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ppt decribes how to differentiates varioius mosquitoes..

ppt decribes how to differentiates varioius mosquitoes..



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Mosquitoes Mosquitoes Presentation Transcript

  • 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
  • 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
  • Medical Entomology • Branch of preventive Medicine • A study of the arthropods of Medical importance is known as Medical Entomology.
  • 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
  • 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
  • Mosquitoes 9
  • General Features of Mosquito 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
  • 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
  • Life history of mosquito 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
  • 2 Aedes • Cigar shaped, • Laid down singly, • no lateral floats 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
  • 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
  • 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
  • • 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
  • 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
  • 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
  • Anopheles Mosquito • Identification features Spotted wings When at rest, inclined at an angle of 45* to the surface No buzzing sound 23 Anopheles
  • Anopheles female Anopheles male Culex female Culex male 24
  • Palpi long In both Anopheles male & female and short in Culicines female SPOTED WINGS Antennae bushy 45* 25 Anopheles
  • Palps are as long as the proboscis 26 Anopheles
  • palps have white rings Anopheles proboscis dark 27
  • palmate hair on abdomen Anopheles 28
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  • Siphon tube-broad & short 30
  • • 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
  • 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
  • Breeding habits: Anopheles 33
  • 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.
  • 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.
  • 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
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  • Culex proboscis and palps dark, palps short 39
  • Culex 40
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  • Breeding places • It profusely breeds in dirty water collections contaminated with sewage. • Stagnant drains • Cesspools • Septic tanks • Burrow pits Culex 42
  • Culex: 43
  • 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
  • • 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
  • Aedes • Sits parallel to the surface • White stripes on black body Aedes 46
  • Aedes 47
  • Aedes 48
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  • Siphon tube-long & narrow Aedes 52
  • 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
  • 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
  • Aedes: 55
  • Time of biting • Day biters • Do not fly more than 100 meter • Mostly found in rainy water Aedes 56
  • 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
  • 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
  • Mansonia: 59
  • mansonia 61
  • palps not more than 1/3 as long as proboscis, ‘club-like’ 62 mansonia
  • Mosquito breeding places anopheles 63
  • Mosquito breeding places Mansonia 64
  • Mosquito breeding places. culex 65
  • Mosquito breeding places. Aedes mosquito 66
  • Thank You 67
  • 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.
  • 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
  • • 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
  • • 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
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  • 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
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  • 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
  • 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
  • • Pupa: anopheline pupa, the siphon tube is short and broad, culicini pupa, it is long and narrow. 83
  • 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
  • • 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
  • • 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
  • 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
  • Key Elements of IVM 88
  • • Vector surveillance • For malaria: 1. Human blood index 2.Sprozoite Rate 3. Mosquito density 4. Man biting Rate 5.Inoculation Rate 89
  • For Dengue: Larval survey • Human index • Container Index • Breateau Index • Pupae Index Adult survey Landing/Biting collection Resting collection Oviposition traps 90
  •  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
  • • Biolarvicide: Bacillus thuringiensis iserailensis (Bti)-Endotoxin : 2.5% suspension, 1 lit/50 m2, once every 2 weeks. 92
  • 2. Anti-adult measures: 93
  • 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
  • • 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
  • • 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
  • • 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
  • 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