Clostridial Diseases

Question 1

____ should be considered a differential for all cases of sudden death in cattle

Answer 1

clostridium

Question 2

why is clostridium “everywhere”?

Answer 2

it is present in soil and water, and it is a part of the intestinal microflora

Question 3

true or false: the prescence of clostridium is enough to cause disease

Answer 3

false! but proliferation is dangerous

Question 4

clostridium produces exotoxins. What does this mean?

Answer 4

exotoxins are soluble proteins that produce toxic effects causing clinical disease

Question 5

how do exotoxins get access to the host?

Answer 5

cows ingest the bacteria and disrupt GIT microflora and proliferate and release toxins, usually after a tissue infection or insult

Question 6

list some risk factors of clostridiosis in cattle?

Answer 6

young animals, failure of passive transfer, open and non opened wounds providing an anaerobic environment, umbillical cord infections or recent castration

contaminated pastures and facillities, unhygenic conditions, soil disturbance

changes in nutrition/changes in pH, excess starches

Question 7

horses are most at risk of what clostridial disease? sheep?

Answer 7

horses: tetanus
sheep: C perfringens type D

Question 8

most common clinical sign of clostridiosis? how is diagnosis made?

Answer 8

sudden death! particularily in spring born calves that are well fed and doing well. diagnosis is mostly done via gross pathology

Question 9

why do you want to collect samples from freshly dead animals or moribund (about to die) animals?

Answer 9

because clostridiosis infected cows autolyze quickly and the bacteria can be hard to actually detect so you need to catch it fast!!

Question 10

how should you perform a culture when you suspect clostridiosis?

Answer 10

sample 5mls of terminal small intestine content in a sterile container and fill it to the brim! You want to remove air because the pathogen is anaerobic.

Question 11

how do you definitively diagnose a clostridium pathogen? 2 ways

Answer 11

fluorescent antibody test (FAT) and PCR

exotoxin ID: for C perfringens, usually only done in academic situations

Question 12

when you suspect clostridial disease, what are important history questions to ask the producer?

Answer 12

-the animals breed, age, etc
-number of animals affected, how many are dead, and what animals are at risk still
-clinical signs of the animal
-vaccine history: has it been given in past 12 months, how many doses, how far apart, how is vaccine stored, given, etc
-any treatments or handling in the last month
-housing of the animals
-feeding: any extra supplements, are the animals grazing?

Question 13

what are the current guidlines for clostridial vaccines in cattle?

Answer 13

vaccines are usually bacterin toxoids usually in combo with many species. requires a booster, and boosting yearly or more frquently depends on the farm’s needs and risks. they CAN cause anaphylaxsis

Question 14

if you’re faced with an outbreak of what you think is clostridial disease, what are some things you can do right away?

Answer 14

revaccination of the herd to prevent more cases in future
can give antibiotics like penicillin, but rarely works
treat with an anti-toxin if available (like tetanus)

Question 15

tetanus causes ________ disease due to _____ and is often associated with ____

Answer 15

spastic paralytic disease due to tetanospamin

associated with wounds

Question 16

how does tetanus cause paralysis?

Answer 16

toxin blocks neurotransmitter release from inhibitory neurons=spastic paralysis

Question 17

clinical signs of tetanus?

Answer 17

fever, sweating, convulsions, stiffness, tremors, ataxia, prolpase of 3rd eyelid, rigid limbs, bloat, and eventual respiratory arrest

Question 18

you are presented with a cow that is ataxic, temoring, has muscle stiffness, and is bloated. The cow was castrated 2 weeks ago. Differential and how will you treat this animal?

Answer 18

anti toxin, penicillin and sedatives like ace, keep in a dark bedded place. Most animals die

Question 19

pathogenesis of botulism?

Answer 19

C. botulinum type C and D produce toxins that attach to motor neurons and inhibit acetylcholine release–>flaccid paralysis

Question 20

how do cows get infected with botulism?

Answer 20

phosphorus deficinecy + licking bones with decaying material, access to dead birds

Question 21

you are presented with a cow that has progressive muscle weakness for the past 2 hours and is now down. On closer examination, the cow’s tongue is sticking out of it’s mouth. differential? how will you treat?

Answer 21

botulism!

could try antitoxin if available and supportive care but often not successful

Question 22

blackleg disease is caused by ______. what is the pathogenesis?

Answer 22

clostridium chauvoei

causes a clostridial myositis

spores are ingested, replicate in the GI and are absorbed and travel into skeletal and cardiac muscle and remain dormant until there is a traumatic event that allows for anaerobic conditions.

Question 23

you are presented with a herd of cows, some of them acutely died and the farmer found them dead. One cow still alive has a massively swollen right forelimb and is severely lame. Upon palpation there is some crepitation in the limb. top differential? how will you confirm your diagnosis?

Answer 23

blackleg (C. chauvoei)

could be malignant edema

i would like to do a necropsy and maybe a FAT to confirm

Question 24

you are investigating a cow that actuely died, an on necropsy you find black rancid gas filled muscles in the limbs, in the heart, and some in the diaphragm too. differential?

Answer 24

blackleg/C chauvoei

Question 25

if you suspect a cow has blackleg disease and is still alive, what treatments can you offer?

Answer 25

penicillin and a fasciotomy

vaccinate the rest of the herd

Question 26

malignant edema is caused by

Answer 26

clostridium septicum (also apparently novyi, sordellii, and perfringens can be involved)

Question 27

pathogenesis of malignant edema

Answer 27

wound contamination or iatrogenic bacteria contamination and proliferation, toxin production, and cellulitis/necrotizing myositis

trauma usually involved can be: parturition, necrotizing vulvovaginitis and metritis

Question 28

you are presented with a cow that recently gave birth, and has localized swelling and emphysema. top differential?

Answer 28

malignant edema

could also be black leg

Question 29

how to treat malignant edema?

Answer 29

penicillin and fasciotomy

make sure vaccines are UTD before calving or any surgery

Question 30

what causes black disease and what is the pathogenesis?

Answer 30

C. novyi type B

liver flukes migrating through the liver causing liver damage, C novyi proliferates in the liver and produces alpha toxins, leading to acute necrotising hepatitis. liver lesions are pale yellow to white necrotic areas surrounded by dark red to black hyperemia.

Question 31

why is it called “black disease”?

Answer 31

carcasses are highly congested and have a dark appearance/ often serous blood tinged fluid in body cavities including the pericardial sac.

Question 32

red water disease is actually called ____ and is caused by____

Answer 32

bacillary hemoglobinemia

clostridium haemolyticium

Question 33

pathogenesis of bacillary hemoglobinemia? what is the primary pathologic lesions?

Answer 33

release of beta toxin causes intravascular hemolysis, anemia, hemoglobinuria, and jaundice

primary lesions is hepatic necrosis (can look like black disease)

Question 34

which clostridial speies causes necrotic hemorrhagic enteritis and enterotoxemia?

Answer 34

clostridium perfringens

Question 35

which types of C perfringens do cows get?

Answer 35

type A: clostridial abmasitis and necrohemorrhagic enteritis

type D: enterotoxemia

Question 36

hemorrhagic enteritis is thought to be caused by ____ but this is controversial. why?

Answer 36

C perfringens type A

it is a commensal of the intestine so we dont actually know…

Question 37

what is the pathogenesis of c perfringens type A?

Answer 37

favorable conditions in the gut such as high starches cause germination and release of alpha toxins which causes fatal hemorrhagic enteritis

Question 38

clinical signs of clostridium perfringens type A?

Answer 38

abdominal distension, colic, depression, anorexia, or sudden death

Question 39

what clostridial species commonly causes enterotoxemia?

Answer 39

C perfrinens type D–>epsilon toxin causes the enterotoxemia

Question 40

which cows are at risk of developing clostridial enterotoxemia?

Answer 40

cattle on high grain rations or high protein diets, and those in stressful environments

Question 41

you’re out on a farm and there are some well fed calves that have suddenly dropped dead. On talking with the producer, the calves showed colic signs last night with some respiratory distress but waited to call you until this morning and now they are dead. On necropsy, you note necrohemorrhagic enteritis, excessive pericardial fluid, friable pulpy kidneys, and some pulmonary edema. Differential?

Answer 41

enterotoxemia from clostridium perfringens type D