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Pertussis Outbreak

Pertussis Outbreak. Raja S. Akhtar. Scenario. On 7/21/02 Upshur County health department receives a call from a physician’s 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.

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Pertussis Outbreak

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  1. Pertussis Outbreak Raja S. Akhtar

  2. Scenario On 7/21/02 Upshur County health department receives a call from a physician’s 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. 3. Verify the diagnosis? Clinical Findings: • 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. What is Pertussis (Whooping cough) ? Highly contagious disease spread by direct or droplet contact with nasopharyngeal secretions of an infected person. Cause: BacteriaBordatella Pertussis Incubation Period: 7-10 days; rarely up to 21 days Understanding Pertussis 06-Aug-03 WVDHHR/BPH/OEHP/DSDC/IDEP

  10. Understanding Pertussis InfectiousPeriod: 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 caseConfirmed: 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. 4.b Identify and Count Cases Surveillance findings • 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. What Next 06-Aug-03 WVDHHR/BPH/OEHP/DSDC/IDEP

  26. Step 9: Implement Control Measures 06-Aug-03 WVDHHR/BPH/OEHP/DSDC/IDEP

  27. 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

  28. 9. Implement Control Measures Pertussis Control: 1. Treatment & Prophylaxis 2. Vaccination 3. Isolation 06-Aug-03 WVDHHR/BPH/OEHP/DSDC/IDEP

  29. 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

  30. 9. Implement Control Measures 1. Treatment & Prophylaxis: Contacts: Recommend chemoprophylaxis of all close contacts with erythromycin regardless of age and vaccination status Chemoprophylaxis > 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

  31. 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

  32. 9. Implement Control Measures 2. Vaccination: • All close contacts < to 6 years of age should be brought up-to-date with pertussis immunization. • Contacts < 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

  33. 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

  34. What Next 06-Aug-03 WVDHHR/BPH/OEHP/DSDC/IDEP

  35. Step 2: Establish Existence of Outbreak 06-Aug-03 WVDHHR/BPH/OEHP/DSDC/IDEP

  36. 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

  37. 06-Aug-03 WVDHHR/BPH/OEHP/DSDC/IDEP

  38. 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

  39. Establish Existence of Outbreak YES Do we have an outbreak? 06-Aug-03 WVDHHR/BPH/OEHP/DSDC/IDEP

  40. What Next 06-Aug-03 WVDHHR/BPH/OEHP/DSDC/IDEP

  41. Step 5: Perform Descriptive Epidemiology 06-Aug-03 WVDHHR/BPH/OEHP/DSDC/IDEP

  42. 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

  43. 06-Aug-03 WVDHHR/BPH/OEHP/DSDC/IDEP

  44. 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

  45. Step 6-8 6. Develop Hypothesis 7. Evaluate Hypothesis 8. As necessary, reconsider/refine hypothesis. 06-Aug-03 WVDHHR/BPH/OEHP/DSDC/IDEP

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