Dengue Fever

Dengue virus is transmitted by female mosquitoes mainly of the species Aedes

aegypti and, to a lesser extent, Ae. albopictus. These mosquitoes are also vectors of
chikungunya, yellow fever and Zika viruses. Dengue Fever is widespread throughout the tropics,
with local variations in risk influenced by rainfall, temperature, relative humidity and unplanned
rapid urbanization.

Dengue causes a wide spectrum of disease. This can range from subclinical disease
(people may not know they are even infected) to severe flu-like symptoms in those infected.
Although less common, some people develop severe dengue, which can be any number of
complications associated with severe bleeding, organ impairment and/or plasma leakage.
Severe dengue has a higher risk of death when not managed appropriately.

Signs and Symptoms

Dengue
Dengue should be suspected when a high fever (40°C/104°F) is accompanied by 2 of the
following symptoms during the febrile phase:

 severe headache
 pain behind the eyes
 muscle and joint pains
 nausea
 vomiting
 swollen glands
 rash.

Severe dengue
A patient enters what is called the critical phase normally about 3-7 days after illness onset. It is
at this time, when the fever is dropping (below 38°C/100°F) in the patient, that warning signs
associated with severe dengue can manifest. Severe dengue is a potentially fatal complication,
due to plasma leaking, fluid accumulation, respiratory distress, severe bleeding, or organ
impairment.

Warning signs that doctors should look for include:

 severe abdominal pain

 persistent vomiting
 rapid breathing
 bleeding gums
 fatigue
 restlessness
  blood in vomit.

Diagnostics
Test Description
1. Dengue NS1 RDT  Requested between 1-5 days of
illness
 Use to detect dengue virus
antigen during early phase of
acute dengue infection
 Test is for free in all health centers
2. Dengue IgM/IgG and selected public hospitals
nationwide
 Requested beyond five days of
illness
 Use to detect dengue antibodies
during acute late stage of dengue
infection (IgM) and to determine
previous infection (IgG)
 May give false positive result due
to antibodies induced by dengue
3. Polymerase Chain Reaction (PCR) vaccine
 May cross react with other
arboviral diseases such as
Chikungunya and Zika
 DOH augmentation is limited to
4. Nucleic Acid Amplification Test- Loop selected government hospitals
Mediated Isothermal Amplification only
Assay (NAAT-LAMP)  One of the gold standard
laboratory tests to confirm dengue
virus.
 Molecular based test confirmatory
test
 Available only in dengue sub-
5. Plaque Reduction Neutralization Test national and national reference
(PRNT) laboratories
 A novel molecular-based
confirmatory test used to detect
dengue virus.
 Work just like PCR but cheaper
and simpler in nature.
6. Other tests:  In the pipeline to be introduced
under the National Dengue
-Total While Blood Cell (WBC) count Prevention and Control Program in
district and provincial hospitals
-Platelet  Gold standard to characterize and
quantify circulating level of anti-
-Hematocrit DENV neutralizing antibody (NAb)
 Available only at the dengue
national reference laboratory
 Routinely used in hospitals as
standard dengue diagnostic tests
 Look for trend of decreasing WBC,
decreasing platelet and increasing
hematocrit

Prevention
Travellers should take meticulous measures to prevent mosquito bites during the daytime.

Use a repellent containing 20%-30% DEET or 20% Picaridin on exposed skin. Re-apply according
to manufacturer's directions.
Wear neutral-coloured (beige, light grey) clothing. If possible, wear long-sleeved, breathable
garments.
If available, pre-soak or spray outer layer clothing and gear with permethrin.
Get rid of water containers around dwellings and ensure that door and window screens work
properly.
Apply sunscreen first followed by the repellent (preferably 20 minutes later).
More details on insect bite prevention.
A vaccine is available for people living in some Dengue endemic countries, but is not
commercially available for travellers.

Treatment
There is no specific treatment for dengue fever.

Fever reducers and pain killers can be taken to control the symptoms of muscle aches and
pains, and fever.

The best options to treat these symptoms are acetaminophen or paracetamol.

NSAIDs (non-steroidal anti-inflammatory drugs), such as ibuprofen and aspirin should be
avoided. These anti-inflammatory drugs act by thinning the blood, and in a disease with risk of
hemorrhage, blood thinners may exacerbate the prognosis.
For severe dengue, medical care by physicians and nurses experienced with the effects and
progression of the disease can save lives – decreasing mortality rates from more than 20% to
less than 1%. Maintenance of the patient's body fluid volume is critical to severe dengue care.
Patients with dengue should seek medical advice upon the appearance of warning signs.