Dr. Darin Madson - Deciphering Diarrhea - What's Important

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Deciphering Diarrhea - What's Important - Dr. Darin Madson, Iowa State University, from the 2012 Allen D. Leman Swine Conference, September 15-18, St. Paul, Minnesota, USA.

More presentations at http://www.swinecast.com/2012-leman-swine-conference-material

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Dr. Darin Madson - Deciphering Diarrhea - What's Important

  1. 1. Deciphering Diarrhea What’s Important Darin Madson Iowa State University madson@iastate.edu
  2. 2. Goal of the PresentationTo firm-up diagnostic issues as it relates to swine diarrhea
  3. 3. Understanding the GI Tract• Small intestinal disease – Normal frequency – High volume (watery) – If blood: digested (brown) – dark green to brown watery stool• Large intestinal disease – High frequency – Low volume – Mucous – If blood: fresh (red) Dysentery – Anorexia
  4. 4. Understanding the GI Tract• Viral Diseases – Virus is present a short time – Select acute pigs for testing (1st 24 hours of diarrhea)• Bacterial Diseases – Therapeutic antibiotics interferes with testing – Select untreated pigs for testing• Intestinal mucosa autolyzes rapidly – Select only euthanized pigs for testing – Fix intestinal segments within 15 minutes of death• Lesions are often segmental in intestine – View many segments at each “level” – Collect multiple segments of each “level”
  5. 5. Understanding the GI Tract• Normal flora – More commonly referred to as the microbiome – Extensive population of bacteria • ~1014 bacterial – Numerous benefits to the pig • Break-down of feed stuffs (metabolic issues) • Water transport • Aids in immunity We are only starting to understand the diverse interaction of the swine microbiome
  6. 6. Diagnostic Interpretation• Understand testing limitations – A positive result does not always indicate cause – A negative result does not always exclude a cause• Beware of your own and other’s bias – Experience is invaluable, but can lead you astray – Be objective during investigations• Interpretation = combining the history with the clinical information and the diagnostic results to make a final judgment; case diagnosis
  7. 7. NEONATAL DIARRHEA
  8. 8. Neonatal Diarrhea Concepts• New-born pigs = sterile gastrointestinal tract• At birth – Race for bacterial colonization – Overgrowth is common – Environment and immunity play a role Neonatal diarrhea is: Often infectious and can be associated with management issues
  9. 9. Management Influences Transmission Dam immunity• Gestation • Gestation – Stalls vs. pens vs. open lots – Stalls vs. pens vs. open lots• Parity distribution • Parity distribution• Gilt acclimation • Vaccination – feed back• Housing design • Sow milking• Sanitation – Feeding practices• Flooring material – Sow comfort• Room management • Pig suckling – pig flow
  10. 10. TGEV Rotavirus (A , B, C) E coli CoccidiosisC perf. type CC perf. type AC difficile 1 2 3 4 Weeks of Age
  11. 11. Neonatal Diarrhea – Game Time
  12. 12. POST-WEANING AND FINISHING DIARRHEA
  13. 13. Immediate Post-Weaning Diarrhea Group A only 6% • Rotaviruses & hemolytic E. 33% ≤7 8 - 20 coli 51% 10% 21 - 42 > 42 – ~ 5 days post-weaning. Group B only • E. coli disease 30% 28% ≤7 – Mostly hemolytic strains 7% 8 - 20 21 - 42 35% > 42 Pathogenic E. coli identified ETEC Group C only F5(K99), F6(987P),Criterion F4(K88) F18 F41 10% ≤7Hemolytic 29% All (not discriminatory) None 8 - 20colonies 56% 21 - 42 Modified from 10th ed: disease of swine > 42 5% KJ Yoon – rotavirus information
  14. 14. Salmonella sp.• S. typhimurium • Diarrhea • Small and large intestine affected • Serogroup B• S. choleraesuis • Septicemia then diarrhea • Serogroup C1• Other isolates • Salmonella spp. isolated from pigs may not be contributing to clinical illness • Carrier pigs• Isolation • Direct culture vs. enrichment
  15. 15. Porcine Proliferative Enteropathy• Proliferative hemorrhagic enteropathy • PHE is “acute hemorrhagic” form• Porcine intestinal adenomatosis • PIA is “proliferative” form• Necrotic enteritis • NPE is “chronic” form• ALL the same disease, caused by: • Lawsonia intracellularis
  16. 16. Catarrhal Colitis• Caused by Brachyspira spp. including: – B. pilosicoli, B. murdochii, possibly others – Weakly hemolytic isolates• Mild diarrhea• Lesions limited to colon• Diagnosis – culture followed by PCR
  17. 17. Swine Dysentery• Associated with strongly beta-hemolytic Brachyspira spp. – B. hyodysenteriae – B. hampsonii• Lesions limited to large intestine – mucohemorrhagic to necrohemorrhagic typhlocolitis
  18. 18. Non-infectious diarrhea Non-specific colitis• Inflammation without pathogen detection – “Dysbacterosis” – Increasing prevalence in diagnostic submission – Disruption in the colonic microbiome • Diet change Can led to infectious diarrhea • Diets ingredient change • Water quality • Mineral levels or mycotoxins – Treatment, duration, and immunity related to an infectious pathogen Mucus – feature or colitis and is not always associated with Brachyspira sp. infection
  19. 19. Non-infectious diarrhea Osmotic diarrhea• Water quality issues – Sulfates and total dissolved solids (TDS) – Prevent colonic water absorption
  20. 20. Grow/Finish Diarrhea – Game Time
  21. 21. Take Home Points• Neonatal diarrhea – Mostly infectious……..but – Related to environment, immunity, and etc. – Race for bacterial colonization• Post-weaning/grow-finish – Mixture of infectious and non-infectious – Diets plays a large role – Often over-interpretation of infectious pathogen detection
  22. 22. Keys to Diagnostic Success1. Sample quality and selection • Non-treated & acutely affected2. Diarrheal causes are not always infectious • Feeding or nutritional microbiome changes3. Pathogen detection ≠ cause • Do not over-interpret results; context4. Be observant (unbiased) • Large bowel vs. small bowel disease • Diet changes
  23. 23. Questions?Thanks for listening

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