What is it?

1
(No Transcript)
2
Dengue Fever
What is it? Mode of transmission Symptoms and
treatment Prevention
3
What is Dengue Fever?

• Dengue fever, also know as breakbone fever, is an
  acute communicable disease caused by virus.
• Infectious agent Dengue viruses
• (categorize into types 1,2,3,4)

4
The Situation Worldwide

• About 50 million cases annually worldwide
• Incidence of dengue fever highest in tropical and
  subtropical regions
• Recent increase in disease activity worldwide

5
Dengue Fever 2001
Regions with dengue fever
6
The Situation in Hong Kong (1)

• 11 cases in 2000
• 17 cases in 2001
• First local case identified in September 2002

Imported cases
Mosquito elimination has become an imminent
matter.
7
The Situation in Hong Kong (2)

• The Department of Health is working closely with
  other government departments to monitor the
  spread of dengue fever in Hong Kong. Prompt
  measures to prevent and control the spread of the
  disease have been put in place.

8
Vectors of Dengue Fever

• Aedes aegypti
• Aedes aegypti is not found in Hong Kong at
  present.
• Aedes albopictus
• Aedes albopictus is very common in Hong Kong.

9
Vector

• Aedes
• albopictus

The life cycle of a vector mosquito is
divided into the 4 stages egg, larva, pupa and
adult
10
Habitual Behaviour of Aedes Albopictus (1)

• Usually breed in stagnant water
• Usually active in dark or shaded places outdoors,
  but indoor activity is also possible

11
Habitual Behaviour of Aedes Albopictus (2)

• Female mosquitoes feed on human blood.
• They are most active 2 hours before sunset
  (around 5pm to 6pm) and at around 8am to 9am.
• Where do they sting?
• Outdoors and indoors.

12
Mode of Transmission

• A healthy person gets the disease when he is
  bitten by an infected mosquito. The virus enters
  his blood from the mosquitos saliva.
• An infected person could transmit the virus to
  mosquitoes if he is bitten by a mosquito anytime
  from the onset to the subsidence of the fever (a
  period of about 6 to 7 days). The disease is then
  spread by mosquitoes.
• Dengue fever is not spread by contact
• with infected persons.

13
Transmission
Infected mosquito
Healthy person
Infected person
Incubation Period 3 to 14 daysMost commonly 4
to 7 days
14
Types
Classical dengue
Dengue haemorrhagic fever
15
Symptoms of Classical Dengue (1)

• Fever continuous for 3 to 5 days
• Severe headache
• Painful limbs, joint pain, muscle pain, back
  pain, pain behind eyeballs

16
Symptoms of Classical Dengue (2)

• Rash appears on the 3rd to 4th day after onset.
• Nausea, vomiting.
• Slight gum bleeding and nasal bleeding.
• Extreme fatigue and depression may follow
  recovery.
• In very rare cases, the condition may worsen
  into dengue haemorrhagic fever, leading to
  haemorrhage, shock or even death.

17
Treatment (1)

• At present, there is no drug that can treat
  dengue fever effectively. Patients infected with
  classical dengue usually recovers in 1 to 2
  weeks.
• For serious cases, supportive treatments are
  provided by hospitals.
• If you suspect that you have dengue fever, you
  should seek medical treatment promptly.

18
Treatment (2)

• Wiping the body with warm water and proper use of
  anti-fever drugs that can relieve the fever.
• Dont take aspirin-containing drugs because they
  worsen the haemorrhage.

19
Protect Yourself against Dengue Fever

• As yet, there is no effective vaccine against
  dengue fever. Therefore, the best prevention is
  to avoid being bitten by mosquitoes by paying
  attention to the following
• Avoid staying in dark, outdoor places such as
  brushwood, pavilions or the shade of a tree
  during the hours when Aedes albopictus is
  active.

20
Control the Spread of Dengue Fever
Prevent the patient from being bitten by
mosquitoes.
21
Prevention of Mosquito Bites
Avoid going out in the hours when Aedes
albopictus feed or wear light-coloured,
long-sleeved clothing and trousers.
22
Prevention of Mosquito Bites

• Apply DEET-containing
• mosquito-repellents
• over exposed parts of the body and clothes
  every 4 to 6 hours.
• For DEET products used by children, its
  concentration should be less than 10.

23
Prevention of Mosquito Bites
Your place of accommodation should have
air-conditioners or mosquito nets. Otherwise,
hang mosquito screens around your bed, use
insecticides or coil incenses to repel
mosquitoes.
24
Prevention of Mosquito Bites
Install mosquito nets to doors and windows so
that mosquitoes cant get in.
25
Elimination of Mosquitoes
The most effective way to eliminate mosquitoes is
to keep the environment clean and to remove
stagnant water so that mosquitoes cant breed.
26
Possible Breeding Grounds of Aedes Albopictus (1)
Artificial containers Vases, saucers underneath
flower pots, trays underneath air-conditioners,
buckets, jars and jugs of earthenware, cement
troughs, dumped tyres and solid wastes such as
cans, disposable cups and bowls, and plastic
bags.
27
Possible Breeding Grounds of Aedes Albopictus (2)

• Natural containers
• The hollow space inside a bamboo,
  hollows of a tree and the rachis of a leaf.

28
Elimination of Mosquitoes
Cover water containers tightly so that
mosquitoes cant get in to lay eggs.
29
Elimination of Mosquitoes

• Dispose of domestic wastes properly to
  prevent the accumulation of stagnant
  water.
• Dispose of empty bottles,
• cans and lunchboxes
• properly, such as into a
• covered bin.

30
Elimination of Mosquitoes

• Change water for vases and aquatic plants at
  least once a week, leaving no water under
  the pots or in the bottom saucers.
• Scrub the container surfaces thoroughly to
  prevent mosquito eggs sticking on them.

31
Elimination of Mosquitoes
Remove or puncture any dumped tyres to prevent
the accumulation of stagnant water.
32
Elimination of Mosquitoes
Ditches should be free from blockage.
33
Elimination of Mosquitoes
Fill up uneven ground surfaces to prevent the
accumulation of stagnant water.
34
Elimination of Mosquitoes
Remove stagnant water immediately if mosquitoes
are found to be breeding. Use environmentally
friendly insecticides such as lavicidal oil if
necessary.
35
Elimination of Mosquitoes
In cultivation ponds, water tanks or large
containers, biological controls such as keeping
fishes to eat mosquito larvae would be a good
option.
36
(No Transcript)
37
Prevention of Dengue Fever - A Whole School
Approach

• The school is an ideal setting for health
  promotion.
• Targets all staff, students and parents.
• Enhance their understanding of mosquito-borne
  diseases.
• Raise their awareness of dengue fever and
  evaluate the risks of it.
• Encourage members of the whole school to play an
  active part in mosquito elimination.
• Eliminate black spots of mosquito breeding.

38
Black Spots of Mosquito Breeding in the Campus

• Garden / gardening corner / saucers underneath
  flower pots / aquatic plants
• Tuckshop
• Rubbish collection stations
• Ditches
• Toilets
• Water tanks / pools

39
Prevention of Dengue Fever - A Whole School
Approach

• Eliminate mosquitoes
• Planning, manpower arrangement, areas to be
  inspected, inspection time and record
• Please call the Food and Environmental Hygiene
  Departments hotline for assistance if required
  2868 0000

40
Mosquito Elimination Checklist (1)

• Are containers and other items where water could
  accumulate disposed of properly?
• (For example, throwing empty cans, foam rubber
  boxes, cups and bottles into a covered bin.)
• Are water containers covered properly?

41
Mosquito Elimination Checklist (2)

• Are ditches free from blockage?
• Are containers with stagnant water cleaned
  regularly?
• (For example, vases, saucers underneath flower
  pots, water storage device of an air-conditioner,
  water tanks and pools.)
• Are uneven ground surfaces filled to prevent the
  accumulation of stagnant water?

42
See Doctor Immediately

• Having been bitten by a mosquito and
  displaying symptoms of dengue fever
  afterwards
• Falling ill, especially having a fever
  within one month after you have returned
  from abroad

43

• If you suspect that you have dengue fever, the
  most important thing to do is to
• see a doctor.

44
Hotline / Web site

• Central Health Education Unit, Departmentof
  Health Hotline [phone]Web site
  www.cheu.gov.hk
• Food and Environmental Hygiene Department (about
  mosquito breeding)Hotline [phone]Web
  site www.info.gov.hk/fehd

45
Prevention of Dengue Fever - A Whole School
Approach

• Lets remove stagnant water
• and eliminate mosquitoes