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15 Cards in this Set
- Front
- Back
Causes of disease by insects
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1. Hypersensitivity to bites or allergy to hair or scales
2. Infestation or direct invasion by mites or parasitic larvae 3. Insects acing indirectly as a vector |
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Vectors
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Arthropods or other invertebrates which transmit infection by inoculation into or through the skin or mucous membrane by:
1. Biting or 2. Deposit of infective materials on the skin or on food or other objects |
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Types of Vector
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1. Mechanical
2. Biologic - as a biologic vector the insect may be the definite host or intermediate host of the infectious agent |
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Transmission of insect borne diseases has these links
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1. Sick person
2. Vector 3. Well person |
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Defensive Measures
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1. Protective Clothing
2. Use of repellants / nets / screens 3. Avoidance of places with insects |
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Offensive or attack measures: defintion and types of control measures
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Directed towards the control of the insect population
1. Naturalistic or environmental control 2. Mechanical control 3. Chemical control 4. Biological control |
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Offensive or attack measure: Naturalistic or environmental control
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-A change in the environment to make it unsuitable for the breeding and growth of the insect; Includes:
1. Proper waste disposal 2. Drainage or flushing of stagnant water 3. Damming 4. Control of water level -Requires a thorough knowledge of insect biodynamics -Involves a long range program and may require agricultural engineering projects *Results are permanent and lasting |
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Offensive or attack measure: Mechanical control
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-The destruction of insects through mechanical means, such as traps, screens, swats, fly paper, swatting, catching, etc.
*Results are immediate but not practical, as these effects are limited and temporary |
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Offensive or attack measure: Chemical control
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-Destruction of insects through chemical means of the use of insecticides and larvicides
*Most popular and practical method of control -A drawback is the tendency of insects to develop some resistance to specific insecticides |
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Offensive or attack measure: Biologic control
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Release of sterile male insects
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Rodents as vector
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Rodents cause harm by serving as a reservoir of infection for plague, Weil's disease (leptospirosis), murine typhus, rat bite fever, salmonellosis, etc., and by destroying food, clothing, furniture, etc.
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Rodent control measures
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1. Killing - poisoning, trapping, fumigation
2. Rodent stoppage and rat proofing - elimination of rodent entrance and avenues 3. Environmental sanitation - cleanliness and proper waste disposal to deny rodents of food |
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Mosquitoes - significance as vector
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Mosquitoes are considered as the most important arthropods from the point of view of public health, being responsible for more morbidity and mortality than any other arthropod
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Four stages of the life cycle of a mosquito
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1. Egg - laid in the surface of the water, 100-300 at a time about 12 times in the lifespan of a female mosquito; hatches into larva in 3 - 4 days
2. Larva - grows into pupa in 1 week 3. Pupa - develops into an adult in about 3 days 4. Adult *Total life cycle is completed in 2 to 3 weeks |
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Four genera of mosquitoes and the diseases they transmit
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1. Anopheles sp. - Malaria
2. Culex sp. - Bancroftian Filiarisis, Japanese Encephalitis 3. Mansonia sp. - Brugian or Malaysian Filariasis 4. Aedes sp. - Dengue hemorragic fever, Chikungunya fever |