Dengue (DENG-gey) fever is a mosquito-borne disease that occurs in tropical and

subtropical areas of the world. Mild dengue fever causes a high fever, rash, and muscle
and joint pain. A severe form of dengue fever, also called dengue hemorrhagic fever,
can cause severe bleeding, a sudden drop in blood pressure (shock) and death.

Millions of cases of dengue infection occur worldwide each year. Dengue fever is most
common in Southeast Asia and the western Pacific islands, but the disease has been
increasing rapidly in Latin America and the Caribbean.

Researchers are working on dengue fever vaccines. For now the best prevention is to
reduce mosquito habitat in areas where dengue fever is common.

Dengue fever is transmitted by the bite of an Aedes mosquito infected with a dengue
virus. The mosquito becomes infected when it bites a person with dengue virus in
their blood. It can’t be spread directly from one person to another person.

Symptoms of Dengue Fever

Symptoms, which usually begin four to six days after infection and last for up to 10
days, may include

 Sudden, high fever

 Severe headaches
 Pain behind the eyes
 Severe joint and muscle pain
 Fatigue
 Nausea
 Vomiting
 Skin rash, which appears two to five days after the onset of fever
 Mild bleeding (such a nose bleed, bleeding gums, or easy bruising)
 Sometimes, symptoms are mild and can be mistaken for those of the flu or
another viral infection. Younger children and people who have never had the infection
before tend to have milder cases than older children and adults. However, serious
problems can develop. These include dengue hemorrhagic fever, a rare complication
characterized by high fever, damage to lymph and blood vessels, bleeding from the
nose and gums, enlargement of the liver, and failure of the circulatory system. The
symptoms may progress to massive bleeding, shock, and death. This is called dengue
shock syndrome (DSS).
  People with weakened immune systems as well as those with a second or subsequent
dengue infection are believed to be at greater risk for developing dengue hemorrhagic
fever.

Treatment for Dengue Fever

There is no specific medicine to treat dengue infection. If you think you may have
dengue fever, you should use pain relievers with acetaminophen and avoid medicines
with aspirin, which could worsen bleeding. You should also rest, drink plenty of fluids,
and see your doctor. If you start to feel worse in the first 24 hours after your fever goes
down, you should get to a hospital immediately to be checked for complications.

Preventing Dengue Fever

The best way to prevent the disease is to prevent bites by infected mosquitoes, particularly if
you are living in or traveling to a tropical area. This involves protecting yourself and making
efforts to keep the mosquito population down. In 2019, the FDA approved a vaccine called
Dengvaxia to help prevent the disease from occurring in adolescents aged 9 to 16 who have
already been infected by dengue. But, there currently is no vaccine to prevent the general
population from contracting it.
Symptoms

Many people, especially children and teens, may experience no signs or symptoms
during a mild case of dengue fever. When symptoms do occur, they usually begin four
to seven days after you are bitten by an infected mosquito.

Dengue fever causes a high fever — 104 F degrees — and at least two of the following
symptoms:

 Headache

 Muscle, bone and joint pain

 Nausea

 Vomiting

 Pain behind the eyes

 Swollen glands
  Rash

Most people recover within a week or so. In some cases, symptoms worsen and can
become life-threatening. Blood vessels often become damaged and leaky. And the
number of clot-forming cells (platelets) in your bloodstream drops. This can cause a
severe form of dengue fever, called dengue hemorrhagic fever, severe dengue or
dengue shock syndrome.

Signs and symptoms of dengue hemorrhagic fever or severe dengue — a life-

threatening emergency — include:

 Severe abdominal pain

 Persistent vomiting

 Bleeding from your gums or nose

 Blood in your urine, stools or vomit

 Bleeding under the skin, which might look like bruising

 Difficult or rapid breathing

 Cold or clammy skin (shock)

 Fatigue

 Irritability or restlessness

Causes

Dengue fever is caused by any one of four types of dengue viruses spread by
mosquitoes that thrive in and near human lodgings. When a mosquito bites a person
infected with a dengue virus, the virus enters the mosquito. When the infected mosquito
then bites another person, the virus enters that person's bloodstream.
After you've recovered from dengue fever, you have immunity to the type of virus that
infected you — but not to the other three dengue fever virus types. The risk of
developing severe dengue fever, also known as dengue hemorrhagic fever, actually
increases if you're infected a second, third or fourth time.

Risk factors

Factors that put you at greater risk of developing dengue fever or a more severe form of
the disease include:

 Living or traveling in tropical areas. Being in tropical and subtropical areas

increases your risk of exposure to the virus that causes dengue fever.
Especially high-risk areas are Southeast Asia, the western Pacific islands, Latin
America and the Caribbean.

 Prior infection with a dengue fever virus. Previous infection with a dengue
fever virus increases your risk of having severe symptoms if you're infected
again.

DENGUE CASE CLASSIFICATION AND LEVEL OF SEVERITY

 Dengue illness is categorized according to level of severity as dengue

without warning signs, dengue with warning signs and severe dengue.

 Dengue without warning warnings can be further classified according to

signs and symptoms and laboratory tests as suspect dengue, probable
dengue and confirmed dengue.

a. dengue without warning signs

a.1 suspect dengue

- a previously well individual with acute febrile illness of 1-

7 days duration plus two of the following: headache, body
 malaise, retro-orbital pain, myalgia, arthralgia, anorexia,
nausea, vomiting, diarrhea, flushed skin, rash (petechial,
Hermann’s sign)

a.2 probable dengue

- a suspect dengue case plus laboratory test: Dengue NS1

antigen test and atleast CBC (leukopenia with or without
thrombocytopenia) or dengue IgM antibody test (optional)

a.3 confirmed dengue

- a suspect or probable dengue case with positive result of

viral culture and/or Polymerase Chain Reaction
(PCR) and/or Nucleic Acid Amplification Test- Loop
Mediated Amplification Assay (NAAT-LAMP) and/
or Plaque Reduction Neutralization Test (PRNT)

b. dengue with warning signs

• a previously well person with acute febrile illness of 1-7 days plus
any of the following: abdominial pain or tenderness, persistent
vomiting, clinical signs of fluid accumulation (ascites), mucosal
bleeding, lethargy or restlessness, liver enlargement, increase in
haematocrit and/or decreasing platelet count

c. severe dengue

severe plasma leakage leading to

 shock (DSS)

 fluid accumulation with respiratory distress

 severe bleeding

 as evaluated by clinician

severe organ impairment

 Liver: AST or ALT ≥ 1000

 CNS: e.g. seizures, impaired
consciousness
 Heart:and other organs (i.e. myocarditis,
renal failure)

PHASES OF DENGUE INFECTION

a. Febrile Phase
 Usually last 2-7 days
 Mild haemorrhagic manifestations like petechiae and mucosal
membrane bleeding (e.g nose and gums) may be seen.
 Monitoring of warning signs is crucial to recognize its
progression to critical phase.
b. Critical Phase
 Phase when patient can either improve or deteriorate.
 Defervescence occurs between 3 to 7 days of
illness. Defervescence is known as the period in which the
body temperature (fever) drops to almost normal (between
37.5 to 38°C).
 Those who will improve after defervescence will be
categorized as Dengue without Warning Signs, while those
who will deteriorate will manifest warning signs and will be
categorized as Dengue with Warning Signs or some may
progress to Severe Dengue.
 When warning signs occurs, severe dengue may follow
near the time of defervescence which usually happens
between 24 to 48 hours.
c. Recovery Phase
 Happens in the next 48 to 72 hours in which the body fluids
go back to normal.
 Patients’ general well-being improves.
 Some patients may have classical rash of “isles of white in the
sea of red”.
 The White Blood Cell (WBC) usually starts to rise soon after
defervescence but the normalization of platelet counts
typically happens later than that of WBC.
1. Group A- patients who may be sent home
These are patients who are able to:

 Tolerate adequate volumes of oral fluids

 Pass urine every 6 hours
 Do not have any of the warning signs particularly when the fever subsides
 Have stable haematocrit
2. Group B- patient who should be referred for in-hospital management

Patients shall be referred immediately to in-hospital management if they have the

following conditions:

 Warning signs\
 Without warning signs but with co-existing conditions that may make dengue
or its management more complicated ( such as pregnancy, infancy, old age,
obesity, diabetes mellitus, hypertension, heart failure, renal failure, chronic
haemolytic diseases such as sickle- cell disease and autoimmune diseases,
etc.)
 Social circumstances such as living alone or living far from health facility or
without a reliable means of transportation.
 The referring facility has no capability to manage dengue with warning signs
and/or severe dengue.
3. Group C- patient with severe dengue.requiring emergency treatment and
urgent referral

These are patients with severe dengue who require emergency treatment and urgent
referral because they are in the critical phase of the disease and have the following:

 Severe plasma leakage leading to dengue shock and/or fluid accumulation

with respiratory distress;
 Severe haemorrhages;
 Severe organ impairment (hepatic damage, renal impairment,
cardiomyopathy, encephalopathy or encephalitis)

Patients in Group C shall be immediately referred and admitted in the hospital within 24
hours.