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