this ppt describes the importance of medical entomolgy.contents are described using pictograms and photographs.useful for students of mbbs and for teaching purposes.

1. Capt. Dr SHIVANGI DIXIT

2. “A study of the arthropods of
medical importance is known as medical
entomology”

4. ARTHROPOD BORNE
DISEASE

5. Transmission of Disease
By 3 means
Direct contact
• directly
transferred
from man to
man through
close
• contact, e.g.,
scabies and
pediculosis,
Mechanical
transmission
• transmission of
diarrhoea,
dysentery,
typhoid, food
poisoning and
trachoma by
the housefly
• disease agent
is transmitted
mechanically
by the
arthropod
Biological
transmission
• disease agent
multiplies or
undergoes
some
developmental
change with or
without
multiplication
in the
arthropod host,
Propagativ
e
Plague-
fleas
Cyclo-
propagativ
e
plasmodiu
m
Cyclo-
development
al
“filaria”

6. Vector
“which transmits infection by inoculation into or through
the skin or mucous membrane by biting, or by
deposition of infective materials on the skin or on food
or other objects”.
Extrinsic incubation period.-
period of time necessary for the development of the
disease agent in the arthropod host
Definitive host
host in which the sexual cycle of the agent occurs
Intermediate host
the asexual cycle of the agent . occurs is called the
Infestation
the lodgement, development and reproduction of
arthropods on the surface of the body or in the clothing

7. Principles of arthropod control
Environmental control
 elimination of breeding places
 Filling and drainage operation
 carefully planned water management
 provision of piped water supply
 Proper disposal of refuse and other
wastes
 cleanliness in and around houses.

8. Chemical control
 organochlorine, organo-phosphorus
and carbamate
 To avoid undue environmental
pollution, replace gradually the highly
persistent compounds such as DDT
with "biodegradable" and less toxic
methoxychlor, abate and dursban.

9. Biological control
 use of larvivorous fish especially
Gambusia
Genetic control
 sterile male technique, cytoplasmic
incompatibility and chromosomal
translocations

10. Newer methods
(a) insect growth regulators
(b) chemosterilants, and
(c) sex attractants or pheromones

11. MOSQUITO
 Mosquitoes in India which are related
to disease transmission are the
Anopheles, Culex, Aedes and
Mansonia.

12. BODY OF MOSQUITO

13. The period that elapses from
the moment a blood meal is
taken until the eggs are laid
is

16. DIFFERENTIATION

17. Anophilines,culex,mansonia,aed
es
Anopheles females feed primarily on
large mammals and a few species
feed readily on humans. Females
deposit single, direct-hatching eggs
onto the surface of standing water
Species of Culex include a complex
known as "house
mosquitoes“·"nuisance
mosquitoDuring day, it may be seen
resting
indoors on walls, underneath furniture,
inside empty pots
and in dark corners.es
Tiger mosquito,first vector for yellow
fever

18. Habits of mosquitoes
FEEDING HABITS
 males never bite
 females on the contrary are
haematophagous. They require a
blood meal, once in 2-3 days for the
development of eggs.

19. TIME OF BITING
 evening or in the early part of the night,
RESTING HABITS
 rest indoors (endophilia), and some
outdoors (exophilia)
 dark corners of houses, -upper part of
walls,behind pictures and under
furniture. vegetation, shrubs, tree holes,
cattle sheds and wells.

20. BREEDING HABITS
 anophelines prefer clean water for
breeding
 cu/icines-prefer dirty and polluted water
 aedes prefer artificial collections of
water

21. HIBERNATION
 hibernate in the adult stage
DISPERSAL
 do not generally fly far from the place
where they breed

22. LIFE SPAN
 normal life span of mosquitoes varies
from 8 to 34 days.

23. Mosquito-borne disease
Anopheles Malaria
Filaria
Culex Bancroftian filariasis
Viral arthritis
J.E
Aedes Yellow fever
Dengue
D.H.F
chikungunya
Mansonoides Brugian filariasis(malayan )

24. MOSQUITO CONTROL
MEASURES
1 ANTI-LARVAL MEASURES
 Environmental control
 Chemical control
 Biological control.
2 ANTI-ADULT MEASURES
 Residual sprays
 Space sprays
 Genetic control.
3 PROTECTION AGAINST MOSQUITO BITES
 Mosquito net
 Screening
 Repellents.

25. ANTI-LARVAL MEASURES
Environmental control
“source reduction”, and comprises minor
engineering methods such as filling, levelling and
drainage of breeding places; and water
management
 adequate collection,removal and disposal of
sewage and waste water.
 get rid of water holding containers such as
discarded tins, empty pots, broken
bottles,coconut shells and similar other artificial
collections of water.
 aquatic plants to which the larvae attach
themselves should be removed or destroyed by

26. Chemical control
Mineral oils
• widely used are
the diesel oil, fuel
oil, kerosene and
various fractions
of crude oils
• application rate
for oils is 40 to 90
litres per hectare
Paris green
• Paris green or
copper
acetoarsenite is
an emerald green,
micro-crystalline
powder practically
insoluble in water
• kills mainly the
Anopheles larva
because they are
surface-feeders.
• recommended
dose is 1 kg of
actual paris green
per hectare of
water surface
Synthetic
insecticides
• Fenthion,(22-112)
Chlorpyrifos(11-
16), and
Abate(56-112)
• concentration of
1.0 ppm has been
found to be a very
effective larvicide,
and also the least
toxic

27. Biological control
 Gambusia a/finis and
 Lebister reticulatus (sometimes known
as Barbados Millions). These fish can
be used in burrow pits, sewage
oxidation ponds, ornamental ponds,
cisterns and farm ponds.

28. ANTI-ADULT MEASURES
Residual sprays g/m2
duration
 DDT 1-2 6-12 mo
 Lindane 0.5 3
 Malathion 2 3
 OMS-'-33 2 3

29. Space sprays
 insecticidal formulation is sprayed into
the atmosphere in the form of a mist
or fog to kill insects.
 i) Pyrethrum extract-nerve poison; 1
oz per 1,000 C. ft. of space
 Residual Insecticides-malathion and
fenitrothion for Ultra low vol. fogging

30. Genetic control
 sterile male technique, cytoplasmic
incompatibility, chromosomal
translocations, sex distortion, and
gene replacement

31. PROTECTION AGAINST
MOSQUITO BITES
 Mosquito net
 Screening
 Repellents-Diethyltoluamide (deet);
for application on the skin

32. HOUSEFLIES
 Musca domestica, M. vicinia, M.
nebulo and M. sorbens
General characters

33. Life history

34. Habits
BREEDING HABITS-
 fresh horse manure
 human excreta
 manure of other animals
 garbage
 decaying fruits and vegetables
 rubbish dumps containing organic
matter
 Ground where liquid wastes are
spilled

35. FEEDING HABITS
 it vomits on solid food to make a
solution of it and sucks in a liquid state
 sputum, faeces, discharges from
wounds and open sores.

36. RESTLESSNESS
 spread of infection mechanically

37. VOMIT DROP
 a culture of disease agents.

38. DEFECATION
 Deposits countless bacteria on
exposed food.

39. RESTING HABITS
 tendency to rest on vertical surfaces
and hanging objects. They have a
tendency to fly towards light.

40. DISPERSAL
 remain close to their breeding places,
but they disperse frequently up to 4
miles

41. Transmission of disease
 potential vectors of many diseases :
typhoid and paratyphoid fevers,
diarrhoeas and dysenteries, cholera,
and gastroenteritis, amoebiasis,
helminthic infestations,poliomyelitis,
conjunctivitis, trachoma, anthrax,
yaws.

42. MECHANICAL TRANSMISSION
 transport microorganisms on their feet
and hairy legs

43. VOMIT DROP
 The regurgitated stomach contents or
"vomit drop" is a rich
 bacterial culture.

44. DEFECATION
 The excrement of housefly has been
 found to contain numerous
microorganisms as well as cysts
 and ova of intestinal parasites.

45. FLY CONTROL MEASURES
Environmental control
 storing garbage,kitchen wastes and other
refuse in bins with tight lids,
 efficient collection, removal and disposal of
refuse by incineration, composting or sanitary
landfill.
 provision of sanitary latrines, e.g., pit
privies,septic tanks, water-seal latrines and
sanitary system.
 stopping open air defecation.
 sanitary disposal of animal excreta, and
 stepping up general sanitation.

46. Insecticidal control
RESIDUAL SPRAYS
 by DDT (5%), methoxychlor (5%),
 lindane (0.5%), or chlordane (2.5%)
sprayed at about
 5 litres per 100 square metres of surface;
for flies resistant to
 diazinon (2%) dimethoate (2.5%),
fenthion (2.5%),
 malathion (5%), or ronnel (5%) may be
used.

47. BAITS
 Poisoned baits containing 1 or 2 per
cent diazinon, malathion,
dichlorvos,ronnel and dimethoate

48. CORDS AND RIBBONS
 Cords and strips impregnated with
diazinon, fenthion, or dimethoate

49. SPACE SPRAYS
 sprays containing pyrethrin and DDT
or HCH

50. LARVICIDES
 Insecticides such as 0.5% diazinon,
2% dichlorovos, 2% dimethoate or 1
% ronnel applied at the rate of 28-56
litres per 100 sq

51. Fly papers
 made by mixing 2 lbs of resin and one
pint of castor oil which should be
heated together until the mixture
resembles molasses.

52. Protection against flies
 Screening of houses, hospitals, food
markets, restaurants

53. Health education
 Fly control campaigns require
organized individual and community
effort which is the basis of a
successful public health programme.

54. SAND FLIES
 Phlebotomus argentipes, P papatasii,
P sergenti, and Sergentomyia
punjabensis.

55. General characters

56. Life history

57. Habits
 noctural pests,bite is irritating and
painful,
 infest dwellings during night, and take
shelter during day in holes and
crevices in walls, holes in trees, dark
rooms, stables and store rooms.
 confined to their breeding places.

58. Disease transmitted
Phlebotamus argentipes Kala azar
Phlebotamus papatasii Sand fly fever
Phlebotamus sergenti Oriental sore
s.Punjabensis Sand fly fever

59. Control of sandflies
INSECTICIDES
 single application of 1 to 2 g/m2 of DDT
or 0.25 g/m2 of lindane has been found
effective
SANITATION
 removal of shrubs and vegetation within
50 yards of human dwellings, filling up
cracks and crevices in walls and floors,
and location of cattle sheds and poultry
houses at a fair distance from human
habitations should receive attention

60. TSETSE FLIES
 bloodsucking flies
 yellow or dark-brown in colour

62. Life cycle

63. Species and habits
 G.palpalis, G.tachinoides, G.morsitans,
and G.pallidepes.
 attack man, animals, wild game of all
kinds,birds, lizards and snakes.
 bite, mainly during day
 rarely enter houses, but they are known
to follow travellers both by road and rail
for considerable distance in order to
obtain a blood meal.
 vectors of trypanosomiasis or "sleeping
sickness"

64. Control of tsetse flies
INSECTICIDES
 DDT (25%) and
 dieldrin (18-20%)
CLEARING OF VEGETATION
GAME DESTRUCTION-
 Large tracts of Africa have been cleared
of the tsetse flies by the destruction of
wild game.

65. GENETIC CONTROL
 "sterile male release"

66. BLACKFLIES
 Simulum indicum is the Indian species
 vectors of onchocerciasis in Africa,
Mexico, and Central and South America.
 larvae are aquatic; they fix themselves to
stones or plants, usually at a depth of 1
foot. The larval stage occupies 3 to 4
weeks
 Abate is used which kills the blackfly
larvae without causing harmful effects to
mammals or other aquatic fauna.
 weekly doses of 0.05 to 0.1 mg/litre over
a period of 10 minutes

67. LICE
 Wingless ectoparasites of mammals
 Head louse,body louse,pubic louse

69. Life history

70. Dissemination
DIRECT CONTACT
 Close contact with lousy or infested persons.
 Overcrowding
INDIRECT CONTACT
 acquired from clothing, bedding, combs or
brushes used by lousy persons.
 Lice tends to leave the host whose
temperature rises above or falls below the
normal

71. Lice and disease
Rickettssia prowazeki Epidemic typhus
Borrelia recurrentis Relapsing fever
Ricketssia quintana Trench fever
Due to scratching and secondary
infection
dermatitis

72. Crab louse
 found in the pubic and perineal Region

73. Control of lice
INSECTICIDAL CONTROL
 Head and crab lice : The present
recommended treatment is a lotion
containing 0.5 per cent
malathion. The lotion should be left on for
12 to 24 hours
when the hair can be washed. Malathion, if
correctly used,
will kill lice and nits. Dust containing
carbaryl is also
effective as louse powder.

74.  Body Lice : Since lice have become
resistant to DDT and HCH, a powder
containing1 per cent malathion will
obviously be the treatment of choice.
Dust containing carbaryl may also be
used

75. PERSONAL HYGIENE
 daily bath with soap and water is
essential. Women with long hair
should wash and clean their hair
frequently. Clothing, towels and sheets
should be washed in hot water and
soap and pressed with hot iron.
 Autoclaving of clothes and bedding in
steam sterilizers may be required for
body louse control.

76. TICKS AND MITES
 Ticks are of two kinds: hard ticks
(ixodidae) and soft ticks( argasidae)

78. Life history

79. Public health importance
Hard ticks transmit the following diseases :
 Tick typhus (Rocky mountain spotted fever)
 Viral encephalitis (e.g., Russian spring-summer
encephalitis)
 Viral fevers (e.g., Colorado tick fever)
 Viral haemorrhagic fevers (e.g. KFD in India)
 Tularaemia
 Tick paralysis, and
 Human babesiosis.
Soft ticks transmit:
 Q fever
 Relapsing fever, and
 KFD.

80. Diff b/n hard and soft ticks

81. TROMBICULID MITES
Spider like arthropods ; vectors of scrub
typhus.
Leptotrobidium deliense
Control of ticks and mites
INSECTICIDAL CONTROL
 DDT, chlordane, dieldrin, lindane,
malathion and toxaphane at rates of 1 to
2 lbs per acre
ENVIRONMENTAL CONTROL
 Cracks and crevices in ground

82. PROTECTION
OF WORKERS :
 wear protective clothing impregnated
with an insect repellent.
 indalone, diethyltoluamide and benzyl
benzoate

83. ITCH MITE
 General description

84. Mode of spread
CLOSE CONTACT
 sleeping in the same bed or by
children playing with each other or
nursing an infested person(scabies)
CONTAMINATED CLOTHES

85. Site of lesions
 affects the hands and wrist (63%),
 The extensor aspect of elbows being
next (10.9%). The axillae, buttocks,
lower abdomen, feet and ankles,
palms in infants are all common sites
of infestation

86. Diagnosis of scabies
 complains of itching which is worse at
night,
 Examination reveals follicular lesions at
the affected site,
 Secondary infection leads to crusted
papules and pustules,
 diagnosis is probable if the other
members of the household are affected,
 confirmation of the diagnosis may be
made by searching for the parasite in the
skin debris under microscope.

88. Control of scabies
 good scrub with soap and hot water.
 BENZYL BENZOATE-below the chin
including the soles of the feet and
allowed to dry.
 repeated after 12 hours, and after a
further 12 hours a bath given and all
underclothes, clothes and sheets
changed and washed

89. HCH
 0.5 to 1.0 per cent strength of gamma-
HCH (lindane) in coconut oil or any
vegetable oil
 TETMOSOL : A 5 per cent solution
 SULPHUR OINTMENT : 2.5 to 10 per
cent daily for 4 days.