MONDAY, AUG 22
Sims Drive Medical Clinic, having noticed an unusual increase in cases with fever, rashes and joint pains, notifies the Ministry of Health (MOH) in the evening.
MOH officials visit the clinic and discuss the cases with a doctor there. The initial belief is that there is a cluster of a mild viral illness.
MOH makes arrangements for the clinic to refer new cases to the Communicable Disease Centre (CDC) for testing, and to start tracing past cases.
Nearby clinics and supervisors of a nearby construction site are also told to increase vigilance and report cases to MOH.
MOH asks the construction site's contractor for records of workers who had had fevers. Meanwhile, a 47-year-old Malaysian woman working in the coffee shop at Block 45 Sims Drive develops a fever, rashes and conjunctivitis.
She visits Sims Drive Medical Clinic and is referred to the CDC.
The woman is confirmed to have Zika. The National Environment Agency (NEA) is notified and starts anti-mosquito measures as well as inspections. NEA also begins outreach efforts to 14 blocks of flats in the Aljunied Crescent and Sims Drive area.
MOH tests another 123 people with Zika-like symptoms, including 118 construction workers.
CDC reports preliminary positives for three of these cases.
By noon, 41 of the 124 people tested are found to have Zika. Most of the results came in late on Saturday night. Another 78 tested negative. Test results are pending for the remaining five.
A joint press conference by MOH and NEA is held just before 4pm to announce the findings.
NEA completes outreach efforts in Aljunied Crescent and Sims Drive. It starts similar efforts in the Sembawang Drive residential area, where one of the Zika cases, a 30-year-old Singaporean man, lives.