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Viruses

Viruses. “an intracellular, infectious parasite capable of living and replicating only in living cells”. Viruses. Page 386 can infect almost any living cell a piece of genetic material wrapped in protein contain either DNA or RNA (not both)

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Viruses

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  1. Viruses “an intracellular, infectious parasite capable of living and replicating only in living cells”

  2. Viruses • Page 386 • can infect almost any living cell • a piece of genetic material wrapped in protein • contain either DNA or RNA (not both) • replicate inside living cells and use cell’s own structures to reproduce more infected cells • some of the smallest human pathogens • lack enzymes such as ATP for producing energy

  3. Inactivation of Viruses • some are sensitive to disinfectants due to lipids in their coverings • detergents and ether dissolve their lipid coverings • e.g. HIV can be inactivated by a solution of 10% sodium hypochlorite (household bleach) in water

  4. Dermatropic (Skin) Diseases • Page 387 • Smallpox: vaccination ended in the 1970s • Monkeypox: Page 389 Figure 27 - 2 • Measles: Page 390 Readings question #1: What is the virus responsible for measles? What is the only reservoir for this virus? • MMR vaccine (measles, mumps, rubella)

  5. Dermatropic Diseases (cont’d) • German Measles: Page 390 • Readings question #2: What is the virus that is responsible for the disease known as German measles? How is it spread? • Color Plate 61 • Chickenpox and Shingles: Page 392 • Color Plate 62 • Shingles rarely occurs in people under the age of 20 and highest incidence is in the elderly • Color Plate 63

  6. Reye’s Syndrome • severe complication of chickenpox, influenza and some other viral diseases • persistent vomiting • signs of brain dysfunction • coma and death • survivors: neurological damage • children and teenagers • use of aspirin to lower fever in chickenpox and influenza increases chance of acquiring this

  7. Dermatropic Diseases (cont’d) • Herpes Simplex 1 and 2: Page 392 Readings question #3: What is caused by the Herpes Simplex 1 virus and how is it transmitted? What is caused by the Herpes Simplex 2 virus and how is it transmitted? • Color Plate 64 • Figure 27 - 6

  8. Pneumotropic (URT) Diseases • Page 394 • Influenza: strains are “antigenic shifts” - vaccines are usually “multivalent” - pandemic 1918-1919 - 2 new drugs: zanamivir (Relenza) oseltamivir phosphate (Tamiflu)

  9. Pneumotropic Diseases (cont’d) • Common Cold: • Hantavirus Pulmonary Syndrome (HPS): • Rodents especially mice • Severe Acute Respiratory Syndrome (SARS): • Asia, North American and Europe • fever greater than 100.4 degrees • close person-to-person contact, resp. droplets

  10. Neurotropic (CNS) Diseases • Page 396 • Rabies: rhabodovirus • shaped like a bullet • spread by “bite” or “aerosols” • colonizes in skeletal muscle and connective tissue • immune system cannot suppress infection because lymph does not circulate in the brain and spinal cord (CSF) • “hydrophobia”

  11. Neurotropic Diseases (cont’d) • Poliomyelitis: (polio virus) Page 396 • ingestion of feces contaminated water • path of the poliovirus once it is ingested: • throat – small intestine- lymph nodes (neck and ileum) – blood (viremia) – final stages: CNS • vaccines: Salk (injection) and Sabin (oral)

  12. Neurotropic Diseases (cont’d) • Viral Encephalitis: Page 397 - inflammation of the brain • arthropod-borne arbovirus (mosquitoes) • EEE (Eastern Equine Encephalitis); WEE (Western Equine Encephalitis); SLE; CE; LCE etc. • control of large populations of mosquitoes to decrease spread

  13. Neurotropic Diseases (cont’d) • West Nile Virus: Page 397 • can infect humans, birds, mosquitoes, horses etc. • causes mild flu-like disease with no long-term health effects • spread limited through mosquito control • Elderly: can cause fatal encephalitis or polio-paralysis

  14. Viscerotropic (Visceral) Diseases • Hepatitis: Hepatitis A (HAV) “infectious” Hepatitis B (HBV) “serum” • Readings question #4: According to OSHA’s Blood-borne Pathogen Rule, what are the rights of funeral home employees regarding the HBV vaccine? • Hepatitis C (HCV): “silent epidemic” • 100,000 people infected/year in the U.S.

  15. Viscerotropic Disease (cont’d) • Infectious Mononucleosis: Page 400 • Epstein-Barr virus (EBV) through transfer of saliva • replicates in parotid salivary glands • Cytomegalovirus: “inclusion bodies” “owls eyes” • Shed in body secretions • 80% of population are carriers • Common in day-care settings • Epidemic Parotitis (Mumps) • Figures 27 – 9 and 27 - 10

  16. Immunological Disease • Page 402 • HIV (Human Immunodeficiency Virus) • transmitted in bodily fluids; multi-drug resistant • affects “T” cells within the immune system • “opportunistic infections” Readings question #5: What is the major threat to embalmers when embalming AIDS victims? What can the embalmer do to protect him/herself?

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