Anthrax (Bacillus anthracis) Flashcards
Structure
aerobic, gram-positive, endospore-producing rods
Reservoir species
None
can infect any mammal
ruminants particularly susceptible (impalas and bison)
carnivores less susceptible and dies less
ostriches, crows, and ducks are susceptible
Is it significant issue
yes, in many national parks worldwide
Why is it special
spores are highly resistant to destruction in environment
History
1st spotted in 700 BC in Egypt and mesopotamia
1877: robert koch used to develop koch postulates
1881: Dr. Louis Pasteur develops 1st vaccine
Used as weapon in WW1
Transmission method
through abraded skin, ingestion, inhalation, or direct injection
Transmission Cycle
once inside, spore germinate within host-> vegetative cells-> fulminant infection-> death of host -> release of blood and bodily fluids into soil-> form biofilms for protection -> sporulates-> enters new host
Rain’s contribution
improving germination and/or bringing spores to surface
Pathogenesis
Can survive for decades in soil, animal hair, wool, and hides
Infect macrophages and then germinate and proliferate
lethal toxin and edema toxin- cause necrosis and edema-> can lead to systemic tissue and organ death
Cutaneous method
least dangerous, Incubation 1-7 days, proliferates at site of infection and draining lymphnodes
Inhalation method
most dangerous (45% mortality), incubation 1-8 weeks
Ingestion method
dangerous with 40% mortality with treatment, incubation 1-7 days, proliferates at site of infection and draining lymph nodes
Peracute clinical signs
(sheep, cattle, wild ruminants)
staggering, dyspnea, trembling collapse, convulsions
Acute clinical signs
sudden onset fever, lethargy, stupor, cardiopulmonary distress, staggering, seizures
Clinical signs
can be so quick that death is only sign
edema or head, neck, thorax, and genitalia
Pathologic Lesions
-dark blood from mouth, nose, and anus (blood fails to clot)
-rigor mortis lacking or incomplete
-hemorrhages on serosal surfaces or abdomen and thorax, epicardium and endocardium, GI tract mucosa, meninges
-edematous, red-tinged effusions commonly under serosa or organs, between skeletal muscle groups, and in subcutis
-ulcers in GI tract
-enlarged, dark red or black, soft, semifluid spleen is common
-liver, kidneys, and lymph nodes congested and enlarged
Diagnostics
PCR, IFA
Sample Collection method
cotton swab dipped in blood and allowed to dry, >3 days dead-nasal turbinate swab and removal
Treatment
antibiotics, long-acting and followed by vaccination 7-10 days after treatment
Management
-preventative vaccination of domestic species
REPORTABLE DISEASE
-move unaffected herds away from contaminated areas
-removal of diseased carcasses
-quarantine of domestic and wild that have movements that can be controlled
-burn affected habitats
