This is a presentation on Dengue and prevention methods by the Directorate of Public Health and Preventive Medicine, Government of Tamilnadu. Since the vector which transmits Dengue virus breeds in clean water collections in domestic and peridomestic areas, a concerted action with community involvement is of paramaount importance in control of Dengue. Understanding the life cycle of this vector, Aedes aegypti is the key to control of Dengue. This presentation depicts the sources of these dangerous mosquitoes which are pervaded among us. Identification of larvae in household water storage containers and destroying them is easier than adult control measures. This is an attempt to throw light on such breeding sources and how to prevent such breeding sources, thereby preventing Dengue infection.

1. The enemy

2. The Aedes Mosquito
An intelligent, cunning and deadly creature

4. Why?
It transmits
• Dengue fever – deadly killer of
mankind particularly children
• Chikungunya - a crippling fever

5. Vector, disease and
susceptible host are available
Vector Aedes Mosquito
Disease Dengue virus
agent
Host Mostly Children

6. Characteristics of the
Aedes Mosquito
It bites during the day
It lays its eggs in
clean, shady, stagnant
water
One distinct physical
feature – black and
white strips on its body
and legs-Hence called
“Tiger Mosquitoes”

7. Life Cycle of Aedes Vector
Egg
1.5 – 3 days
Adult Larva
21 days 6 – 8 days
Pupa
1.5 – 3 days

8. Larvae in a plastic cup

9. Vector Bionomics
Eggs withstand desiccation for years
Flight range is mostly < ½ km
Day biting mosquito (Early morning and
late afternoon)
Longevity - about 3 weeks

10. Vector Bionomics
Ambient temperature for breeding 16 C
to 40 C
Indoor - rests in dark and cool places
Out door - shady places
High humidity and High temperature
enhance the vectorial capacity

11. Aedes Farms

12. Man made Aedes farms
• Water storage tank • Discarded food and
or cistern drink containers
• Drums • Used tyres
• Flower vase filled • Discarded large
with water appliances
• Potted plants with • Discarded buckets
saucers • Rubber collection
• Roof gutters shells

13. Man made Aedes farms
• Animal water • Tender cocunut
container shells
• Air coolers • Plastic covers used
• Water coolers for covering fruits in
• Discarded tins the trees
• Window gutters • Air conditioners

14. Natural Aedes farms
• Tree holes
• Rock holes
• Leaf axils

15. Man made Aedes farms

16. Tyres- Potential Threat

17. Tyres on a city main road

18. Water storage tank or cisterns

19. Breeding in uncovered water tank

20. Generous mind to Aedes, a
huge breeding source!

21. Water containers

22. Tyres every where

23. Perfect Home for the enemy

24. Enemy everywhere

25. Tyres adjoining a house

26. Tyres in a residential locality

27. Inviting the enemy

28. Enemy praying to Rain GOD

29. Looks very clean

30. Roof top view shows clean water
collection and Aedes breeding

31. Concrete mixer

32. Roof gutters

33. Plastic Containers - Ideal homes

34. Washing with bleaching powder and
brush is the most effective way

35. Awareness generation

36. Mother and daughter are trying
to understand the problem

37. Unused containers

38. Unwilling to dispose

39. Aedes in animal water
container in rural areas

40. All in one place

41. Mini homes for the enemy

42. Sweet home for the enemy

43. Opening the door for the enemy

44. Devil safe behind the God

45. What a devotion !!!

46. Coconut shells behind a hotel
kitchen

47. Coconut shells

48. Clean water for the enemy

49. Clean water for the enemy

50. Hey! Stop eating my guava!

51. But! Aedes in the plastic bags

52. Mangoes and Aedes

53. Variety of enemy’s shelters

54. Variety of enemy’s shelters

55. BREEDING SOURCES

56. BREEDING SOURCES

57. Enemy fed water everyday

58. All in one house

59. BREEDING SOURCES

60. Breeding Sources

61. Drums without lids are
emerging as a major challenge

62. Flower Pots in an otherwise
safe house

63. That water may be
Dangerous if you don’t
discard!
Remove water from flowerpot plates on
alternate days.

64. Flower Jars
Change water in vases on alternate days.

65. Often missed spot
Clear blockages and put Bti insecticide in roof
gutters monthly.

66. Variety of breeding places

67. Most favoured home

68. Variety of breeding places in a
single house

69. Tyres behind a house in which a
child died due to dengue fever

70. The unrecognised enemy

71. Unused cement tank waiting for rains

72. Natural Aedes farms

73. Tree holes

74. Tree hole harbouring Aedes

75. Plantain leaf axil

76. Factors favouring Aedes breeding
Inadequate water supply
Engineering defects
Wide use of non-biodegradable
materials
Improper disposal of solid wastes
Inadequate attention on awareness
generation among public

77. Components of Aedes Control
• Advocacy and social mobilization
• Collaboration within the health sector and
other sectors
• Integrated approach to vector control
• Legislation
• Capacity building
• Evidence based decision making

78. Simpler Solutions

79. Problem to solution

80. Angry VHN in action- enemy’s
home under attack

81. Appears to be complex problem-
but solutions are simpler

82. Upside down
unused grinder stone

83. Washing with bleaching powder
or ash and a brush

84. Discarding the water by tilting
the container

85. Lock the concrete mixer in
upside down position after work

86. War waged by children

87. Trained eyes searching for
the enemy

88. Accepts the problem: Thinks
deeply to find solution

89. Eureka!

90. Source Reduction Activities
by NSS Students

91. Cover with cloth, for
whatever use it may be!

92. Enemies are deprived of shelter

93. Used tyres collection campaign

94. Trained eyes carefully looking
for the enemy

95. Awareness generation campaign

96. Young minds are trained to
identify the enemy

97. Demonstration of larval breeding
sources

98. Awareness camps for
community involvement

99. Fever screening camps used for
surveillance, on the spot awareness
generation in the villages, improving
health care access and confidence
building

100. Awareness Generation Campaign

101. Awareness Generation
Campaign in Tenkasi

102. Hands on training for the field staff

103. A well trained man keenly looks for Aedes
larvae and gives a permanent solution

104. Motivated Health Staff train the People

105. What to do with the tyres?
• Remove to areas away from
human dwellings
• Bury
• Drill or slice vertically into half
• Recycle

106. Determined to win the war

107. Moved out for recycling/destruction

108. Small but dangerous

109. Effective campaign by motivated staff

110. Motivated staff make the
difference

111. Tyres removed from roof tops

112. A word of appreciation

113. Aerial inspection of roof tops

114. Unused open sintex tanks
on the terrace

115. Drilling Equipment

116. Driller Making a big hole

117. Big hole to drain off water

118. Tyre sliced (vertically) and used as
signage for an automobile workshop
at a location in NH 7A

119. Why mosquito nets in a hospital?

120. Hospitals? Beware!
• Hospitals may pool infection from all
over and act as epicentre
• Inside and outside of the hospitals
should be free from Aedes

121. Breeding inside a tank in toilet

122. Breeding in front of a GH where
dengue fever cases are admitted

123. Fogging as an emergency
operation to knock down
adult mosquitoes

124. Fogging into residences infested with the enemy

125. Indoor fogging- move backwards
from the backyard of the house

126. Move backwards!
Back to the front

127. Fogging in the streets

128. Fogging in public places

129. Fogging inside cinema halls
before matinee show will
interrupt transmission

130. Fogging inside parks will
interrupt transmission

131. Fogging inside market areas
will interrupt transmission

132. Community Involvement

133. Where ever possible go for permanent
solution instead of Temephos: In this
case the water can be let out easily by
removing the block

134. Cleaning drive

135. Source Reduction Activities

136. Removal of solid waste

137. Community Involvement

138. Mass Cleaning Drive

139. House Index
No. of Houses infested
HI = X 100
No. of Houses Inspected
(>10% - High risk ; <1% - Low risk)

140. Container index
The percentage of water holding containers
infested with Aedes larvae or pupae
No. of positive containers
CI =
No. of containers Inspected X 100

141. Breteau Index
No. of positive containers per 100 inspected houses
No. of positive containers
BI = X 100
No. of Houses searched
(> 50 % - High risk; < 5% - Low risk)

142. Special ward for fever cases

143. ORS corner in fever ward

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145. Together we can bring the change!