Clostridial Diseases Flashcards
____ should be considered a differential for all cases of sudden death in cattle
clostridium
why is clostridium “everywhere”?
it is present in soil and water, and it is a part of the intestinal microflora
true or false: the prescence of clostridium is enough to cause disease
false! but proliferation is dangerous
clostridium produces exotoxins. What does this mean?
exotoxins are soluble proteins that produce toxic effects causing clinical disease
how do exotoxins get access to the host?
cows ingest the bacteria and disrupt GIT microflora and proliferate and release toxins, usually after a tissue infection or insult
list some risk factors of clostridiosis in cattle?
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
horses are most at risk of what clostridial disease? sheep?
horses: tetanus
sheep: C perfringens type D
most common clinical sign of clostridiosis? how is diagnosis made?
sudden death! particularily in spring born calves that are well fed and doing well. diagnosis is mostly done via gross pathology
why do you want to collect samples from freshly dead animals or moribund (about to die) animals?
because clostridiosis infected cows autolyze quickly and the bacteria can be hard to actually detect so you need to catch it fast!!
how should you perform a culture when you suspect clostridiosis?
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.
how do you definitively diagnose a clostridium pathogen? 2 ways
fluorescent antibody test (FAT) and PCR
exotoxin ID: for C perfringens, usually only done in academic situations
when you suspect clostridial disease, what are important history questions to ask the producer?
-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?
what are the current guidlines for clostridial vaccines in cattle?
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
if you’re faced with an outbreak of what you think is clostridial disease, what are some things you can do right away?
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)
tetanus causes ________ disease due to _____ and is often associated with ____
spastic paralytic disease due to tetanospamin
associated with wounds
how does tetanus cause paralysis?
toxin blocks neurotransmitter release from inhibitory neurons=spastic paralysis
clinical signs of tetanus?
fever, sweating, convulsions, stiffness, tremors, ataxia, prolpase of 3rd eyelid, rigid limbs, bloat, and eventual respiratory arrest
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?
anti toxin, penicillin and sedatives like ace, keep in a dark bedded place. Most animals die
pathogenesis of botulism?
C. botulinum type C and D produce toxins that attach to motor neurons and inhibit acetylcholine release–>flaccid paralysis
how do cows get infected with botulism?
phosphorus deficinecy + licking bones with decaying material, access to dead birds
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?
botulism!
could try antitoxin if available and supportive care but often not successful
blackleg disease is caused by ______. what is the pathogenesis?
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.
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?
blackleg (C. chauvoei)
could be malignant edema
i would like to do a necropsy and maybe a FAT to confirm
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?
blackleg/C chauvoei
