Date post: | 11-May-2015 |
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Health & Medicine |
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What is Dengue Fever?
• Dengue fever, also know as breakbone fever, is an acute communicable disease caused by virus.
• Infectious agent: Dengue viruses (categorize into types 1,2,3,4)
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Vectors of Dengue Fever
• Aedes aegypti - Aedes aegypti is not found in Hong
Kong at present.• Aedes albopictus
- Aedes albopictus is very common in Hong Kong.
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Aedes mosquito
Aedes Aegypti Aedes Albopictus
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Vector
Aedes albopictus
The life cycle of a vector mosquito is dividedinto the 4 stages: egg, larva, pupa and adult
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Habitual Behaviour of Aedes Albopictus (1)
• Usually breed in stagnant water
• Usually active in dark or shaded places outdoors, but indoor activity is also possible
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Habitual Behaviour of Aedes Albopictus (2)
• Female mosquitoes feed on human blood.
• They are most active 2 hours before sunset (around 5pm to 6pm) and at around 8am to 9am.
• Where do they sting?
Outdoors and indoors.
DO YOU KNOW…
• Dengue fever and dengue haemorrhagic fever are the most common mosquito-borne viral diseasein the world.•
• Only the female mosquito feeds on blood. This is because they need the protein found in blood to produce eggs. Male mosquitoes feed only on plant nectar.
• •The mosquito is attracted by the body odours, carbon dioxide and heatemitted from the animal or humans.
• •The female Aedesmosquito searches for suitable places to lay their eggs.
• •Aedes are day-biters, most active during dawn and dusk.
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• About 50 million cases annually worldwide
• Incidence of dengue fever highest in tropical and subtropical regions
• Recent increase in disease activity worldwide
The Situation Worldwide
10Regions with dengue fever
Dengue Fever 2001
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Mode of Transmission
• A healthy person gets the disease when he is bitten by an infected mosquito. The virus enters his blood from the mosquito’s saliva.
• An infected person could transmit the virus to mosquitoes if he is bitten by a mosquito anytime from the onset to the subsidence of the fever (a period of about 6 to 7 days). The disease is then spread by mosquitoes.
• Dengue fever is not spread by contact with infected persons.
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Transmission
Infected person
Healthy person
Infected mosquito
Incubation Period: 3 to 14 daysMost commonly 4 to 7 days