Shiga-toxin producing E. coli (STEC)


Cause: Shiga toxin-producing E. coli strains (STEC) including E. coli O157:H7.

Illness and treatment: Symptoms include abdominal cramping and severe or bloody diarrhea, usually without fever. Serious complications include hemolytic uremic syndrome (HUS) or thrombotic thrombocytopenic purpura (TTP). Most persons will recover without treatment. Treating STEC diarrhea with antibiotics may increase the risk of developing HUS.

Sources: Cattle are the most important source, although other herbivores may also carry STEC. Other known sources are unpasteurized milk, undercooked ground beef and contaminated raw produce. There can be person-to-person and animal-to-person transmission, but most cases are due to ingesting contaminated food or water.

Additional risks: Children under 5 years of age are diagnosed most frequently and are at the greatest risk of developing HUS.

Prevention: Wash hands thoroughly after contact with farm animals, visiting farm environments, and handling raw meat. Thoroughly cook ground beef and venison and wash preparation areas to avoid contaminating other foods. Wash produce thoroughly before eating.

Recent Washington trends: For the past several years there have been about 140 - 200 reports each year. STEC has a seasonal pattern. Most cases occur during summer and fall months.

Purpose of Reporting and Surveillance

  • To prevent further transmission from cases.
  • To identify outbreaks and potential sources of ongoing transmission.
  • To prevent further transmission from such sources.

Legal Reporting Requirements

  • Health care providers and Health care facilities: immediately notifiable to local health jurisdiction
  • Laboratories: Shiga toxin-producing E. coli (enterohemorrhagic E. coli including, but not limited to, E. coli O157:H7) and Shiga-toxin positive stool assays immediately notifiable to local health jurisdiction; submission required – isolate or if no isolate specimen associated with positive result, within 2 business days.
  • Veterinarians: animal cases may be notifiable to Washington State Department of Agriculture (see:
  • Local health jurisdictions: notifiable to DOH Office of Communicable Disease Epidemiology (CDE) within 7 days of case investigation completion or summary information required within 21 days