Mosquitoes

ppt decribes how to differentiates varioius mosquitoes..

2. 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.

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PHYLUM: ARTHROPODA
INSECTA ARACHNIDA CRUSTACEA
qMOSQUITO
qFLIES
qLOUSE
qFLEAS
qREDUVID BUG
qSOFT TICK
qHARD TICK
qITCH MITE
qTROMBICULID MITE
qCYCLOPS
CLASS

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Characters:
Insecta ArachnidaCrustacea
Body
division:
Head
Thorax &
Abdomen
Cephalo-
thorax &
Abdomen
Cephalo-
thorax &
Abdomen
Legs: 3 pairs 4 pairs 5 pairs
Antennae:1 pair - 2 pairs
Wings: 1 pair or
Wingless
- -
Habitat:Land Land Water

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

7. Transmission of Arthropod borne diseaseslH: doeddeh d
TransmissionsLeHt3sc.h s:3s
5Hhoco: cshco:
C3:1etd
ptue3bnhded
Direct Contact
From man to man
Scabies
pediculosisxt3i: e3:n
Le:HHit:
Ladt stHa
lapiheu
lH:3iho:c
Mechanical
Diarrhea
Dysentery
Typhoid
Trachoma 7ehnhye3:n
BiologicalgHhp:y:se8t
0 nacobnsepne3:seh
*hcut8tnhpot s:n
gn:ybtc1:3ennece cH:sc
rnt:
Propagative
Only multiplication
No developmental
Plague bacilli in rat
flea.a3nhcpHhp:y:se8t
xbnsepne3:seh
ut8tnhpot s:n
x:n:He:cp:H:destdce c
ohdAbesh
Cyclo propagative
Multiplication
developmental
Malaria parasites in
mosquito.a3nhut8tnhpot s:n
*hcobnsepne3:seh
c ut8tnhpot s:n
5en:He:cp:H:dest
2 cohdAbesh
Cyclodevelopmental
No multiplication
developmental
Filaria parasite
In mosquito

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Mosquitoes

9. General Features of Mosquito
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10. General features
•Body consist of 3 parts:
HeadHead::
-Semi globular in outline
Pair of large compound eyeseyes,
Needle like structure called
proboscisproboscis, with which it bites.
PalpiPalpi situated on either side
of proboscis.
Pair of antennae antennae or feelers.
bushy in male, bushy in male, not so in
female.

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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
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12. Life history of mosquito
13

13. Eggs
•Eggs are laid on the
surface of water,100 -250
at time.
1.1.AnophelesAnopheles
•lays her eggs lays her eggs singlysingly, ,
• boatboat shaped and shaped and
•possess possess lateral floatslateral floats
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14. 2 Aedes2 Aedes
•Cigar shaped,
•Laid down singly,
•no lateral floats
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15. Eggs……….
3. Culex 3. Culex small clusters
4. Mansonia4. Mansonia lays her eggs
in star shaped clustersstar shaped clusters,
attached to the under
surface of certain aquatic
plants.
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The period that elapses from the moment of blood
meal until the eggs are laid is called “gonotrophic
cycle” about 48 hours.48 hours.
Egg stage of mosquito lasts for Egg stage of mosquito lasts for 1-2 days1-2 days

16. Larva
•The larva is a The larva is a free swimming creature free swimming creature
with an elongated body divisible into with an elongated body divisible into
head, thorax & abdomen.head, thorax & abdomen.
•It feeds on algae, bacteria, and
vegetable matters.
•Passes through 4 stages of growth Passes through 4 stages of growth
called Instars called Instars with moulting between
each stage.
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17. AnophelesAnopheles larva:
•Exclusively surface feeder,Exclusively surface feeder,
•Floats horizontally just below the Floats horizontally just below the
surface of water, surface of water,
•very active with swift movementvery active with swift movement
•No siphon tube, butNo siphon tube, but
•breathing apparatus consist of breathing apparatus consist of
parallel air tube at the tail end.parallel air tube at the tail end.
Culicines Culicines Larva:
•suspended in water with head suspended in water with head
downwards, downwards,
•much slower with snake like much slower with snake like
movementmovement
•Has long narrow siphon tube.Has long narrow siphon tube.
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18. •Larva of MansoniaMansonia are
attached to rootlet of aquatic
plant by their siphon tube.
Larval stage occupies:
•2 days 2 days in anophelesanopheles &
•5-7 days in Culicines.5-7 days in Culicines.
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19. Pupa
comma shaped in appearance
with large rounded cephalothorax
and a narrow abdomen.
Two small respiratory tubes or small respiratory tubes or
trumpets 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 days1-2 days
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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 The life cycle from the egg to adult is
complete within complete within 7-10 days7-10 days
•Normally adult mosquito lives for about 2
weeks.
•Males are generally short lived.
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21. Anopheles Mosquito
•Identification featuresIdentification features
Spotted wings
When at rest,
inclined at an
angle of 45*angle of 45* to the
surface
No buzzing sound
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Anopheles

22. 24
Anopheles
female Anopheles
male
Culex female
Culex male

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

24. Palps are as long as the
proboscis
26
Anopheles

25. palps have white rings
proboscisproboscis
darkdark
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Anopheles

26. palmate hair on
abdomen
28Anopheles

27. 29

28. 30
Siphon tube-broad & shortSiphon tube-broad & short

29. •Food PreferenceFood Preference: it is both anthropophilic & anthropophilic &
zoophiliczoophilic, a blood meal on the part of female
Anophelines is essential for maturation of the
ovum.
•Resting HabitResting Habit: : EndophilicEndophilic, i.e. indoor resting
habit for the purpose of digesting blood meal
& for the development of the ovum.
•Flight:Flight: can cover long distance, about 0.75-about 0.75-
1.5 km1.5 km, it significant for practical control of
mosquito vector.
•Life span: Life span: usually in India it lives for one one
monthmonth, hibernating mosquito lives longer
about 6months
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Anopheles

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

31. 33
Breeding habits: Anopheles

32. Bio-Ecological Characteristics of Principal Bio-Ecological Characteristics of Principal
Malaria Vectors in IndiaMalaria Vectors in India
•About 45 species of anopheles
•7 are vectors of malaria
1)1)An. Culicifacies: An. Culicifacies:
• It is most important vector in malaria
transmission in India & very widely distributed in
RURAL 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
low disturbance places.

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33. 2) An. StephensiAn. 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. MinimusAn. Minimus: in N.E. states, North West Bengal
4) An. FluviatilisAn. Fluviatilis: seen along Himalaya range
seepage and in irrigation channels.
5) An. DirusAn. Dirus: deep forest in N.E. region.
6) An. SundaicusAn. Sundaicus: Andaman and Nicobar Island-
breeds in brackish water.
7) An. PhilippinensisAn. Philippinensis: is the vector for the plains of
West Bengal and N.E. region.
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34. Culex
Identification featuresIdentification features
•When at rest, the
body exhibits hunch hunch
backback(i.e. the thorax
makes an angle with
the abdomen)
•Wings unspotted
•Buzzing noise
produce by beating of
wings,
37Culex

35. 38

36. proboscis and palps dark, palps short
39
Culex

37. 40Culex

38. 41

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

40. 43
Culex:

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

42. •Highly anthropophilicHighly anthropophilic
•Dispersal is about 11 km11 km, strong winged
mosquito
•Average life span : 21 days21 days
•The vector is mainly outdoooutdoor resting and
outdoor feeding.
Diseases
•Bancroftian Filariasis ( Cu. FatigansCu. Fatigans)
•JE (Cu. VishnuiCu. Vishnui)
•West Nile fever
•Viral arthritis 45Culex

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

44. 47Aedes

45. 48
Aedes

46. 51

47. 52
Aedes
Siphon tube-long & narrowSiphon tube-long & narrow

48. Aedes….
•Because it bites vigorously and fearlessly
to many persons, so it is also called as
tiger mosquitotiger mosquito
•Adult seek dark and quit places to rest in Adult seek dark and quit places to rest in
bedrooms, kitchen, on walls, furniture, bedrooms, kitchen, on walls, furniture,
hanging articles like clothing, ropes and hanging articles like clothing, ropes and
closetsclosets
•Average survival for male is 20 days and Average survival for male is 20 days and
for female 30 days.for female 30 days.
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49. Breeding placesBreeding places
Aedes aegypti profusely breeds in
Artificial accumulation of waterArtificial accumulation of water
•Behind refrigetor & Behind refrigetor &
coolers,coolers,
• Storage tanks,Storage tanks,
• Earthen pots and other Earthen pots and other
receptacles with rain receptacles with rain
water, water,
•In flower vases,In flower vases,
• Tyres, Tyres,
•Broken glasses, Broken glasses,
•Plastic containers and Plastic containers and
tins which have been tins which have been
discarded.discarded.
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Aedes

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Aedes:

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

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

53. MansoniaMansonia
•breed on aquatic plants ( Pistia straitiotes ) aquatic plants ( Pistia straitiotes )
for the supply of oxygenfor the supply of oxygen
•Two species of the vector:Two species of the vector:
--Mansoniodes uniformis and M. Mansoniodes uniformis and M.
annuliferaannulifera
-transmit -transmit Brugia malayi infection of FilariasisBrugia malayi infection of Filariasis
in India in India
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54. 59
Mansonia:

55. 61mansonia

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

57. Mosquito breeding places
anopheles
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58. Mosquito breeding places
Mansonia 64

59. Mosquito breeding places.
culex
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60. Mosquito breeding places.
Aedes mosquitoAedes mosquito
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61. Thank YouThank You
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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
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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
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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
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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
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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
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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
•This stage last for 2 days
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77. •Pupa:
anopheline pupa, the siphon tube is
short and broad,
culicini pupa, it is long and narrow.
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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
•Female require blood meal for every 2-3 days for
oviposition
•Blood required from animal(zoophilic) or man
( anthrophilic)
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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
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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

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81. 87
INTEGRATED VECTOR MANAGEMENT
Evidence based implementation of one or
more, appropriate and effective, vector
control interventions (chemical and/or non-
chemical), 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.

82. Key Elements of IVMKey Elements of IVM
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83. •Vector surveillance
•For malaria:
1. Human blood index
2.Sprozoite Rate
3. Mosquito density
4. Man biting Rate
5.Inoculation Rate
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84. For Dengue:
Larval survey
•Human index
•Container Index
•Breateau Index
•Pupae Index
Adult survey
Landing/Biting collection
Resting collection
Oviposition traps
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85. 91
Larvivorous Fish
Advantages
Environmental friendly
Easy to introduce
Self propagating & self sustainable
User friendly
Helps build community participation &
intersectoral collaboration
Cost-Effective - no recurrent costs
Limitations
•Extremes of temperatures and pollution
•Suitable for some types of breeding
sources only
•Needs proper planning with mapping of
breeding sources & promotional efforts
Lebister reticulatus

Gambusia affinis
Aphanius dispar

86. •Biolarvicide: Bacillus thuringiensis
iserailensis (Bti)-Endotoxin : 2.5%
suspension, 1 lit/50 m
2
, once every 2 weeks.
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87. 2.Anti-adult measures:
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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.
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89. IEC
with
BCC
95
• More emphasis on IEC
using various media
• Increased budgetary
provisions for regular
IEC campaigns
• Observance of anti-malaria
month during
June every year

90. •Life cycle: Egg, Larvae and Adult, i.e.
metamorphosis is incomplete.
6-9 days 10-15 days
Egg (nits) Larvae
Adult
(3 molts)
•Life span of an adult is 3-5 weeks.
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91. •Breeding places (habitat): long hairs,
cloths.
Overcrowding and poor personal hygiene
favours the transmission.
Places like hostels, prisons, beggar houses.
•Diseases:-
1)Pediculosis
2)Dermatitis (Vagabond’s disease)
3)Epidemic typhus (Rickettsia Prowazeki)
4)Trench fever (R. quintana)
5)Relapsing fever (Borrelia recurrentis)
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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
•1
st
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 5
th
abdo segment bifid
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