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Common viral infections HERPES VIRUS INFECTIONS

Common viral infections HERPES VIRUS INFECTIONS. The objectives of this lecture: To know the clinically important HVs. To know the common characteristics of HVs. To know the common modes of transmission of different HVs

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Common viral infections HERPES VIRUS INFECTIONS

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  1. Common viral infectionsHERPES VIRUS INFECTIONS • The objectives of this lecture: • To know the clinically important HVs. • To know the common characteristics of HVs. • To know the common modes of transmission of different HVs • To know the clinical features of these infections, diagnostic methods and treatment.

  2. HERPES VIRUSES • Herpes Simplex Virus type1 (HSV-1) • Herpes Simplex Virus type2 (HSV-2) • Varicella Zoster Virus (VZV) • Cytomegalovirus (CMV) • Epstein-Barr Virus (EBV) • Human Herpes Virus 6 (HHS-6) • Human Herpes Virus 7 (HHS-7) • Human Herpes Virus 8 (HHS-8)

  3. Characteristics: DNA viruses Encapsulated Latency after the initial infection Mostly require close contact for transmission Human beings are the only reservoir HERPES VIRUSES

  4. HERPES VIRUSESStructure

  5. HERPES VIRUSES

  6. HERPES VIRUSES • HSV-1 vs HSV-2 Non-genital vs Genital Herpes infection Primary vs Recurrent infections Neonatal infection

  7. HERPES VIRUSES • Transmission by close contact with body secretions • Exposure to HSV at mucosal surfaces or abraded skin sites permits entry of the virus and initiation of replication in epidermis anddermis • After initial infection the virus infects the sensory and autonomic nerves and become dormant in the ganglion (trigeminal nerve for HSV1 and sacral root for HSV2)

  8. HSV Gingivostomatitis Gingivostomatitis and pharyngitis are the most frequent clinical manifestations of first-episode HSV-1 infection

  9. Herpes Labialis Recurrent herpes labialis is the most frequent clinical manifestation of reactivation HSV infection

  10. NON-GENITAL HSV

  11. Genital HSV Herpetic ulceration of the vulva Penile herpes simplex (HSV-2) infection

  12. Diagnosis of HSV • Clinical picture • Viral culture • Cytology • PCR

  13. HSV TREATMENT • Acyclovir 200 mg five times daily. • Famciclovir 250 mg 8-hourly. • Valaciclovir 500 mg 12-hourly. • The treatment is usually for 5 days

  14. VARICELLA ZOSTER VIRUS • Primary infection • Chickenpox • Recurrent infection • Herpes zoster

  15. VARICELLA ZOSTER VIRUS The virus is spread by the respiratory route and replicates in the nasopharynx or upper respiratory tract. Followed by localized replication at an undefined site, which leads to seeding of the reticuloendothelial system and, ultimately, viremia. The virus establishes latency within the dorsal root ganglia.

  16. CHICKENPOX Overall, chickenpox is a disease of childhood, because 90% of cases occur in children younger than 13 years of age.

  17. VARICELLA ZOSTER Reactivation of VZV leads to VZ

  18. VARICELLA ZOTER

  19. VARICELLA ZOTER

  20. VZV treatment • Acyclovir • Valacyclovir • Famciclovir Prevention VZV vaccination VZV immunoglobulin (VZIG)

  21. Cytomegalovirus (CMV) • The largest virus that infects human being • World wide distribution • Latency after primary infection • Infection ranges from asymptomatic to severe multisystem disease

  22. CMVSeroepidemiology

  23. Cytomegalovirus (CMV) Primary infection • Asymptomatic • Infectious mononucleosis Secondary infections in immunocompromised patients: • Pneumonitis • Retinitis • GI such as colitis • Multisystem involvement

  24. CMV Retinitis

  25. Cytomegalovirus (CMV) Diagnosis: Diagnosis almost always depends on laboratory confirmation and cannot be made on clinical grounds alone. • Viral cultures from blood ,urine ,tissue • Serologic tests (antigen detection) • PCR

  26. Cytomegalovirus (CMV) TREATMENT: • ganciclovir • foscarnet • cidofovir

  27. Epstein-Barr Virus (EBV) • Ubiquitous human herpes virus. • By adulthood 90 to 95% of most populations arepositive. • Spread occurs by intimate contact between susceptible individuals and asymptomatic shedders of EBV. • Mostly causes asymptomatic infections. • Strong association with African Burkitt's lymphoma and Nasopharyngeal carcinoma.

  28. Epstein-Barr Virus (EBV) Infectious mononucleosis Clinical: • Fever, Sore throat ,Lymphadenopathy Hematologic: • >50% mononuclear cells • >10% atypical lymphocytes Serologic: • Transient appearance of heterophile antibodies • Permanent emergence of antibodies to EBV

  29. Epstein-Barr Virus (EBV) Diagnosis: • Heterophile Antibodies are present in about 90% • Hematologic Findings: • Lymphocytosis, neutropenia , thrombocytopenia • EBV specific antibodies

  30. EBV InfectionAtypical Lymphocytes

  31. EBV InfectionAtypical Lymphocytes

  32. EBV Infection

  33. Epstein-Barr Virus (EBV) Treatment: Treatment of infectious mononucleosis is largely supportive because more than 95% of the patients recover uneventfully without specific therapy Corticosteroids

  34. Suggested readings; • Davidson’s Principles and Practice of Medicine 20th edition • Kumar & Clark's clinical medicine 7th edition

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