1. Herpesviruses Topics: large, enveloped ds DNA viruses. HHV1-8: major pathogens include HSV-1 & 2, VZV, CMV, EBV Cause productive & latent infections. Latent infections ensure survival in population and resistance to immune and drug pressure. Diseases: HSV-1 & 2: genital herpes, encephalitis, keratitis VZV: chicken pox, shingles CMV: congenital infections, retinitis, infectious mononucleosis EBV: infectious mononucleosis, Burkitt’s lymphoma HHV8 (KSHV): Kaposi’s Sarcoma HHV6: roseola

4. Herpesvirus latency Human Herpesviruses Acronym Name Site of latency HSV-1Herpes simplex virus 1 sensory neurons HSV-2 Herpes simplex virus 2 sensory neurons VZV Varicella-Zoster virus sensory neurons CMV Human cytomegalovirus monocytes, endothelial cells HHV-6A T cells, monocytes HHV-6B T cells, monocytes HHV-7 T cells EBV Epstein Barr Virus B lymphocytes HHV-8(Kaposi’s sarcoma Monocytes ? associated virus)

5. Herpes Simplex Replication: Alternative life styles In epithelial cells: lytic infection All the bells & whistles: ~84 genes including DNA polymerase Exquisitely timed gene expression Cell lysis In some neurons: latent infection Only 1 RNA is expressed (LAT). Immune implication: virus cannot be recognized Drug implication: target enzymes are not expressed Under stress conditions: reactivation in neurons leads to reinitiation of lytic cycle

6. Intraneuronal transport of virus

7. Natural history of herpes simplex virus 1 Establishment of latency Retrograde transport Disseminated infection of newborn Adult encephalitis No manifestations or.. Anterograde transport Reactivation Recurrent keratitis

8. Clinical Manifestations of Herpes Simplex Infections

9. 700,000 new genital HSV-1 & HSV-2 infections 20-30 million people with recurrent genital lesions caused by HSV 40,000 caesarian deliveries justified by fear of transmission of HSV to newborn. 1: 1200 infants acquire HSV-2 or HSV-1 at birth. 5,000+ cases of adult HSV encephalitis 500,000 episodes of herpes keratitis Severe disease in immunocompromized individuals. The Annual US Toll Cost: >10 billion per year

10. Antiviral drugs: All anti HSV drugs currently licensed are dependent on being activated by viral enzymes. Effective in treating actively replicating virus, but not latent virus that does not express the viral enzymes.

11. DNA ACG-TP ACG-DP ACG-MP Viral Thymidine kinase Wide substrate range ACG Inhibits polymerase; DNA terminator DNA GCG-TP GCG-DP GCG-MP Viral protein kinase GCG Anti-HSV drugs Anti-CMV drugs Inhibits polymerase Activation of acyclovir (ACG) and gancyclovir (GCG) by viral enzymes

12. Varicella Zoster Virus

13. Infection of respiratory mucosa Viral infection of regional nodes Primary viremia: viral replication in liver and spleen. Incubation period Varicella zoster infection Secondary viremia: mononucleated cells transport virus to skin and mucous membranes. Virus release into respiratory secretions Replication in epidermal cells, colonization of dorsal root ganglia VZV specific immunity, resolution of infection Acute phase Varicella = chicken pox

14. Varicella Fatality Rate in Healthy Persons *Deaths per 100,000 cases *Rate per 100,000 population. National Health Interview Survey data Varicella Age-Specific Incidence United States, 1990- 1994 *Infections per 1000 cases Infection common early in life, risks greater when infected later

15. NATURAL HISTORY OF ZOSTER IN THE NORMAL HOST Acute neuritis may precede rash by 48 - 72 hours. Maculopapular eruption, followed by clusters of vesicles Unilateral dermatomal distribution Events of healing: - Cessation of new vesical formation:3 - 5 days - Total pustulation: 4 - 6 days - Total scabbing: 7 - 10 days - Complete healing may require 2 - 4 weeks Cutaneous dissemination can occur: visceral dissemination is extremely rare Postherpetic neuralgia (cranial nerve pain) in 10% - 40% of cases zoster = “belt” = shingles

16. Mucocutan Manifest Viral Dis; Tyler, Stephen; pg 129 Varicella-Zoster Virus Clinical Manifestations A B C A - Bilateral herpes zoster in an AIDS patient B - Herpes zoster in a pregnant woman with AIDS C - Scarring from herpes zoster D- Herpes Zoster Opthalmicus (trigeminal ganglion) D

17. Varicella Vaccine CompositionLive virus CompositionLive virus Efficacy95% Efficacy95% Duration of >7 years Immunity Duration of >7 years Immunity Schedule1 Dose (<13 years of age) May be administered simultaneously with measles, Schedule1 Dose (<13 years of age) May be administered simultaneously with measles, mumps, and rubella (MMR) vaccine

18. Cytomegalovirus CMV-induced chorioretinitis in an HIV-infected patient Mucocutan Manifest Viral Dis; Tyler, Stephen; pg 183 “Large cell virus”

19. Cytomegalovirus Epidemiology Present in all human populations Present in all human populations No non-human vectors (human CMV) No non-human vectors (human CMV) Acquisition occurs at an earlier age in underdeveloped countries (62-95% prior to adolescence) Acquisition occurs at an earlier age in underdeveloped countries (62-95% prior to adolescence) Transmission requires direct contact Transmission requires direct contact Group-care and increased breast feeding have increased infection in younger children in developed countries Group-care and increased breast feeding have increased infection in younger children in developed countries Most common cause of congenital infection in the U.S. Most common cause of congenital infection in the U.S.

20. CMV Infection in Pregnancy N Engl J Med 1985;313:270-74 10% develop normally 90% develop sequelae 10-15% infected infants may have clinically apparent disease (mild to severe) 5-15% develop sequelae 85-95% develop normally 85-90% infected infants are asymptomatic 40% Transmission to Fetus Primary Maternal CMV Infection

21. Symptomatic Congenital CMV Clinical Findings At Birth Abnormality% Petechiae(purple spots)76 Jaundice67 Hepatosplenomegaly60 Neurologic abnormality68 Microcephaly (small head)53 Pediatr Infect Dis J 1992;11:93-9

22. Symptomatic Congenital CMV Laboratory Abnormalities Test% Increased ALT (liver damage)83 Decreased Platelets 53 Hyperbilirubinemia (jaundice) > 2 mg/dl81 > 4 mg/dl69 Pediatr Infect Dis J 1992;11:93-9 Treatment: gancyclovir

23. CMV in Immunocompromised hosts HIV, transplants (esp. bone marrow), chemotherapy, etc. A number of susceptible organs: Eye (retinitis) Lung (pneumonia 15-75% mortality) GI Brain (Seizures, encephalitis) Liver -recommend gancyclovir + CMV Ig prophylaxis for bone marrow transplant Gancyclovir & forscarnet control infection & disease progression to varying degrees dependent on immune status and target organ

24. Epstein-Barr Virus Infects human oropharyngeal and salivary cells (lytic infection) and human and primate B lymphocytes (latent infection) Infects human oropharyngeal and salivary cells (lytic infection) and human and primate B lymphocytes (latent infection) Cells latently infected with EBV grow continuously and contain circular genome plasmid Cells latently infected with EBV grow continuously and contain circular genome plasmid Acquisition occurs at an earlier age in underdeveloped countries Acquisition occurs at an earlier age in underdeveloped countries Adolescent seroprevalence: Adolescent seroprevalence: Undeveloped: >90% Undeveloped: >90% Developed:40-50% Developed:40-50%

25. Epstein-Barr Virus Pathogenesis Infection of B cells Infection of B cells –Up to 20% are infected –Immortalization of B cells Atypical lymphocytes--cytotoxic suppressor T lymphocytes Atypical lymphocytes--cytotoxic suppressor T lymphocytes –Kill infected B cells Wright stain

26. Epstein-Barr Virus Clinical Manifestations - Acute Asymptomatic (frequency inversely related to age) Asymptomatic (frequency inversely related to age) Infectious Mononucleosis, esp. age 15-25 Infectious Mononucleosis, esp. age 15-25 “kissing disease” “kissing disease” Neurologic Neurologic –Nerve palsy, esp. Bell’s palsy –Guillian-Barré Syndrome (acute auto-immune demyelination) –Meningoencephalitis –Transverse myelitis (spinal cord demelination) Thrombocytopenia purpura (low patelets) Thrombocytopenia purpura (low patelets)

27. Time after exposure Clinical manifestations Laboratory analyses Other notes 3-7 wk 3-5 day prodromal period of fatigue, malaise, and headache Screening with heterophile antibody test (negative in 10% of patients) Infection in younger children is often asymptomatic or causes a mild, nonspecific febrile illness 3½ - 7½ wk Classical triad of fever, pharyngitis, and tender lymphadenopathy (80% of cases). A variety of mucocutaneous manifestations may occur in a minority of patients Definitive diagnosis by specific EBV serologies - Pharyngitis typically consists of moderate to severe sore throat with tonsillar enlargement and occasional exudate. Tonsillar crypt abscessess are not uncommon - Lymphadenopathy most often involves the posterior cervical nodes, followed in frequency by the anterior cervical and submandibular nodes. Axillary and inguinal lymphadenopathy may also occur 5 ½ - 10 ½ wk Resolution of illness after 2-3 wk. Fatigue and malaise may last longer. Chronic mononucleosis is extremely rare Splenomegaly and hepatomegaly may be present Clinical Manifestations of Infectious Mononucleosis

28. IHMF Herpes Vol 3 Number 2 Oct 96 Heterophile antibody: non-specific agglutination of non-human red blood cells EBV us. Het Ab+ (90% of time) CMV Het Ab- EBV Mono Diagnosis Cont. Tonsilitis

29. Mucocutan Manifest Viral Dis; Tyler, Stephen; pg 152 Characteristic EBV-specific antibody responses observed in young adults with acute infectious mononucleosis Seroconversion in Infectious Mononucleosis

30. IM treatment Mucocutan Manifest Viral Dis; Tyler, Stephen; pg 150 A B A, B – Macular eruption in a patient with infectious mononucleosis who had taken ampicillin - don’t treat with antibiotics! acetominophen, non-steroidal anti-inflammatory drugs NOT aspirin (risk for Reye’s syndrome) Acyclovir ineffective No penicillin, unless co-infection with Strep (see below)

31. Epstein-Barr Virus Clinical Manifestations - Malignancies Burkitt’s Lymphoma Burkitt’s Lymphoma Nasopharyngeal carcinoma Nasopharyngeal carcinoma Hodgkin’s disease (some are EBV- associated) Hodgkin’s disease (some are EBV- associated)

32. Mucocutan Manifest Viral Dis; Tyler, Stephen; pg 155 Epstein-Barr Virus African Burkitt’s lymphoma with marked cervical lymphadenopahty

33. Human Herpesvirus 6 Primary infection common in first year of life; peaks in second 6 months of life Primary infection common in first year of life; peaks in second 6 months of life Fever, then transient rash Fever, then transient rash Major cause of febrile illness in infants 6-18 months of age; 20% of ER visits for this age group Major cause of febrile illness in infants 6-18 months of age; 20% of ER visits for this age group Most adults are HHV-6 seropositive (76-90%) Most adults are HHV-6 seropositive (76-90%) Roseola

34. Human Herpesvirus 8 HHV-8 = Kaposi’s sarcoma - associated herpesvirus (KSHV) HHV-8 = Kaposi’s sarcoma - associated herpesvirus (KSHV) –gamma herpesvirus HHV-8 is implicated as the etiologic agent of: HHV-8 is implicated as the etiologic agent of: –Kaposi’s sarcoma (HIV+/HIV-) (found in 95%) –Monoclonal B cell lymphomas in HIV

35. Kaposi’s Sarcoma and Transplantation IHMF: Herpes 7:1 2000

36. Human Herpesvirus 8 Mucocutan Manifest Viral Dis; Tyler, Stephen; pg 224 Classic Kaposi’s sarcoma lesions most often affect the lower legs and feet as seen in this elderly man

37. Human Herpesvirus 8 Human Herpesvirus 8 Epidemiology PopulationSeropositivity Rate US Children2-8% US Adults25% US HIV+ IVDU23% US HIV+ women21% US HIV+ homosexual men90% US HIV+ /KS+96% African endemic KS100%

38. Human Herpesvirus 8 Human Herpesvirus 8 Treatment Pre-tumor: gancyclovir somewhat effective Post-tumor: Surgery, irraditation, chemotherapy HAART therapy of HIV patients limits KS

39. 10,000BC - Likely emerged 10,000BC - Likely emerged 1500BC - Certain evidence 1500BC - Certain evidence 500’s - Smallpox enters Europe 500’s - Smallpox enters Europe Late 500’s - “Variola” coined by Bishop Marius of Avenches, from Latin “varius” or “varus” Late 500’s - “Variola” coined by Bishop Marius of Avenches, from Latin “varius” or “varus” Late 1400’s - writers distinguish small pox (variola) from great pox (syphillis) Late 1400’s - writers distinguish small pox (variola) from great pox (syphillis) Ramses V Smallpox

40. Smallpox 1520’s - Cortes brings Smallpox to Americas (Tenochtitlan. Aztec capitol, site of modern Mexico City) 1520’s - Cortes brings Smallpox to Americas (Tenochtitlan. Aztec capitol, site of modern Mexico City) Within a year, ~25% of Tenochtitlan died, including the emperor. Cortes takes Tenochtitlan. Within a year, ~25% of Tenochtitlan died, including the emperor. Cortes takes Tenochtitlan. Smallpox kills 3.5 million Aztecs Smallpox kills 3.5 million Aztecs Early 1500’s - smallpox epidemic in Incan empire from unclear source Early 1500’s - smallpox epidemic in Incan empire from unclear source Within several years - chain of command decimated, along with ~67% of population Within several years - chain of command decimated, along with ~67% of population Late 1700’s - smallpox accounts for ~400,000 deaths per year in Europe Late 1700’s - smallpox accounts for ~400,000 deaths per year in Europe

41. Smallpox vaccine Early 1700’s - Variolation: inoculating with variolar scabs/puss Early 1700’s - Variolation: inoculating with variolar scabs/puss Variolation-induced fatality was 1/10th of natural acquisition Variolation-induced fatality was 1/10th of natural acquisition 1790’s - Edward Jenner notices dairymaids appear immune 1790’s - Edward Jenner notices dairymaids appear immune Jenner theorizes that emulating variolation, but with cowpox (cow = vaccinus, thus “vaccination”) would be safer and effective Jenner theorizes that emulating variolation, but with cowpox (cow = vaccinus, thus “vaccination”) would be safer and effective Almost died due to variolation in 1756

42. To test this theory, Jenner takes his gardener’s healthy 8-year-old son, James Phipps, and gives him cowpox To test this theory, Jenner takes his gardener’s healthy 8-year-old son, James Phipps, and gives him cowpox Phipps recovers in 6 weeks, as expected Phipps recovers in 6 weeks, as expected Before the FDA… With fingers crossed, Jenner injects Phipps with smallpox Phipps remains asymptomatic Smallpox eradicated in 1980

43. Poxvirus Replication -cytoplasmic life cycle unique for DNA viruses.

44. Complications of Vaccination Eczema vaccinatum Eczema vaccinatum Necrosis, patients have a congenital defect in cell-mediated immunity Necrosis, patients have a congenital defect in cell-mediated immunity Generalized vaccinia Generalized vaccinia Ocular vaccinia Ocular vaccinia AB CD

45. Smallpox Causative agent Variola major Causative agent Variola major Diagnosis is clinical, i.e. people develop skin symptoms Diagnosis is clinical, i.e. people develop skin symptoms Other diagnostics: EM, antibody and DNA tests are not adequate to scan the environment for Variola Other diagnostics: EM, antibody and DNA tests are not adequate to scan the environment for Variola Prevention: Vaccination Prevention: Vaccination Therapy: Vaccination, Vaccinia Immune Globin, Therapy: Vaccination, Vaccinia Immune Globin, Cidofovir? Cidofovir?

46. Small Pox vs. Chicken Pox Becomes ill 7-17 days after exposure Becomes ill 7-17 days after exposure Has fever and feels ill 2-4 days before rash appears Has fever and feels ill 2-4 days before rash appears Pox appear over 1-2 days Pox appear over 1-2 days Lesions are all in the same stage of development Lesions are all in the same stage of development Most numerous on face, arms, legs - usually present on palms & soles Most numerous on face, arms, legs - usually present on palms & soles Scabs form in 10 - 14 days and fall off 14 - 28 days after rash appeared Scabs form in 10 - 14 days and fall off 14 - 28 days after rash appeared Centrifugal distribution Centrifugal distribution Becomes ill 14-21 days after exposure Becomes ill 14-21 days after exposure Usually has no symptoms until the rash appears Usually has no symptoms until the rash appears Pox are most numerous on the body - never found on the palms & soles Pox are most numerous on the body - never found on the palms & soles Scabs form in 4 – 7 days and fall off within 14 days after rash appeared Scabs form in 4 – 7 days and fall off within 14 days after rash appeared Centripetal distribution Centripetal distribution

47. So… Why do we care about a virus that has been eradicated?

48. Smallpox & Bioterrorism: Dark Winter Exercise Summary -simulated smallpox bioterrorist attack on Oklahoma City