Gas Gangrene <ul><li>Epidemiology </li></ul><ul><ul><li>War wounds; dirt contamination of wounds, tissue death, impaired c...
Plague <ul><li>Symptoms </li></ul><ul><ul><li>Sudden onset of high fever,  large lymph nodes (buboes) ,  skin hemorrhages,...
Transmission of  Yersinia pestis
Yersinia pestis
Plague <ul><li>Epidemiology </li></ul><ul><ul><li>Endemic in wild animals and fleas </li></ul></ul><ul><ul><li>Rare but  <...
Lyme Disease – Phases <ul><li>Phase 1:   </li></ul><ul><li>Erythema migrans characteristic rash present – 80% of cases </l...
Lyme Disease –  Borrelia burgdorferi
Lyme Disease <ul><li>Causative Agent </li></ul><ul><ul><li>Borrelia burgdorferi  – microaerophilic spirochete </li></ul></...
The life cycle of  Ixodes
Ixodes scapularis  – Black-legged tick
Lyme Disease <ul><li>Epidemiology </li></ul><ul><ul><li>Increased prevalence – encroachment on wooded areas; increase in d...
Lyme disease in the U.S.
<ul><li>Viral infections of the cardiovascular system </li></ul>
Mononucleosis <ul><li>Symptoms </li></ul><ul><ul><li>Fatigue , fever,  sore throat ,  lymph node enlargement   </li></ul><...
Diseases associated with Epstein-Barr virus
Mononucleosis <ul><li>Epidemiology </li></ul><ul><ul><li>Spread in: </li></ul></ul><ul><ul><li>Kissing is common mode of t...
Viral Hemorrhagic Fevers <ul><li>Signs and symptoms – Fever, fatigue, dizziness, muscle pain, exhaustion </li></ul><ul><ul...
Viral Hemorrhagic Fevers <ul><li>Epidemiology </li></ul><ul><ul><li>Primarily in Africa </li></ul></ul><ul><ul><li>No huma...
Some viral hemorrhagic fevers
Sites of Marburg and Ebola virus epidemics
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Gas gangrene

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Gas gangrene

  1. 1. Gas Gangrene <ul><li>Epidemiology </li></ul><ul><ul><li>War wounds; dirt contamination of wounds, tissue death, impaired circulation in patients with poor circulation </li></ul></ul><ul><ul><li>Common after: </li></ul></ul><ul><ul><li>Arteriosclerosis, diabetes predispose </li></ul></ul><ul><ul><li>40% mortality (with therapeutic care) </li></ul></ul><ul><li>Prevention and treatment </li></ul><ul><ul><li>Prompt cleaning of wounds is: </li></ul></ul><ul><ul><li>Surgical removal of dead and infected tissues </li></ul></ul><ul><ul><li>Treatment with hyperbaric oxygen, antitoxin </li></ul></ul><ul><ul><li>Penicillin to kill vegetative C. perfringens </li></ul></ul>
  2. 2. Plague <ul><li>Symptoms </li></ul><ul><ul><li>Sudden onset of high fever, large lymph nodes (buboes) , skin hemorrhages, severe cough, bloody and frothy sputum </li></ul></ul><ul><li>Pathogen – Yersinia pestis </li></ul><ul><ul><li>Capsulated bacterium, multiple virulence factors </li></ul></ul><ul><ul><li>Virulence factors: </li></ul></ul><ul><li>Pathogenesis </li></ul><ul><ul><li>Y. pestis contracted from bite of infected flea </li></ul></ul><ul><ul><li>Survive phagocytosis and infect lymph nodes -> </li></ul></ul><ul><ul><li>May be carried into bloodstream -> </li></ul></ul><ul><ul><li>Hemorrhages under skin result in dark patches, skin color </li></ul></ul><ul><ul><li>Lung infection -> contagious, lethal pnuemonic plague -> </li></ul></ul>
  3. 3. Transmission of Yersinia pestis
  4. 4. Yersinia pestis
  5. 5. Plague <ul><li>Epidemiology </li></ul><ul><ul><li>Endemic in wild animals and fleas </li></ul></ul><ul><ul><li>Rare but </li></ul></ul><ul><ul><li>Transmitted person to person via fleas </li></ul></ul><ul><ul><li>Pneumonic plague: coughing – </li></ul></ul><ul><li>Prevention and treatment </li></ul><ul><ul><li>Vaccine offers short-term protection </li></ul></ul><ul><ul><li>Avoid contact with wild rodents </li></ul></ul><ul><ul><li>Insecticides and rat control </li></ul></ul><ul><ul><li>to prevent high mortality </li></ul></ul>
  6. 6. Lyme Disease – Phases <ul><li>Phase 1: </li></ul><ul><li>Erythema migrans characteristic rash present – 80% of cases </li></ul><ul><li>Malaise; chills; fever; headache; stiff neck; joint and muscle pain; backache </li></ul><ul><li>Phase 2: </li></ul><ul><li>Cardiac dysfunction </li></ul><ul><li>Neurological symptoms (meningitis, encephalitis, peripheral nerve neuropathy </li></ul><ul><li>Phase 3: </li></ul><ul><li>Arthritis; joint pain, tenderness, swelling </li></ul><ul><li>Chronic nervous system impairments </li></ul>
  7. 7. Lyme Disease – Borrelia burgdorferi
  8. 8. Lyme Disease <ul><li>Causative Agent </li></ul><ul><ul><li>Borrelia burgdorferi – microaerophilic spirochete </li></ul></ul><ul><li>Pathogenesis </li></ul><ul><ul><li>Spirochetes injected into skin: </li></ul></ul><ul><ul><li>Multiply -> </li></ul></ul><ul><ul><li>Tissue damage result of immune response </li></ul></ul>
  9. 9. The life cycle of Ixodes
  10. 10. Ixodes scapularis – Black-legged tick
  11. 11. Lyme Disease <ul><li>Epidemiology </li></ul><ul><ul><li>Increased prevalence – encroachment on wooded areas; increase in deer populations </li></ul></ul><ul><ul><li>Spread by infected tick bite – </li></ul></ul><ul><ul><li>Ixodes – preferred host: white-footed mouse, white-tailed deer </li></ul></ul><ul><li>Prevention and Treatment </li></ul><ul><ul><li>Prevent by: </li></ul></ul><ul><ul><li>Antibiotics are effective: </li></ul></ul><ul><ul><ul><li>Penicillin, doxycycline </li></ul></ul></ul><ul><ul><li>Prolonged antibiotics late in infection may be curative </li></ul></ul>
  12. 12. Lyme disease in the U.S.
  13. 13. <ul><li>Viral infections of the cardiovascular system </li></ul>
  14. 14. Mononucleosis <ul><li>Symptoms </li></ul><ul><ul><li>Fatigue , fever, sore throat , lymph node enlargement </li></ul></ul><ul><ul><li>Most people return to school/ work: </li></ul></ul><ul><li>Causative agent – Epstein-Barr virus (EBV) </li></ul><ul><ul><li>dsDNA virus, herpesvirus family </li></ul></ul><ul><ul><li>Isolated from Burkitt’s lymphoma </li></ul></ul><ul><li>Pathogenesis </li></ul><ul><ul><li>Virus enters throat -> </li></ul></ul><ul><ul><li>Infection of B cells -> </li></ul></ul><ul><ul><li>Hemorrhage of spleen is rare but serious complication </li></ul></ul><ul><ul><li>May play role in causing malignant tumors – </li></ul></ul>
  15. 15. Diseases associated with Epstein-Barr virus
  16. 16. Mononucleosis <ul><li>Epidemiology </li></ul><ul><ul><li>Spread in: </li></ul></ul><ul><ul><li>Kissing is common mode of transmission </li></ul></ul><ul><ul><li>Lifelong recurrent shedding of virus in saliva </li></ul></ul><ul><ul><li>Very common in college students </li></ul></ul><ul><li>Prevention and treatment </li></ul><ul><ul><li>Avoid sharing items contaminated by saliva </li></ul></ul><ul><ul><li>Acyclovir beneficial in some cases </li></ul></ul>
  17. 17. Viral Hemorrhagic Fevers <ul><li>Signs and symptoms – Fever, fatigue, dizziness, muscle pain, exhaustion </li></ul><ul><ul><li>Minor petechiae </li></ul></ul><ul><ul><li>Severe internal hemorrhaging and bleeding from mouth, eyes and ears </li></ul></ul><ul><ul><li>Death from: </li></ul></ul><ul><li>Pathogens – ssRNA viruses – Filoviridae family </li></ul><ul><ul><li>Enveloped, filamentous virus </li></ul></ul><ul><li>Pathogenesis </li></ul><ul><ul><li>Hemorrhaging due to malfunction of blood clotting system </li></ul></ul><ul><ul><li>Infected macrophages trigger localized blood clotting -> </li></ul></ul>
  18. 18. Viral Hemorrhagic Fevers <ul><li>Epidemiology </li></ul><ul><ul><li>Primarily in Africa </li></ul></ul><ul><ul><li>No human carriers but natural animal hosts </li></ul></ul><ul><ul><li>Transmission through: </li></ul></ul><ul><ul><li>Airborne? </li></ul></ul><ul><ul><li>Ebola – 90% fatal </li></ul></ul><ul><ul><li>Marburg – 25% fatal </li></ul></ul><ul><li>Prevention and Treatment </li></ul><ul><ul><li>No effective antiviral drugs </li></ul></ul><ul><ul><li>Currently no vaccine for humans </li></ul></ul>Ebola virus
  19. 19. Some viral hemorrhagic fevers
  20. 20. Sites of Marburg and Ebola virus epidemics

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