SAFETY DAY Let s Talk About DENGUE. 5 to 7 Aug Prepared by: Koh Yao Ming (Env & Security)







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5 to 7 Aug 2020




• Dengue Fever is one of the most

common mosquito-borne viral diseases in the world.

• Dengue Fever is an illness caused by

infection with a virus transmitted by the Aedes mosquito.

• There are four serotypes of this virus

(DEN-1, DEN-2, DEN-3 and DEN-4) which can infect you.


How does Dengue spread?

• Dengue fever is spread though the bite of the Aedes mosquito.

• To prevent dengue fever, you must therefore prevent the breeding of the Aedes


• Aedes mosquitoes are identified by the black and white stripes on their bodies. • You can get rid of the Aedes mosquito by frequently checking and removing


How does Dengue spread?

• The Aedes mosquito prefers to breed

in clean, stagnant water easily found in our homes.

• All it takes is clean, stagnant water as

small in volume as the size of a 20-cent coin, for mosquitoes to breed.

• During the Circuit Breaker period, NEA

observed a five-fold increase in the incidence of Aedes mosquito larvae detected in homes and common corridors in residential areas.


What is Aedes mosquito?

Did you know?

• Only the female Aedes mosquito bites, as it needs the protein in

blood for its eggs to develop.

• The mosquito becomes infective approximately seven days after

it has bitten a person carrying the virus. This is the extrinsic incubation period, during which time the virus replicates in the mosquito and reaches the salivary glands.

• Peak biting is at dawn and dusk

• The average lifespan of an Aedes mosquito in nature is two


• The mosquito can lay eggs about three times in its lifetime, and

about 100 eggs are produced each time.

• The eggs can lie dormant in dry conditions for up to about nine

months, after which they can hatch if exposed to favourable conditions, such as water and food.

Less than

1 day 4 days

2 days 3 days


What are the symptoms of Dengue?

• Sudden onset of fever for two to seven days;

• Severe headache with retro-orbital (behind the eye) pain; • Joint and muscle pain;

• Skin rashes;

• Nausea and vomiting;

• Bleeding from the nose or gums; • Easy bruising of the skin


Dengue cases in 2020

• The number of dengue cases increase five-fold during the Circuit Breaker period

“The number of dengue cases in Singapore this year has

surpassed the total number of cases for the whole of 2019." - NEA, 14 Jul 2020


Dengue surveillance data

4,773 dengue cases (including 11 dengue

haemorrhagic fever cases) were notified in the quarter from Jan-Mar 2020.

• There were seven reported deaths due to local

dengue infection from Jan-Mar 2020. The cases were between 60 and 80 years of age. All seven cases resided or worked within dengue clusters.

• Results of positive dengue samples serotyped

between Jan and Mar 2020 indicated that

DEN-3 accounted for majority of the typed samples, followed by DEN-2, DEN-1 and DEN4 (Figure 1) *.


Dengue Community Alert System

• NEA launched the Dengue

Community Alert System to display colour-coded banners (yellow, red or green banners) in dengue cluster areas to

provide timely information to residents of the dengue


Surveillance of the Aedes aegypti Mosquito Population

with Gravitraps

• The Gravitrap, developed by NEA’s Environmental

Health Institute (EHI), is designed to attract and trap female Aedes adult mosquitoes that are looking for sites to lay their eggs in.

• Female Aedes mosquitoes attempting to lay their

eggs in the traps will be captured and prevented from biting other people.

• The Gravitrap also traps and prevents the emergence

of any mosquitoes from eggs that are laid in the trap.

• Gravitraps, when distributed across an area, help to

monitor the Aedes mosquito population in the area and its vicinity.


In Summary

• From a public health point of view, dengue threats are as real as COVID-19 as it

can transmit easily from person to person

• Dengue requires the transmitting media, in this case Aedes mosquito, to transmit

the disease

• Hence, in order to break the chain of transmission, we should break the chain of

mosquitoes breeding

Recap: Senoko was fined in June 2017 for mosquito breeding

Recap: Two (2) cases were reported in hospital and NEA ‘forced’ entry into

Senoko for inspections. Only one (1) case was reported internally.


Source of information

Retrieved 13 Jul 2020:



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