Confirmed Cases of Pertussis
May 18, 2018
The Windsor-Essex County Health Unit is following up on several confirmed cases of pertussis in the Leamington/Comber area. We would like to take this opportunity to provide a brief update to clinicians and remind them to consider pertussis as a differential diagnosis for clients that may present with compatible symptoms.
Clinical Evidence: Clinically compatible signs and symptoms include one or more of the following:
- Paroxysmal cough of any duration
- Cough ending in vomiting or gagging (without any other cause), or associated with apnea
- Cough with inspiratory “whoop”
- Any cough lasting 2 weeks or longer
Notification: Pertussis is a mandatory reportable disease, according to Health Protection and Promotion Act, R.S.O., 1990. All clinically diagnosed, probable and confirmed pertussis cases must be reported to the Health Unit as soon as possible. After calling the Health Unit, please complete the Pertussis Reporting Form found under the “forms” section of our website and fax to 226-783-2132.
- Please ensure that you indicate the date of symptom onset and immunization status and dates.
Diagnosis and Management of Pertussis Cases:
Diagnosis: Immunity against pertussis is not lifelong and wanes after approximately 7-20 years of naturally acquired active immunity and 4-12 years after immunization. Thus, a high index of clinical suspicion for pertussis may still be appropriate despite vaccination status. The Provincial Case Definition for pertussis outlines the laboratory evidence required and the diagnostic tests approved. If pertussis is suspected or diagnosed, please ensure confirmation with lab evidence
Lab Evidence: Lab testing should only be performed on patients with appropriate clinical signs and symptoms. For suspected cases or contacts of pertussis, please ensure the following:
- Use the B. Pertussis BP Collection Kit. Ensure the PCR transport medium is colourless, and not pink.
- Collect appropriate clinical specimen (e.g. nasopharyngeal swab, throat swab, and tracheal aspirate) prior to initiation of antibiotic therapy.
- Submit specimen for standard culture or nucleic acid amplification testing (NAAT) for B. pertussis.
- Optimal timing for NAAT assays is within 3 weeks of cough onset. Testing asymptomatic persons who are household contacts of a person with pertussis should be avoided as positive predictive value of the test will be low in this situation.
Public Health Ontario Laboratory is available for consultation on laboratory testing with health care providers as needed at (toll free) 1-877-604-4567.
Management: Azithromycin, erythromycin, and clarithromycin are appropriate first-line antimicrobial agents, if not contraindicated. Cases should be advised to avoid contact with vulnerable persons (i.e. young children, infants, and women in their third trimester of pregnancy), until the completion of five days of appropriate antibiotic therapy or 21 days after onset of cough. Symptomatic individuals should remain at home until they are well.
Chemoprophylaxis of Contacts:
The Health Unit follows up directly with pertussis contacts for chemoprophylaxis. The Health Unit will contact clinicians if your patient is deemed a contact and provide recommendations for chemoprophylaxis. Chemoprophylaxis should be implemented as soon as possible after exposure to increase efficacy, and thus, reporting probable or diagnosed cases immediately to the Health Unit is essential. Please note a contact recommended for chemoprophylaxis is defined as:
- Household contacts (including home day care attendees) where there is a vulnerable person defined as an infant <1 year of age [immunized or not] or a pregnant woman in their third trimester; and
- For out of household exposures, vulnerable persons defined as infants <1 year of age regardless of immunization status and pregnant women in their third trimester who have had face-to-face exposure and/or have shared confined air for more than 1 hour
Vaccination is the best protection against pertussis. Receiving the 2, 4, and 6 month doses of acellular pertussis vaccine on schedule is critical in reducing infant mortality and hospitalization rates. Encourage your community to obtain publicly-funded pertussis vaccination from their health care provider.
Our website (www.wechu.org) is a reference for health care providers and patients. For additional information or consultation, please call the Health Unit during regular office hours at 519-258-246 ext. 1420. During after hours and weekends, please call 519-973-4510.
Dr. Wajid Ahmed, MBBS, MAS, MSc, FRCPC
Acting Medical Officer of Health