Health Alert
UPDATE TO PERTUSSIS OUTBREAK IN KENT COUNTY, DELAWARE

The Delaware Division of Public Health (DPH) is issuing an update to a June 20 health alert regarding an outbreak of pertussis (whooping cough) in Kent County, Delaware.

SUMMARY

DPH has been investigating an outbreak of pertussis in the Amish population in Kent County, Delaware. As of August 18, 2018, the number of pertussis cases has increased to 97 including: nine laboratory confirmed cases, 35 epi-linked and 53 probable cases.

Additionally, the disease has now been identified in a Kent County child living outside the Amish community, increasing the risk for spread among the general population.

DPH is again asking physicians and other health care providers to consider pertussis when evaluating a patient with a new onset cough illness. Persons with a clinical picture compatible with pertussis should have samples sent for laboratory testing (see laboratory testing below).

DPH also asks physicians to strongly encourage vaccination not only among pediatric patients, but also encourage Tdap vaccination among pregnant women, teens, and adult patients.

Pertussis is a reportable disease in Delaware. Confirmed and suspected cases of pertussis should be reported to DPH. This will allow for appropriate DPH follow-up with patients, and the initiation of interventions to prevent further spread of the disease in the community.

Report known or suspected cases of pertussis promptly to the DPH Office of Infectious Disease Epidemiology at 302-744-4990, fax to 302-223-1540, or email to reportdisease@delaware.gov.

BACKGROUND

Pertussis, or whooping cough, is a highly contagious communicable disease caused by the bacterium, Bordetella Pertussis. Pertussis is transmitted through air-borne droplets (coughing, sneezing) or direct contact with fluids or respiratory secretions of infected persons.

Pertussis is characterized by coughing paroxysms that are often followed by a characteristic "whoop" sound and/or post-tussive vomiting. Its incubation period is about 4 to 21 days (average 7 to 10 days). Illness onset is insidious with symptoms similar to those of a minor upper respiratory infection (catarrhal period). During the first 1 to 2 weeks of illness, coryza with an intermittent non-productive cough is common; this period is followed by episodes of paroxysmal coughing which frequently last for several weeks (paroxysmal period).

Pertussis may occur among persons of any age, including teens and adults who were vaccinated only at a young age, although infants aged less than one year have the highest rates of complications.

It is important to know that many babies with pertussis do not cough at all. Instead it causes them to stop breathing and turn blue.

Also of note, in those who have received a pertussis vaccine:

• In most cases, the cough won't last as many days
• Coughing fits, whooping, and vomiting after coughing fits occur less often
• There is a lower percentage of children with apnea (long pause in breathing), cyanosis (blue/purplish skin coloration due to lack of oxygen) and vomiting

The last outbreak of pertussis in Delaware occurred in late 2013- early 2014, also among Kent County's Amish population. More than 200 people were affected.

As the disease has now spread outside of the Amish community, it is important to enhance efforts to prevent further spread of the disease.

REPORTING

• Report suspect pertussis cases to DPH at 302-744-4990, fax to 302-223-1540, or reportdisease@delaware.gov .

LABORATORY TESTING

• All suspected cases of pertussis should have a nasopharyngeal (NP) aspirate or swab obtained for culture and/or PCR from the posterior nasopharynx. (Throat and anterior nasal swabs have unacceptably low rates of recovery of B. pertussis.) NP specimens should be obtained using a Dacron (not cotton) swab inserted slowly through the nostril to the posterior pharynx. Gently rotate swab for 10 seconds before withdrawing.
• Samples may be sent to the Delaware Public Health Laboratory (DPHL) for PCR or to commercial laboratories (i.e. Mayo, LabCorp, Quest) for PCR and culture.
• Detailed guidance on sample collection and transport of specimens is available at https://www.cdc.gov/pertussis/clinical/diagnostic-testing/index.html
• Testing performed at DPHL must be coordinated through the Office of Infectious Disease Epidemiology. Call 302-744-4990 or send report (email: reportdisease@delaware.gov or fax: 302-223-1540) prior to submitting samples to DPHL.
• Note that serology is not beneficial as a diagnostic tool for pertussis.
• Macrolide antibiotics (azithromycin, erythromycin) are the drugs of choice for treatment for persons with pertussis as well as for chemoprophylaxis for exposed persons.
• Exposure is defined as face-to-face contact, direct contact with respiratory, oral, or nasal secretions, or being in the same room or ward with a coughing pertussis patient.

For Additional Information

• CDC - Pertussis: http://www.cdc.gov/pertussis/
• Pertussis Diagnostic Testing: https://www.cdc.gov/pertussis/clinical/diagnostic-testing/index.html
• Pertussis Vaccination: https://www.cdc.gov/pertussis/vaccines.html
• Pertussis Frequently Asked Questions: https://www.cdc.gov/pertussis/about/faqs.html
• Postexposure Antimicrobial Prophylaxis: https://www.cdc.gov/pertussis/outbreaks/pep.html

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