Medical Entomology - Mosquito

A study of the arthropods of medical importance is known as medical entomology which is an important branch of preventive medicine.

1. MEDICAL ENTOMOLOGY Dr. SASI KUMAR PJ, M.D. Asst. Professor

2. Medical Entomology : It is the branch of community medicine, which deals with the study of arthropods of medical importance. Medical Entomology :

3. CLASSIFICATION OF ARTHROPODS The phyllum arthropoda consists of three important classes Insecta Arachnida Crustacea

4. Insecta Arachnida Crustacea Body shape Cylindrical Circular or Oval Pear shaped Body division Head, Thorax and Abdomen Cephalothorax and Abdomen Cephalothorax and Abdomen Antennae in head 1 pair Absent 2 pairs Wings Some are winged, some are wingless Absent Absent Legs 3 pairs 4 pairs 5 pairs Living On land On land In water Examples Winged - Mosquito, Flies Wingless - Fleas, Lice, Bugs Ticks, Mites, Spiders, Scorpions Cyclops, Crabs, Lobsters, Prawns

5. VECTOR Direct Mechanical vector Biological vector

6. ARTHROPOD BORNE DISEASES Causative agent Disease Vector Virus Yellow fever, Dengue fever, Chickengunya, Japanese encephalitis Mosquito Rickettsiae Epidemic typhus, Scrub typhus, Q- fever, Rocky mountain spotted fever Louse
Rat flea
Tick
Tick Bacteriae Typhoid, Cholera, Shigellosis, Plague House fly
Rat flea Spirocheta Relapsing fever Louse Protozoa malaria
Leishmaniasis Mosquito
Sandfly Nematoda Filariasis
Dracunculosis Mosquito
Cyclops

7. Extrinsic Incubation Period : The period of time required for the disease agent to undergo multiplication or a phase of cyclic development or both, inside the body of the arthropod.

8. Definitive Host : It is the one in which the sexual phase of the development or life cycle of the parasite takes place.

9. Intermediate Host : It is the one in which asexual phase of the development or life cycle of the parasite takes place.

10. Infestation : It means the lodgement, growth, development and reproduction of the arthropod parasite on the surface of the body.

11. Principles of arthropod control Environmental control Chemical control Biological control Genetic control Integrated Approach

12. MOSQUITO Anopheles Culex Aedes Mansonia

13. Morphology of Mosquito

14. Anopheles culex Eggs are laid singly and
horizontally on
the surface of the water. Eggs are vertically laid in
clusters on
the surface of the water. Eggs are boat shaped. Eggs are cigar shaped. Each egg has two lateral
air floats,
which help them in floatation. Eggs of culex mosquito are
not provided with
lateral air floats. Eggs are laid on clean water. Eggs are laid on dirty water.

15. Anopheles culex Larva of anopheles mosquito
is surface feeder. Larva of culex mosquito
is bottom feeder. The respiratory siphon is short. The respiratory siphon is long. It remains parallel with
water surface. It forms an angle inside water.

16. Anopheles culex The pupa is green. The pupa is colourless. The respiratory trumpets
are short and wide. The respiratory trumpets are
long and narrow. The abdomen is more bent. The abdomen is less bent.

17. Anopheles culex Body is provided with
delicate legs. Body is provided with
stouter legs. Wings are spotted and
cannot fly for long distance. Wings are transparent and
can fly for long distance. The proboscis and palpi
have same length. There is presence of small
palpi near proboscis. At rest body is inclined at an angle of 45 to the surface. At rest body lies parallel
to the surface. It transmits malarial parasite. It transmits filarial parasite.

18. HABITS

19. FEEDING HABIT : Males never bite (they subsist on plant juices) Females - Haematophagous (once in 2-3 days) TIME OF BITING : Evening RESTING HABITS : Dark & Cool corners (endophila, exophilia) BREEDING HABITS: Anopheles - Fresh water Culex - Dirty & polluted water Aedes - Artificial collection of water Mansonia - Water containing aquatic vegetation

20. HIBERNATION : Adult (not favourable) DISPERSAL : Do not fly far, currents of wind, flight range - 11 kms. LIFE SPAN : Temperature & humidity, 8- 34 days, males - sh o rt lived.

21. Type of mosquito Disease Anopheles Malaria
Filaria (not in India) Culex Bancroftian filariasis
Japanese encephalitis
West nile fever
Viral arthritis Aedes Yellow fever (not in India)
Dengue
Chickengunya
Filaria (not in India) Mansonia Malayan filariasis
Chickengunya fever Mosquito borne diseases

22. MOSQUITO CONTROL MEASURES

23. Integrated Approach is recommended Integrated approach means : Various combinations of Anti larval Anti adult mosquito Personal protection measures

24. 1) Anti-larval measures Environmental control Chemical control Biological control 2) Anti-adult measures Residual sprays Space sprays Genetic control

25. 3) Protection against mosquito bite Mosquito net Screening Repellents

26. 1) Anti-larval measures Environmental control Environmental control means reducing the breeding places of mosquitoes Also known as source reduction It is the important method of mosquito control Filling of breeding places Levelling of breeding places with cement Drainage of breeding places like dessert coolers Water management e.g.;Intermittent irrigation Changing the salinity of water Covering water storage tanks

27. Chemical control 1) Anti-larval measures Mineral oils : diesel oil, kerosene, MLO etc, they forma thin film on the surface and hence cut off the oxygen supply to the larvae and pupae Apply once a week - larval stage lasts for 8 days Harms other water creatures too

28. Chemical control 1) Anti-larval measures Paris green : Copper aceto - arsenite Kills only if ingested by the larva Mainly for anopheles larvae

29. Chemical control 1) Anti-larval measures Synthetic insecticides : These are OP compounds Fenthion Chlorpyrifos Abate Temephos

30. Biological control 1) Anti-larval measures

31. 2) Anti-adult measures Residual sprays : It is the application of insecticides to the inside of dwellings, on walls and other surface that serves as a resting place for mosquitoes. IRS kills mosquito when they come in contact with treated surfaces. Disadvantage : Resistance eg: DDT, Malathion etc

32. 2) Anti-adult measures Space sprays (fogging) Insecticide is sprayed into the air as mist or fog of spray No residual action Temporary reduction in number of mosquitoes Done mainly as emergency situations to immediately reduce mosquito population eg : pyrethrum extract

33. 3) Protection against mosquito bites Mosquito nets Screening of buildings Repellents

34. THANK YOU

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