NEA warns of outbreak of DenV-3 strain of dengue not dominant in S'pore in last 30 years

As fewer people have been infected, there's low herd immunity, and hence, higher rates of transmission.

Belmont Lay | February 12, 2020, 01:46 AM

What is happening on the dengue front?

The National Environment Agency said dengue infections in Singapore are rising in 2020.

This is due to a rise in proportion of DenV-3 cases.

DenV-3 is also known as dengue-3 serotype.

In the past 30 years at least, DenV-1 and DenV-2 have been the predominant circulating serotypes in Singapore.

And that switch is occurring.

The Straits Times reported that the monthly proportion of DenV-3 cases in January 2020 was approximately 47 percent, which was higher than the proportion of DenV-2 cases at 39 percent.

What are the overall figures of dengue infection in 2020 so far?

The 1,723 cases in the first five weeks of this year is 60 percent higher than the 1,057 infections diagnosed over the same period in 2019.

Last year, Singapore saw the third-highest annual rate of dengue infections which resulted in 20 deaths.


A greater number of infections is due to a possible switch in dominant serotype, which usually precedes an outbreak.

For the past 30 years at least, the rising mosquito-transmitted virus type DenV-3 has not been dominant here.

The switches have always been between DenV-1 and DenV-2.

A big outbreak is likely to occur as a result.

Higher rates of transmission is due to low herd immunity in the population as fewer people would have been infected.

What are the latest figures?

In January, there were 400 dengue infections last week, up from 371 in the previous week.

There were another 63 between Sunday and 3pm on Monday, Feb. 10.

Since mid-December, weekly cases have been rising.

It peaked at 404 cases in mid-January.

It dropped the following week, but is on the rise again.

The number of dengue infections this year has ranged between 303 and 404 a week.

There are 23 “red” dengue clusters, where more than 10 people have been infected.

There are 114 active dengue clusters with large clusters.

These are located at

Begonia Drive (166 cases),

Gangsa Road (96 cases),

Jalan Kembangan (85 cases),

Ang Mo Kio Avenue 10 (67 cases) and

Jurong West Street 91 (57 cases).

Cases are linked if the onset of symptoms are within 14 days, the maximum incubation period.

The location of cases must be within 150m of each other.

Top image via Pixabay