Arthropods of Medical Importance 1 Dr Manveer Singh MBBS, MD Contact: drmanveersingh21@gmail.com SCAN TO FOLLOW

1. Arthropods of Medical
Importance
1
Dr Manveer Singh
MBBS, MD
Contact:
drmanveersingh21@gmail.com
SCAN TO
FOLLOW

2. Medical Entomology
‘ A study of arthropods of medical importance’.
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3. Arthropods of medical importance
Class: Insecta Class: Arachnida Class: Crustacea
1. Mosquitoes:
• Anophelines
• Culicines
2. Flies:
• Houseflies
• Sandflies
• Tsetse flies
• Blackflies
3. Human lice:
• Head and body lice
4. Fleas:
• Rat fleas
• Sand fleas
5. Reduviid bugs
1. Ticks :
• Hard ticks
• Soft ticks
2. Mites :
• Trombiculd mites
• Itch mite
Cyclops
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4. Distinctive characters
Insecta Arachnida Crustacea
1. Body divisions Head
Thorax
Abdomen
Cephalothorax and
abdomen
Cephalothorax
and abdomen
2. Legs 3 pairs 4 pairs 5 pairs
3. Antenne 1 pair None 2 pairs
4. Wings One or two
pairs
None None
5. Where found On land On land On land
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5. Arthropod borne diseases
Arthropod Diseases transmitted
1. Mosquito Malaria, filaria, viral encephalitis, viral fevers ( Dengue,
West Nile),Viral haemorhagic fevers (Yellow fever,
Dengue haemorhagic fever)
2.Housefly Typhoid and paratyphoid fevers, Diarrhoea, Dysentery,
Cholera, Gastro-enteritis, Amoebiasis, Helminthic
infestations, Poliomylitis, Conjunctivitis, Trachoma,
Anthrax, etc.
3. Sandfly Kala-azar, Oriental sore, Sandfly fever, Oraya fever
4. Tsetse fly Sleeping sickness
5. Louse Epidemic typhus, Relapsing fever, Trench fever,
Pediculosis
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6. Arthropod borne diseases – contd..
6. Rat flea Bubonic plague, Endemic typhus, Chiggerosis,
Hymenolepis diminuta
7. Blackfly Onchocerciasis
8. Reduviid bug Chagas disease
9. Hard tick Tick typhus, viral encephalitis, KFD, Tularemia,
Human babesiosis
10. Soft tick Q fever, Relapsing fever
11. Trambiculid mite Scrub typhus, Rickettsial pox
12. Itch mite Scabies
13. Cyclops Guinea-worm disease, fish tape worm
14. Cockroaches Enteric pathogens
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7. Transmission of arthropod- borne diseases
By 3 types:-
1. Direct contact:
• Arthropods are directly transferred from man to man
through close contact, e.g. scabies and pediculosis.
2. Mechanical Transmission:
• The disease agent is transmitted mechanically by the
arthropod, e.g. diarrhoea, dysentery, typhoid, food poisoning
by the housefly.
3. Biological Transmission:
• Disease agent multiplies or undergoes some developmental
change with or without multiplication in the arthropod
host. This may be of 3 types; 7

8. Types of Biological Transmission:
a) Propagative-
• Disease agent undergoes no cyclical change, but
multiplies in the body of the vector;
e.g.- plague bacilli in rat fleas
b) Cyclo-propagative-
• Disease agent undergoes cyclical change and multiplies
in the body of the arthropod;
e.g.- malaria parasite in anopheline mosquito
c) Cyclo-developmental-
• Disease agent undergoes cyclical change but does not
multiply in the body of arthropod;
e.g.- filarial parasite in culex mosquito 8

9. Principles of Arthropod control
1. Environmental control
2. Chemical control
3. Biological control
4. Genetic control
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10. 1. Environmental control of arthropods
• Best approach, because results are likely to be permanent,
• Elimination of breeding places ( source reduction)
• Filling and drainage operation
• Carefully planned water management
• Provision of piped water supply
• Proper disposal of wastes
• Cleanliness in and around houses etc.
• Health education
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11. 2. Chemical control of arthropods
• Insecticides available for vector control-
Organo-chlorine compounds- DDT, BHC, Lindane
Organo-phosphorus compounds- Malathion
Carbamate groups- Carbaryl, Propoxur
• Insecticides alone are no longer fully effective
because resistance has appeared in over 100
species of medically important arthropods.
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12. 3. Biological control of arthropods
• By larvicidal fish ‘Gambusia’ and ‘Lebister’
• Fungi of genus Coelomomyces
This method is effective only when used in conjunction
with other methods.
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13. 4. Genetic control of arthropods
Techniques-
• Sterile male technique
• Cytoplasmic incompatibility
• Chromosomal translocation
• Sex distortion
• Gene replacement
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14. Newer methods
• Insect growth regulators
• Chemosterilants
• Sex attractants or pheromons.
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15. Present Trends
• To adopt an ‘Integrated Approach’ for vector
control.
• Combining two or more methods to obtain
maximum results with minimum efforts.
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16. THANX
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