Anthrax Flashcards
Where does the name of anthrax come from?
“coal” from the black colour of the cutaneous lesions
What does anthrax mainly have a history of?
Bioterrorism
What are the four main ways that anthrax can be transmissed into humans?
- Cutaneous
- Inhalation
- Gastrointestinal
- Any groups at risk (wool sorters, bone processors, slaughterhouse workers)
What is the main transmission of anthrax?
Spores found in the soil
What are the peak anthrax zones and weather?
- Any soil with a pH under 6
- wet spring, followed by a hot, dry period
- Grass or vegetation damaged by the flood-drought sequence
What does oxygen exposure do to anthrax?
Formation and contamination of spores
What are the clinical features of cutaneous anthrax in humans?
- 95% of all cases globally
- Incubation: 2 to 3 days
- Spores enter skin through open wound or abrasion
- Papule > vesicle > ulcer > eschar (dry, dark scab)
- Case fatality rate 5 to 20%
- Untreated – septicemia and death
What is the anthrax lifecycle?
- Spores are uptaken from feed or water, they enter via lesions in the GI tract
- bacterial multiplication in the spleen
- endothelial breakdown of blood vessels
- release of bacilli and toxins in the bloodstream
- death
- shedding into the environment and sporulation of the released vegetative cells
- exposure of new hosts via scavengers, wind etc.
What species is a dead end host in anthrax transmission?
Humans
What are the four ways human transmission of anthrax can occur?
- Cutaneous- contact with infected tissues, wool, hides etc.
- Inhalation- tanning hides, processing wool/ bone
- Gastrointestinal- undercooked meat
- Groups at risk- wool sorters, bone processors
What three ways is anthrax transmissed in humans?
- Spores (not vegetative cells) - the natural reservoir is in soil- no soil replication = no saprophytic lifecycle
- Anthrax zones (any soil rich in organic matter)
- Anthrax weather (wet spring followed by a hot, dry period, grass or vegetation damaged by the flood-drought sequence)
- Cattle are primarily affected
Where are anthrax bacteria present in the carcass?
They are not present in a closed carcass
They are present in haemorrhagic exudate from the mouth, nose and anus
Oxygen exposure = causes sporulation
How do animals mainly transmit anthrax bacteria?
- Ingestion- contaminated soil or contaminated meat
- Inhalation
- Mechanical (via insects)
What are the clinical features of cutaneous anthrax?
- Spores enter the skin via open wounds or abrasion
- dry, dark scab
- untreated it can cause septicaemia and death
What are the clinical features of inhalation anthrax?
- Nonspecific/ initially- causes mild fever
- Second phase- severe respiratory distress, dyspnea, cyanosis, medaistinal widening
- case fatality is 75-90% if left untreated
