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| Aedes mosquito |
Dengue fever is a acute viral infection caused by the dengue virus which is transmitted by the bite of an infected female Aedes mosquito.
The dengue virus has 4 strains called serotypes 1, 2, 3 and 4.
An infection with one serotype does not protect you from the other serotypes.
A second dengue infection, especially with serotype 2, can cause aneven worse infection such as Dengue Haemorrhagic Fever and Dengue Shock Syndrome which can be fatal.
The incubation period in mosquito is 8-12 days and 3-14 days in humans.
Symptoms usually last 3-14 days.
1.High, acute, prolonged fever (usually lasts for 5 to 7 days)
2.Severe headache
3.Pain behind the eyes
4.Muscle and joint pains
5.Rashes
6.Nausea , vomiting
7.Abdominal discomfort
8.Loss of appetite
9.Fatigue
10.Diarrhoea
A rash usually appears 3-4 days after the fever.
There are 3 types of dengue rash.
1.Petechial Rash:
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This is the most common with the petechial rash appearing as red dots under the skin.
The rashes are usually found on the limbs and lower abdomen and is due to the bleeding under the skin.
2.Diffuse erythematous rash with areas of normal skin:
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The whole skin becomes reddish with scattered, small areas of normal skin .
3.Maculopapular rash:
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The last type of rash appears as red flat or raised lesions (Maculopaular).
The rash can be itchy .
The complications of Dengue Fever are:
1.Dengue Hemorrhagic Fever
a. Fever
b.bleeding likely to occur from the nose, mouth, and gums.
Bruises and ecchymosis may appear as a sign of bleeding under the skin.
There are small red spots on the skin.
c.the urine may contain blood.
d. vomiting of blood and melena(black stools) indicate bleeding in the stomach.
e.low platelet count of <100,000
f. Hypoalbuminaemia
g.pleural effusion
h.neurological disturbances(seizures,cranial nerve signs and coma) may indicate bleeding in the brain
2. Dengue Shock Syndrome
Without prompt treatment for the bleeding, the person can go into a.shock
b.hypotension
c.narrowed pulse pressure(< 2omm Hg)
d. impaired organ perfusion which result in organ failure and death.
Dengue Haemorrhagic Fever and Dengue Shock Syndrome is fatal in about 5 percent of the cases, mostly among children and young adults.
History of mosquito bite,acute fever and bleeding signs
A low platelet count (<100,000)is suggestive of dengue fever.
Specific blood test(IgG and IgM antibody) for dengue virus can also be conducted. IgM antibodies occur on the 5th day of illness and last for 2 months.
There is no specific anti-viral drug to treat the disease or a vaccine to prevent a person from being infected with the dengue virus.
Treatment is mainly supportive.
1. Rest
2.drinking lots of water to prevent dehydration will help.
3. Paracetamol for fever, severe headaches and body aches( Avoid aspirin and NSAIDs due to the risk of bleeding) to reduce the discomfort.
4. Intravenous fluids for hypotension and dehydration.
5.Daily blood tests (platelets and hematocrit)may be necessary to monitor the risk of bleeding
6. Platelets transfusion when the the platelet count is less than 20,000.
The illness can last up to 10 days, but complete recovery can take as long as a month.
Dengue Fever is spread only through the bite of the infected Aedes mosquitoes.
The transmission cycle for dengue starts when:
1.Infected Aedes mosquito bites a healthy person.
2.4-7 days later,the infected person develops fever
3..When fever starts, the person is infectious for about 5 days.
4.If an Aedes mosquito bites the person during this time when he is infectious, it will be infected by the the dengue virus.
5.The virus will multiply in the second mosquito for 5-7 days.
6.The mosquito then becomes infective.
7.The cycle starts again when it bites another person.
To prevent dengue fever, you must prevent the breeding of its carrier, the Aedes mosquitoes, identified by their black and white stripes on the body .
A puddle of water about the size and depth of 20-cent coin is sufficient for an Aedes mosquito to breed in.
The Aedes mosquitoes are commonly found breeding in clear stagnant water in flower vases, flower pot plates, roof gutters, earthen jars for water storage or decorative purposes, watering cans, and bamboo pole holders.
The Aedes mosquito can also breed in unusual places such as water trapped in the hardened soil in potted plates, and the rim of unwanted pails
Every other day
Change water in flower vases.
Scrub the inside of vase to remove mosquito eggs filling in fresh water.
Remove water in plant pot plates.
Scrub the plate thoroughly to remove mosquito eggs.
Clear fallen leaves and stagnant water in drains and garden. Some leaves can collect water.
Once a month
Add prescribed amounts of sand granular insecticide into containers, vases, gully traps and roof gutters, even if they are dry.
Sand granular insecticide can be purchased from plant nurseries and DIY stores. (Caution: Do not add the chemical into drinking water. Keep out of reach of children.)
Clear away leaves in roof gutters and apron drains.
Remove roof gutters wherever feasible.
At all times Turn pails and watering cans over and store them under shelter.
Place/ store all articles that can collect rain water under shelter at all times.
Cover bamboo pole holders when they are not in use.
Cover rarely used gully traps.
If possible, replace gully trap covers with non-perforated ones and install anti-mosquito valves.
Do not block the flow of water in scupper drains along common corridors in appartments.
Do not place potted plants and other paraphernalia over the drains.
Do not litter.
Paper cups and water bottles thrown indiscriminately into drains, grass verges, roadside, vacant lands and other public places can collect rainwater and breed mosquitoes.
If you are vacating your home or away on long holiday
Cover the toilet bowls.
Seal off the overflow pipe of the flushing cistern.
Cover all gully and floor traps.
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