Pertussis (Whooping Cough)

 

  • Bordetella pertussis is a bacterial illness transmitted by respiratory droplets and secretions.

 

  • Pertussis is especially serious in infants under 12 months of age (70% hospitalised, 30% apnoea)

 

  • Incubation period 7-10 days (range 5-21)

 

  • Cases are most infectious from the onset of catarrhal symptoms to 3 weeks after onset of cough

 

  • 80% of non-immune household contacts will acquire the disease

 

CLINICAL FEATURES

 

CDC website pertussis

 

 

Catarrhal stage (7-10 days)

 

  • Fever, Runny nose, Malaise, Cough

 

Paroxysmal/Toxaemic stage (6-8 weeks)

 

  • Severe prolonged coughing. May end with:
  • Inspiratory whoop
  • Apnoea
  • Vomiting
  • Infants < 6 months and immunised cases may not have a typical whoop. Infants may only present with apnoea.

 

Complications

 

  • Secondary infections
  • Sequelae of prolonged coughing. e.g. sub conj. haemorrhage, epistaxis, petechiae, hernia, CNS haemorrhage, pneumothorax

 

Mode of transmission

Droplets of respiratory, oral or nasal secretions. Indirect spread via contaminated objects occurs rarely.

 

Period of communicability

Pertussis is highly infectious in the catarrhal stage before the paroxysmal cough stage, and during the first 2 weeks of the paroxysmal stage of the cough. Transmissibility gradually decreases after that.

For control purposes, the communicable stage lasts from the catarrhal stage to 3 weeks after the onset of paroxysmal cough in a case not treated with antibiotics. When treated with an effective antibiotic (eg, azithromycin), infectivity lasts until 2 days of antibiotics have been taken. This lengthens to 5 days if other antibiotics are used (eg, erythromycin).

Contact tracing and management- The aim of contact management is two-fold:

To identify symptomatic contacts for treatment – a contact can be defined as someone who has been in close proximity (within 2 meters) of the index case for 1 hour or more, during the cases infectious period, or who has had direct contact with respiratory secretions.

To provide chemoprophylaxis to reduce the odds of infection in high priority contracts:

  • Infants under 12 months
  • Pregnant women in their 3rd trimester
  • Immune compromised, those with chronic disease
  • Contacts who themselves have daily contact with infants under 12 months, pregnant women, or others at risk of severe illness or complications

Chemoprophylaxis of contacts:

See clinical pathway below from the Auckland Regional Public health service (ARPHS)

https://arphs.cwp.govt.nz/resources/clinical-pathway-pertussis/

 

Exclusion of contacts

 

All contacts should be advised to avoid attending early childhood centers, school, work or associating with high risk individuals if they become symptomatic

 

Contact exclusion for 14 days after their last exposure to the infectious case is recommended where:

 

Contacts have been advised prophylaxis (high priority contacts AND they are incompletely immunised for age AND they refuse to take prophylactic antibiotics

Recommendations sourced from ARPHS website (see link above)

 

 

References and additional resources:

 

http://www.arphs.health.nz/resources/category/whooping-cough-pertussis

https://www.cdc.gov/pertussis/index.html

http://www.immune.org.nz/diseases/pertussis

Questions for staff:

 

What is the incubation period for Pertussis?

 

 

What are the symptoms in the Paroxysmal stage?

 

 

What is are the complications of Pertussis?

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