SHIGELLOSIS

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SHIGELLOSIS

• Maria del Rosario, MD, MPH
• WVDHHR/BPH/IDEP
• IDEP Training - February 2008

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Objectives

• To orient the audience about Shigellosis
  protocol.
• To discuss important aspects of Shigellosis
  (found on the protocol).
• To discuss key steps in the management of
  outbreaks.

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The Protocolhttp//www.wvdhhr.org/idep/pdfs/idep
/Shigellosis/Shigella_Protocol_07.pdf

• Health Care Provider Responsibilities
• Laboratory Responsibilities
• Public Health Action includes outbreak
  management
• Surveillance, Disease Prevention and Control
  Objectives
• Epidemiology
• Clinical Aspects
• Disease Prevention and Control including
  treatment
• References

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Epidemiology (1)

• Agent genus Shigella (bacteria)
• 4 species
• S. sonnei,
• S. boydii,
• S. flexneri,
• S. dysenteriae
• Reservoir Humans

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Epidemiology (2)

• Mode of Transmission
• Person-to-person fecal-oral, oral-genital, MSM
• Ingestion of contaminated food and/or drink
• Contact with contaminated inanimate objects
• Incubation Period
• Average 1-3 (up to 4) days
• Range 12 to 96 hours, up to a week

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Epidemiology (3)

• Infectivity
• Easily transmitted from person-to-person
• Low infective dose 10 to 100 organisms
• Asymptomatic individuals or those with mild
  illness can transmit the disease
• Antibiotic Treatment
• No treatment required
• Most infections are self-limited (48-72 hrs.)
• Reasons for treatment
• Decrease duration of diarrhea and eradicate
  bacteria from feces
• Prevent spread of disease

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Epidemiology (4)

• Public health implications
• Outbreak occurrence
• In crowded living conditions
• Reasons see Infectivity
• Increasing and rapid development of antibiotic
  resistance
• No vaccine

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Clinical Description

• Disease presentation, severity, and case fatality
  - dependent upon
• Host
• Bacterial serotype
• Disease Presentation
• Asymptomatic
• Fever, nausea, abdominal pain, vomiting,
  dysentery (blood, mucus)
• Convulsions, intestinal perforation, HUS

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Case Ascertainment (1)

• Clinical description
• An illness of variable severity characterized by
  diarrhea, fever, nausea, abdominal pain, and
  tenesmus. Headache and convulsions have been
  reported in some cases. Asymptomatic infections
  may occur.
• Laboratory criteria for diagnosis
• Isolation of shigella sp. from a clinical
  specimen.

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Case Ascertainment (2)

• Case classification
• Probable a clinically compatible case that is
  epidemiologically linked to a confirmed case.
• Confirmed a case that meets the laboratory
  criteria for diagnosis.

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• Public Health Action

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Is it reportable? (1)

• YES !
• WHAT and WHEN
• Sporadic cases - report within 72 hours of
  diagnosis
• Outbreak situation report IMMEDIATELY

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Is it reportable? (2)

• WHO
• Healthcare providers and facilities should report
  a (confirmed, probable) case/s, including
  susceptibility test results.
• Laboratories
• Report test results, including antibiotic
  susceptibility results.
• Send isolate to OLS for testing.
• For details see
• http//www.wvdhhr.org/idep/PDFs/IDEP/Reportable20
  Diseases_20Conditions_20Events_07.pdf

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Investigation

• Ascertain case/s
• Investigate all cases of shigellosis
• Initiate general control measures
• Good hand hygiene
• Assure safe water supply/source
• Proper storage and cooking of food
• Exclude infected (symptomatic or asymptomatic)
  individuals from handling and/or preparing food
• Advise individuals with diarrhea not to use
  recreational water venues for 2 weeks after
  resolution of symptoms
• Determine occurrence
• Outbreak report immediately to IDEP
• Sporadic cases report within 72 hours
• Report in WVEDSS

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WVEDSS Form
Complete the form.
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OUTBREAK

• Definition
• Increase in the number of cases of disease over
  and above the expected number of cases
• Food-borne outbreak 2 or more cases
  experiencing similar illness after ingestion of a
  common food
• Water-borne outbreak 2 or more cases
  experiencing similar illness after consumption or
  use of water intended for drinking (also includes
  unintentional ingestion of water in association
  with exposure recreational water)

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Outbreak Response (1)

• Ascertain cases.
• Immediately notify IDEP of the outbreak.
• Initiate control and preventive measures.
• Report in WVEDSS.
• Create a linelist of cases (probable and
  confirmed) and close contacts.

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Sample Line List

• Update line list form as often as possible
• Send/fax the line list form to IDEP as soon as
  created or updated

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Outbreak Response (2)

• Create an epi-curve (graphical presentation of
  data obtained from the linelist) Purpose
• To assess the pattern of disease transmission
• To guide the investigation
• To establish appropriate preventive and control
  measures

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Outbreak Response (3)

• Focus the interview /investigation on specific
  risk factors based on the pattern of disease
  transmission depicted by the epi-curve

Epi-curve Point Source disease transmission

• Ask about
• Food history
• Restaurant exposure
• Swimming
• Visit to waterparks
• Other activity history

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Outbreak Response (4)
Epi-curve Person-to-person disease transmission

• Ask about
• Daycare
• School
• Occupational exposure
• Activity history

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Outbreak Response (5)

• Evaluate preventive and control measures.
• Assure that cases are appropriately treated
• Susceptible bacteria Ampicillin, TMP-SMX
• Bacterial susceptibility unknown or Ampicillin
  and TMP-SMX-resistant Ceftriaxone or
  Azithromycin
• Exclusion or restriction of foodhandlers/preparers
  
• 2005 Food Code
• Until 2 negative stool cultures taken 24 hours
  apart, collect specimen after 48 hours of
  completion of antibiotic treatment
• See protocol for details

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Outbreak Response (6)

• Preventive and Control Measures
• Child care centers
• Exclude all infected
• Emphasize hand hygiene
• Supervise handwashing of young children
• Access to handwashing sinks for young children
• Eliminate access to shared water play areas
• Sanitary diaper changing techniques and cleaning
  of diapering areas

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Outbreak Response (7)

• Preventive and Control Measures
• Child care centers cont.
• Sanitary food handling
• Culture all symptomatic persons. If positive,
  treat.
• Infected foodhandlers follow Food Code
• Exclude non-foodhandlers from childcare till
  diarrhea stops and culture taken 24 hours after
  antibiotic completion is negative
• Cohorting when resources allow

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Outbreak Response (7)

• Preventive and Control Measures cont.
• Preschool, Kindergarten, Grade school
• Exclude all infected
• Emphasize hand hygiene
• Supervise handwashing of young children
• Eliminate access to shared water play areas
• Sanitary food handling
• Culture all symptomatic persons. If positive,
  treat.
• Infected foodhandlers follow Food Code
• Infected non-foodhandlers treat, exclude until
  diarrhea stops and negative culture

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Outbreak Response (8)

• Preventive and Control Measures cont.
• Institutional setting (HCF, LTCF, etc.)
• Strict attention to hand hygiene
• Sanitary food handling
• Culture all symptomatic persons. If positive,
  treat.
• Infected foodhandlers follow Food Code
• Infected non-foodhandlers treat, exclude until
  diarrhea stops and negative culture taken 24
  hours after completing treatment
• Cohort if resources allow

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Outbreak Response (9)

• Forward outbreak paper report to IDEP.
• Several entities may need to be involved in the
  write-up

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References

• IDEP Shigellosis
• http//www.wvdhhr.org/idep/a-z/a-z-shigellosis.asp
  Protocol
• Food and Waterborne Outbreak Manual
• Coming soon!