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What is Dengue?
· Dengue is a serious viral disease transmitted by the bite of the
mosquito, Aedes aegypti.
· Dengue occurs in two forms: dengue fever and dengue haemorrhagic
fever.
· Dengue feveris a severe, flu-like illness that affects older children
and adults but rarely causes death.
· Dengue hemorrhagic fever (DHF) is a second more severe form, in which
bleeding and occasionally shock occur, leading to death; it is most
serious in children.
· Persons suspected of having dengue fever or DHF must see a doctor at
once.
· Dengue haemorrhagic fever is a deadly disease and early diagnosis and
treatment can save lives. Unless proper treatment is given promptly, the
patient may go into shock and die.
· The symptoms of dengue fever vary according to the age and general
health of the patient. Infants and young children may have a fever with
a measles-like rash, which is difficult to distinguish from influenza,
measles, malaria, infectious hepatitis and other diseases with fever.
Older children and adults may have similar symptoms or symptoms ranging
from mild illness to very severe disease.
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Characteristics of Dengue Fever
· Abrupt onset of high fever
· Severe frontal headache
· Pain behind the eyes which worsens with eye movement
· Muscle and joint pains
· Loss of sense of taste and appetite
· Measles-like rash over chest and upper limbs
· Nausea and vomiting
Characteristics of Dengue Haemorrhagic Fever &
Shock
· Symptoms similar to dengue fever
· Severe and continuous stomach pains
· Pale, cold or clammy skin
· Bleeding from the nose, mouth and gums and skin bruising
· Frequent vomiting with or without blood
· Sleepiness and restlessness
· Constant crying
· Excessive thirst (dry mouth)
· Rapid weak pulse
· Difficulty in breathing
· Fainting
Who is most affected?
Children, tourists and travellers are usually at a higher risk for
Dengue transmission. However, adults living in endemic areas
are in danger too.
When do Dengue mosquitos bite?
Dengue mosquitoes bite in the early morning and the late afternoon.
Where does the Dengue mosquitoe live?
The mosquito rests indoors, in closets and other dark places. Outside,
they rest where it is cool and shaded. The female mosquito lays her eggs
in water containers in and around homes,schools and other areas in towns
or villages. The larvae, known aswigglers, hatch from the mosquitoe
eggs, and live in the water forabout a week; they then change into a
round pupal stage forone or two days, after which the adult mosquito
emerges, ready to bite.
Where does the Dengue mosquitoe breed?
Dengue mosquitoes breed in any water-catching or storage containers in
shaded or sunny places. Favored breeding places are- Barrels, drums,
jars, pots, buckets, flower vases, plant saucers, tanks, cisterns,
bottles, tins, tyres, pans, plant saucers and roof gutters, refrigerator
drip pans, catch basins, drains, soak-away pits, cement blocks, cemetery
urns, plant leaf axils, bamboo stumps, tree cavities and a lot more
places where rainwater collects or is stored.
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How is Dengue spread?
Dengue is spread by the bite of an infected female, Aedes aegypti
mosquitoe which has got the dengue virus by taking a blood meal on a
person who is ill with dengue. The infected mosquito then transmits the
disease through its bite to other people who in turn becomes ill, and
the chain continues. The diagram below, illustrates this action.
There is no way to tell if a mosquito is carrying the dengue virus,
therefore people must protect themselves from all mosquito bites, which
will also protect against malaria and other mosquito-borne diseases.
How can Dengue be prevented?
As there is no drug to cure dengue or vaccine to prevent it, there are
two key measures that can be applied to prevent the spread of Dengue.
Elimination of mosquitoe breeding places
· Cover water containers -Tight covers on water storage containers, will
prevent the mosquitoes laying their eggs there. If the cover is loose,
mosquitoes can go in and out.
· Septic tanks and soak-away pits -Cover and seal these, so that dengue
mosquitoes cannot breed there.
· Removal of rubbish -Garbage articles and other rubbish found around
houses can collect rainwater. They should be removed or smashed and
buried in the ground or burned, where this is permissible.
· Biological control -Mosquito wigglers can be controlled by small
larva-eating fish, such as guppies. These fish can be found in streams
or ponds or obtained through pet shops. Bacterial pesticides will also
kill mosquito wigglers.
· Chemical control -Safe and easily used larvicides such as temephos
sand core granules can be placed in water containers to kill developing
wigglers.
Prevent mosquitoe bites
People can protect themselves from mosquito bites by using any of the
following means-
· Mosquito coils and electric vapour mats -Slow burning mosquito coils
or electric vapour mats are effective in the rainy season, just after
sunrise and/or in the afternoon hours before sunset, when dengue
mosquitoes bite.
· Mosquito nets -Nets placed over sleeping places can protect small
children and others who may rest during the day. The effectiveness of
such nets can be improved by treating them with permethrin (a pyrethroid
insecticide) . Curtains (cloth or bamboo) can also be treated with
insecticide and hung at windows or doorways, to repel or kill
mosquitoes.
· Repellents -Mosquitoe repellents can be applied to exposed parts of
the body where mosquitoes bite. Care should be taken in using repellents
on small children and the elderly.
· Screens -Screens on windows and doorways are effective protection
against the entry of mosquitoes in homes.
· Protection of people sick with dengue -Mosquitoes become infected when
they bite people who are sick with dengue. Mosquito nets and mosquito
coils will effectively prevent mosquitoes from biting sick people and
help stop the spread of dengue.
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