Corynebacterium diphtheriae, toxigenic strains
2 - 5 days (range 1-10 days)
Up to 2 - 4 weeks after onset of illness
Close contact of nasopharyngeal secretions of case or asymptomatic human carrier or from skin lesion exudate.
Diphtheria has been eradicated from Singapore as a result of the comprehensive coverage of the childhood immunization programme. In a 2008-2010 MOH serosurvey, virtually all children below 17 years of age possessed antitoxin immunity against diphtheria (99.4%). An isolated case reappeared in 1992 in a 41 year old male with multiple co-morbid conditions. Corynebacterium diphtheriae var gravis was isolated from his blood. He subsequently died from septicaemia secondary to bacterial endocarditis.
The disease is still endemic in many countries (see below) but rare in developed countries despite waning immunity.