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The ecology of anthrax spores: Tough but not invincible

The ecology of anthrax spores: Tough but not invincible. Sonja Brockmüller Seminar presentation based on a paper by Daniel C. Dragon and Robert P. Rennie The Canadian Veterinary Journal Volume 36, May 1995, pgs. 295 - 301

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The ecology of anthrax spores: Tough but not invincible

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  1. The ecology of anthrax spores:Tough but not invincible Sonja Brockmüller Seminar presentation based on a paper by Daniel C. Dragon and Robert P. Rennie The Canadian Veterinary Journal Volume 36, May 1995, pgs. 295 - 301 (A copy of the paper is available in the course folder „Science News“ on OLAT)

  2. Short introduction to Anthrax: Biologische Kampfsoffe sind wieder zu beachten Artikel von Marc Deschka in: Die Schwester / Der Pfleger 42, Jahrg 3/03

  3. Summary of possible bio-weapons

  4. Anthrax (Bacillus anthracis) • pulmonary-, cutaneous- and gastrointestinal-anthrax • Incubation time: First symptomes after 48 h (2-7 d) • Therapie: Antibiotics (Ciprofloxazin, Doxycyclin, Penicilin)

  5. Cutaneous-anthrax

  6. Ecology of anthrax spores • Spore integument respon-sible for the spores‘s surface hydrophobicity • --> Protect inner spore • Inside core less water • Spores interact with their surroundings • Vegetative cells need a nutrient rich environement --> spore formation and lysis of vegetative cell (See also BBOM 9th ed. Chapter 3.15)

  7. Ecology of anthrax spores • Vegetative cells need a nutrient rich environement --> spore formation and lysis of vegetative cell • Endospore coat component: Dipicolinic acid (DPA) -> ingestion by host macrophage cells is limited

  8. Ecology of anthrax spores • Vegetative cells need a nutrient rich environement -> spore formation and lysis of vegetative cells • Endospore coat component: Dipicolinic acid (DPA) -> ingestion by host macrophage cells is limited • Endospores resist even prolonged exposure to chemical disinfectants, desiccation and extremes in pH, temperature, pressure, UV and ionizing radiation.

  9. Ecology of anthrax spores • Vegetative cells need a nutrient rich environement -> spore formation and lysis of vegetative cells • Endospore coat component: Dipicolinic acid (DPA) -> ingestion by host macrophage cells is limited • Endospores resist even prolonged exposure to chemical disinfectants, desiccation and extremes in pH, temperature, pressure, UV and ionizing radiation. • Global in its geographical distribution and endemic to many parts of Europe, Asia, Africa, North- and South America, Australia

  10. The ecology of anthrax spores: Tough but not invincible

  11. The ecology of anthrax spores: Tough but not invincible Bison - Mortality in Northern Canada caused by Anthrax

  12. The ecology of anthrax spores: Tough but not invincible • Dissemination of spores • Weather and its consequences • Soil quality • Epidemiology of Anthrax with respect to Bisons • Summary

  13. Dissemination of spores • Scavengers and carnivores can act as carriers by dispersing ingested spores in their feces over large distances. • Insects (mosquitoes, flies) • Soil on the coat of wallowing animals (bison) • Water and wind

  14. The ecology of anthrax spores: Tough but not invincible • Dissemination of spores • Weather and its consequences • Soil quality • Epidemiology of Anthrax with respect to Bisons • Summary

  15. Weather and his consequence • Anthrax epidemics generally occur during dry summer months following prolonged periods of heavy rain • Water collects and concentrates the spores in „storage“ areas • Water evaporates and allows the spores to be dispersed via the air

  16. The ecology of anthrax spores: Tough but not invincible • Dissemination of spores • Weather and its consequences • Soil quality • Epidemiology of Anthrax with respect to Bisons • Summary

  17. Soil and its quality • Outbreaks were most freqently associated with calcareous soils, rich in Ca2+ and nutrients • High levels of calcium in the soil may buffer the internal supply of anthrax spores and greatly extend their viability • “incubator area“ hypothesis: alkaline pH, high soil moisture, organic matter

  18. The ecology of anthrax spores: Tough but not invincible • Dissemination of spores • Weather and its consequences • Soil quality • Epidemiology of Anthrax with respect to Bisons • Summary

  19. Epidemiology of anthrax with respect to bison • Mortality among sexually mature males is higher than females and immature bisons. • High temperatures, breeding activity, high levels of insect harassment, and population size of bisons -> immunity is weak -> low oral doses -> lethal infections • Rutting agression-> stamping, wallowing -> dust clouds of aerosolized spores

  20. The ecology of anthrax spores: Tough but not invincible • Dissemination of spores • Weather and its consequences • Soil quality • Epidemiology of Anthrax with respect to Bisons • Summary

  21. Summary • Long lasting, highly resistant spores • Correlation between disease and soil factors (likes calceouros soils) • Vegetative cells are unlikely to survive outside a host

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