Anthrax, Tetanus, Botulism Flashcards
what are the forms of anthrax?
peracute
acute/subacute
chronic
who is the peracute form of anthrax common in?
goats
sheep
cattle
who is the acute/subacute form of anthrax common in?
horses
cattle
sheep
who is the chronic form of anthrax common in?
swine
carnivores: dogs and cats
what lesions does the anthrax toxin lead to?
hemorrhage
necrosis
edema
inflammation
extracellular rods
what is transmissible with Bacillus anthracis?
spores
what are the sources of Bacillus anthracis spores?
environment
animal products
how is anthrax controlled?
avoid
report
disinfect
incinerate
vaccinate
how should you diagnose anthrax?
blood smear: encapsulated rod-shaped bacilli
why is Bacillus anthracis so toxic?
vascular damage
virulence factors: capsule and toxin
what is special about the Bacillus anthracis capsule?
Poly-y-D-glutamic acid (PGA) inhibits phagocytosis
what do the Bacillus anthracis toxins do?
impair signaling, innate immune cells, and cause vascular damage
what are the anthrax toxins?
protective antigen (PA)
edema factor (EF) and lethal factor (LF)
spores are phagocytosed by macrophages, transform to _____________________ and ____________________, kill cells, and grow extracellularly
vegetative bacilli
produce toxins
what is the causative agent of botulism?
Clostridium botulinum
what is the effect of the botulinum toxin on the muscle?
unable to contract
what type of paralysis does botulinum toxin cause?
flaccid paralysis
what is the name of botulism in birds?
limberneck in fowl
species susceptibility in botulism is linked to _______________________
receptor expression
what does tetanus block?
release of chemical signals from inhibitory neurons
what type of paralysis does tetanus cause?
spastic paralysis
too much muscle contraction
who is exquisitely sensitive to tetanus?
horses
where is anthrax endemic?
africa
who does anthrax primarily affect?
ruminants
is the vegetative state of Bacillus genus infectious?
no: make toxin
oxygen makes spores which are transmissible
do most Bacillus spp cause disease?
no
what signs are associated with the acute/subacute form of Bacillus anthracis?
fever
depression
respiratory signs
incoordination
convulsions
death
what signs are associated with the chronic form of Bacillus anthracis?
pharyngeal and laryngeal edema
intestinal
what signs are associated with ingestion of Bacillus anthracis in horses?
fever
anorexia
colic
bloody diarrhea or other discharge
neck swelling
dyspnea
asphyxiation
what signs are associated with insect bite subacute/acute anthrax in horses?
hot, painful swelling at site
horse flies
what areas are affected by chronic anthrax in swine and carnivores?
neck
pharynx
larynx
gastrointestinal tract
what can be seen in chronic anthrax?
necrosis
hemorrhage
edema
fever
anorexia
why should you not open a dead cow before testing for Bacillus anthracis?
vegetative bacilli exposed to oxygen: triggers sporulation
environmental contamination
what are some signs of endothelial damage due to Bacillus anthracis toxin?
hemorrhages and leaky blood vessels
vascular collapse, shock, and death
what does the Bacillus anthracis capsule allow?
extracellular proliferation
what does the PXO1 plasmid of Bacillus anthracis encode?
protective antigen: PA
lethal factor: LF
edema factor: EF
what does protective antigen from Bacillus anthracis do?
binds receptors on macrophages, dendritic cells, neutrophils, endothelial cells, epithelial cells
low pH changes ______________ shape to a pore that shuttle ___________________________ into the cytoplasm for Bacillus anthracis
protective antigen
lethal factor and edema factor
what are the disruptive functions of protective antigen, lethal factor, and edema factor of Bacillus anthracis?
inhibit phagocytosis
inhibit innate immunity
contribute to vascular damage
what are the general characteristics of Clostridium sp?
anaerobes
gram positive rods
vegetative cells in vivo
spores in the environment
toxin producing
can affect both humans and animals
when does Clostridium botulinum produce botulism neurotoxin?
anaerobic conditions
what happens when vertebrates eat pre-formed botulism neurotoxin?
flaccid paralysis
does the botulism neurotoxin have an effect on invertebrates?
no
how many serotypes of Clostridium botulinum are there?
8
what is the path of botulinum toxin?
binds to autonomic neurons and neuromuscular junctions
travel to CNS
transcytosis from axon by inhibitory neurons
blocks acetylcholine receptors and prevents release of acetylcholine
what do the A-B do in botulinum exotoxin?
B: binds to host cell receptor and trigger endocytosis
A: enzyme activity disrupts intracellular proteins
what happens if a cell lacks the receptor for the B subunits of botulinum toxin?
not vulnerable to toxin
species susceptibility linked to receptor expression
how susceptible are horses to botulinum toxin?
extremely
what is the mortality rate of tetanus toxin in neonates?
80-90% even when treated
who are the three most susceptible to Clostridium tetani/tetanus toxin?
horses most
lambs
humans
what is the path of tetanus toxin?
binds to peripheral neurons innervating muscle
travels to CNS by retrograde axon transport
transcytosis from axon to inhibitory neurons
blocks release of chemical signals from inhibitory neuronss
how do animals get exposed to Clostridium tetani?
spores in soil
wound: metal puncture, docking, castration
what is the incubation period of Clostridium tetani?
10-14 days
