Dengue fever is caused by infection with one of four dengue viruses transmitted by the Aedes mosquito. It is characterized by fever, severe headache, backache and joint pains. There is no vaccine currently available, so prevention focuses on eliminating stagnant water where Aedes breed and protecting against mosquito bites. Community education and participation are important to control the disease.

2. What is dengue fever?
Dengue Fever is an illness caused by
infection with a virus transmitted by the
Aedes mosquito.

3. Symptoms of Dengue Fever
Example of a skin rash due
to dengue fever

4. Do you know…
Dengue Fever (DF) and Dengue
Haemorrhagic Fever (DHF) are the most
common mosquito-borne viral disease in the
world.
It can be fatal.

5. Characteristics of the
Aedes Mosquito
One distinct physical
feature – black and
white stripes on its
body and legs.
Bites during the day.
Lays its eggs in
Close-up of an Aedes mosquito
clean, stagnant water.

6. Do you know…
Only the female Aedes mosquito
feeds on blood. This is because
they need the protein found in
blood to produce eggs. Male
mosquitoes feed only on plant
nectar.
On average, a female Aedes
mosquito can lay about 300 eggs
during her life span of 14 to 21
days.

7. Life cycle of the Aedes Mosquito
1-2 days
Pupae Larvae Eggs
4-5 days 2-3 days
Stagnant water

8. How Do Aedes Mosquitoes Transmit
Diseases...
Mosquito bites and sucks And passes the virus
blood containing the virus to healthy people
from an infected person. when it bites them.
Virus is carried in its
body.

9. This is what you
can do to help…

10. Prevent Aedes from Breeding!
Remove ALL sources of
stagnant water.
Deny the Aedes mosquito of any chance
to breed.

11. 10-Minute Mozzie Wipe-Out
Exercise
Turn over all pails and water
storage containers.
Clear blockages and put Bti insecticide in
roof gutters monthly.
Remove water from flowerpot plates on
alternate days.
Do not litter. Rubbish such as cups and
bottles can collect rain water and breed
mosquitoes.
Change water in vases on alternate days.

12. Before you leave for holidays…

13. Before you leave for holidays…
• Cover all toilet bowls in your home.
• Seal off the overflow pipe of the flushing cistern.
• Cover all gully/floor traps.
• Add sand granular insecticide to places that
mosquitoes could potentially breed, such as flower
vases and places where stagnant water could not be
removed.

14. Dengue fever
• Dengue is an arthropod-borne disease caused by any
one of four closely related viruses, (Arbovirus).
• Characterized by fever, severe headache, backache joint
pains nausea and vomiting, eye pain and rash
• Occasionally produces shock and hemorrhage, leading
to death.
• Also called breakbone fever, dandy fever or dengue
fever.

16. Dengue Viruses
• Four closely related single-stranded RNA Dengue
viruses (DEN-1, DEN-2, DEN-3 and DEN-4)
• Each serotype provides specific lifetime immunity,
and short-term cross-immunity (A person can be
infected as many as four times, once with each
serotype)
• All serotypes can cause severe and fatal disease

17. Replication and Transmission
of Dengue Virus
1. Virus transmitted 1
to human in mosquito saliva
2
2. Virus replicates 4. Virus released and
4
in target organs circulates in blood
3
3. Virus infects white
blood cells and
lymphatic tissues

18. Aedes aegypti Mosquito

19. Aedes Mosquito
• Dengue transmitted by infected female Aedes aegypti
or Aedes albo pictos mosquito
• Primarily, it is a daytime feeder
• Highly domesticated tropical mosquito, lives around
human habitation
• Lays eggs and produces larvae preferentially in
artificial water containers inside and around the
houses for example; plastic containers, flower vases,
buckets, used automobile tires,..

20. Dengue Clinical Syndromes
• Undifferentiated fever (87% of
Patients are asymptomatic or mild
fever)
• Classic dengue fever (DF)
• Dengue hemorrhagic fever (DHF)
• Dengue shock syndrome (DSS)

21. Clinical Characteristics
of Dengue Classic Fever
• Incubation period 3-14 days (commonly 4-7
days)
• Fever
• Headache
• Muscle and joint pain
• Nausea/vomiting
• Rash
• Hemorrhagic manifestations

22. Dengue Hemorrhagic Fever (DHF)
4 Necessary Criteria:
• Fever, or recent history of acute fever
• Hemorrhagic manifestations
• Low platelet count (100,000/mm3 or less)
• Objective evidence of “leaky capillaries:”
– elevated hematocrit (20% or more over
baseline)
– low albumin
– pleural or other effusions

23. Dengue Shock Syndrome (DSS)
• 4 criteria for DHF
• Evidence of circulatory failure.

24. Treatment of Dengue Fever
• Antipyretics (Acetaminophen) preparations to
manage the pain and fever.
• Rest and drink plenty of fluids
• Monitor blood pressure, hematocrit, platelet
count,...
• Keep patient in screened sickroom or under a
mosquito net
• Mosquito barriers are only needed until fever
subsides, to prevent Aedes aegypti mosquitoes
from biting patients and acquiring virus.

25. Prevention
• Personal protection against mosquito biting by:
– Screening doors and windows
– Protective clothing
– Application of mosquito repellents on exposed
skin
• However, the best preventive measure is vector
control.

26. Vector Control Methods:
• Biological control
– Largely experimental
– Option: place fish in containers to eat larvae
• Environmental control
– Elimination of larval habitats; Cover water holding
containers, Discard artificial containers,…
– It is the most likely method to be effective in the long
term.

27. Vector Control Methods:
• Chemical Control
• Larvicides may be used to kill immature aquatic stages
• Ultra-low volume fumigation is ineffective against adult
mosquitoes as Aedes aegypti is fully domesticated
• Mosquitoes may have resistance to commercial aerosol
sprays.

28. Dengue Vaccine?
• No licensed vaccine at present
• Effective vaccine must be tetravalent
• Field testing of an attenuated tetravalent
vaccine currently underway
• Effective, safe and affordable vaccine will not
be available in the immediate future.

29. Community Participation
• Active community involvement and participation to
reduce larval breeding sources is the key for
prevention and control.
• Educate the public in the basics of dengue, such as:
– Where the mosquito lays her eggs
– The link between larvae and adult mosquitoes
– General information about dengue transmission,
symptoms and treatment

30. Public Education
• Dengue fever is NOT contagious through person-to-
person contact
• Early hospitalization is important.
• Reduce Aedes vector populations
• Reduce exposure to Aedes.
– Use insect repellent.
– Sleep under a mosquito net in affected areas.
– Wear protective clothing.
• Vaccine is NOT available.