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17 May 2017

Causative agent

It is caused by the bacterium Corynebacterium diphtheriae.

Clinical features

Diphtheria is an acute infectious disease affecting mainly the respiratory tract (respiratory diphtheria), and occasionally the skin (cutaneous diphtheria), caused by the action of bacterial toxin. Symptoms will depend on the site of infection. 

Persons with respiratory diphtheria may have fever, sore throat with patches of greyish membrane adhered to the throat, and breathing difficulty. In serious cases, it can cause airway obstruction, heart failure and nerve damage. Fatal cases can occur.

Mode of transmission

It is spread by contact with patient or carrier. Less commonly, a person may get infected through contact with articles soiled with discharges from affected persons.

Incubation period

The incubation period ranges from 1 – 10 days, usually 2 – 5 days.


Treatment for diphtheria includes diphtheria antitoxin, antibiotics and supportive care. Household members and people having close contact with the patient should be monitored closely for early signs and symptoms of infection.


Maintain good personal hygiene

  • Wash hands frequently with liquid soap and water, especially before touching the mouth, nose or eyes, or after touching public installations such as handrails or door knobs.
  • Cover nose and mouth with tissue paper when coughing or sneezing, and wash hands thoroughly afterwards. Dispose of soiled tissue paper in a lidded rubbish bin.
  • Put on a surgical mask when having respiratory symptoms. Refrain from work or school and seek medical advice promptly. 
  • Clean broken skin immediately and cover properly with waterproof adhesive dressings. Wash hands before and after touching wounds. Consult doctor promptly if symptoms of infection develop.

Maintain good environmental hygiene

  • Maintain good indoor ventilation.
  • Frequently clean and disinfect touched surface such as furniture, toys and commonly shared items with 1:99 diluted household bleach (mixing 1 part of 5.25% bleach with 99 parts of water), leave for 15 - 30 minutes, and then rinse with water and keep dry. For metallic surface, disinfect with 70% alcohol.
  • Use absorbent disposable towels to wipe away obvious respiratory secretions, and then disinfect the surface and neighbouring areas with 1:49 diluted household bleach (mixing 1 part of 5.25% bleach with 49 parts of water), leave for 15 - 30 minutes and then rinse with water and keep dry. For metallic surface, disinfect with 70% alcohol.


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