Viral: Adenovirus (serotypes 3, 7, 8, 19), enterovirus 70, coxsackievirus A24v and herpes simplex virus.
Bacterial: Staphylococcus aureus (common in adult), Staphylococcus epidermidis, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Neisseria gonorrhoeae (in newborns) and Chlamydia trachomatis (in newborns).
1 - 12 days depending on pathogen
Throughout the duration of illness; up to 14 days with adenovirus
Highly contagious; direct person-to-person transmission and via contaminated surfaces and articles such as towels. Public swimming pools have not been implicated in the transmission of conjunctivitis in Singapore due to good chlorination. However, the crowded condition facilitates person-to-person transmission.
Epidemics of acute haemorrhagic conjunctivitis caused by picornavirus recurred in a five-year cycle in the 1970s and 1980s. The 1970, 1975 and 1985 epidemics were caused by coxsackievirus A24v and the 1980 epidemic by enterovirus 70.
Coxsackievirus A24 continued to cause outbreaks in 1987, 1992, 2002 and 2005. Most of the viruses isolated during small outbreaks in the inter-epidemic period were adenoviruses.
In 2009, the restructured polyclinics reported 24,084 attendances for conjunctivitis.