the ecology of anthrax spores: tough but not invincible
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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 - PowerPoint PPT PresentationTRANSCRIPT
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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)
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Short introduction to Anthrax:
Biologische Kampfsoffe sind wieder zu beachten
Artikel von Marc Deschka
in: Die Schwester / Der Pfleger 42, Jahrg 3/03
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Summary of possible bio-weapons
Category A Category B Category C
- Bacillus anthracis- Var iolavirus- Francisella tularensis- Botulinum-Toxin- Ebola-, Marburg-, Lassafever
- Coxiella burnetii- Brucella- Aophaviruses- Ricin-Toxin- Epsilon-Toxin of Clostridium perfringens- Staphylococcus Eterotoxin B
- Bipahvirus- Hantavirus- Multiresistant Tuberculosis- Haemoragic fever
spread by ticks
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Anthrax (Bacillus anthracis)• pulmonary-, cutaneous-
and gastrointestinal-anthrax
• Incubation time: First symptomes after 48 h (2-7 d)
• Therapie: Antibiotics (Ciprofloxazin, Doxycyclin, Penicilin)
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Cutaneous-anthrax
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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)
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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
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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.
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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
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The ecology of anthrax spores: Tough but not invincible
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The ecology of anthrax spores: Tough but not invincible
Bison - Mortality in Northern Canada caused by Anthrax
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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
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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
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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
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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
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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
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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
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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
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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
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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
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Summary
• Long lasting, highly resistant spores
• Correlation between disease and soil factors (likes calceouros soils)
• Vegetative cells are unlikely to survive outside a host