8. Life cycle of the Aedes Mosquito 1-2 days Stagnant water Pupae 4-5 days Larvae Eggs 2-3 days
9. How Do Aedes Mosquitoes Transmit Diseases... Mosquito bites and sucks blood containing the virus from an infected person. Virus is carried in its body. And passes the virus to healthy people when it bites them.
22. Spread the dengue prevention message to others… Let your family , friends and neighbours know about the dangers of breeding Mozzies!!
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28. Mean Annual Number of DHF Cases Thailand, Indonesia and Vietnam, by Decade * Provisional data through 1998
29. Reported Cases of DHF in the Americas, 1970 - 1999 * Provisional data through 1999
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32. Distribution of suspected and confirmed Dengue fever in KSA Year N. of suspected cases N. of confirmed cases 1994 1995 1996 1997 1998 1999 2000 2001 2002 673 136 57 62 31 26 17 07 11 289 6 2 15 00 3 0 0 4 Total 1020 319
35. Transmission of Dengue Virus by Aedes aegypti Viremia Viremia Extrinsic incubation period DAYS 0 5 8 12 16 20 24 28 Human #1 Human #2 Illness Mosquito feeds / acquires virus Mosquito refeeds / transmits virus Intrinsic incubation period Illness
36. Replication and Transmission of Dengue Virus (Part 1) 1. Virus transmitted to human in mosquito saliva 2. Virus replicates in target organs 3. Virus infects white blood cells and lymphatic tissues 4. Virus released and circulates in blood 3 4 1 2
37. Replication and Transmission of Dengue Virus (Part 2) 5. Second mosquito ingests virus with blood 6. Virus replicates in mosquito midgut and other organs, infects salivary glands 7. Virus replicates in salivary glands 6 7 5
45. Increased Probability of DHF Hyperendemicity Increased circulation of viruses Increased probability of secondary infection Increased probability of occurrence of virulent strains Increased probability of immune enhancement Increased probability of DHF Gubler & Trent, 1994
57. ANSWER: It can carry the dengue virus and infect a healthy person with dengue fever.
58. Name the 5 steps in the 10-Minute Mozzie Wipe-out Exercise
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60. What are the things that you should do before going for a holiday?
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Notes de l'éditeur
Good morning/afternoon everyone, I’m sure you all know that dengue is a serious problem now, but how much about dengue do you really know?
Today I’ll be sharing with you more information about dengue, meant for all schools, from The National Environment Agency. I will explain how dengue is spread and what we can do to stop it. Please listen carefully as dengue can strike anyone…you and me.
So what is dengue fever? Dengue fever is an illness caused by the dengue virus which is spread by the Aedes mosquito.
How do you know if you have dengue fever? You have dengue fever if you have a fever that does not go away even after a few days; You may also experience headaches, muscle and joint pains, skin rash, and vomiting.
Dengue fever and dengue haemorrhagic fever are the most common diseases spread by the Aedes mosquitoes. The mosquitoes can carry 4 different types of dengue viruses hence you can be infected with dengue fever more than once. If you had dengue fever before and are infected again, you are more likely to develop the more deadly and serious dengue haemorrhagic fever.
Now I’ll tell you about the Aedes mosquito which spreads dengue. 1) You can identify an Aedes mosquitoe from other mosquitoes by the black & white stripes on its body and legs. Because of this, it is also known as the ‘tiger mosquito. 2) It usually bites during the day. 3) The Aedes mosquito lays its eggs in clean, stagnant water. A pool of water as small as a twenty cent coin is all that is needed for it to breed.
Only the female mosquitoes feed on blood, as they need the blood protein to lay their eggs. Despite a short life span of two to three weeks, each female Aedes mosquito is able to lay up to 300 eggs.
As seen in this diagram of the Aedes mosquito’s life cycle, it only takes about a week for the mosquito complete the 4 stages consisting of the egg, larva and pupa stage before it becomes an adult mosquito. As one female mosquito lays up to 300 eggs each time, just imagine how many mosquitoes can be hatched!
We all know by now that the Aedes mosquito spreads the dengue virus, but how exactly do they do it? Mosquitoes cannot transmit the dengue virus amongst themselves, they need to first bite a person who is already infected with the dengue virus. The infected mosquito will then carry the dengue virus and pass it onto a healthy person when it bites him/her and causing them to fall sick. The cycle then continues with the new victim.
So now that you know more about the dengue, what can you do to stop it?
The most important thing you need to do is to stop the Aedes mosquito from breeding. Remove all stagnant water. Don’t let it lay its eggs.
Here are the 10-minute mozzie wipe out exercise that you could work on to help get rid of stagnant water in and around your house.
Change water in vases on alternate days.
Remove water from flower-pot plates on alternate day.
Turn over all pails and water storage containers.
Tell your parents or any adults in your house to cover bamboo pole holders when they are not in use.
And tell your parents or any adults in your house to clear blockages and put BTI insecticide in roof gutters monthly.
Do not litter. Rubbish such as cups ad bottles can collect rain water and breed mosquitoes.
If you are going on holiday and there is no one in your house, there are a few things you should do before you leave to stop mosquitoes from breeding.
Cover all toilet bowls in your home. Seal off the overflow pipe of the flushing cistern. Cover all gully/floor traps. This prevents mosquitoes from getting to the water inside these places and breeding when you are away. Add sand granular insecticide to places that mosquitoes could potentially breed, such as flower vases and places where stagnant water could not be removed.
Clear blockages and add Bti insecticide in roof gutters. Ask a relative or close friend to check your home regularly for stagnant water if you are going away for a long period of time. Leave your contact with your neighbours or the neighbourhood police post / centre you can be reached easily.
You can also help prevent dengue by telling people what you have learned today. Tell your family, friends and neighbours why mosquito breeding is bad and how they can help stop it.
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We will now have a quiz to test how much you have learnt about dengue and Aedes mosquito. We are giving away some tokens for those who answer correctly.
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