bionomics aedes

Bionomics of Aedes aegyptiBionomics of Aedes aegypti

Life CycleLife Cycle 10-12 days complete metamorphosis10-12 days complete metamorphosis Egg to larva to pupa to adultEgg to larva to pupa to adult

EggEgg 2-3 days2-3 days Oval shapeOval shape Laid singly above water levelLaid singly above water level Never on a dry surfaceNever on a dry surface Thick exochorion (outer covering)Thick exochorion (outer covering) Remains viable for long periodsRemains viable for long periods

2-4 months2-4 months 262 days stored under dry condition262 days stored under dry condition

LarvaLarva

4 instars (14 instars (1stst, 2, 2ndnd, 3, 3rdrd & 4 & 4thth)) 7 days at 277 days at 27°C°C 8-13 days at fairly warm weather8-13 days at fairly warm weather 60-100 days due to starvation60-100 days due to starvation Characteristic movement of extreme Characteristic movement of extreme

restlessnessrestlessness Swimming & gliding movementSwimming & gliding movement

LarvaLarva

FeedingFeeding Gnawing & swallowing solid particles Gnawing & swallowing solid particles

using mandibleusing mandible Pharyngeal filtration of minute Pharyngeal filtration of minute

particles by browsingparticles by browsing Rest at an angle to the water surfaceRest at an angle to the water surface Favorable temperature: 16-24Favorable temperature: 16-24°C°C Does not mature: 12 & 39°CDoes not mature: 12 & 39°C

LarvaLarva

Affected by chemical factorsAffected by chemical factors 1-2.3% salt kills the larvae1-2.3% salt kills the larvae 50% sea water kills larvae in 24 hrs.50% sea water kills larvae in 24 hrs. Pure sea water kills larvae in 2-4 hrs.Pure sea water kills larvae in 2-4 hrs. Soap causes drowning by preventing Soap causes drowning by preventing

larvae to obtain airlarvae to obtain air Oil kills by asphyxiation by the film Oil kills by asphyxiation by the film

formed cuts contact with the airformed cuts contact with the air

PupaPupa Cease to feed; no longer glidesCease to feed; no longer glides Still swims if disturbedStill swims if disturbed 44-4844-48°C causes 100% mortality°C causes 100% mortality 36°C shortens its life36°C shortens its life At 4.4°C, it becomes dormantAt 4.4°C, it becomes dormant Affected by chemicalsAffected by chemicals

Resistant to chemicals other than vapors & Resistant to chemicals other than vapors & gases because of waxy substance on or within gases because of waxy substance on or within the cuticlethe cuticle

Soap deprives the respiratory trumpet to Soap deprives the respiratory trumpet to obtain airobtain air

AdultAdult EmergenceEmergence

Emerge from pupal stageEmerge from pupal stage More males than females (5:3)More males than females (5:3)

Mating & fertilizationMating & fertilization Mating takes place 24 hrs after emergenceMating takes place 24 hrs after emergence Males don’t swarm, chase the females & uniteMales don’t swarm, chase the females & unite Females remain fertile throughout her life after Females remain fertile throughout her life after

fertilization. After 72 hrs, fertile eggs are laid, fertilization. After 72 hrs, fertile eggs are laid, spermatozoa are stored in the spermatozoa are stored in the spermathecaspermatheca

AdultAdult

Feeding/bitingFeeding/biting 11stst blood meal after mating blood meal after mating Need about 0.5 – 3.5 mg of bloodNeed about 0.5 – 3.5 mg of blood ““day-biters” with 2 peaksday-biters” with 2 peaks

1-2 hrs after sunrise1-2 hrs after sunrise 1-2 hrs before sunset1-2 hrs before sunset

Only females bite/blood mealOnly females bite/blood meal Feeds on vertebrate host, mammals, birds, Feeds on vertebrate host, mammals, birds,

bats, chickens, rabbit, guinea pigs, etc…bats, chickens, rabbit, guinea pigs, etc…

AdultAdult

Prefers hands with low moisture outputPrefers hands with low moisture output Attracted to warmer skinAttracted to warmer skin Movement doubles attractiveness of animalsMovement doubles attractiveness of animals Temperature requirements:Temperature requirements:

2828°C – most active°C – most active 26-35°C – largely feed26-35°C – largely feed 19-25°C – slowly bite19-25°C – slowly bite 4040°C - lethal°C - lethal

AdultAdult Act of feedingAct of feeding

No frontal attackNo frontal attack Approaches from behindApproaches from behind Attack from different quarter if 1Attack from different quarter if 1stst attempt fails attempt fails

Color choice is secondary to the urge of biteColor choice is secondary to the urge of bite Next blood meal is after laying eggsNext blood meal is after laying eggs Resting habitResting habit

Prefers dark corners, shades, dark objectsPrefers dark corners, shades, dark objects Settle on sides away from light indoorSettle on sides away from light indoor

AdultAdult OvipositionOviposition

60-100 eggs/batch60-100 eggs/batch 2-6 pm peak of oviposition2-6 pm peak of oviposition 5-6 hrs to lay all its eggs5-6 hrs to lay all its eggs Prefers dark background container with clean, Prefers dark background container with clean,

stagnant, non-polluted waterstagnant, non-polluted water Flight range Flight range

Fly upwind towards the lightFly upwind towards the light 50-300 meters from breeding source50-300 meters from breeding source

Seasonal abundance (during rainy months)Seasonal abundance (during rainy months) Life span (20-30 days)Life span (20-30 days)

Methods of Methods of AedesAedes aegyptiaegypti Control Control Against the larvaAgainst the larva

LarvicidesLarvicides Insecticides on the breeding sitesInsecticides on the breeding sites

Source reductionSource reduction Disposal of useless containersDisposal of useless containers Cleaning of useful containersCleaning of useful containers Clean clogged guttersClean clogged gutters Bore holes on used tiresBore holes on used tires Tightly cover/mosquito proof water containersTightly cover/mosquito proof water containers

Biological control Biological control Use/seeding of larvivorous fishUse/seeding of larvivorous fish

Methods of Methods of AedesAedes aegyptiaegypti Control Control Against the adultAgainst the adult

Space spray (fogging)Space spray (fogging) Chemicals applied in the form of fog/mistChemicals applied in the form of fog/mist

EnvironmentalEnvironmental Modify/manipulate environment to Modify/manipulate environment to

render it favorable for development such render it favorable for development such as:as:

• Turn upside down water containersTurn upside down water containers• Fill up holes (trees, hollow blocks, Fill up holes (trees, hollow blocks,

bamboo stumps) with soil or cementbamboo stumps) with soil or cement

Strategies on Prevention & ControlStrategies on Prevention & Control

Integrated vector controlIntegrated vector control Combination of 2 or more vector control Combination of 2 or more vector control

activities supplementary to each other activities supplementary to each other towards reduction of breeding sitestowards reduction of breeding sites

Community participation & mobilizationCommunity participation & mobilization Health education & promotionHealth education & promotion LegislationLegislation Environmental sanitation & managementEnvironmental sanitation & management Mosquito controlMosquito control

Early Case Detection & ManagementEarly Case Detection & Management Case identificationCase identification

Notifiable diseaseNotifiable disease Increase number of cases during rainy Increase number of cases during rainy

seasonseason High suspicion if increased fever cases High suspicion if increased fever cases

in the community, deaths of in the community, deaths of undetermined causesundetermined causes

Tool for investigationTool for investigation


Early Case Detection & ManagementEarly Case Detection & Management Case managementCase management

Refer to hospitalRefer to hospital Not all cases need to be hospitalizedNot all cases need to be hospitalized Treatment is symptomaticTreatment is symptomatic Home treatment VS hospitalizationHome treatment VS hospitalization Vector controlVector control


SurveillanceSurveillance Very important for a disease that is prone Very important for a disease that is prone

to epidemicto epidemic Types:Types:

ClinicalClinical LaboratoryLaboratory EpidemiologicalEpidemiological VectorVector


Health educationHealth education Social mobilizationSocial mobilization

Community organizing, advocacy, Community organizing, advocacy, networking/linkagingnetworking/linkaging

Interpersonal communicationInterpersonal communication Consultation/lectures, focus group Consultation/lectures, focus group

discussion, mother’s classdiscussion, mother’s class Mass mediaMass media

Print, broadcast (TV, radio, cinema)Print, broadcast (TV, radio, cinema)


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bionomics aedes

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