Pertussis Outbreak

1

• Pertussis Outbreak

Raja S. Akhtar
2
Scenario

• On 7/21/02 Upshur County health department
  receives a call from a physicians office
  reporting a case of Pertussis in a 6 month old
  female infant. The child has had clinical
  signs/symptoms of pertussis and laboratory
  results are pending.

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
3

• What do you do?

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
4
Step 3
Verify the Diagnosis
06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
5
3. Verify the diagnosis?

• 1. Review clinical findings to see if patient
  has
• signs/symptoms of pertussis
• 2. Review Laboratory results for
• Isolation of Bordatella Pertussis from clinical
  specimen or
• Positive polymerase chain reaction for B.
  Pertussis

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
6
Clinical Findings
3. Verify the diagnosis?

• 10-day history of severe coughing spells.
• The illness started with a "cold" but had gotten
  progressively worse in the last week.
• The baby's coughing was so violent that she
  often became cyanotic and gasped for breath when
  the coughing subsided.
• In addition, the baby had several episodes of
  vomiting associated with his coughing.

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
7
Laboratory Findings
3. Verify the diagnosis?

• PCR positive for Pertussis
• No culture results

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
8
Step 1
Understanding Pertussis
06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
9

• Understanding Pertussis

What is Pertussis (Whooping cough) ? Highly
contagious disease spread by direct or droplet
contact with nasopharyngeal secretions of an
infected person. Cause Bacteria Bordatella
Pertussis Incubation Period 7-10 days
rarely up to 21 days
06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
10
Understanding Pertussis

• Infectious Period
• From prodrome (early symptom) onset to 3 weeks
  after paroxysm (cough) onset, or five days after
  starting antibiotic treatment.
• Reservoir
• Pertussis is a human disease. No animal or
  insect source or vector is known to exist.

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
11
Understanding Pertussis

• Symptoms
• Adults usually have milder symptoms
• Children can have
• Fever
• Coughing
• Severe cough with a "whooping" sound
• Vomiting and exhaustion after severe coughing
• Difficulty breathing

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
12
Understanding Pertussis

• Complications
• Pneumonia
• Seizures
• Brain damage
• Death

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
13
Understanding Pertussis

• Treatment Prevention
• Antibiotics are given to make the illness less
  contagious, but they do not reduce the symptoms
  unless given very early in illness.
• Bring children up to date on their shots,
  especially the diphtheria, tetanus, pertussis
  (DTaP) series.
• Persons who have been in very close contact with
  a person with pertussis should take medication to
  prevent illness.

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
14
Understanding Pertussis

• Epidemiology
• Most severe in infants under 1 year old.
• More than half of infants who get the disease
  must be hospitalized and some even die.
• Pertussis in older children and adults is less
  severe and often not recognized as pertussis.
• Adults with milder, undiagnosed symptoms can
  transmit the disease to infants and children.

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
15

• What Next?

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
16
Step 4

• a. Establish a Case Definition
• b. Identify and Count Cases

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
17
4.a Establish a Case Definition (i)

• Clinical Case Definition
• A cough illness lasting greater than or equal to
  2 weeks with one of the following paroxysms of
  coughing, inspiratory "whoop," or post-tussive
  vomiting, without other apparent cause

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
18
4.a Establish a Case Definition (ii)

• Laboratory criteria for diagnosis
• Isolation of Bordetella pertussis from clinical
  
• specimen or
• Positive polymerase chain reaction for
• B. pertussis

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
19
4.a Establish a Case Definition (iii)

• Confirmed
• Probable
• Possible

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
20
4.a Establish a Case Definition (iv)
Case Classification for Pertussis Probable A
case that meets the clinical case definition, is
not laboratory confirmed, and is not
epidemiologically linked to a
laboratory-confirmed case Confirmed A case
that is laboratory confirmed or one that meets
the clinical case definition and is either
laboratory confirmed or epidemiologically
linked to a laboratory-confirmed case

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
21
Based on our case definition the baby is

• Probable case ?
• Confirmed case ?

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
22
4.b Identify and Count Cases

• Initiate active surveillance
• Individually phone/visit schools to search for
• additional cases.
• Enhanced passive surveillance
• Disseminate written request for reports of
• additional cases
• Cast a wide net
• Investigate forwards
• Investigate backwards

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
23
4.b Identify and Count Cases

• Gather critical information from your
  surveillance
• to include
• History of Exposure
• (where the baby may have been)
• Onset dates
• Cause of illness ( What they think)
• Others (who they know or think were exposed or
  have/had symptoms)

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
24
Surveillance findings
4.b Identify and Count Cases

• Household contacts of the index case 5
• 3 Cough
• 2 No symptoms
• Other close contacts of the index case 3
• Several contacts of contacts identified.

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
25
(No Transcript)
26

• What Next

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
27
Step 9

• Implement Control Measures

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
28
9. Implement Control Measures

• Provide educational information to
• Public
• (Letters to parents from the school/LHD,
• public information sheets)
• Providers
• (Physicain alert, phone calls, visit, provider
• information sheets)
• Communication between IDEP and LHD
• important.

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
29
9. Implement Control Measures

• Pertussis Control
• 1. Treatment Prophylaxis
• 2. Vaccination
• 3. Isolation

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
30
9. Implement Control Measures

• 1. Treatment Prophylaxis
• Cases
• Initiate treatment as soon as pertussis is
  suspected in a patient

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
31
9. Implement Control Measures

• 1. Treatment Prophylaxis
• Contacts
• Recommend chemoprophylaxis of all close contacts
  with erythromycin regardless of age and
  vaccination status
• Chemoprophylaxis gt 3 weeks after exposure
  limited benefit
• Chemoprophylaxis for high risk contacts (e.g
  infants) can be
• considered up to 6 weeks after exposure

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
32
9. Implement Control Measures
Newer macrolides, azithrmycin 10-12 mg/kg per
day orally in 1 dose) or clarithromycin (15-20
mg/kg per day orally in 2 divided doses
maximum, 1 g/d), may be effective in shorter
courses of 5-7 days however their efficacy is
unproven.
06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
33
(No Transcript)
34
9. Implement Control Measures

• 2. Vaccination
• All close contacts lt to 6 years of age
  should be brought up-to-date with pertussis
  immunization.
• Contacts lt to 6 years who have not completed
  the four-dose series should complete the series
  with minimum intervals.
• Children aged 4-6 years who have completed a
  primary series but have not received the
  pertussis vaccination booster dose should be
  given this dose.

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
35
(No Transcript)
36
9. Implement Control Measures

• 3. Isolation
• Patients should refrain from contact outside
  the household for first 5 days after start of a
  full course of antimicrobial treatment or until
  21 days from onset of cough in those who do not
  receive antimicrobial therapy.

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
37
(No Transcript)
38

• What Next

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
39
Step 2

• Establish Existence
• of Outbreak

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
40
Establish Existence of Outbreak

• Outbreak (epidemic)
• Occurrence of more cases than expected in a
  given area or among a specific group of people
  over a particular period of time
• Cluster
• Aggregation of cases in a given area over a
  particular period without regard to whether the
  number is more than expected

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
41
06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
42
Establish Existence of Outbreak

• For Pertussis
• Two or more cases involving two or more
  households clustered in time and space where
  transmission is suspected to have occurred (e.g.
  a school).
• One case in an outbreak must be lab
  confirmed (PCR positive and meets case
  definition, or culture positive).
• In outbreak settings a case may be defined
  as a cough illness lasting 14 days or more.

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
43
(No Transcript)
44
Establish Existence of Outbreak
YES

• Do we have
• an outbreak?

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
45

• What Next

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
46
Step 5

• Perform Descriptive Epidemiology

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
47
Perform Descriptive Epidemiology

• Describe outbreak by
• Person - Age, Sex, Exposure (Occupation)
• Vaccination history
• Place - Community, Facility, School,
  Hospital, etc.
• Time - Determine time course
• - Future course
• - Exposure period

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
48
06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
49
Perform Descriptive Epidemiology

• Your conclusions
• Number of Confirmed cases 2
• (1 PCR confirmed, 1 Epi linked)
• Place Upshur County
• Population at-risk household
• Vaccination history both cases inadequately
  immunized
• Future course of action

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
50
Step 6-8

• 6. Develop Hypothesis
• 7. Evaluate Hypothesis
• 8. As necessary, reconsider/refine
• hypothesis.

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
51
Step 6-8

• Vaccine failure or failure to
  vaccinate?
• Is the age distribution similar to the
  national, state trend?

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP
52
06-Aug-03
WVDHHR/BPH/OEHP/DSDC/ID
EP
53
Pertussis WV- 2002 Data Analysis
Total Cases 2002 37Vaccination status
available 24Of the 24 cases with known
vaccination status - 16 (43 ) lt 3
dosesAge 7 month to 4 years 9 casesOf these
9 cases - 2 (22) no dose - 2 (22)
1 or 2 doses - 5 (56) 3 or more doses
06-Aug-03
WVDHHR/BPH/OEHP/DSDC/ID
EP
54
PERTUSSIS Reported cases per 100,000 population,
by year, United States, 1971-2001
CDC
55
PERTUSSIS Reported cases, by age group, United
States, 2001
CDC
56
06-Aug-03
WVDHHR/BPH/OEHP/DSDC/ID
EP
57
Step 10

• Communicate Findings
• Conference call
• Right now

06-Aug-03
WVDHHR/BPH/OEHP/DSDC/IDEP