Neonatal diarrhea Flashcards
What are the 5 common causes of diarrhea in calves <21 days of age?
Enterotoxigenic E. coli
Rotavirus
Coronavirus
Cryptosporidium parvum
Salmonella
What age calves get enterotoxigenic E. coli
< 3 days
What age calves get attaching and effacing E. coli
20-30 days
What age calves get rotavirus?
5-15 days
What age calves get coronavirus?
5-21 days
What age calves get Cryptosporidium?
5-35 days
What age calves get Salmonella?
5-42 days
What age calves get Clostridium perfringens C and D?
5-15 days
What age calves get Eimeria?
> 30 days
What disease causes unique diarrhea symptoms? What are the symptoms?
Salmonella- yellow to white diarrhea, fever, dysentery, abdominal pain, tenesmus
What is the primary goal for treating acute undifferentiated diarrhea in calves?
Correct dehydration, acid-base status, electrolyte abnormalities, and negative energy balance until the GI tract has healed and the diarrhea has resolved
What pathogen causes disease in calves, piglets, lambs, and foals? What term is used to describe it?
Enterotoxigenic E. coli- called colibacillosis
Describe the bacteria enterotoxigenic E. coli
Gram negative rod, part of the normal flora, non-invasive, adheres to small intestine and colonizes it producing enterotoxins
What are the different strains of enterotoxigenic E. coli?
O- somatic (LPS/endotoxin)
K- capsular
H- flagellar
F- fimbrial (highly immunogenic)
What is the primary virulence factor for enterotoxigenic E. coli?
Adhesions in their pili or fimbriae- allows them to adhere to intestinal villus epithelial cells and prevents peristaltic elimination
What is the most common and second most common adhesin antigen for enterotoxigenic E. coli?
F5- makes heat stable enterotoxin
F41- fimbrial antigen
Describe the pathophysiology of enterotoxigenic E. coli
E. coli is ingested, multiplies in the ileum and ascends to the small intestine where it adheres to epithelial cells and colonizes the gut
At what age are calves resistant to adhesion of enterotoxigenic E. coli?
Day 4
How does enterotoxigenic E. coli cause disease?
Produces heat-stable enterotoxins altering the movement of ions and water, produces cGMP, causes hypersecretion (particularly of chloride) in cryptal cells, inhibits Na-Cl cotransporter, causes excessive loss of Na and Cl into intestinal lumen
How is enterotoxigenic E. coli transmitted?
Fecal-oral route (calf to calf or dam to calf, or survives in environment)
What are the risk factors for enterotoxigenic E. coli?
Age (<3 days), lack of colostral immunity, environmental factors and hygiene, calves born later than expected
What are the clinical signs associated with enterotoxigenic E. coli?
Yellow watery diarrhea (no blood or tenesmus), increased fecal pH, starting between 12 hours and 4 days old
How is enterotoxigenic E. coli diagnosed?
Age of animal and clinical signs
Need to detect specific enterotoxic strain to confirm diagnosis (PCR, IFA)
On necropsy- fluid filled intestines with an intact mucosa histologically, with clusters of gram negative rods adhered to villi of jejunum and ileum
How is enterotoxigenic E. coli treated?
Correct dehydration and electrolyte abnormalities (oral/IV fluids), possible use of antibiotics (ceftiofur, aminoglycosides, potentiated sulfas), possible use of immune stimulants
How is enterotoxigenic E. coli controlled?
Provide good colostrum management, vaccinate dams in late gestation with F5 antigen, oral administration of anti-K99 monoclonal antibodies in neonates (expensive), provide clean environment
What kind of virus is rotavirus?
From family reoviridae, double-stranded RNA virus with 7 serologic classifications, non-enveloped, environmentally stable
Describe the pathophysiology of rotavirus
Calves are infected from other calves, the environment, or dams; virus incubates for 24 hours then infects brush border of epithelial cells in small intestine causing sloughing and villus atrophy- makes enterocytes incapable of synthesizing enzymes and secretions, causes immature replacement of cells that are incapable of absorbing nutrients causing lactose intolerance and maldigestive/malabsorptive diarrhea, acts as enterotoxin affecting intracellular calcium, only lasts 24 hours but diarrhea continues until replacement cells mature
What clinical signs are associated with rotavirus?
High morbidity and low mortality, white-yellow watery diarrhea without blood or tenesmus, starting between 4 and 7 days old
How is rotavirus diagnosed?
PCR, ELISA (may get false positive), electron microscopy, IFA, latex agglutination
How is rotavirus treated?
No specific treatment- supportive care only
How is rotavirus controlled?
Isolate new animals, handle neonates prior to adults, isolate sick calves, disinfect hutches, vaccinate dams prior to birthing
Describe the coronavirus
Pneumoenteric virus- single stranded RNA with large envelope and 4 structural proteins, has 5 antigenic groups, bovine is group 2
How is coronavirus transmitted?
Fecal oral route- calf to calf, from environment, or from dam, shed more during the winter and at time of parturition, can also spread through respiratory secretions
Describe the pathophysiology of coronavirus
24-72 hour incubation period where virus infects villus epithelial cells and crypt cells of large and small intestines, causes atrophy of villi and fusion to adjacent villi causing proliferation of immature villi which have impaired electrolyte transport and intestinal enzyme loss. Diarrhea is due to maldigestion/malabsorption. Can also infect upper respiratory epithelium causing rhinitis, coughing, sneezing, and predisposing to secondary bacterial infection.
What clinical signs are associated with coronavirus?
White-yellow diarrhea with no blood or tenesmus in calves 4 days to 1 month old, depression, anorexia, dehydration, hypoglycemia, metabolic acidosis, electrolyte abnormalities
How is coronavirus diagnosed?
PCR, electron microscopy, IFA, histopathology with villus atrophy and fusion of villi in small intestines and loss of colonic ridges in large intestine
How is coronavirus treated and controlled?
No specific treatment- supportive care only
Provide good colostral immunity, vaccinate dams in late gestation, decrease exposure to feces/clean environment
What type of organism is cryptosporidium parvum?
A protozoa
Describe the lifecycle of cryptosporidium
Oocysts are ingested and multiply in brush border of ileal intestinal epithelium -> excystation -> motile sporozoites adhere to villus epithelial cells, are enveloped and become trophozoites -> multiply asexually (merogony) to produce type I meronts -> infect additional enterocytes -> create type I and II meronts containing merozoites -> merozoites released from type II meronts and infect enterocytes and multiply sexually (gametogony) to form male and female microgamont -> microgametes released from male microgamont to fertilize female macrogamete and form zygote -> undergoes meiosis (sporogony) to form oocyst with 4 sporozoites
What are the two types of oocysts of cryptosporidium?
Thin walled- rupture in intestinal lumen resulting in autoinfection
Thick walled- passed in feces in sporulated form, immediately infective, huge numbers of infective oocysts shed in feces
What is the prepatent period of cryptosporidium?
2 to 7 days
Are animals that recover from cryptosporidium chronic carriers?
No
Describe the pathophysiology of cryptosporidium
Villus atrophy and hyperpalstic crypt epithelium impair absorption and digestion resulting in malabsorption and altered electrolyte transport
What clinical signs are associated with cryptosporidium?
White-yellow diarrhea (may have blood) in calves 5 days to 1 month old, depression, anorexia, dehydration, hypoglycemia, metabolic acidosis, electrolyte abnormalities
How is cryptosporidium diagnosed?
Iodine stained wet mount of feces, acid-fast stain of fecal material, saffranin-methylene blue stain of fecal material, fecal float, IFA, histology of distal jejunum and ileum
Definitive diagnosis requires oocysts in feces or trophozoites/schizonts in epithelium + characteristic histologic lesions
How is cryptosporidium treated?
Halofuginone experimentally used, otherwise no treatment
Is cryptosporidium zoonotic?
Yes
What type of bacteria are Salmonella?
Gram negative facultative intracellular bacteria of family Enterobacteriaceae
What are the most common serotypes of Salmonella in calves?
Salmonella enterica serotype dublin and Salmonella enterica serotype typhimurium
How is Salmonella spread?
Fecal oral route, directly or indirectly. Persists in environment for a long time.
Describe the pathophysiology of Salmonella?
After ingestion, bacteria invades intestinal wall and progresses to mesenteric lymph nodes, produces exotoxins, spread to liver and bloodstream causing septicemia, spreads to ileum, cecum, and colon creating enteritis and malabsorptive/maldigestive diarrhea
What are the two exotoxins produced by Salmonella?
Enterotoxin- stimulates prostaglandin release, causes increased chloride and water secretion and decreased sodium absorption
Cytotoxin- inhibits protein synthesis in mucosal cells causing cell damage and increasing permeability of cells and cell junctions
What clinical signs are associated with Salmonella?
May see sudden death, bloody diarrhea with mucosal shreds and tenesmus, fever, poor appetite, lethargy, leukopenia, etc.
How is Salmonella diagnosed?
Fecal culture, PCR (possibly too sensitive), serology (only used for monitoring) CBC for systemic signs
How is Salmonella in calves treated?
Antibiotics (ceftiofur, amoxicillin, oxytetracyclien)- however use is controversial, NSAIDs, fluids
How is Salmonella controlled?
Vaccination with autogenous vaccine or mutant strain, general farm and calf hygiene
Describe the pathophysiology of attaching and effacing E. coli
Attaches to microvilli from enterocytes, doesn’t produce enterotoxins but produces verotoxins causing necrosis and sloughing of enterocytes
What are the clinical signs associated with attaching and effacing E. coli?
Watery bright red diarrhea in calves 18-21 days old
Describe the pathophysiology of clostridium perfringens type C
Adheres to small intestinal villi and multiplies to produce beta toxin (necrotizing, hemorrhagic), causing toxemia and death
What are the clinical signs associated with clostridium perfringens type C?
Death due to hemorrhage and toxemia > diarrhea
Usually in calves with good milk intake
How is clostridium perfringens type C diagnosed?
Histological changes of small intestine with isolation of the toxin
How is clostridium perfringens type C prevented?
Vaccinate dam at 6 weeks and 2 weeks before calving, give antitoxin to neonates
What are the causative agents of coccidiosis?
Eimeria zurneii and Eimeria bovis
Describe the pathophysiology of coccidiosis
Oocysts ingested from environment cause mild enteritis in small intestine and severe pathology of large intestine damaging the cecum and colon and causing diarrhea
What is the prepatent period for coccidiosis?
16-30 days
What clinical signs are associated with coccidiosis?
Bloody diarrhea with mucus, mucosal shreds and tenesmus in juvenile calves
How is coccidiosis diagnosed?
Quantitative fecal egg count (>5k/g) typhlitis and colitis on histopathology
How is coccidiosis controlled?
Decrease stocking rates, do not feed directly on the ground, feed oral anticoccidial agents (ionophores, amprolium, sulfonamides)
What type of giardia infects calves?
Giardia duodenalis
How is giardia diagnosed in calves?
Presence of motile trophozoites in fecal wet mount, however may be normal in their feces
How is giradia treated?
Fenbendazole, however may be re-infected 28 days later
What are the general vaccine recommendations for dairy and beef cattle?
Vaccinate all pregnant females (heifers twice) with:
Rotavirus, coronavirus, ETEC
Vaccinate calves deprived of colostrum with:
What are the general vaccine recommendations for dairy and beef cattle?
Vaccinate all pregnant females (heifers twice) with:
Inactivated rotavirus and coronavirus, ETEC antigen
Vaccinate calves deprived of colostrum with:
Modified live rotavirus and coronavirus, ETEC monoclonal antibodies
Which vaccines may be recommended in specific dairy and beef operations?
Autogenous Salmonella bacterin, Clostridium perfringens type C bacterin
How will a calf with 6% dehydration appear?
Normal
How will a calf with 6-8% dehydration appear?
Depressed with 2-4mm sunken eye and 1-3s skin tenting
How will a calf with 8-10% dehydration appear?
Depressed with 4-6mm sunken eye and 2-5s skin tenting
How will a calf with 10-12% dehydration appear?
Comatose with 6-8mm sunken eye and 5-10s skin tenting
How will a calf with >12% dehydration appear?
Dead :(
How would you assess for metabolic acidosis in calves?
Blood gas analysis (ideal)
TCO2 from serum or plasma to estimate base deficit
Depression scores
Are younger or older calves more tolerant of a base deficit?
Older calves >8 days
Why should you not use plasmalyte in calves?
It contains gluconate which they can’t metabolize
What is the cutoff for which calves’ dehydration can be fixed with oral fluids?
Calves <8% dehydrated can receive oral, if >8% they need IV
What should you consider in terms of osmolality when providing oral fluids for calves?
Use a hyperosmotic solution if milk is withheld, use a iso-osmotic solution if you continue feeding milk
What are characteristics of a good oral fluid for dehydrated calves?
Proper osmolality considering milk intake, 90-130mM/L sodium, neutral amino acids like glycine or glutamine, an alkanizing agent 40-80mM/L (acetate, propionate, bicarbonate), strong cation presence 60-80mEq/L, contains glucose, should be used in conjunction with milk, should be warmed
How do you calculate the fluid deficit in a dehydrated calf?
Body weight x % dehydration = liters of replacement fluid needed
Max rate is 80mL/kg/hr, replace over 2-6 hours
What kinds of fluids are used to correct acidosis?
LRS if acidosis is more mild, bicarbonate if acidosis is severe (pH <7.2, BE <-15)
How do you calculate the amount of isotonic bicarbonate needed to correct acidosis?
Base deficit x 0.6 x body weight = mEq HCO3- required, divide by 12 for g NaHCO3 required
What is the rate of maintenance and continuing loss of fluids in calves?
Maintenance- 60-80ml/kg/day
Continuing loss- 20-60ml/kg/day
What use does hypertonic saline have in dehydrated calves?
Can rapidly expand plasma by drawing water into the extravascular space
Which calves with diarrhea require antibiotics?
Those with a fever, concurrent infection, decreased suckle reflex, blood or mucosal shreds in feces, or FPT
What antibiotics are used for calf diarrhea?
Ceftiofur IM, amoxicillin or ampicillin IM or PO, amoxicillin-clavulanic acid PO, potentiated sulfonamides IV
