Lecture 11 Anthrax Flashcards
What are some traits of Bacillus Anthracis?
- Aerobic
- Gram positive
- rod/ Long shape
- thin
What are the 2 forms of anthracis?
- spores
2. vegetative state
What are the steps spore formation of anthracis?
- Inert spores formed upon exposure to O2
- Infectious form, hardy
- Approximately 1µm in size
- The spores do not divide; have no measurable metabolism
What are the the steps of the vegetative state of anthracis?
- Once ingested, spores get taken up by macrophages and carried to the lymph nodes.
- The spores begin to germinate and enter the vegetative state in the macrophages, eventually lysing them, and overwhelming the lymph node.
- The infection then enters the blood stream.
How are anthracis spread from animals to humans?
- Animals in the late stages of infection bleed through the nose, mouth, and bowel.
- The blood exposes the surrounding soil to the vegetative bacteria, as does the corpse of the infected animal when it dies.
- Exposure to O2 at this stage stimulates formation of spores which stay stored in the soil for repeat of the bacterial life cycle.
What are the environmental survival characteristics of spores?
spores are hardy, and soil is favorable for spore viability
What factors of the soil make it viable for spore formation?
- High moisture
- Organic content
- Alkaline pH
- High calcium concentration
What factors of the spores help the survive?
- Resistant to drying, boiling <10 minutes, ultraviolet light, and even gamma radiation
- Survive for years in soil (natural reservoir)
- Still viable for decades in permafrost
What are the 3 mechanisms of transmission of anthrax?
- cutaneous
- GI
- Inhalation
How can anthrax be inhaled?
- Handling hides/skins of infected animals
- Microbiology laboratory
- Intentional aerosol release
- Small volume powdered form
How can anthrax be cutenously transmitted?
- Handling hides/skins of infected animals
- Bites from arthropods (very rare)
- Handling powdered form in letters, etc.
- Intentional aerosol release
How can anthrax be transmitted intestinally?
- Ingestion of meat from infected animal
- Ingestion of contaminated food and water
- Ingestion from powder-contaminated hands
What are the 3 stages of inhalation infection?
- Asymptomatic incubation period; 2-43 days
- Prodromal (Early) phase; several hours-3 days
- Fulminant Phase
What are the symptoms of the prodromal phase of inhalation?
Nonspecific flu-like symptoms: Fever, malaise, myalgias (muscle pain)
Labored breathing, nonproductive cough, mild chest discomfort
What are the symptoms of the prodromal phase of inhalation?
Critically ill: Fever, high level of perspiration
Respiratory distress/failure, cyanosis (bluish discoloration of skin due to poor circulation or insufficient oxygen levels)
Septic shock, multiorgan failure, DIC
50% develop hemorrhagic meningitis - Headache, delirium, coma
Usually progresses to death in <36 hrs
What is the fulminat phase correlated with?
Correlates with high-grade bacteremia/toxemia