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clostridium
- gram positive spore forming anaerobic bacilli
- transmission by ingestion
- natural inhabitant of GI, soil
- C. difficile, C. novyi, C. piliforme, C. perfringens (aero-tolerant, not endogenous)
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clostridium difficile
- gram positive spore forming anaerobic bacilli, transmission by ingestion
- hemorrhagic necrotizing enterocolitis in (newborn) swine and (any age) horses
- chronic diarrhea in dogs and cats
- may be zoonotic, reverse zoo and/or food borne
- dz from lack of colonization resistance (microbiome out of whack). Spores in intestines germinate after trigger, produce enterotoxins that are cytotoxic to colon epithelium and macrophages.
- not routinely fatal (because toxin stays in intestines)
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clostridium novyi
- 3 types: A (skin and wound), B (Black Disease) and D (Redwater)
- usually cattle, sometimes sheep. Rapid death.
- Spores present in liver until anaerobic environment appears (liver flukes). Dif toxins for each disease
- dx at necropsy, bacterin-toxoid vax
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Black Disease
- Clostridium novyi type B (liver flukes cause anaerobic environment, endogenous spores germinate)
- usually sheep, some cattle
- infectious necrotic hepatitis - toxin kills multiple cell types = focal necrosis
- darkening of SQ tissues (hemorrhage). Endogenous infection
- rapid death
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Redwater
- clostridium novyi type D (liver flukes cause anaerobic environment, endogenous spores germinate)
- usually cattle, sometimes sheep
- bacillary hemoglobinuria, high fever, jaundice, hemoglobinuria. Endogenous infection.
- toxin targets RBCs causing hemolytic crisis, rapid death.
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Clostridium perfringens
- gram positive aero-tolerant anaerobic spore-forming bacillus.
- types A-E. A = mucohemorrhagic diarrhea in dogs and cats. B-E = ulcerated congested mucosa, acute death. Toxin susceptible to digestive enzyme, so worse in nursing and overfed
- Zoonotic
- Toxemia (not bacteremia like e coli). Lots of toxins, different combos. One increases intestinal permeability to let others go systemic and kill everything.
- C. perfringens enterotoxin is c/d diarrhea.
- High fiber low protein diets.
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Clostridium piliforme
- Tyzzer's Disease
- gram variable obligate intracellular bacillus (has a gram + cell wall), spore-forming
- hepatic necrosis and rapid death in lagomorphs, foals, cats and dogs.
- Induced by stress (endogenous)
- enlarged liver with necrotic foci on necropsy
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mycobacterium avium ssp paratuberculosis
- gram positive acid fast obligate aerobic bacillus
- Johne's Disease, REPORTABLE
- Lives in intestinal tract in INFECTED animals, spread fecal-oral, milk and colostrum
- young infected but 1-5YEAR incubation period, not susceptible after 1 year, but don't show signs until older
- Granulomatous disease - iliocecal macrophages cuase thickened intestines, malabsorption and loss of proteins.
- Cattle: chronic weight loss, severe diarrhea, drop in milk production but normal appetite and no fever.
- sheep and goats: mild or no diarrhea, herd unthriftiness.
- MAJOR economic losses, tests aren't perfect and positive are culled (abx but not economically feasible). (LN smears, intestinal or rectal scrapings, PCR of grown fecal samples, ELISA, etc)
- pasteurize milk, remove calves, vax not available in US - concern with cross-reactivity to TB test.
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Prototheca
- saprophytic achlorophyllus algae (not a fungus but LIKE one)
- GI, CNS, Ocular
- found in raw/treated sewage, animal wastes
- ingestion, traumatic innoculation. Lots of species (zopfii, wickerhamii)
- Colitis (bloody D, vomiting, weight loss) with multisystemic dissemination, ocular involvement in BOTH eyes (clouding cornea or pupil, blindness)
- CNS - ataxia, circling
- Tx not effective if disseminated.
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