The Ministry of Health (MOH) has confirmed that local human-to-human transmissions of the Wuhan virus has occurred.
There are six new cases of the Wuhan novel coronavirus in Singapore on Feb. 4, making it a total of 24 confirmed cases so far.
This comes after two days without new cases being reported.
Local transmission through droplets
Out of the six, four are local human-to-human transmissions.
Three of these cases can be traced to contact with recent travellers from Guangxi, China.
The fourth case is a close contact of one of the local transmission cases.
According to MOH, this new cluster of cases constitutes "limited local transmission", and there is as yet no evidence of widespread sustained community transmission.
Current evidence suggests that the likely modes of transmission at this point are mainly through contact with droplets from infected individuals.
This can happen either directly or indirectly through hands that have come into contact with the droplets.
These four cases were identified as a result of enhanced surveillance at local hospitals.
MOH adds that Singapore has been preparing for such clusters.
They are also contacting individuals with similar profiles to the four cases above.
Limited vs. community transmission
MOH defines "limited transmission" as when they can identify those involved, especially the source.
This means that the ministry can do contact tracing and keep it under control.
On the other hand, community transmission/ spread is when there are multiple clusters and there is difficulty in finding out the source.
Case 19 is a 28-year-old female Singapore resident with no recent travel history to China.
She is currently warded in an isolation room at Singapore General Hospital (SGH).
She works at Yong Thai Hang, a Chinese health store at 24 Cavan Road that primarily serves Chinese tourists.
The patient developed sore throat and fever on Jan. 29, and went to a General Practitioner clinic (GP) on the same day.
On Jan. 30, she visited Tan Tock Seng Hospital's (TTSH) emergency department, but was discharged when chest x-rays came back negative for pneumonia.
She reported that she did not leave her home at Jalan Bukit Merah from Jan. 31 to Feb. 2.
On Feb. 3, she went to SGH and was classified as a suspect case.
Subsequent test results revealed that she was a confirmed case past 11pm on the same day.
Case 20 is a 48-year-old Singapore resident with no recent travel history to China.
She is currently warded in an isolation room at the National Centre for Infectious Disease (NCID).
She is a colleague of case 19 and stays at Hougang Street 61.
The patient reported onset of symptoms on Jan. 25, and went to NCID, where she was classified as a suspect case and immediately isolated.
Test results confirmed her status on the morning of Feb. 4.
Case 21 is a 44-year-old female Indonesian national with no travel history to China.
She is the domestic helper of case 19 and is currently warded in an isolation room at SGH.
She reported onset of symptoms on Feb. 2, and was admitted to SGH emergency department on Feb. 3.
Test results on the afternoon of Feb. 4 confirmed that she was infected.
The helper has not left her place of residence since the onset of symptoms.
Cases 19, 20, and 21 had close contacts with one another.
Case 22 and 23
Case 22 and 23 are Singaporean residents evacuated from Wuhan on Jan. 30.
They were asymptomatic on the flight and put under quarantine upon landing in Singapore.
Both tested positive for the virus on Feb. 3, although they continue to show no symptoms.
They are currently warded in isolation rooms at NCID.
Case 24 is a 32-year-old Singapore resident and tour guide with no recent travel history to China.
She is currently warded in an isolation room at NCID.
The tour guide had brought tour groups to Yong Thai Hang, where cases 19 and 20 worked at.
She was asymptomatic when she went to NCID on Feb. 3, where she was immediately isolated.
Test results confirmed her status on the afternoon of Feb. 4.
None of the six cases are in critical condition, although some require oxygen support.
Top image via Andrew Koay and Google Maps