contaminated secretions SalivaSexual contact during birth [perinatal] AgeChildren Adolescent & adults Source Herpetic lesions Asymptomatic shedding EpidemiologyHSV1 HSV2
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Asymptomatic Diseases of HSV-1 Oral infections 1ْGingivostomatitis / herpetic stomatitis Pharyngitis / tonsillitis Herpes labialis (cold sores) – R HSV-1 Infections
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Keratoconjunctivitis : Keratitis R dendritic ulcer R may cause blindness Diseases of HSV-1 Herpetic whitlow: 1 o & R Toddlers Nurses & dentists
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1. 1.Oral infections Gingivostomatitis / herpetic stomatitis Pharyngitis / tonsillitis Herpes labialis (cold sores( – R 2. 2.Herpetic whitlow : 1 o & R Nurses & dentists Toddlers 3. 3.Keratoconjunctivitis: Keratitis dendritic ulcer may cause blindness 4. 4.Encephalitis 5. 5.Disseminated disease Immuno ed patients 1 o or R Diseases of HSV -1 RR
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Genital herpes: STD 1 o or R Neonatal herpes Aseptic meningitis Diseases of HSV2
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Comparison of Diseases Caused by HSV-1 and HSV-2 SiteDisease Caused By HSV-1Disease Caused by HSV-2 SkinVesicular lesions above the waist Vesicular lesions below the waist (especially genitals) MouthGingivostomatitisRare EyeKeratoconjunctivitisRare Central nervous systemEncephalitis (temporal lobe)Meningitis NeonateRareSkin lesions and disseminated infection Dissemination to viscera in immunocompromised patients YesRare
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Clinically Lab Dx. A. A.Direct ex: 1. 1.Vesicular fluid for E/M & virus isolation 2. 2.Cells scraping from the base of vesicles ImmunoFluorescent test (Ag)** Tzanck smear (Giemsa stain) 3. 3.CSF for DNA-HSV by PCR in HE B. B.Serological test: 1. 1.IgM AB* 2. 2.≥ 4 fold increase in AB titers b/t acute & convalescent sera. Diagnosis HSV
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Acyclovir Severe diseases Systemic diseases Immuno ed patients Foscarnet Acyclovir resistant strains of HSV Prevention Avoid contact with herpetic lesions & its secretions Gloves & hand washing C/S for pregnant lady with infected birth canal Sex education No vaccine Treatment HSV
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Varicella : Chickenpox: 1 o illness Generalized vesicular rash Zoster: Shingles: Recurrent form Localized VR Varicella - Zoster Virus VZV
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Varicella Children Late winter & early spring highly infectious disease (communicable) Epidemic Respiratory droplets Direct & Indirect contact TransplacentalZoster Adults & immuno ed host No seasonal distribution Sporadic Rarely May give V in s-host Rarely Age Incidence Transmission VZV
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Pathogenesis VZV remains latent in trigeminal ganglia, or in dorsal root ganglia. Immunity : to Varicella, not to zoster VZV
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IP = 2 -3 wks Vesicular rash Starts on trunk, spread to face & limbs Appears in successive waves Healing without scarring Mild in children, Severe in adults & immuno ed patients Varicella Complications Secondary bacterial infection of skin lesions Reye’s syndrome Pneumonia Encephalitis VZV
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Severe disease in pregnant women e.g. pneumonia Intrauterine infections Congenital varicella syndrome Neonatal varicella < 7 days of delivery severe disease > 7 days before delivery mild disease Varicella in Pregnancy VZV
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A localized unilateral VR & pain Thoracic zoster R dorsal root g Ophthalmic zoster R trigeminal g Ramsay-Hunt syndrome rare Post-herpetic neuralgia Dissemination of zoster in immuno ed patients zoster VZV
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Clinically Lab Dx. A. A.Direct ex: 1. 1.Vesicular fluid for E/M & virus isolation 2. 2.Cells scraping from the base of vesicles ImmunoFluorescent test (Ag)** Tzanck smear (Giemsa stain) 3. 3.CSF for DNA-VZV by PCR in encephalitis B. B.Serological test: 1. 1.IgM AB* 2. 2.≥ 4 fold increase in AB titers b/t acute & convalescent sera. Diagnosis VZV
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Indications Neonates Immuno ed patients Adults with moderate to severe disease Patients with complications Ophthalmic zoster Antiviral drugs: Acyclovir Valacyclovir Famicilovir A acyclovir resistant strains of VZVFoscarnet Treatment: VZV
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Infection control practice Live -attenuated Varicella vaccine Two doses Immunocompetent children & Adults VZIG Immuno ed patient & non-immune pregnant & neonate born to mother who acquired varicella around delivery <4 days after exposure Prevention VZV
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HHV-4, gammaherpesvirinae Special features It is lymphotropic It has oncogenic properties Its antigenic composition Epstein – Barr Virus EBV
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Distribution :worldwide Transmission: Saliva [kissing disease] Blood [rarely] Age: Socio-economic status: SE Low SE class early childhood High SE classadolescence Epidemiology EBV
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Asymptomatic Infectious mononucleosis [glandular fever] Mainly in teenagers & young adults IP = 4-7 weeks Fever, pharyngitis, malaise, LAP, hepatosplenomegaly & abnormal LFT Rash may follow ampicillin Last 2- 3 weeks Complications ( acute air way obstruction, splenic rupture, CNS inf) Chronic EBV infection Clinical Features: Immunocompetent host Immunocompetent host EBV
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Lymphoproliferative disease ( LD) Patients with decrease CMI Transplant recipients PTLD Oral hairy leukoplakia (OHL) Non-malignant lesion HIV-infectedpatients immuno ed patients Clinical Features : Immunocompromised host Immunocompromised host EBV
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Burkitt’s lymphoma A tumor of lymphoid tissue African children Malaria can act as a cofactor Nasopharyngeal carcinoma A tumor of epithelial origin Adults China EBV – Associated Malignancies EBV
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Hematology: WBC lymphocytosis Atypical lymphocytes Diagnosis : EBV
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Serology: Non-specific AB test Heterophile Abs +ve Paul-Bunnell or mono-spot test EBV-specific AB test: IgM Abs to EBVirus capsid antigen Serology is not reliable in immuno ed patients EBV Ags & EBV-DNA in lymphoid & other tissues Diagnosis : EBV
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Treatment: Antiviral drug is not effective in IMN Acyclovir is used in treating OHL Prevention : No vaccine Management : EBV
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Betaherpesvirinae – HHV-5 Special features Its replication cycle is longer Infected cell enlarged with multinucleated [cyto=cell, megalo=big] Resistant to acyclovir Latent in monocyte & lymphocyte & other Cytomegalovirus CMV
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Distribution: worldwide Transmission Early in life: Transplacenta Birth canal Breast milk Young children: saliva Later in life: sexual contact Blood transfusion & organ transplant Epidemiology CMV
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Immunocompetent host Asymptomatic Self-limited illness Hepatitis Infectious mononucleosis like syndrome [Heterophile AB is –ve] Immunocompromised host 1 o or R Pneumonia, Hepatitis, Encephalitis Retinitis, Esophagitis, Colitis Acquired Infection CMV
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Congenital Infections: Clinically normal 15% Hearing defect mental retardation 4% Cytomegalic inclusion disease 1% death CMV
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Lab. Diagnosis Histology : Intranuclear inclusion bodies [Owl’s –eye] CMV
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Lab. Diagnosis Culture: Culture: In human fibroblast 1-4 wks CPE Shell Vial Assay 1-3 days Serology: Serology: ABIgM: 1 or R inf. IgG: previous exposure AgCMV pp65 Ag by IFA PCR PCR CMV
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Treatment Ganciclovir is effective in the Rx of severe CMV inf. is effective in the Rx of severe CMV inf. e.g. CMV retinitis, pneumonia Foscarnet : the 2nd drug of choice CMV
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Prevention: Screening organ donorsorgan donors Organ recipientsOrgan recipients Blood donorsBlood donors Leukocyte-depleted blood Chemoprophylaxis: Ganciclovir Immunoprophylaxis: CMVIG No vaccine CMV
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Betaherpesvirinae Latent infection in lymphoid tissue Transmitted by saliva Most infections are asymptomatic Human Herpes Virus Type 6
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Exanthem subitum = Roseola infantum Fever followed by maculopapular rash on the trunk &neck Young children Mononucleosis with cervical LAP Adults Reactivation may occur in immuno ed patients Disease HHV6
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Human Herpes Virus Type 7 It is closely related to HHV6 Roseola Infantum Diseases remain to be established
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Human Herpes Virus Type 8 Gammaherpesvirinae Kaposi’s sarcoma Transmitted by Sexual contact (mainly) Saliva (possible) Organ transplants
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