EDEMA DSS

• Edema Disease - (Gut Edema, Escherichia coli enterotoxemia)
• Etiology

  • Escherichia coli - strains veroxytotoxin and Shiga-like toxin
• Transmission - Feco-oral transmission
• Affected groups - Rapidly growing weaner and pigs bet 4 and 12w of age
• •  F18 receptos important in ED are not fully expressed in pigs under 20d of age
• common in weaner to grower
• • Stxe is absorbed into circulation = vascular damage to the target organs
• In brain -> changes may be exacerbated by anoxia results from slow blood flow
• Ingestion of edema dss strains of E. coli↓ Colonization of bacteria in the intestine in pigs ↓Binds to the fimbrae receptors of the intestine ↓Release Shiga toxin 2e ↓Toxin is absorbed by the intestine into the circulation↓It targets the vascular endothelium w/c have high concentrations of toxin receptors↓Damage to vascular endothelium results in edema
• Outbreak is sudden in onset but short-lived, averaging 8d and seldom exceeding 15d
• PWD (post-weaning diarrhea) and ED occurs simultaneously
• • Case mortality rate varies -> 50-90%
• • Thriftiest pigs are most likely to be affected
• • Piglets die in 6-36 hrs
• While affected animals are still alive, fecal samples shld be cultured to determine presence of hemolytic E. coli
• ED principle is cytotoxic to Vero cells and may be useful in an assay system for dx
• Diagnostic Tests - Culture specific organism in the ileum, colon, mesenteric LN
• Lesions

   Facial edema Full stomach Mesenteric edema
• DDX

  • Pseudorabies
  • Viral encephalomyelitisof pigs (Teschen dss)
  • Encephalomyocarditis
  • Streptococcal meningitis
  • Salt poisoning
  • Organic arsenic poisoning
  • Mulberry heart dss
  • Poisoning by Amaranthus spp. And Chenopodium album
• Tx

  • None (ineffective)
  • Oral antimicrobial prophylaxis in affected pens, based on antimicrobial sensitivity testing
• • Sick pigs shld be treated initially w/ antimicrobials and electrolytes parenterally because they do not eat or drink
• Drug should be highly active in the lumen of gut - (fluoroquinolones, cephalosporins, apramycin, ceftiofur, neomycin, or trimethropim)
• Control/Prevention

  • Avoid drastic changes in diet
  • Passive immunity
  • Vaccination
  • Nurseries -> managedas all-in/all-out facilities and properly cleaned, disinfected and dried, and rested before the next arrivals
• • Both organic acids and medication w/ 50 ppm of enrofloxacin -> useful in controlling and/preventing PWD and ED
• • Tx w/ anti-VT2E serum -> provide protective immunity against ED in pigs
• Characterized by sc and subserosaal edema, progressive ataxia, recumbency and death
•  Associated w/ E. coli strains producing a Stx, Stx2e toxin, enters blood-stream and damages vessel walls
• 3 serogroups: O138, O139 and O141 and sometimes O147 ( all nearly alpha-hemolytic)
• Strains have adhesins that enable bacteria to colonize the intestine and elaborate protein exotoxins
• Bacteria colonize the SI w/o causing significant changes bbe means of adherence factor F18 (F107), usually F18ab or occasionally F18ac, as the fimbral adhesin
• Recovered pigs have protective antibodies to Stx2e