Presentation on theme: "Project: Community Action for the Control of Aedes aegypti Suggestion of presentation to groups of people Hermione E.M.C. Bicudo UNESP-São José do Rio."— Presentation transcript:
Project: Community Action for the Control of Aedes aegypti Suggestion of presentation to groups of people Hermione E.M.C. Bicudo UNESP-São José do Rio Preto
The Aedes aegypti mosquito, a public health problem Aedes aegypti: very serious health problem in tropical and subtropical countries, where it may transmit viruses causing the diseases: dengue, dengue hemorragic fever, yellow fever Vaccine exists only for the yellow fever. Even with this advantage, there is still threat of epidemics of this disease in many places of the world.
These diseases are very serious! Dengue is a very painful disease, leaves sequels; in the hemorrhagic form has a high mortality rate. In 2007 more than 500,000 people had dengue in Brazil, at least 250 died of dengue hemorrhagic fever. Yellow fever also causes high mortality. - So what can we do to prevent the spread of these diseases? The answer is: Combating the mosquito! This is our great challenge!
Knowing the Aedes aegypti to combat it The development of the mosquito lasts more or less 7 days and goes through 4 stages:The development of the mosquito lasts more or less 7 days and goes through 4 stages: egg larva pupa adult From egg to pupa the development occurs in the water. The adult is formed inside the pupa and, when ready, gets off by an opening in the back of the pupa and flies.
Mosquito egg photographed in the microscope With naked eye it is the size of a black dot made with a sharp pencil
Larva of the Aedes aegypti. It getts off the egg very small, feeds intensively on the detritus in the water, is very fast moving and grows......
Pupa The larva grows and develops to pupa, which also moves quickly but doesn´t feed nor eliminate excreta (it is “closed” to the environment)
Aedes aegypti adult. It is easy to recognize because it is striped black and white
How do mosquitoes transmit the virus? Only the adult females feed on blood. So only them bite people and transmit the virus diseases. When bites a sick person, the female ingests viruses that are in her or his blood. The viruses multiply in the mosquito body and stay in its saliva. When the infected female bites another person, a bit of saliva containing viruses is injected, the person becomes ill too and so the disease spreads.
An infected female makes a ”chain” of transmission Once infected, the mosquito female becomes a virus vector until its death, leading the disease to many people who can also be bitten by other mosquitoes that in turn bite other people This chain of transmission can only be broken if there are no mosquitoes. This is our major task: fight the mosquito. Without adult mosquitoes the viruses transmission will not occur.
Aedes aegypti: “enemy” full of advantages Females lay eggs in stagnant water, clean or dirty. They lay eggs even in very small quantity of water (for example, the water accumulated in a bottle cap, in broken egg shells, in a piece of plastic, in everything that forms a concavity, left in the dew). And even if the water dries, the eggs of the mosquito do not die, they can stay alive for up to a year and when new water fills that little space they can develop. All this is very good for the survival of the mosquito, but is bad for us.
More “arms" of the “enemy” Each female lays about 300 eggs. Therefore, a single female can create a “crowd" of mosquitoes! Another feature that is great for the mosquito, but is terrible for us.
How to combat the Aedes aegypti We may think: we combat eliminating adults by spraying insecticides. Wrong. Nowadays the spraying with insecticides should be made only in special situations because: 1. the mosquitoes hide inside the houses, hide in the middle of the plants and in other places, avoiding the contact with the insecticide 2. the adult mosquitoes are becoming resistant, i.e. the insecticides no longer kill them. This is another feature that benefits the mosquito, but makes our task more difficult.
Still strategies to eliminate the mosquito We may think of another possibility: killing the mosquitoes with insecticides at the stage of larva, in which they can ingest toxic products mixed to the water. If there is no larva, adults will not be produced, eliminating the risk of transmission of the viruses. However, even the process of eliminating the larvae with insecticides is not efficient because the larvae are also becoming resistant to the insecticides.
On insecticides is still important to know that... The use of insecticides is not appropriate for killing neither adult mosquitos nor larvae because they cause damage to the nature: in the attempt to kill the mosquitoes, the insecticides kill useful insects (like bees), can intoxicate birds that eat poisoned insects, are brought into the rivers where poison the fishes, etc.... and are also toxic to humans and domestic animals. Thus, the use of insecticides, instead of solving the problem, can create others, more extensive. Then, what to do to kill the mosquitoes ?
How to fight the mosquitos The best way is: to eliminate the potential breeding sites, that is, the containers or objects which can accumulate stagnant water, where the mosquito female lays eggs that develop till adults. However, there are possible breeding sites that cannot be discarded. What to do?: Eliminate those that can be eliminated and maintain vigilance on those that cannot be eliminated
The commonest breeding sites –Some of the places where Aedes raising often occurs are: clogged slabs and rain channels, uncovered water tanks, tires, bottles, cans and any other container left in the open where the rain water can be accumulated, the outlet drains where water accrues (inside or outside the home), sanitary vases not used but kept open, trays of refrigerators, untreated swimming pools, water vessels for domestic animals etc. Larvae of Aedes have been found even in the water inside steam iron! –Actually each house has specific breeding sites for Aedes. They vary greatly with people's habits and the local conditions. Thus, nobody than the residents can better find, eliminate, monitor and treat the mosquito potential breeding sites
Some of the many possible breeding sites Tires with water inside Pieces of plastic forming spaces that retain water Bottles or any other vessel containing water Caps of bottles or glasses of any kind and Egg shells left in the open Water tank Keep the water tank always well covered
Breeding sites common in gardens In the gardens, the main breeding sites are: dishes under the pots used to hold the excess of water from irrigation, rain water accumulated on the hard land of flowerpots left in the open or due to excess of irrigation, and in plants with chalice-shaped leaves or flowers (such as bromeliads) into which water can be accumulated
Breeding sites for Aedes aegypti in pots The water accumulated on the hard land of pots The water accumulated in the dishes under the pots
Breeding sites for Aedes aegytpi in bromeliads The water accumulated in the spaces is a potential breeding site One of the many kinds of bromeliads:
Alternative treatments that have been recommended for control The municipal authorities responsible for the population health have recommended to kill the larvae in the breeding sites that can not be eliminated, such as drains for water drainage (inside and outside the houses) and bathroom fittings, the use of: -fine cuisine salt (a tablespoon in a glass of water) -sanitary water (a tablespoon in five liters of water) The best treatment for the swimming pools is chlorine, in the concentration recommended according to the amount of water they contain. Do not forget that around swimming pools there may be also breeding sites, for example, in drains not working properly and in the cascades for decoration.
The used coffee grounds are toxic to the larvae of Aedes aegypti. Working with my post-graduate students in the laboratory of Vectors-IBILCE- UNESP in Sao Jose do Rio Preto,SP, Brazil we observed, in tests repeated many times, that a proportion of four soup spoons filled with used coffee grounds (the powder that remains after preparing the percolated coffee) for a glass of water, intoxicates and kills the larvae between 24 and 48 hours. Even those that take longer to die do not evolve to the next phases of development; therefore, they do not reach the adult stage. Because the used coffee grounds do not kill the plants, they have been used with success mainly in gardens, inside the “chalices” of the bromeliads and over pots land. Important, however, is that new used coffee grounds must be added to every seven days because, as any substance, it also loses its validity.
Here there are problems too The alternative products are helpful but they may not work if they are not used correctly. Then, what is the best way to combat the mosquitoes? The solution that works best is : to eliminate the stagnant waters (breeding sites) and to maintain continuous vigilance and care over those that cannot be eliminated. This is our main mission in this problem. We all need to be aware of this important and urgent need!
Why do we have to be involved in this task? The involvement of the health authorities in the combat of Aedes aegypti is essential, mainly in the elimination or treatment of the breeding sites that are out of our reach and in the transmission of knowledge to the public. But our involvement is also absolutely necessary because most of the breeding sites are in our houses.
How to eliminate the danger Eliminating empty bottles, tyres, everything that no more is useful, or keeping them in covered places; unclodging the rain channels frequently; keeping clean and covered the sanitary vases and any other water container and maintaining constant awareness for the presence of larvae and adults in our houses. Checking also the existance of stagnant water in our house pathway and in the neighborwood ground. Help to make the other people alert. The mosquitos raised around our houses also threat us.
How to proceed in the gardens? 1.remove the dish under the pot or decrease the amount of water for irrigation in order to not leak to the plate and not accumulate over the hard land of the flowerpot; 2.bring the vessels to covered places or transfer the plants to the flower bed; 3.in plants with "chalice", such as bromeliads, planted in pots, water only the land and "turn" the pot to pour the water that eventually is accumulated into the "chalices." 4.if the bromeliads are planted in bed and you do not have time or are not in the mood to take care of them, it is better to transfer some to pots, where they can be cared more easily, and eliminate the others. The time is of emergency and what may seems absurd is just the necessary
Such care is for today, tomorrow and the future The care with the Aedes aegypti does not have time established to finish. We must teach this to our children and our grandchildren and they may have to continue to transmit this knowledge to their offspring. Just a neglect and the mosquitoes become again very numerous. Moreover, in today's world, where people (healthy or sick) and objects (often containing eggs of mosquitoes, such as tires and others) travel among very distant places, it is always possible that new epidemics emerges. Making such care a habit will help to curb the spread of the virus
One for all and all for one If each of us does his part, we will reduce the risks of contracting dengue, dengue hemorrhagic fever and even the yellow fever, also transmitted by the Aedes aegypti. Remember that the lives of many are in our hands, including ours and our family´s. Transmit this knowledge to other people and encourage their participation!