Disease Outbreaks Steps of Investigation

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Disease OutbreaksSteps of Investigation

• Susan Chandler, R.N., MPH
• P. H. Nurse Consultant
• N. C. Immunization Branch

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Steps of Investigation
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Steps of Investigation

• Receiving Reports
• Confirming/Defining Cases
• Investigating
• Implementing Controls
• Managing Cases
• Managing Contacts
• Analyzing Effectiveness of Controls
• Reporting

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Step 1Receiving Reports

• Goals
• Protection
• Reduced exposure
• Limited spread

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What Illnesses are Reportable?

• Summary on N. C. Report Card
• Bold Italics
• Within 24 Hours
• All Others
• Within 7 Days

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Who Must Report?

• Physicians
• Medical and laboratory facilities
• Local health directors
• School principals and day care operators

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Immunity of Persons Who Report

• A person who makes a report pursuant to the
  provisions of the law shall be immune from any
  civil or criminal liability that might otherwise
  be incurred or imposed as a result of making that
  report.

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Confidentiality of Records

• All information and records, whether publicly
  or privately maintained, that identify a person
  who has AIDS virus infection or who has or may
  have a disease or condition required to be
• reported pursuant to the provisions of the
  law shall be strictly confidential...

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How Do You Insure that Reporting Occurs?

• Encourage communication within healthcare
  community
• Build relationships with local providers
• Educate, educate, educate!!!

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Example Reporting Pertussis

• Bold italics
• Reportable within 24 hours of diagnosis (even
  suspicious of disease) .

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Step 2Confirming and Defining Cases

• Lab Confirmation
• Appropriate test
• Appropriate time
• Appropriate method
• Appropriate handling

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Confirming and Defining Cases

• Case Definition
• Clinically compatible case symptoms fit the
  clinical presentation of disease
• Confirmed case clinically compatible and either
  lab confirmed or epi-linked
• Probable case meets the clinical case
  definition and is not lab confirmed or
  epi-linked

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• Case Definition-continued
• Suspect case person whose medical history and
  symptoms suggest infection
• Lab-confirmed case one or more laboratory
  diagnosis methods present positive results
• Epi-linked case patient has had contact with a
  diseased person

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Defining a Case

• Gather disease specific information
• Type of symptoms
• Duration of symptoms
• Exposure to someone with like symptoms
• Laboratory diagnostics

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Significance of Case Definition

• If you dont have lab results to confirm a case,
• use the case definition to see if the symptoms
  rise to a level of suspicion or

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• Or..
• If symptoms are intense and yet lab results show
  (perhaps a false) negative,
• you might still call it a case, based on case
  definition standards having been met

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Example Pertussis...

• Clinical Case Definition Cough illness lasting
  at least 2 weeks with one of the following
• Paroxysms of coughing or
• Inspiratory whoop or
• Post-tussive vomiting
• And without other apparent cause (as reported by
  health professional)

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Example Pertussis...

• Confirmed Case
• An acute cough illness of any duration
  associate w/ B. pertussis isolation, or
• A case that meets clinical case definition and
  is confirmed by PCR, or
• A case that meets clinical definition and is
  epi-linked to a case confirmed by culture or PCR.

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Example Pertussis...

• Probable Case
• Meets clinical case definition,
• Is not lab confirmed, and
• Is not epi-linked to lab confirmed
• case.

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Step 3Investigation

• Local Health Director shall investigate...
• cases of communicable
• diseases and conditions
• reported to the local health director.

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Investigation

• Determine if illness warrants investigation
• Identify other similar cases previously or
  currently reported
• Determine if illness can be considered
  transmissible person to person.

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Investigation

• Determine if reported case is one for which every
  case will be investigated
• Determine if reported case is similar to other
  reported cases
• Determine if reported case is in a special
  high-risk population

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Investigation

• Determine if diagnosis of illness has been made
• Determine if reported case has appropriate
  diagnostic labs, or meets case definition, or is
  epi-linked

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Investigation

• Inform appropriate individuals and/or
  organizations of investigation activities
• Determine message to be relayed to individual
  and/or organization

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Example Pertussis

• Disease transmits person to person
• Every case is to be investigated
• Have you had other recent cases? Is this case
  epi-linked?
• Is this case or are contacts a high risk group?

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High Risk for Pertussis

• Infants
• Close contact of infant
• Day care w/ young children
• Immunodeficient
• Health Care Worker-direct patient care
• Baby sitter
• Woman who is pregnant

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Step 4Implementing Controls

• The local health director
• has the authority and
• responsibility to
• implement control
• measures to prevent the
• spread of reportable
• communicable disease...

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The Local Health Director has...

• The authority to
• Isolate
• The authority to...

Quarantine
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All Persons...

• Shall comply with control measures, including
  submission to examinations, and tests, prescribed
  by the Commission subject to the limitations of
  G. S. 130A-148
• Control of Communicable Diseases Manual (American
  Public Health Association) is codified in N.C.
  General Statutes as the requirements for control
  measures.

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Do you really want to wait?
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Getting Started...

• Report in a timely manner
• All facilities - hospitals, doctors office,
  school, college infirmary or child care nurse,
  report to local health department immediately
• Time is of the essence to interrupt the spread of
  disease
• Dont wait for Lab confirmation

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Your Local Health Director

• Involve the Health Director early

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An Epi Team

• Notify and involve early
• Many steps need to be taken in a short period of
  time
• Epi-Team is critical to meeting the needs

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Step 5Managing Cases

• Ensure that case is appropriately managed in
  order to prevent transmission of illness

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Managing Cases

• Determine if still infectious-obtain lab
  confirmation
• While awaiting lab results, assume this is a case
  if illness meets case definition
• Follow guidelines in Control of CD Manual to
• Require personal practices to
• prevent transmission
• Require medical treatments to
• prevent transmission

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Example Pertussis

• Confirmatory Labs-
• DFA (smear)
• Culture
• PCR (Polymerase Chain Reaction)

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Example Pertussis

• Isolate-remove from presence of young
  children/infants until case receives 5 days of
  minimum of 14-day Rx of antibiotic
• Without Rx with antibiotic, isolate for 3 weeks
  from cough on set

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Step 6Managing Contacts

• Identify individuals at risk of infection as a
  result of exposure to known source
• Ensure that contacts identified receive
  appropriate preventive treatment and that
  appropriate surveillance of contacts is conducted

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Managing Contacts

• Determine if contact is susceptible to infection
  to which exposed
• Identify nature and duration of exposure
• Determine if exposure is likely to have resulted
  in transmission of agent

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Managing Contacts

• Determine if contact is currently in another
  public health jurisdiction If so, inform
  appropriate public health authority
• Determine if contact is infected or ill. If so,
  manage as case
• Inform contact about a) exposure
• b) incubation period c) Signs/symptoms d) Seek
  medical attention and contact public health
  authority if becomes ill

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Managing Contacts-continued

• Determine if contact should be placed under
  active surveillance
• Follow guidelines for contact management in
  Control of CD Manual
• or current CDC recommendations

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Example Pertussis

• Inadequately immunized household contacts years should be excluded for 21 days after last
  exposure or until received 5 days of 14 day
  treatment of antibiotic
• Immunize by guidelines
• A 14-day course of erythro. For household and
  close contacts regardless of vaccine Hx and age

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Step 7Analyze Effectiveness of Controls

• Determine if there are any additional cases which
  meet clinical and/lab criteria of case definition
• If additional cases identified, determine if
  onset occurred after last date cases should have
  occurred-? controls

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Analyze Effectiveness of Controls

• If case occurred beyond last date cases should
  have occurred, determine if case resulted from
  exposure to or acquired from 1) original source
  2) any original contacts
• Assess application of controls
• Determine if changes in investigation or
  management of cases or contacts should have
  occurred

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Step 8Reporting the Event

• Call Regional Immunization Consultant as soon as
  case reported to LHD
• Complete surveillance form required for
  reportable disease

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