L5 - Diseases of the GI Tract Flashcards
____ is an increase in frequency of defecation or fecal volume
Diarrhea
Fecal volume is increased by increasing _____.
Fecal water content
TRUE/FALSE
The water in the GI tract is from ingestion and must all be absorbed.
FALSE
Water is ingested and the gut secretes more water. The majority must be absorbed, but some remains to be excreted with feces.
What are the two types of diarrhea?
Malabsorptive
Secretory
What is the pathogenesis of malabsorptive diarrhea?
Damage to villous epithelium & loss of enterocytes → shortening of villi because loss > replacement
What are the effects of malabsorptive diarrhea?
- ↓ SA inhibits absorptive ability
- Loss of mature enterocytes that possess enzymes necessary for membranous-phase digestion & transport proteins for sodium co-transport. → inhibition of digestion & absorption of nutrients (necessry for osmotic absorption of water)
What are the most common causes of malabsorptive diarrhea?
- Viruses
- Bacteria
- Protozoa
What is the pathogenesis of secretory diarrhea?
- Secretion of water > absorption
- Abnormal stimulation of small intestinal crypts leads to hyper secretion of water
- Stimulation ↑ adenyl cyclase activity and production of cAMP within cells → opening of chloride gates and secreting water, electrolytes & bicarb
____ diarrhea is more common in neonates.
Secretory
*exception: occasionally see ETEC in adults
What are the most common pathogens associated with secretory diarrhea?
- Enterotoxins
i. e. those produced by gram (-) bacteria (ETEC) and sometimes rotavirus
What are the common serotypes of Salmonella enteric that infect cattle?
Tymphimurium
dublin
newport
What are the systemic signs of endotoxemia caused by salmonella?
- Fever
- Tachypnea
- Tachycardia
- Scleral injection
- Weakness
- Rumen stasis
What kind of diarrhea is produced by salmonella?
- Maldigestion - loss of mucosal epithelial cells
- +/- secretory → enterotoxin produced
What are treatment and prevention methods for salmonella?
- Fluid therapy
- NSAIDs (flunixin meglimine IV)
- Antibiotics (C/S)
- Prevention: management
- Colostrum
Johne’s disease is caused by _____.
Bonus: what is the morphology of this organism?
Mycobacterium avium subspecies paratuberculosis (MAP)
Morphology: small rod shaped bacterium
The primary route of infection of Johne’s disease is _____.
Ingestion (manure, contaminated milk, water, feed)
other: intrauterine
What CS are seen during the advanced stages of john’s disease?
- Severe emaciation
- Diarrhea
- Bottle jaw
- wasting
What is the cause of the development of bottle jaw in Johne’s disease?
-Chronic protein losing enteropathy
What tests can be performed to diagnose Johne’s disease?
- Culture (isolate from manure, tissue, environmental samples)
- PCR, ELISA, AGID (milk or blood)
What are some prevention methods for Johne’s disease?
- ID shedding animals and eliminate from the herd
- Test entire herd with ELISA
- Test positive with PCR
- Cull based on positive test
- Retest in 6-12 months
TRUE/FALSE
The main CS of Bovine Viral Diarrhea is secretory diarrhea.
FALSE
It mainly cause reproductive and respiratory signs.
Winter dystentery is caused by ____.
Bovine coronavirus
What are the characteristics of bovine coronavirus?
- Enveloped virus that is sensitive to heat and common disinfectants
- Can survive in cold temperatures
- Stable at pH 3-8 s can survive in the gut
The most common route of transmission for winter dysentery is _____.
Fecal-oral route
_____ are thought to be a reservoir for winter dysentery.
Wild ruminants
TRUE/FALSE:
During an outbreak, morbidity is low but mortality is high.
FALSE
Morbidity is high and mortality is low
What age of cows is at higher risk for winter dysentery?
2-6 y/o
What factors may increase transmission of winter dysentery?
- Close confinement of cattle
- Poor manure handling
What CS characterize winter dysentery?
- Anorexia
- Fever
- Liquid/bloody diarrhea
- frequently associated with respiratory signs
- Drop in milk production
TRUE/FALSE
Incubation time of winter dysentery is 3-8 days & diarrhea exists for 1-6 days. Fecal and nasal shedding occurs for 1-4 days.
TRUE
How can winter dysentery be diagnosed?
- Detect with electron microscopy, ELISA, RT-PCR on intestinal tissues, feces, fectal or nasal swab fluids
- Samples must be collected within 1-3 days of onset of diarrhea. Stored in PBS or scell culture medium & stored frozen for shipment
What are the treatment options for winter dysentery?
- Symptomatically or oral fluids to alleviate dehydration
- Antibiotics for secondary bacterial infections
TRUE/FALSE
Winter dysentery can be prevented with a vaccine since it is caused by a virus.
FALSE
State the clostridial agent for each disease:
- Myonecrosis
- Black Disease
- Bacillary Hemoglobinuria
- Braxy
- Clostridial Enterotoxemia
- Hemorrhagic Bowel Syndrome
- Clostridium novyi Type A
- Clostridium novyi Type B
- Clostridium novyi type D, Clostridium hemolyticum
- Clostridium septicum
- Clostridium prefringens
- Clostridium prefringens Type A
What is the myonecrosis caused by clostridium novyi Type A?
- Massively edematous wound infection
- Affects bighead in young rams
- Pathogenesis mediated by alpha toxin
Black disease affects which organ?
-Liver → causes infectious necrotic hepatitis.
What is the most common sequelae to black diseases?
Parachute death
-venous congestion darkens the underside of the skin
How does the course of black disease differ in cattle vs. sheep?
1-2 hrs in sheep
1-2 DAYS in cattle
What diseases may follow fiscal infection?
- Black disease
- Bacillary hemoglobinuria
What gross lesions will be seen with bacillary hemoglobinuria?
- SubQ edema
- Petechial ecchymotic hemorrhage
- Hepatic infarcts → pathognomonic
TRUE/FALSE
Herd outbreaks of Bacillary hemoglobinuria occur in poorly drained pastures because spores accumulate in the environment.
TRUE
What kind of cows are most commonly affected by clostridium novyi D?
Most common in well nourished >1yr old calves
Malignant edema following wound infection, hemorrhage, edema and necrosis that spreads along the fascial planes from the point of infection is known as _____.
Braxy
How does a wound progress when infected with clostridium septicum?
aka braxy
Lesion starts warm and painful then becomes crepitant and cold
-Fever, anorexia an depression lead to death within 24 hrs
TRUE/FALSE
All clostridium prefringens types can be found within the intestines of normal animals.
TRUE
-Disease occurs when conditions favor multiplication of C. perfringins and accumulation of toxins
What types of clostridium prefringens are most common in N. America?
A, C, D
How can clostridial infections be prevented?
Vaccination against toxin
Describe the pathogenesis of hemorrhagic bowel syndrome.
- Sporadic, frequently fatal enteric disease
- Massive hemorrhage into the small intestine with subsequent intraluminal formation of large clots and casts of blood
- creates obstruction
What are the clinical signs of hemorrhagic bowel syndrome?
Peracute onset of progressive weakness and abdominal distention
- Papple
- Transient pings throughout
- Fluid splashing sounds
Describe what the findings would be for a cow with hemorrhagic bowel syndrome on the following tests:
- Rectal exam
- Transabdominal US
- Ruminal gas accumulation. Otherwise NL
2. Dilated loops of small intestine & clotted blood
What is the progression of hemorrhagic bowel syndrome?
Found dead or in septic shock within 24-48 hrs
What is the toxin and GI signs associated with Blister buttercup?
- Toxin: Ranunculin (glycoside converted to protoanemonin)
- Irritates mouth and causes gastroenteritis
- Excessive salivation
- Redenned oral mucosa
- Diarrhea, often bloody
What is the toxin and GI signs associated with Pokeweed?
Toxins include saponins, oxalates, and alkaloid phytolacine
Causes severe bloody diarrhea, colic, excessive salivation and death
What is the toxin and GI signs associated with Coffee weed?
Sesbania?
The toxin causes severe gastrointestinal irritation and liver
degeneration
-Severe hemorrhagic diarrhea and death
-Necropsy findings include severe hemorrhagic abomasitis, enteritis,
liver & kidney degeneration & necrosis
Treat with laxatives to clear GI tract & activated charcoal to bind toxins
____ are glycoproteins that inhibit protein synthesis.. They are one of the most toxic of known plant compounds. They are concentrated in the seeds and released following chewing.
Lectins
What plants contain lectins?
- Castor bean - ricin
- Rosary pea - abrin
- Black locus - robinin
What signs do lectins cause?
- Severe intestinal irritation and profound purgation
- Severe hemorrhagic diarrhea
- Abrupt stop to action
- Affected animals die of hypovolemic chock
What are medical treatment options for the ingestion of lectin containing plants?
- Activated charcoal
- Magnesium hydroxide
The principle toxin in Box, Box shrub is _____.
What are the signs?
Toxic alkaloids
Signs: Severe gastroenteritis, colic, hemorrhagic diarrhea
What are some common causes of rectal prolapse?
- Tenesmus (coccidiosis, colitis, etc)
- Dysuria (cystitis, urolithiasis, dystocia, neoplasia)
- Neuropathy (‘riding’ during estrus, spinal lymphoma, spinal abscess)
- Chronic coughing (BRD)
- Genetics
How is rectal prolapse treated?
- Purse string suture pattern using umbilical tape
- 5-10 days
- Surgical amputation
- Rectal ring
TRUE/FALSE
Rectal prolapse is usually a primary problem that can be permanently resolved.
FALSE
Must treat underlying issue
Recurrence is common