1. VI. Viral Diseases A. Influenza
B. Diseases Caused by the Herpes Family
C. Viral Hepatitis
D. Human Immunodeficiency Virus
E. Miscellaneous Viral Diseases

2. VI. A. Influenza Properties Member of the Orthomyxovirus family
Enveloped RNA virus
Two envelope proteins
Hemagglutinin and Neuraminidase
Segmented RNA
8 segments; packaged into helical nucleocapsids
Antigenic variation & genetic exchange lead to the appearance of new strains; requires use of different vaccine combinations each year

3. VI. A. Influenza Symptoms & Complications of Influenza
Respiratory Tract Symptoms
Fever
Neurological Complications:
Guillain-Barré Syndrome
Reye’s Syndrome

4. VI. B. Diseases Caused by the Herpes Family
Properties of the Herpes Virus Family
Large, enveloped DNA viruses
Icosahedral capsids
DNA replicates in the nucleus of host cells
Cells may become permanently infected
Host chromosomes may be altered
Herpes infections associated with certain cancers

5. VI. B. Diseases Caused by the Herpes Family
Herpes Simplex
Two major strains
Type I: Oral Herpes
Type II: Genital Herpes
Skin lesions form at site of the infection
Virus travels along sensory neurons to ganglia, where it remains
During times of stress or weakened immunity, virus may travel along same neurons to re-infect the initial skin sites

6. VI. B. Diseases Caused by the Herpes Family
Herpes Simplex (cont.)
Other complications
Herpes encephalitis
Congenital herpes
Cervical cancer
Treatment: Acyclovir

7. VI. B. Diseases Caused by the Herpes Family
Chicken pox & Shingles
Cause: Varicella-zoster virus
Chicken pox symptoms
Shingles symptoms
Treatment
Chicken pox vaccine
Connection to Reye’s syndrome

8. VI. B. Diseases Caused by the Herpes Family
Infectious mononucleosis
Cause: Epstein-Barr virus
Lymph node swelling; fever; fatigue
Heterophile antibody production
Monospot Test
Other complications
Burkitt's Lymphoma
Chronic Fatigue Syndrome??!?

9. VI. B. Diseases Caused by the Herpes Family
Cytomegalovirus
Mild symptoms in otherwise healthy individuals
Major complications
Miscarriages when contracted during pregnancy
Severe infections in AIDS patients
Major cause of blindness in AIDS patients

10. VI. C. Viral Hepatitis Hepatitis A Also known as: Viral Properties
Infectious hepatitis
Short-incubation hepatitis
Viral Properties
Picornavirus Family
Small nonenveloped RNA viruses
Family includes common cold (rhinovirus) & polio viruses

11. VI. C. Viral Hepatitis Hepatitis A (cont.) Transmission:
Virus particles are present in the stool
Fecal-oral route via contaminated food or water
Saliva contact, sexual contact, and arthropods also have been implicated

12. VI. C. Viral Hepatitis Hepatitis A (cont.) Symptoms:
Two to four week incubation period
Nausea, vomiting, fever
Abdominal pain
Jaundice in many but not all cases
Duration usually several weeks

13. VI. C. Viral Hepatitis Hepatitis A (cont.) Treatment & Prevention:
Prolonged rest
Hepatitis A Immune Globulin
Hepatitis A vaccine

14. VI. C. Viral Hepatitis Hepatitis B Also known as: Serum hepatitis
Long-incubation hepatitis

15. VI. C. Viral Hepatitis Hepatitis B (cont.) Viral properties:
Hepadnavirus family
Nucleocapsid consists of DNA surrounded by hepatitis B core antigen (HBcAg)
The core is surrounded by a lipoprotein envelope containing the hepatitis B surface antigen (HBsAg)
The virus has also been called the Dane particle
Large amounts of excess HBsAg are found in the serum & may be detected serologically

16. VI. C. Viral Hepatitis Hepatitis B (cont.) Transmission:
Contact with infected body fluids
Blood, blood products, semen, vaginal secretions (urine, saliva also implicated)

17. VI. C. Viral Hepatitis Hepatitis B (cont.) Symptoms:
Incubation period: four weeks - six months
Nausea, fever
Dark urine & clay-colored stools
Abdominal tenderness
Jaundice
Duration of symptoms: months
About 10% of patients remain carriers for several months

18. VI. C. Viral Hepatitis Hepatitis B (cont.) Treatment & prevention
Hepatitis B Immune Globulin
Hepatitis B vaccination

19. VI. C. Viral Hepatitis Non-A non-B (NANB) Hepatitis Hepatitis C
NANB serum hepatitis
Enveloped virus of the Flavivirus family
Transmission & symptoms similar to B
Delta hepatitis
A small defective RNA virus that requires coinfection with Hepatitis B to replicate
Co-transmitted with Hepatitis B

20. VI. C. Viral Hepatitis Non-A non-B (NANB) Hepatitis (cont.)
Hepatitis E
NANB infectious hepatitis
A small nonenveloped RNA virus of the calcivirus family
Transmission & symptoms similar to Hepatitis A

21. VI. D. Human Immunodeficiency Virus
Viral Properties
A retrovirus
An enveloped RNA virus that replicates through a DNA intermediate
The DNA intermediate is synthesized by reverse transcriptase: an enzyme that makes a DNA molecule using an RNA template
The DNA intermediate is spliced into host chromosomes, making the infection permanent

22. VI. D. Human Immunodeficiency Virus
Viral Properties (cont.)
Host cells for HIV: CD4+ cells
Helper T (T-4) lymphocytes
Macrophages
Damage to the helper T cell population cripples the immune system of the host

23. VI. D. Human Immunodeficiency Virus
Transmission
Contact with infected body fluids
Blood, blood products, semen, vaginal secretions, breast milk

24. VI. D. Human Immunodeficiency Virus
What is the difference between HIV & AIDS?
HIV: the Human Immunodeficiency Virus
The cause of AIDS
Also known as: HTLV-III and LAV
Two known types: HIV-1 and HIV-2
AIDS: Acquired Immune Deficiency Syndrome
Catastrophic immune system failure caused by HIV infection
Symptoms & cases are usually defined by the CDC case surveillance definition

25. VI. D. Human Immunodeficiency Virus
CDC Case Surveillance Definition for AIDS
Based on:
Clinical Symptoms: Categories A, B, C
Helper T-4 lymphocyte count: Categories 1, 2, 3
Category A
Asymptomatic HIV infection
Persistent Generalized L ymphadenopathy
Acute HIV infection

26. VI. D. Human Immunodeficiency Virus
CDC Case Surveillance Definition for AIDS (cont.)
Category B
Symptomatic HIV infection with constitutive illness & certain opportunistic infections
Often an early indication that AIDS is developing
*Category C
Symptomatic HIV infection with opportunistic infections listed in the CDC surveillance case definition

27. VI. D. Human Immunodeficiency Virus
CDC Case Surveillance Definition for AIDS (cont.)
Category 1
T-4 count greater than 400 per microliter of blood
Category 2
T-4 count between 400 and 200 per microliter of blood
*Category 3
T-4 count less than 200 per microliter of blood

28. VI. D. Human Immunodeficiency Virus
CDC Case Surveillance Definition for AIDS (cont.)
*These categories (C and 3) meet the CDC surveillance definition to be included among the AIDS cases
Many HIV-infected individuals show no symptoms, yet are capable of transmitting the virus

29. VI. D. Human Immunodeficiency Virus
Symptoms & Secondary Infections Associated with AIDS
Acute Infection
Fever, lymph node swelling, aches, fatigue, “flu-like” or “mono-like” symptoms
Persistent Generalized Lymphadenopathy
Lymph node swelling for greater than 6 months in two or more body areas (excluding the groin)
Often an early manifestation that AIDS has developed

30. VI. D. Human Immunodeficiency Virus
Symptoms & Secondary Infections Associated with AIDS (cont.)
Constitutive Illness
Weight loss, persistent fever, diarrhea
Cancers
Kaposi’s sarcoma
Certain lymphomas

31. VI. D. Human Immunodeficiency Virus
Symptoms & Secondary Infections Associated with AIDS (cont.)
Bacterial Secondary Infections
Mycobacterium
Listeria
Salmonella
Mycoplasma
many others

32. VI. D. Human Immunodeficiency Virus
Symptoms & Secondary Infections Associated with AIDS (cont.)
Fungal Secondary Infections
Candida and others
Protozoan Secondary Infections
Toxoplasma gondii
Cryptosporidium
Pneumocystis carinii

33. VI. D. Human Immunodeficiency Virus
Symptoms & Secondary Infections Associated with AIDS (cont.)
Viral Secondary Infections
Herpes simplex
Cytomegalovirus
Many others
Treatments
Inhibitors of DNA replication
Protease Inhibitors

34. VI. E. Miscellaneous Viral Diseases
Miscellaneous Pneumotrophic Viruses
Rhinovirus
Adenovirus
Respiratory Syncytial Virus

35. VI. E. Miscellaneous Viral Diseases
Miscellaneous Dermotrophic Viruses
Measles (Rubeola)
Rubella
Mumps
Fifth disease
Papilloma (HPV)

36. VI. E. Miscellaneous Viral Diseases
Miscellaneous Viscerotrophic Viruses
Enterovirus (Coxsackie & Echo Viruses)
Rotavirus
Norwalk Virus

37. VI. E. Miscellaneous Viral Diseases
Miscellaneous Neurotrophic Viruses
Poliomyelitis
Rabies
Arbovirus
Arenavirus (lymphocytic choriomeningitis)

38. VI. E. Miscellaneous Viral Diseases
Prion Diseases
Bovine Spongiform Encephalopathy
Scrapie
Creutzfelt-Jakob Syndrome
Kuru