- Immature stage: The document discusses the different immature stages of mosquitoes including the egg, larva, and pupa stages. It notes key distinguishing characteristics between anopheline and culicine mosquitoes at each stage. - Adult mosquitoes: The three main genera of mosquitoes - Anopheles, Culex, and Aedes - are described. Key identification features, breeding sites, biting behaviors, and diseases transmitted for each are outlined. - Medical importance: Mosquitoes transmit many important diseases like malaria, dengue, yellow fever, and filariasis. Studying medical entomology and the arthropod vectors is important for preventing such diseases.

2. Introduction:
•
•
•
•
The study of diseases caused by arthropods
Entomo (gr) = ‘segmented’
logy= ‘study’
Arthron = ‘jointed’
Poda = ‘foot’
Arthropods: largest phylum in the animal
kingdom
• B/L symmetrical segmented body, supported by
exoskeleton(chitin), do not have bones, but the
hard outer covering supports the muscles.
• The appendages are jointed.
• The body is formed of a number of segments.
2

3. PHYLUM: ARTHROPODA
CLASS
INSECTA
q
q
q
q
q
MOSQUITO
FLIES
LOUSE
FLEAS
REDUVID BUG
ARACHNIDA
q
q
q
q
SOFT TICK
HARD TICK
ITCH MITE
TROMBICULID MITE
CRUSTACEA
q CYCLOPS
4

4. Characters:
Insecta
Arachnida
Crustacea
Cephalothorax &
Abdomen
Cephalothorax &
Abdomen
Legs:
Head
Thorax &
Abdomen
3 pairs
4 pairs
5 pairs
Antennae:
1 pair
-
2 pairs
Wings:
1 pair or
Wingless
Land
-
-
Land
Water
Body
division:
Habitat:
5

5. Medical Entomology
• Branch of preventive Medicine
• A study of the arthropods of Medical
importance is known as Medical
Entomology.

6. Why study of this is important?
1
Mosquito
Malaria, Filaria, JE, Dengue Fever,
Chikungunya
2
Housefly
Typhoid, Cholera, Diarrhea & Dysentery,
Poliomyelitis, Gastroenteritis, Trachoma
3
Itch Mite
Scabies
4
Cyclops
Guinea worm disease
5
Sand fly
Kala-azar
6
Tsetse fly
Sleeping sickness
7
Louse
Epidemic Typhus
8
Rat flea
Bubonic Plague
9
Reduvig bug
Chagas disease
10 Hard tick
Tick typhus, Viral encephalitis
11 Soft Tick
Q fever, Relapsing fever

7. Transmission of Arthropod borne diseases
Transmissions
Transmissions
Direct Contact
Direct Contact
From man to man
From man to man
Scabies
Scabies
pediculosis
pediculosis
Propagative
Propagative
Only multiplication
Only multiplication
No developmental
No developmental
Plague bacilli in rat
Plague bacilli in rat
flea
flea
Mechanical
Mechanical
Diarrhea
Diarrhea
Dysentery
Dysentery
Typhoid
Typhoid
Trachoma
Trachoma
Cyclo propagative
Cyclo propagative
Multiplication
Multiplication
developmental
developmental
Malaria parasites in
Malaria parasites in
mosquito
mosquito
Biological
Biological
Cyclodevelopmental
Cyclodevelopmental
No multiplication
No multiplication
developmental
developmental
Filaria parasite
Filaria parasite
In mosquito
In mosquito

8. Mosquitoes
9

9. General Features of Mosquito
10

10. General features
• Body consist of 3 parts:
Head:
-Semi globular in outline
 Pair of large compound eyes,
eyes
 Needle like structure called
proboscis, with which it bites.
proboscis
 Palpi situated on either side
of proboscis.
 Pair of antennae or feelers.
bushy in male, not so in
female.
11

11. Thorax:
 Large & rounded in appearance.
 Bears pair of wings dorsally which produces
buzzing noise.
 Three pair of legs ventrally.
Abdomen:
 Long & narrow, composed of 10 segment,
last two segments are modified to form
external genitalia.
 Clasper in male n round in female
12

12. Life history of mosquito
13

13. Eggs
• Eggs are laid on the
surface of water,100 -250
at time.
1.Anopheles
• lays her eggs singly,
• boat shaped and
• possess lateral floats
14

14. 2 Aedes
• Cigar shaped,
• Laid down singly,
• no lateral floats
15

15. Eggs……….
3. Culex small clusters
4. Mansonia lays her eggs
in star shaped clusters,
clusters
attached to the under
surface of certain aquatic
plants.
The period that elapses from the moment of blood
meal until the eggs are laid is called “gonotrophic
cycle” about 48 hours.
Egg stage of mosquito lasts for 1-2 days
16

16. Larva
• The larva is a free swimming creature
with an elongated body divisible into
head, thorax & abdomen.
• It feeds on algae, bacteria, and
vegetable matters.
• Passes through 4 stages of growth
called Instars with moulting between
each stage.
18

17. Anopheles larva:
• Exclusively surface feeder,
• Floats horizontally just below the
surface of water,
• very active with swift movement
• No siphon tube, but
• breathing apparatus consist of
parallel air tube at the tail end.
Culicines Larva:
• suspended in water with head
downwards,
• much slower with snake like
movement
• Has long narrow siphon tube.
19

18. • Larva of Mansonia are
attached to rootlet of aquatic
plant by their siphon tube.
Larval stage occupies:
• 2 days in anopheles &
• 5-7 days in Culicines.
20

19. Pupa
 comma shaped in appearance
with large rounded cephalothorax
and a narrow abdomen.
 Two small respiratory tubes or
trumpets project from the upper
surface of the thorax.
 represents the resting phase in
the life history of mosquito.
 Doesn’t feed & prefer to stay
quite at water surface.
 The pupal stage lasts 1-2 days
21

20. Adult Mosquitoes
• When development is complete, pupal skin
split along the back & adult mosquito
emerges.
• It rests for a while on the pupal skin to allow
its wings to expand & harden & then flies
away.
• The life cycle from the egg to adult is
complete within 7-10 days
• Normally adult mosquito lives for about 2
weeks.
• Males are generally short lived.
22

21. Anopheles Mosquito
• Identification features
Spotted wings
When at rest,
inclined at an
angle of 45* to the
surface
No buzzing sound
23
Anopheles

22. Anopheles
female
Anopheles
male
Culex female
Culex male
24

23. Palpi long In both
Anopheles male &
female and short in
Culicines female
SPOTED
WINGS
Antennae
bushy
45*
25
Anopheles

24. Palps are as long as the
proboscis
26
Anopheles

25. palps have white rings
Anopheles
proboscis
dark
27

26. palmate hair on
abdomen
Anopheles
28

27. 29

28. Siphon tube-broad & short
30

29. • Food Preference: it is both anthropophilic &
Preference
zoophilic, a blood meal on the part of female
zoophilic
Anophelines is essential for maturation of the
ovum.
• Resting Habit: Endophilic, i.e. indoor resting
Endophilic
habit for the purpose of digesting blood meal
& for the development of the ovum.
• Flight: can cover long distance, about 0.751.5 km, it significant for practical control of
km
mosquito vector.
• Life span: usually in India it lives for one
month, hibernating mosquito lives longer 31
month
Anopheles
about 6months

30. Prefers clean water for • Time of biting :
breeding
Evening or early
• Irrigation channel,
part of night
•
•
•
•
•
•
•
River beds,
Ponds, pools, lakes,
spring,
brackish water,
burrow pit,
fruit & vegetable garden
and even s in Open
overhead tanks or in wells.
• Feeding Habits:
Only female bites,
male never bites.
Anopheles
32

31. Breeding habits:
Anopheles
33

32. Bio-Ecological Characteristics of Principal
Malaria Vectors in India
• About 45 species of anopheles
• 7 are vectors of malaria
1)An. Culicifacies:
•
It is most important vector in malaria
transmission in India & very widely distributed in
RURAL area of North, South and Central India
•
more zoophilic than anthropophilic,
•
bite in Dusk, peak time is 10.30pm to12.30
midnight, survives for 4 weeks.
• Resting Habits: Predominantly indoor rester-cattle
sheds and human dwellings and prefer pools with 34
low disturbance places.

33. 2) An. Stephensi: it is normally vector for URBAN
area, particularly in coastal region and prefer
small collection of clean water,
prefer human dwelling & cattle sheds
bites soon after dusk,
peak at 4 to 6 am.
3) An. Minimus: in N.E. states, North West Bengal
Minimus
4) An. Fluviatilis: seen along Himalaya range
Fluviatilis
seepage and in irrigation channels.
5) An. Dirus: deep forest in N.E. region.
Dirus
6) An. Sundaicus: Andaman and Nicobar IslandSundaicus
breeds in brackish water.
7) An. Philippinensis: is the vector for the plains of
Philippinensis
35
West Bengal and N.E. region.

34. Culex
Identification features
• When at rest, the
body exhibits hunch
back(i.e. the thorax
back
makes an angle with
the abdomen)
• Wings unspotted
• Buzzing noise
produce by beating of
wings,
Culex
37

35. 38

36. Culex
proboscis and palps dark, palps short
39

37. Culex 40

38. 41

39. Breeding places
• It profusely breeds in dirty water
collections contaminated with sewage.
• Stagnant drains
• Cesspools
• Septic tanks
• Burrow pits
Culex
42

40. Culex:
43

41. Time of biting
• At night- enters the houses at dusk &
reaches maximum density at midnight
• Peak time of biting is at midnight
Site of biting – legs, below the knee
Culex
44

42. • Highly anthropophilic
• Dispersal is about 11 km, strong winged
km
mosquito
• Average life span : 21 days
• The vector is mainly outdoor resting and
outdoo
outdoor feeding.
•
•
•
•
Diseases
Bancroftian Filariasis ( Cu. Fatigans)
Fatigans
JE (Cu. Vishnui)
Vishnui
West Nile fever
Viral arthritis
Culex
45

43. Aedes
• Sits parallel to the surface
• White stripes on black body
Aedes
46

44. Aedes
47

45. Aedes
48

46. 51

47. Siphon tube-long & narrow
Aedes
52

48. Aedes….
• Because it bites vigorously and fearlessly
to many persons, so it is also called as
tiger mosquito
• Adult seek dark and quit places to rest in
bedrooms, kitchen, on walls, furniture,
hanging articles like clothing, ropes and
closets
• Average survival for male is 20 days and
for female 30 days.
53

49. Breeding places
Aedes aegypti profusely breeds in
Artificial accumulation of water
• Behind refrigetor &
• Tyres,
coolers,
• Broken glasses,
• Storage tanks,
• Plastic containers and
• Earthen pots and other
tins which have been
receptacles with rain
discarded.
water,
• In flower vases,
54
Aedes

50. Aedes:
55

51. Time of biting
• Day biters
• Do not fly more than 100 meter
• Mostly found in rainy water
Aedes
56

52. Species
Diseases
• A. aegypti and A. sentellaris :
breeds in peri- domestic
• Dengue
artificial collection of water.
• A. Albopictus : breeds in
natural rather than artificial
water collections.
• DHF
• Chikungunya fever
• Yellow fever
• A. vittatus : seen outside India,
not domestic mosquito.
57
Aedes

53. Mansonia
• breed on aquatic plants ( Pistia straitiotes )
for the supply of oxygen
• Two species of the vector:
-Mansoniodes uniformis and M.
annulifera
-transmit Brugia malayi infection of Filariasis
in India
58

54. Mansonia:
59

55. mansonia
61

56. palps not more than 1/3 as long as proboscis,
‘club-like’
62
mansonia

57. Mosquito breeding places
anopheles
63

58. Mosquito breeding places
Mansonia
64

59. Mosquito breeding places.
culex
65

60. Mosquito breeding places.
Aedes mosquito
66

61. Thank You
67

62. Vector:
It is defined as an arthropod or any living
carrier that transport an infectious agent to a
susceptible individual by inoculating into or
through the skin/mucous membrane or by
depositing infected material on skin/food or
other object.

63. Some terminology:
• Extrinsic incubation period:
It is the period of time required for the disease agent
to undergo multiplication or a phase of cyclic
development or both inside the body of arthropod
Eg. In malaria 10- 14 days
• Definitive host:
It is a one which the sexual phase of the development
or life cycle of the parasite takes place
Eg. Female anopheline mosquito in malaria
• Intermediate host:
It is one in which asexual phase of the development or
life cycle of the parasite takes place
Eg. Cyclops in dracontiasis
69

64. • Infestation:
The lodgement, growth, development and
reproduction of the arthropod parasite on the
surface of the body Eg. Louse infestation
• Metamorphosis:
Changes that take place in size, shape and structure
during the different stages of life cycle of the
arthropod from the stage of egg to adult stage
 Incomplete metamorphosis( Hemimetabola)
Stages: egg, nymph, adult..
Eg. Louse, ticks
 Complete metamorphosis( Holometabola)
Stages: egg, larva, pupa, adult
Eg. Mosquito, fly and flea
70

65. • Infected Mosquito: A mosquito is said to
be infected when it has the disease agent
inside the body but may not be infective
• Infective Mosquito: A mosquito capable
of transmitting the disease agent. It
become so after the extrinsic incubation
period
71

66. 72

67. 73

68. 74

69. 75

70. Abdomen:
 Narrow tube like, having 10 segments.
 Last 2 segments are modified into genitalia, a
pair of claspers in male & a pair of cerci in
female.
 Claspers are long and curved
 Cerci are small and rounded
They are help for sex identification
76

71. 77

72. 78

73. 79

74. 80

75. Aedes larva
Culex larva
Bottom feeders
Suspended downwards with lateral angles
Palmate hairs are scanty
Siphon tube open at surface for respiration
Siphon tube is short and
barrel shaped
Siphon tube is long and
narrow
81

76. Pupa stage:
• Head and thorax is fused to form cephalothorax
and cylindrical abdomen is curved looks like tail.
• Thus this stage looks like comma shaped
structure
• Bear a pair of eyes. Mouth is absent so does not
feed
• Respiratory apparatus ( 2 siphon tubes for
breathing ) disappear from the last abdominal
segments of the larva and developed on the
cephalothorax of pupa
• Tip of abdomen has caudal paddles and caudal
hairs
• This stage is resting or quiescent stage
82

77. • Pupa:
anopheline pupa, the siphon tube is
short and broad,
culicini pupa, it is long and narrow.
83

78. Adult stage
• Also called as imago stage
• When development is complete, pupal skin split along the
back & adult mosquito emerges.
• It rests for a while on the pupal skin to allow its wings to
expand & harden & then flies away.
• The life cycle from the egg to adult is complete within 7-10
days
• Adult male mosquito live for 2 weeks, the female live little
longer
• Male mosquito smaller,slender and female are
larger,aggressive
• Male never feed on blood but on vegetable juice
84
• Female require blood meal for every 2-3 days for
oviposition

79. • Before copulation the males collect in
swarms and engage in nupitial dance,
mating occurs in high up in air during
evening timings.
• Fertilization usually takes place 12- 24
hours after the emergence of the young
adults, the female lays eggs which marks
the repetition of life cycle
• Egg (2days )→ larva (6-8days) → pupa(2
days) → adult
85

80. • scutellum: Crescent shaped with
long hairs at regular interval
• Maxillary palpi: Long in both sexes,
tip is club shaped in male and not
club shaped in female
• Antennae: bushy and more hairy in
males and less in femal
86

81. INTEGRATED VECTOR MANAGEMENT
Evidence based implementation of one or
more, appropriate and effective, vector
control interventions (chemical and/or nonchemical), in a carefully managed operation to
limit disease transmission, with a view to
obtain maximum effect with minimal inputs
and also to minimize the excessive use of any
one method, thereby minimizing the risk of
emergence of resistance or environmental
pollution.
87

82. Key Elements of IVM
88

83. • Vector surveillance
• For malaria:
1. Human blood index
2.Sprozoite Rate
3. Mosquito density
4. Man biting Rate
5.Inoculation Rate
89

84. For Dengue:
Larval survey
• Human index
• Container Index
• Breateau Index
• Pupae Index
Adult survey
Landing/Biting collection
Resting collection
Oviposition traps
90

85.  Larvivorous Fish
Advantages
Gambusia affinis






Environmental friendly
Easy to introduce
Self propagating & self sustainable
User friendly
Helps build community participation &
intersectoral collaboration
Cost-Effective - no recurrent costs
Limitations
Lebister reticulatus
•
•
•
Aphanius dispar
Extremes of temperatures and pollution
Suitable for some types of breeding
sources only
Needs proper planning with mapping of
breeding sources & promotional efforts
91

86. • Biolarvicide: Bacillus thuringiensis
iserailensis (Bti)-Endotoxin : 2.5%
suspension, 1 lit/50 m2, once every 2 weeks.
92

87. 2. Anti-adult measures:
93

88. 3. Protection against mosquito-bite:
a) Mosquito net: ITBN treated with Deltamethrin
b) Screening: of windows, not >0.0475 inch in any
diameter.
c) Repellants : DEET, indalone, diethyl benzamide,
dimethyl phathalate.
94

89. •
More emphasis on IEC
using various media
• Increased budgetary
provisions for regular
IEC campaigns
• Observance of anti-malaria
month during
June every year
IEC
with
BCC
95

90. • Life cycle: Egg, Larvae and Adult, i.e.
metamorphosis is incomplete.
6-9 days
Egg (nits)
Adult
10-15 days
Larvae
(3 molts)
• Life span of an adult is 3-5 weeks.
96

91. •
Breeding places (habitat): long hairs,
cloths.


•
Overcrowding and poor personal hygiene
favours the transmission.
Places like hostels, prisons, beggar houses.
Diseases:1)
2)
3)
4)
5)
Pediculosis
Dermatitis (Vagabond’s disease)
Epidemic typhus (Rickettsia Prowazeki)
Trench fever (R. quintana)
Relapsing fever (Borrelia recurrentis)
97

92. Crab louse:
(pubic louse – Phthirus pubis)
•
•
•
•
•
•
•
found in pubic hair.
Short and stout, square shaped body,
Head impacted on the thorax
Powerful legs with claws
1st pair of leg is slender than others
Thorax is broader than abdomen
Abdomen has only five visible segment and
each segment has lateral protuberances
• Aedegus is small not clearly visible in male
and female 5th abdo segment bifid
98