Reporting and Investigation of Botulism

Table of Contents

A. Purpose of Surveillance and Reporting

  • To assist in the diagnosis and treatment of potential cases.
  • To identify sources of public health concern (e.g., a commercially-distributed food product) and stop transmission from the source.
  • To properly classify reported cases as foodborne, infant or wound botulism.
  • To identify cases and clusters of human illness that may be associated with a bioterrorist event.

B. Laboratory and Healthcare Provider Reporting Requirements

Iowa Administrative Code 641-1.3(139) stipulates that the laboratory and the healthcare provider must immediately report any suspected or confirmed case. The reporting number for IDPH Center for Acute Disease Epidemiology (CADE) is (800) 362-2736. If you call after business hours, you may call the Iowa State Patrol Office at (515) 323-4360. They will page a member of the on-call CADE staff.

Laboratory Testing Services Available

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

C. Local public health agency (LPHA) and Follow-Up Responsibilities

Case Investigation

  1. LPHA should immediately call IDPH Disease Reporting Hotline (800) 362-2738 upon learning of a suspected case of botulism.

  2. Case investigation of botulism in Iowa residents will be directed by IDPH Center for Acute Disease Epidemiology (CADE) in collaboration with local and federal agencies.
  3. Following notification of IDPH, the LPHA may be asked to assist in investigating any case(s) of botulism. The investigation form is available from the Iowa Disease Surveillance System (IDSS).  Use the following guidelines in the investigation:
  4. Determine type of botulism: Foodborne botulism is a true medical and public health emergency, and should be investigated as such. Infant and wound botulism do not require the same investigative urgency, so it is essential to determine which illness is occurring.

Foodborne botulism

The source of exposure and names of all potentially exposed persons must be identified.  The case must be interviewed concerning possible food sources. In most cases, information will need to be obtained from family members or other close contacts, since the case’s condition will most likely not permit interviewing. Use of IDPH Enteric Disease Investigation Report will facilitate recording information pertinent to foodborne transmission. Please contact IDPH Center for Acute Disease Epidemiology for assistance in determining possible food sources. Use the following guidelines to investigate.

  1. Identify all home-canned foods eaten during the week prior to symptoms. The most suspect foods are those eaten less than two days before onset, low in acid, and not eaten by persons who stay well. Keep in mind that some cases may experience less severe symptoms later than the identified case.
  2. Identify all commercially canned foods eaten during the week prior to the onset of illness. For each implicated food, determine and record the brand, manufacturer, package size, lot number, and place and date of purchase.
  3. Identify all sausage and other preserved meats eaten during the week prior to onset of illness. Meat or potato products not adequately refrigerated should also be suspected.
  4. Identify all smoked or otherwise preserved fish eaten during the week before onset of symptoms.
  5. Identify other potentially exposed persons. All persons who have eaten implicated foods must be reached as soon as possible and advised to seek healthcare immediately. Depending on the time of ingestion, other exposed persons might be candidates for purging. At the very least they should be under close medical supervision.
    1. Obtain the name, address, and telephone number of every person who may have eaten the suspected food item.
    2. Obtain the name, address, and telephone number of every person who may have the suspect home-processed food in his or her possession.
    3. Remove implicated food items from the environment for testing. The University of Iowa State Hygienic Laboratory will coordinate testing of food samples.

Wound botulism: Investigate to determine the cause and do possible traceback.

Infant botulism: Ask caretakers about honey consumption; otherwise, extensive epidemiological follow-up is not usually required. Prevention education should be provided. 

Adult infectious botulism: As with infant botulism, extensive epidemiological follow-up is not usually required. Prevention education should be provided.

Botulism Testing

In all cases of suspected botulism, the Center for Acute Disease Epidemiology and the case’s healthcare provider determine the appropriateness of botulism testing, based on available clinical and epidemiological data.  Arrangements are then made to submit appropriate specimens.

Botulism Antitoxin

Antitoxin therapy is only administered to adult patients with foodborne or wound botulism. Antitoxin is a horse serum product, and may cause serum sickness in approximately 20% of treated persons. Antitoxin is not indicated in cases of infant botulism. The healthcare provider, in consultation with the Center for Acute Disease Epidemiology must determine the need for antitoxin therapy. CDC must release and approve its use. If needed, antitoxin will immediately be flown to the nearest airport. LPHAs should be prepared to assist with logistic arrangements. The decision to administer antitoxin must be made immediately. The longer the wait, the less effective it will be. Testing for the presence of toxin or bacteria in clinical specimens can take many days. The decision to administer antitoxin cannot wait for testing results to confirm the infection.  Tests to rule out myasthenia gravis, stroke and Guillain-Barre syndrome should be completed before antitoxin is released by the Centers for Disease Control and Prevention (CDC).