A Simple Guide to Dengue Fever

A Simple Guide to Dengue Fever
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What is dengue fever?
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Dengue fever is a acute viral infection caused by the dengue virus which is transmitted by the bite of an infected female Aedes msoquito.

What are the Types of Dengue Fever?
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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 an even worse infection such as Dengue Haemorrhagic Fever and Dengue Shock Syndrome which can be fatal.

What are the Symptoms of Dengue Fever?
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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 leisons(Maculopaular).
The rash can be itchy .

What are the Complications of Dengue Fever?
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The complications of Dengue Fever are:

1.Dengue Hemorrhagic Fever
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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 malena(black stools) indicate bleeding in the stomach.

e.low plalelet 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
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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.

How do you diagnose Dengue Fever?
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1.History of acute fever and bleeding signs

2.A low platelet count (<100,000)is suggestive of dengue fever.

3.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.

What is the treatment of dengue fever?
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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.

How is dengue fever spread?
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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.


How can you prevent being infected with the dengue virus?
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To prevent dengue fever, you must prevent the breeding of its carrier, the Aedes mosquitoes.

This will be explained another time