The Windsor-Essex County Health Unit (WECHU) is reporting a case of pertussis (whooping cough) in the Leamington community and exposures have been identified. In this context, clinicians should consider pertussis as a differential diagnosis in patients who present with respiratory symptoms. This communication summarizes some important guidance related to the diagnosis and management of pertussis.

Clinical Presentation:  

• Any cough lasting 2 weeks or longer
• Paroxysmal cough of any duration
• Cough with inspiratory “whoop”
• Cough ending in vomiting or gagging, or associated with apnea

Notification: As a disease of public health significance, clinicians are required to report all suspected and confirmed cases of pertussis to the health unit within one business day. Please fully complete the Pertussis Investigation and Reporting Form found on WECHU website (www.wechu.org/forms), and fax to 226-783-2132.

Diagnosis and Management of Pertussis Cases

Laboratory Evidence: Laboratory testing should only be performed on patients with appropriate clinical signs and symptoms. When testing, please ensure the following:

• Collect a nasopharyngeal (NP) swab using the Bordetella pertussis BP collection kit (colourless medium). This disease-specific collection kit must be ordered from the Public Health Ontario Laboratory. It is recommended that clinicians routinely keep a few kits in stock.
• Submit the specimen for Bordetella- PCR
• Specimen collection should occur prior to initiation of antibiotic therapy
• Optimal timing for using PCR to detect Bordetella pertussis is within 3 weeks of cough onset

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: Cases should be advised to avoid contact with others (i.e., young children, infants, and women in their third trimester of pregnancy) until completion of 5 days of appropriate antibiotic therapy or 21 days post cough onset. Symptomatic individuals should remain at home until they are well.

Management of Pertussis Contacts 

Antibiotic chemoprophylaxis is only recommended for the following contacts of confirmed pertussis cases:

• Household contacts (including attendees at home child care settings) where there is a vulnerable person defined as an infant < 1 year of age [immunized or not] or a pregnant woman in the 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 > 1 hour.

Chemoprophylaxis should be implemented as soon as possible after exposure to increase efficacy. The WECHU will notify clinicians of patients who are identified as contacts of pertussis and provide recommendations for chemoprophylaxis. Please consider prescribing prophylactic antibiotics for contacts of confirmed pertussis cases (see Appendix A). A macrolide antibiotic (i.e., azithromycin, erythromycin, or clarithromycin) may prevent or moderate clinical pertussis when given during the incubation period or in the early catarrhal stage. During the paroxysmal phase of the disease, antibiotics may not shorten the clinical course but may reduce the possibility of complications. Laboratory diagnostic testing of contacts should not be done to guide decisions around who should receive chemoprophylaxis

Vaccination

Vaccination is the best protection against pertussis. Clinicians should encourage their patients to obtain publicly-funded pertussis vaccine. The current schedule for acellular pertussis vaccine is 2, 4, 6, and 18 months, and booster doses at 4-6 years, and 14-16 years. Receiving the 2-, 4-, and 6-month doses on schedule are critical in reducing infant mortality and hospitalization.
 
One dose should also be given to all adults 18 years of age and older. In addition, one dose should be administered in every pregnancy, ideally between 27 and 32 weeks of gestation.
 
If you have any questions or concerns, please call the Infectious Disease Prevention Department, Monday to Friday, between 8:30am and 4:30pm, at 519-258-2146, ext. 1420.

For more information:

• Canadian Immunization Guide: Pertussis vaccine
• Ministry of Health Pertussis (Whooping Cough) Case Definitions and Disease-Specific Information
• Public Health Ontario Laboratories: Bordetella- Respiratory Specimen Collection and Handling
• WECHU Whooping Cough (Pertussis) Fact Sheet

Appendix A: Antibiotic indicated for chemoprophylaxis among people without contraindication
The Antibiotics below are indicated for chemoprophylaxis among people without contraindications (CDC, 2005). Azithromycin is the preferred antimicrobial for infants < 1 month of age. Clarithromycin is not recommended during pregnancy as it is classified as a Category C drug. Pregnancy is not a contraindication to azithromycin or erythromycin; both are classified as Category B drugs.