Neuro pathogens

Question 1

What are the characteristics of Clostridium botulinum?

Answer 1

Gram-positive, Anaerobic, Rod-shaped, Forms endospores

Forms endospores look like bowling pins.

Question 2

How many types of toxins have been found from Clostridium botulinum?

Answer 2

7 (A, B, C, D, E, F, G)

Question 3

What species is the most resistant to Clostridium botulinum?

Answer 3

Cats

Question 4

What causes foodborne botulism?

Answer 4

The ingestion of pre-formed toxin

Question 5

What causes toxico-infectious botulism?

Answer 5

Spores that germinate in wounds or in the intestinal tract

Question 6

Describe the pathogenesis of Clostridium botulinum.

Answer 6

1. Botulinum toxin absorbed in intestines or enters via a wound
2. Toxin enters the bloodstream
3. Toxin blocks release of acetylcholine at the neuromuscular junction
4. Flaccid paralysis occurs

Question 7

Clostridium botulinum causes which type of paralysis?

Answer 7

Flaccid

Question 8

What are the five clinical signs of botulism?

Answer 8

Dilated pupils, Dry mucous membranes, Decreased salivation, Tongue flaccidity, Dysphagia

Question 9

How does botulism lead to death?

Answer 9

Flaccid paralysis of the respiratory muscles

Question 10

How can you confirm a diagnosis of botulism?

Answer 10

Mouse inoculation, ELISA, PCR

Question 11

How can you treat botulism?

Answer 11

Polyvalent antiserum can be administered, Tetraethylamide and guanidine hydrochloride can be given, Flush the wound if bacteria are present.

Question 12

Is there a vaccine available for Clostridium botulinum?

Answer 12

Yes

Question 13

What are the characteristics of Clostridium tetani?

Answer 13

Gram-positive, Anaerobic, Rod, Forms endospores

Forms endospores have a drumstick appearance.

Question 14

What species are the most resistant to tetanus?

Answer 14

Chickens

Question 15

What is the most important virulence factor of Clostridium tetani?

Answer 15

The neurotoxin it creates (tetanospasmin)

Question 16

What is tetanospasmin?

Answer 16

The neurotoxin released by Clostridium tetani

Question 17

What are common ways Clostridium tetani gains entry to the body?

Answer 17

Deep penetrating wounds, Castration and tail docking, Dystocia lesions, Ear tags, Umbilical cord, Surgical wounds

Question 18

Describe the pathogenesis of Clostridium tetani.

Answer 18

1. The toxin binds at the neuromuscular junction and blocks GABA receptor
2. Spastic paralysis

Question 19

The binding of tetanospasmin is _____________

Answer 19

Irreversible

Question 20

Where does inhibition due to tetanospasmin occur?

Answer 20

At the synapse between inhibitory neurons and motor neurons

Question 21

What are the main clinical signs associated with Clostridium tetani?

Answer 21

Sahorse stance, Lock jaw, Stiffness, Dysphagia

Question 22

What condition in dogs can look similar to tetanus?

Answer 22

Strychnine poisoning. You need to make a smear and look for drumstick spores to confirm tetanus.

Question 23

How do you treat Clostridium tetani?

Answer 23

1. Neutralize any unbound toxin with an antitoxin IV for 3 days
2. Kill any bacteria with large doses of penicillin IV and flush lesions
3. Remove any bacteria from lesion site with surgical debridement

Question 24

How many types of toxins have been found from Clostridium tetani?

Answer 24

Only one

Question 25

Describe how Clostridium botulinum differs from Clostridium tetani.

Answer 25

Clostridium tetani doesn't enter the blood while Clostridium botulinum does; Clostridium tetani is contracted through a contaminated wound while Clostridium botulinum is contracted mostly through ingesting contaminated feed; Clostridium tetani causes spastic paralysis while Clostridium botulinum causes flaccid paralysis; Clostridium tetani has one antigenic type while Clostridium botulinum has seven.

Question 26

How can you diagnose both Clostridium botulinum and Clostridium tetani?

Answer 26

PCR or serology (they are both difficult to culture and we often get false positives)

Question 27

What are three characteristics of Listeria monocytogenes?

Answer 27

Gram-positive, Rods, Do not form spores

Question 28

True or False: Listeria monocytogenes is zoonotic

Answer 28

True

Question 29

What are two important virulence factors held by Listeria and what do they allow them to do?

Answer 29

1. Internalins (adherin) - allows adherence to epithelial cells 2. Listeriolysins - protects bacteria from phagocytosis by host's immune system

Question 30

What are three possible outcomes from infection with Listeria?

Answer 30

1. Abortion 2. Septicemia 3. Encephalitis ## Footnote Less frequently it can cause mastitis or silage eye.

Question 31

How does Listeria monocytogenes enter the body?

Answer 31

Through ingestion of contaminated feed

Question 32

What are clinical signs of encephalitis caused by Listeria monocytogenes?

Answer 32

Head tilt, Drooling, Dropping of ear or eyelid, Ataxia, Recumbency, Death

Question 33

Are there vaccines available for Listeria?

Answer 33

Yes, but not in Canada

Question 34

How do you treat an infection with Listeria monocytogenes?

Answer 34

Encephalitis → treat with high doses of ampicillin or amoxicillin + aminoglycoside Septicemia → treat with ampicillin or amoxicillin Silage eye → treat with antimicrobials injected sub-conjunctivally

Question 35

How can farmers protect their flock from Listeria?

Answer 35

Avoid poor quality silage and ensure silage has a pH of 4.2 or less

Question 36

What are the two primary routes of infection that cause otitis media/interna?

Answer 36

1. External ear infection → tympanic membrane → middle ear → internal ear 2. Pharyngeal bacteria → auditory tube → middle ear → internal ear

Question 37

Antimicrobial therapy for otitis media cases should be continued for _____________

Answer 37

6-8 weeks

Question 38

In cases of otitis interna, antimicrobial therapy should be carried out for at least _____________

Answer 38

3 months