Reporting & Investigation of HUS and TTP

Table of Contents

A. Purpose of Surveillance and Reporting

  • HUS has been clearly demonstrated to be an important sequela of infection with E. coli EHEC strains. Because HUS cases generally come to medical attention, surveillance for HUS can serve as a marker for E. coli EHEC activity in the community and may lead to the identification of outbreaks at the state or local level. HUS is also an important event for assessing morbidity caused by E. coli EHEC strains.

  • TTP may also occur after infection caused by E. coli EHEC, therefore risk factors for the disease must be assessed as in HUS.

  • To identify whether the case may be a source of infection for other persons (e.g., a diapered child, child care attendee or food handler) and, if so, to prevent further transmission.
  • To identify transmission sources of public health concern (e.g., a restaurant or a commercially contaminated food product) and to stop transmission from such sources.

B. Laboratory and Healthcare Provider Reporting Requirements

Iowa Administrative Code 641-1.3(139) stipulates that the laboratory and the healthcare provider report any case of HUS or TTP related to E. coli O157:H7 or enterohemorrhagic E. coli (non-O157). The reporting number for IDPH Center for Acute Disease Epidemiology (CADE) is (800) 362-2736. After completing the investigation and gathering the information to complete the report form, enter information into IDSS, or FAX the report form with supporting laboratory documentation to (515) 281-5698 or mail (in an envelope marked "Confidential") to the IDPH/CADE, mailing address:

Iowa Department of Public Health, CADE
Lucas State Office Building, 5th Floor
321 E. 12th St.
Des Moines, IA 50319-0075

Laboratory Testing Services Available

After communicating with IDPH, contact the University of Iowa State Hygienic Laboratory (SHL) bacteriology for further instructions at (319) 335-4500.

C. Local Public Health Agency Reporting and Follow-Up Responsibilities

Case Investigation

  1. It is the LPHA responsibility to complete an HUS Case Investigation form by interviewing the case and others who may be able to provide pertinent information. The Iowa Disease Surveillance System (IDSS) is the preferred method of recording case information.

  2. Use the following guidelines to assist you in completing the investigation:

    • Accurately record the demographic information, date of symptom onset, symptoms, and medical information.
    • When asking about exposure history (food, travel, activities, etc.), use the incubation period of 21 days.
    • If possible, record any restaurants at which the case ate, including food item(s) and date consumed. If it is suspected that the case became infected through undercooked food, especially ground meats, refer to the Iowa Foodborne Illness Outbreak Investigation Manual.
    • Ask questions about unpasteurized juices and the water supply. >
    • Ask what grocery stores they have bought food at.
    • Household/close contact, pet or other animal contact, child care, and food handler questions are designed to examine the case’s risk of having acquired the illness from, or potential for transmitting it to, these contacts. Determine whether the case attends or works at a child care facility or is a food handler.
    • If several attempts have been made to obtain case information, but have been unsuccessful (e.g., the case or healthcare provider does not return calls or respond to a letter, or the case refuses to divulge information or is too ill to be interviewed), complete the case report with as much information as possible. Note on the form the reason why it could not be filled out completely, or if using IDSS, select the appropriate reason under the Event tab in the Event Exception field.
  3. After completing the case investigation form, enter the data into IDSS, FAX or mail to CADE. Reports may be faxed to CADE’s secured fax at 515 281-5698. The mailing address is:

    Iowa Department of Public Health
    Center for Acute Disease and Epidemiology
    321 East 12th Street
    Des Moines, Iowa 50319

  4. Institution of disease control measures is an integral part of case investigation. It is the LPHA responsibility to understand, and, if necessary, institute the control guidelines listed in the Controlling Spread tab.